Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts, I'm Dr Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Dr Greg Hundley: Hundley, Associate Editor from the Pauley Heart Center in Richmond, Virginia at VCU Health. Well Carolyn, our featured article this week addresses the age at which to initiate clinical screening of relatives for hypertrophic cardiomyopathy. Our guidelines suggest screening of relatives from age ten and onwards but data are lacking to substantiate this suggestion. I look forward to the authors' discussion of their findings regarding initiation of screening in children. For now though, do you have an article that you'd like to share?
Dr Carolyn Lam: You bet, Greg. So, the first paper I chose really demonstrates that patients inducible pluripotent stem cells or IPSC cardio derived myocytes can be used as a disease modeling platform to delineate the functional mechanisms that underlie cardiac hypertrophy and in this particular case they looked at Noonan Syndrome and showed that how these techniques can be subsequently used to identify novel molecular and genetic therapeutic targets. So, Greg, here's your quiz. The genetics of Noonan Syndrome.
Dr Greg Hundley: I remember it was on our board exam.
Dr Carolyn Lam: Let me tell you about it. So more than 90% of patients with Noonan Syndrome have a mutation in the hinge region CR2 domain of Raf-1 and they exhibit severe hypertrophic cardiomyopathy for which there is no treatment. Authors, Dr Jaffrey from Cornell University and Dr Kontaridis from Masonic Medical Research Institute in Utica in New York and their colleagues used Noonan Syndrome Raf-1 patient and CRISPR corrected IPSC cardiomyocytes to recapitulate the Noonan Syndrome cardiac phenotype.
These Noonan Syndrome IPSC derived cardiomyocytes exhibited the same hypertrophy and myofibrillar disarray that's really observed in Noonan Syndrome patient hearts, so mechanistically the authors showed that activation of mitogen-activated protein kinase or mech-1 or -2, but not the extracellular regulated kinase, which is ERK1 or 2 triggered abnormal cardiomyocytes structure and conversely ERK5 mediated increased cell size in these Noonan Syndrome mutant IPSC derived cardiomyocytes.
RNA sequencing further identified genes dysregulated in the Noonan Syndrome cardiomyocytes that may underlie hypertrophic cardiomyopathy downstream if the mech-1 or -2 and ERK5 genes.
Dr Greg Hundley: So, Carolyn, that's a lot of genetic information, so what can I take home as I think about this further and what may come down the line as we manage patients with Noonan Syndrome?
Dr Carolyn Lam: Thanks, Greg. The real take home message is that these pathways could serve as novel therapeutic targets to treat hypertrophic cardiomyopathy in patients with Noonan Syndrome and Raf-1 mutations. Overall, the elucidation of rare disease mechanism of hypertrophic cardiomyopathy may further unravel and reveal causes of other more common idiopathic congenital disorders and hypertrophic diseases.
Dr Greg Hundley: Oh, very good. Well, I'm going to switch gears and talk a little bit about infective endocarditis prophylaxis and this article comes from Pallavi Garg at the London Health Scientist Center. Carolyn, as you may recall, given the lack of proven efficacy and concerns about the perceived risks of antibiotic prophylaxis like development of antibiotic resistance, the American Heart Association in 2007 and the European Society of Cardiology in 2009 published revised guidelines recommending cessation of antibiotic prophylaxis prior to dental procedures for patients at moderate risk of infective endocarditis while continuing the practice in high risk patients. This Canadian study was conducted from 2002 to 2014 among all adults and those at high and moderate risk for infective endocarditis and they were stratified by age. Prescriptions for antibiotic prophylaxis were obtained from the Ontario Drug Benefit Database for adults 65 and older and outcomes regarding antibiotic prophylaxis prescription rates and the incidents of infective endocarditis related hospitalization were assessed.
Dr Carolyn Lam: Ooh, interesting. What did they find?
Dr Greg Hundley: The authors found a sustained reduction in antibiotic prophylaxis prescriptions among individuals at moderate risk for infective endocarditis that coincided with the change in guidelines. In contrast, while there was a decreasing trend in antibiotic prophylaxis among individuals at high risk of infective endocarditis and a minimal drop following the guidelines released, the overall rates of prophylaxis prescribing in this group continued to climb since early 2007, and collectively, these findings suggest that appropriate uptake of the revised AHA guidelines occurred.
Furthermore, over the thirteen-year study period, the authors identified an increase in hospitalizations for new episodes of endocarditis approximately three years after the AHA guidelines were revised. This timeline along with the rise of endocarditis incidents in both the high and moderate risk groups suggests that this observed increase in endocarditis is likely unrelated to the change in the prescribing practice of antibiotic prophylaxis. This conclusion is further supported by the overall decrease in endocarditis cases attributable to streptococcal infections over time, a finding contrary to what might be expected as a result of the reduction in antibiotic prophylaxis.
Dr Carolyn Lam: Oh, very interesting, Greg. At first a little bit scary and then after when you described it more, it does seem a little bit more reassuring. Very interesting. Well, thank you. My next paper deals with functional tricuspid regurgitation, which as you know is really common in heart failure with reduced ejection fraction or HFrEF and mostly consequent to pulmonary hypertension. However, what is the access mortality associate with functional tricuspid regurgitation in HFrEF? Well, this paper from Dr Maurice Serrano from Mayo Clinic and colleagues looked at all Mayo Clinic patients from 2003 to 2011 diagnosed with heart failure stage B and C and an ejection fraction less than 50% who had functional tricuspid regurgitation grading and systolic pulmonary artery pressure measured by Doppler echocardiography.
Now among more than 13,000 patients meeting these inclusion criteria, functional tricuspid regurgitation was detected in 88%. Functional tricuspid regurgitation was independently associated with more dyspnea, more impaired kidney function, and lower cardiac output. For the long term outcomes, the higher the degree of functional tricuspid regurgitation compared with a group with trivial tricuspid regurgitation was independently associated with a higher mortality hazard. The five year survival was substantially lower with increasing severity of tricuspid regurgitation so it was 68% on average for trivial functional tricuspid regurgitation versus 34% for severe functional tricuspid regurgitation.
Importantly, this access mortality observed with moderate or severe functional tricuspid regurgitation was independent of pulmonary hypertension and any other clinical characteristics.
Dr Greg Hundley: Hmm, interesting but Carolyn, wouldn't we expect this?
Dr Carolyn Lam: You know what, you may expect it, but this is really the largest series, I think, that has shown this and shown this in the systematic way that functional tricuspid regurgitation in and of itself may play an important pathophysiologic role and thus, may represent a potential therapeutic target in HFrEF. In other words, the present study really advocates for a trial to test treating functional tricuspid regurgitation in patients with HFrEF.
Dr Greg Hundley: Oh wow, you really put that in great perspective, Carolyn. Well, your reward is going to be a quiz.
Dr Carolyn Lam: Oh my gosh, Greg.
Dr Greg Hundley: We're going to talk about ...
Dr Carolyn Lam: What now?
Dr Greg Hundley: Caveolin-1, an atherogenesis and nitric oxide and this is from Professor Carlos Fernandez Hernando at the Yale University School of Medicine. Okay, multiple choice. What are caveolae? Now I'm going to give you some choices, you get to pick A. Are they crypts within the walls of vessels. B. Crypts within the membranes of endothelial cells. Or C. Crypts within the border zones of infarcts.
Dr Carolyn Lam: Wait a minute, Greg. I'm not even sure we're pronouncing it the same. You're asking about caveolae like ... Potato potata. They're invaginations of cell membranes, that's all I know.
Dr Greg Hundley: Oh wow, fantastic. This study focused on the effect of Caveolin-1, a protein integral to the formation of caveolae. The investigators found in a series of mouse experiments that A. The athero-protection observed in mice lacking Caveolin-1 is independent of endothelial nitric oxide synthase activation and nitric oxide production. B. Endothelial Caveolin-1 controls lipoprotein infiltration in vascular inflammation in early stage atherosclerotic lesion. C. Endothelial Caveolin-1 promotes pro-atherogenic matrix deposition leading to endothelial cell activation in atheroprone regions of the aorta and finally, D. Atheroprone regions of the aorta are characterized by increased intracellular and basolateral caveolae distribution in endothelial cells compared to athero-resistant areas.
Dr Carolyn Lam: Wow, I like the way you broke that down into four points, but could you summarize what it means clinically?
Dr Greg Hundley: Yeah, so I think if you had to summarize all of this in a sentence, perhaps the suppression of Caveolin-1 expression in endothelial cells might prevent the progression and promote the regression of atherosclerosis so in the future perhaps an interesting target to treat atherosclerosis. Well, now Carolyn, I guess we should proceed to that talk with our featured discussion.
Dr Carolyn Lam: Absolutely. Thanks, Greg.
Hypertrophic cardiomyopathy is an inheritable myocardial disease with age-related penetrance. Current guidelines recommend that clinical screening of relatives start from the age of ten years onwards by the European Society of Cardiology and twelve years onwards by the American College of Cardiology or American Heart Association. There are of course caveats for earlier screening but the clinical value of this approach has really not been systematically evaluated. That is until today's feature paper and we are so pleased to be here discussing it. This is Greg Hundley and Carolyn Lam and we're your co-hosts for Circulation on the Run. So happy to welcome Dr Juan Pablo Kaski who's the corresponding author of today's feature paper from Great Ormand Street Hospital in London and we also have Dr Gerald Greil, Associate Editor from UT Southwestern.
Welcome, everyone. Juan, if you don't mind, could you start by summarizing this very important study of yours?
Dr Juan Pablo Kaski: Thank you very much. Hypertrophic cardiomyopathy is a genetic muscle condition that is characterized by hypertrophy and is most commonly inherited as a dominant trait. Previous studies have suggested that in familial disease at least ventricular hypertrophy doesn't usually present until adolescence and this has led to the current guidelines which do not recommend routine screening of children below the age of twelve according to the American guidelines below the age of ten and the European guidelines for hypertrophy cardiomyopathy but own clinical experience was different and suggested that perhaps sarcomeric disease and familial disease could present in younger children, so what we aimed to do with this study was to assess the validity of this approach and tried to assess the yield of clinical screening in children from families of hypertrophic cardiomyopathy.
Dr Juan Pablo Kaski: We took our collective experience in our institution over a period of many years and recruited just on the 1,200 consecutive children all aged less than eighteen years at the time of initial assessment coming from just under 600 families and these were children who were referred for clinical screenings because a first degree relative had been diagnosed with hypertrophic cardiomyopathy. What we found was that in 5% of these children and in fact, in 8% of the families that we screened, we were able to pick up early phenotypic features of hypertrophic cardiomyopathy. In 72% of patients, we made a diagnosis before the age of twelve, so before current clinical screening guidelines we'd recommend and importantly, a third of these patients during follow up had a change in their management as a result of the diagnosis. Their medication was commenced, they underwent procedures or implantations of defibrillators.
Dr Greg Hundley: Juan, this is Greg Hundley and I was wondering when did the participants that were enrolled experience events? Did those that were say under fourteen or even under twelve, did they experience events relative to those that were a little older?
Dr Juan Pablo Kaski: The events that our participants experienced were relatively few. Many of these occurred during the childhood age but some occurred once the children had transitioned into the adult age. We did look to see whether there was any difference in terms of early diagnosis and subsequent events, but we didn't find anything, we didn't identify two separate populations in that respect.
Dr Greg Hundley: And then did you perform genetic analyses? I know you described phenotypic characterization of the patient population but how about genetically? What results did you find there?
Dr Juan Pablo Kaski: The main aim of the study really was to determine a yield of clinical screenings, so this is a reflection of a real-world practice where genetic testing may not necessarily be routinely available. Having said that, we did have genetic data in a third of our families and in fact, in maybe 70% of those children who made clinical diagnosis of hypertrophic cardiomyopathy was made and what we find in those individuals who have undergone genetic testing is that the vast majority of those had mutations in sarcomeric protein genes and pathogenic or likely pathogenic variants in sarcomeric genes in just under 70% and these were well characterized mutations that are very similar to those that are seen in adolescence or adult onset hypertrophic cardiomyopathy.
I think what was interesting about these genetic results is that we seem to have identified a population of early onset sarcomeric disease that genetically appears to be indistinguishable from a sort of later onset adult disease but with the clinical presentation and natural history curve shifted somewhat to the left.
Dr Greg Hundley: Gerald, just switching over, can you tell us some of your thoughts about how the results of this study will impact clinical practice, both in the European countries as well as U.S.?
Dr Gerald Greil: I mean, I was obviously delighted to see the study being submitted to circulation because there's a very important message particularly for pediatric cardiologists which is potentially influencing the guidelines and Dr Kaski may comment on this as well as the next step meaning that it seems like screening patients older than ten or twelve years and once again, there's a slight discrepancy between the European and U.S. guidelines, seems to be ... Can be questioned and potentially we should screen these patients earlier.
Another amplification of this study is that we should think about how much genetic screening can be an essential tool in our methods in looking at these patients and I want to point out that because of these discrepancies we also initiated an editorial letter for this publication done by Dr Ommen and by Dr Mital kind of pointing out there needs a lot of work to be done maybe even including rewriting the current guidelines.
There's another paper that came out recently in European Society Cardiology, the European Heart Journal about a similar topic so it's something which is very, very heavily discussed in our community. We think how we are looking at these patients and how we're following them up.
Dr Greg Hundley: What would you suggest are next steps for the world community in this space in regards to modifying those guidelines?
Dr Gerald Greil: I think there's now enough literature around which suggests that we should look at these patients earlier and screen them earlier on both sides in European, in the U.S., in the Asian world, and ideally these two groups should sit together and write combined guidelines. It's still interesting that the European and U.S. guidelines are slightly different in that we're talking about a similar group of patients, so I'm very, very delighted to see that this is coming up in the national literature as a new topic and I think everything is open now to rethink this topic and rewrite these guidelines.
Dr Greg Hundley: Do you think prospective studies would be necessary because I believe, and Dr Kaski please weigh in here, this was a retrospective review, and do you think there could have been triggering circumstances that prompted early screening? I mean, would a next step be some sort of prospective registry?
Dr Gerald Greil: I mean definitely that's the next step. I think we have enough data material around once again to rethink the strategy which age these patients should be looked at. A prospective registry and Dr Kaski can probably comment on it better than I can, I think that something which is a logical next step and there may be even something being on the way to make this happen.
Dr Juan Pablo Kaski: I agree. I think further validation and confirmation of these data from prospective studies would be extremely helpful. I think one of the things that we need to bear in mind is the potential cost implications of expending screening to ever increasing populations and so perhaps an additional further step would be to try to refine the screening tools so that we are able to identify clinical by a chemical of those individuals who are more likely to present in childhood and perhaps set a target screening towards that population.
I can just go back to one of your sort of previous points also about a potential bias and it is true that these patients were referred for clinical screening at a time when clinical recommendations do not suggest that this is necessary and although we didn't specifically in this cohort look at those that would have fulfilled current early screening criteria, the vast majority of the patients were asymptomatic at the time that they were referred. We also looked to see whether there was any link between those individuals who had a family history of early onset disease and an early diagnosis, and that was the only factor that came up as potentially significant so perhaps the current guidelines that do recommend considering earlier screenings if there's a family history of childhood disease are still applicable.
Dr Carolyn Lam: That was just an amazing interview, by the way. I've learned so much and thank you so much for publishing this very important paper with us.
You've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is Copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, also Associate Editor from the Pauley Heart Center at VCU Health in Richmond, Virginia.
Dr Carolyn Lam: I'm so excited about our feature discussion today, Greg, because it is about a familiar but very important problem of hypertension, and we will be looking at trial results of a new drug, a first in its class type of drug. And tackling a problem that is particularly important perhaps in black patients with hypertension. Well, more very soon. First, let's discuss some papers, shall we? Do you have one?
Dr Greg Hundley: My paper is from Joseph Burgoyne from King's College in London and pertains to resveratrol. Now, resveratrol is a non-flavonoid polyphenolic compound that has been found in the skin of several fruits, with the most notable being grapes. The compound exhibits beneficial effects, including the prevention of cardiovascular neurologic diseases, cancer, metabolic syndrome, as well as it promotes bone and eye health. And in this study, the investigative team explains how resveratrol may mediate its numerous beneficial effects including lowering of blood pressure by direct thiol oxidation. Also, they demonstrate that resveratrol can counter-intuitively induce direct protein oxidation, a process that is enhanced under pro-oxidative conditions associated with disease. The oxidation of cyclic GMP dependent protein kinase 1 alpha, or PKG1 alpha, by resveratrol lowers blood pressure in hypertensive mice.
Dr Carolyn Lam: Okay. But what does that mean for us clinically, Greg?
Dr Greg Hundley: Well, the results demonstrate how blood pressure can be lowered by using resveratrol, and targeting cysteine 42, or PKG1 alpha, may provide a new class of anti-hypertensive agents. In addition, identifying additional proteins modified by resveratrol may provide new targets for therapy to treat cardiovascular disease. Carolyn, how about your first paper?
Dr Carolyn Lam: We are going to look at the further results of the ODYSSEY OUTCOMES trial. And as a reminder, ODYSSEY OUTCOMES was a double-blind randomized comparison of the PCSK9 antibody Alirocumab with placebo in almost 19,000 patients who had an acute coronary syndrome 1-12 months previously and elevated at the atherogenic lipoproteins despite intensive statin therapy.
And that trial found that Alirocumab reduced the risk of the primary composite outcome of coronary heart disease, death, ischemic stroke, myocardial infarction, or unstable angina requiring hospital admissions. The current paper looked further at the effects of Alirocumab on death.
Dr Greg Hundley: So Carolyn, what did they find?
Dr Carolyn Lam: Well, there are quite a number of findings here. The first, there were fewer deaths in total that occurred with the PCSK9 inhibitor Alirocumab versus placebo, and this resulted from a non-significantly cardiovascular and non-cardiovascular deaths with Alirocumab. The second finding was that in a pre-specified analysis of more than 8,200 patients eligible for 3 or more years of follow-up, Alirocumab reduced death.
And then, the third finding was that patients with non-fatal cardiovascular events were at increased risk for both cardiovascular and non-cardiovascular deaths, and a post-Hoc analysis found that compared to patients with a lower LDL, those with a baseline LDL above 100 had a greater absolute risk of death, and a larger mortality benefit with Alirocumab. In the Alirocumab group, all cause death declined with a lower achieved LDL achieved at 4 months of treatment to a level of approximately 30.
So in summary, Alirocumab added to intensive statin therapy, has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for 3 or more years, and if baseline LDL is 100 or more, or if achieved LDL is low.
Dr Greg Hundley: That's great, Carolyn. My next paper is going to talk a little bit about endothelial cells. And what I think we're going to learn is that not all endothelial cells are alike. This comes from Dr Rajat Gupta from Brigham and Women's Hospital, and I really thought this was an interesting article that used single-cell RNA sequencing to make it possible to identify and characterize cellular sub-populations.
Dr Greg Hundley: The investigative team performed enzymatic dissociation of 4 whole mouse aortas, followed by single-cell sequencing of over 10,000 cells.
Dr Carolyn Lam: Wow. What did they find?
Dr Greg Hundley: Well using cluster analysis of gene expression from the aortic cells, they identified 10 populations of cells representing each of the main arterial cell types. There were fibroblasts, vascular smooth muscle cells, endothelial cells, immune cells, including monocytes, macrophages, and lymphocytes. And importantly, there were 3 distinct endothelial cell sub-populations with differences in them driven by major functional gene programs including adhesion and lipid handling.
Comparison of aortic single-cell RNA sequence data sets from normal and Western diet-fed mice suggested that these sub-populations exist under both dietary conditions and have some unified responses to diet alteration. Also, immunofluorescence using single marker genes to identify endothelial cell sub-populations showed that the VCAM1 positive population was spatially located in regions of disturbed flow like the lesser curve of the aorta.
Dr Carolyn Lam: Okay. So bring it home for us, Greg. What does this mean clinically?
Dr Greg Hundley: Yeah exactly, Carolyn. So, characterizing functional sub-populations may serve as a novel method for understanding endothelial health in patients with vascular disease. And although aortic endothelial cell sub-populations demonstrate some unified responses to vascular disease relevant stimuli, like a Western diet, functionally different sub-populations may contribute differentially to vascular diseases, enabling sub-population targeted therapies to perhaps be implemented in the future.
Dr Carolyn Lam: Cool. So Greg, cardiomyopathies have often been seen as genetic in origin, but what about potentially modifiable causes? So, this next paper that I picked looked at that, and it's from corresponding author Dr Rosengren from Sahlgrenska University in Gothenburg, Sweden, who with her colleagues, sought to investigate a potential link between obesity in adolescence and being diagnosed with cardiomyopathy in adulthood.
So, this was a nation-wide register-based prospective cohort study of almost 1 million 690,000 adolescent men who were enlisted for compulsory military service from 1969 to 2005. Now at baseline, body mass index, blood pressure, and medical disorders were registered, along with test results for fitness and muscle strength. Cardiomyopathy diagnosis was then identified from the National Hospital Register and Cause of Death Register.
So, they found that during a median follow-up of 27 years, 4,477 cases of cardiomyopathy were identified, of which 59% were dilated, 15% were hypertrophic, and 11% were alcohol or drug-induced. Increasing body mass index, or BMI, was strongly associated with elevated risk of cardiomyopathy, especially dilated cardiomyopathy, starting at levels considered normal, meaning a BMI of 22.5 to less than 25 kilograms per squared meters.
And this was even after adjusting for age, years, center, and baseline comorbidities. There was a more than 8 fold increased risk of cardiomyopathy at a body mass index of 35 and above, compared with a BMI of between 18.5 and less than 20.
Dr Greg Hundley: So, it sounds like BMI elevations and cardiomyopathies don't go together. So, what are the clinical implications?
Dr Carolyn Lam: This really shows that even mildly elevated body weight in late adolescence may contribute to being diagnosed with cardiomyopathy in adulthood. So, the already marked importance of weight control in youth is really further strengthened by these findings, as well as the greater evidence for obesity as a potential important cause of adverse cardiac remodeling that is independent of clinically evident ischemic heart disease.
Dr Greg Hundley: Outstanding. So, BMI, not good.
Dr Carolyn Lam: Nope, Greg. High BMI, not good. That was fun, Greg. So, shall we move on to our feature discussion?
Dr Greg Hundley: Absolutely.
Dr Carolyn Lam: For our feature discussion today, we are talking about a familiar problem, but just so very important, and that is hypertension. And guess what? Our feature paper discusses a new first in class centrally-acting renin-angiotensin system blocker that has such remarkable initial results. I am so pleased to have with us the corresponding author for the paper, Dr Keith Ferdinand from Tulane University School of Medicine, as well as our Guest Editor, Dr David Calhoun from University of Alabama and Birmingham.
Keith, could you start by telling us a little bit about the kinds of patients you see there in New Orleans that struggles with hypertension control perhaps? And then, please tell us about Firibastat.
Dr Keith Ferdinand: I'm in New Orleans. In fact, I'm a native New Orleans. And as you know, most of the south and southeast and part of the United States has a high proportion of African American or US blacks. This population has higher rates of hypertension, increased prevalence, more severe hypertension, and more uncontrolled hypertension.
We also note in the south that there tends to be an increase in obesity, which is a powerful risk factor for all patients with hypertension, regardless of race or ethnicity. And unfortunately, the rates of obesity appear to be increasing. So based on the fact that we have an increase in obesity, we have many patients whose blood pressures are not controlled, and some of the previous data have suggested less response to first step or monotherapy with ACE inhibitors and angiotensin receptor blockers, I initiated a trial with a first in its kind oral active brain aminopeptidase A inhibitor.
Dr Carolyn Lam: Wow. Could you tell us a little bit more about brain aminopeptidase, and this new drug Firibastat?
Dr Keith Ferdinand: Most people don't know anything about this molecule, because this is something that was discovered by some French physiologists. They approached me to design the clinical trial here in the United States. And what it does is, it blocks the conversion of angiotensin II to angiotensin III in the brain. Angiotensin III is actually the active component of the renin-angiotensin system centrally, and if you block angiotensin III production, it has a triple therapy effect.
One is that it causes the diuresis. It decreases sympathetic tone, and it stimulates the carotid artery, such that you have, again, a decrease in sympathetic tone. Now, why choose it for patients who are obese, and why want to include a large proportion of non-Hispanic blacks here in the United States? Well, the reasons are that when you look at some of the bench research using rats, it appears to have a more beneficial effect in DOCA-salt rats, which is a model for salt-resistant hypertension.
Salt-resistant hypertension is more common in blacks, more common in patients with obesity, and may indeed be one of the reasons why monotherapy or first-step with conventional renin-angiotensin system agents, specifically ACE inhibitors and ARBs, have not been as effective in the past.
Dr Carolyn Lam: Gosh. That is so interesting, and it's really making me think about my patients too here in Asia, where we have a lot of salt-sensitive hypertension. Now, could you please tell us about the trial you did, and what you found?
Dr Keith Ferdinand: We looked at a cohort of patients. All of the patients were overweight and obese. They were washed out for 2 weeks, and had a systolic blood pressure of 145-170, and a diastolic of less than 105. We wanted to get at least 50% self-identified blacks or Hispanics, and I suspect that any patient who meets this phenotype, and that would include Asians, or even Whites, may respond similarly.
We then placed them in an open label format, and I can discuss why we used an open label, with monotherapy with Firibastat. After 2 weeks, we then titrated the dose level from 250 twice daily to 500 twice daily if needed, and we had a low dose thiazide and hydrochlorothiazide 25 mg addition, if needed, for escape, if patients had a blood pressure greater than 160/100.
The other thing that was interesting and unique about this particular trial is that we used the automatic office blood pressure, where the blood pressure was taken 6 times. The first time was discarded, and then averaged, without a particular doctor or a nurse being there to do the blood pressure. We felt that this was a valid means of getting blood pressure loaded. It tends to mimic, to a large extent, what you see in 24 hour inventory daytime systolic blood pressure.
So, this was a valid means of measuring blood pressure loads. This was a relatively high risk patients. And these were patients whom, previously, probably would not have responded as well to monotherapy with ACE inhibitors or ARBs.
Dr Carolyn Lam: That's really clear, and clever design. I would love to hear a little bit more about why the open label, and of course, the results.
Dr Keith Ferdinand: Well, that's one of the criticisms of this study, but actually, we presented to the FDA when we were discussing designing this trial, perhaps doing a placebo control trial. And we were told by the FDA that if you use a valid means of measuring blood pressure load, so that would be ambulatory blood pressure, or automated office blood pressure, that a placebo would not be necessary, because those means of checking blood pressure load would be considered a true valid means of finding a blood pressure effect.
The other thing is, dealing with minority patients, and really dealing with patients in general, for blood pressure, if they have substantial hypertension, the message has been out there that this is a killer and cause of cardiovascular disease. It would probably have been very difficult to enroll the patients, you've got 254 patients in a national study. It would have been very difficult to enroll these patients, who would have known easily that they had substantial elevation of blood pressure, and we said, "You know, 50% chance you're going to get a sugar pill that has no effect."
Dr Carolyn Lam: Right. Right. Very nice. The results?
Dr Keith Ferdinand: Well, the results were a robust 9.7 mm reduction in systolic blood pressure. At day 56, the p-value was less than 0.0001. And when you do a sub-group analysis of patients who were in the study, it was effective for persons who are under 65, or over 65, male or female. All patients were overweight, and the patients who were obese, with a BMI of 30 or above, had a trend towards even a better blood pressure effect, which again, is not seen with first step with conventional ACE and ARBs.
We also did an analysis based on black and non-black, and there was no difference, again with the trend towards the black patients actually doing fairly well. So, the take home from the particular study was this is the first in its kind, new approach to central Ras blockage with aminopeptidase A inhibitor, that was effective in a population which was overweight and obese, with over 50% minority, and showed substantial blood pressure reduction using a valid means of checking blood pressure, the automated blood pressure in the clinic.
Dr Carolyn Lam Keith, congratulations. A very important study. David, could I bring you in here? What were your thoughts as you were managing this paper, and what do you think are the future steps here?
Dr David Calhoun: Looking at the submission, I was obviously excited about the results and the potential implications. I think, like Keith, in treating a lot of resistant or obesity-related hypertension, we're frustrated that control rates are not better, that the initial response to monotherapy is not better, and that's particularly true of Ras blockers. I think many of us are investigating the initial use of Ras blockers for a variety of reasons related to outcome benefit and reduction in incident and diabetes.
So, I know I like to start with such an agent. I'm particularly excited that there may be, firstly, a new opportunity to block the Ras system, and potentially comparable or even better in the most difficult patients to treat. That is, the African American and the Hispanic patients, who often have very severe hypertension. So, my initial reading was I was very excited to see the potential, and that was brought out by the reviews as well. They shared my excitement. So, I'm looking forward to Keith advancing this compound.
Dr Carolyn Lam: Indeed. Keith, I'm sure everyone's thinking now, wow, remarkable results. What's the drawbacks? How well-tolerated was this drug?
Dr Keith Ferdinand: One of the drawbacks is that the structure of Firibastat included a sulfhydryl group. And we saw with early studies with captopril, which also has a sulfhydryl group, some skin rash, and we saw those similar changes with some of the patients in this particular study. At least 2 of them were suggested to potentially have erythema multiforme, although this was not proven. This was an investigator initiated adverse event.
So, I don't know if we're going to be able to structure a similar type of aminopeptidase inhibitor without a sulfhydryl group. The other thing is that in its presence formulation, it's given twice daily. We know optimally you'd like to have a long-acting agent that can be given once daily. And I don't think we need a placebo control trial, but we may need to do a trial where patients are on 2 or more medications, and then, you add the Firibastat versus adding placebo. But, I don't think at this particular point, we need to get some of these more difficult to treat patients, and just place them on placebo, and watch and see what happens.
We know what happens. The blood pressure goes up. Many of them may have acute heart failure, or progression of renal failure. And I just don't think it's necessary. And the FDA doesn't think it's necessary to prove that hypothesis.
Dr Carolyn Lam: David, what do you think about that? Do we need a placebo control trial? And that use of ambulatory blood pressure, that's novel aspects of this trial too.
Dr David Calhoun: I think use of placebo comparison has been for the traditional or conventional approach. I think most investigators, most clinicians, sort of anticipate seeing the placebo corrected effect. So, I think the results would have been, or will be potentially, more compelling if that's done. But, I can also appreciate Keith's contention, and it sounds like the FDA, that in this day and age, with use of automated office blood pressure measurements tend to minimize that white coat effect, and particularly true of ambulatory monitoring, that it may be that not using a placebo comparison maybe is compelling as well.
Dr Carolyn Lam: Indeed. I really enjoy actually just digging deep into the study like this. Keith, if I could just ask for some final words from you, learning lessons, or even what have you got planned next.
Dr Keith Ferdinand: The first lesson is, we need to continue to pay attention to hypertension. It's kind of been placed on the back burner with more interest now in diabetes and sugar, a lot of interest in lipids because of some of the new agents. But if you look across the globe, Asians, blacks, whites, regardless of race or ethnicity or geography, hypertension is the most potent cardiovascular risk factor, and I think we need to continue to address that.
In terms of this particular agent, I believe that we will have to have some sort of placebo arm, but again, I think it's going to be built on a conventional medication, and then randomized with Firibastat versus placebo on top of conventional medications. In a more severe or a more difficult to treat hypertension, I'm just not really convinced that we need to do a purely placebo arm.
Dr Carolyn Lam: Great, Keith. And David, how about yourself? Any take home messages?
Dr David Calhoun: I think when there's a new in-class compound, I think that's always exciting, particularly when it has the initial results, preliminary results, that Keith is reporting. As many agents as there are out there to treat hypertension, we still are not doing as well as we should be. I think it can only help to have additional classes of agents as therapeutic options, and I think that's particularly true with minority patients, who are, as Keith has indicated, are at the biggest need in terms of controlling blood pressure. Keith, these initial results are very exciting, and I look forward to future studies.
Dr Carolyn Lam: Completely sharing your enthusiasm here. Thank you so much, Keith, for publishing this remarkable paper with us at Circulation. Thank you, David, for helping us manage it.
And thank you, audience, for joining us today. You've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Greg Hundley Welcome back everyone from our week hiatus for this July 2nd issue of Circulation On the Run. I'm Dr Greg Hundley, from the Pauley Heart Center at VCU health in Richmond, Virginia.
Dr Carolyn Lam: And I'm Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore. So good to be back, Greg.
Dr Greg Hundley Absolutely. So Carolyn, our featured articles going to focus on amyloid and transthyretin amyloid is recognized in middle age and older individuals with increases in LV mass and heart failure. And in our featured article from the United Kingdom, Dr Gilmore and colleagues are going to discuss the natural history of this disease and compare outcomes of those with acquired versus hereditary forms of the disease. But before we get to that interview, how about we discuss several other original articles?
Dr Carolyn Lam: For sure, Greg. Thanks. I want to pick two genetic papers in this issue. They're really exciting. The first one is actually the first study to consider the association between rare genetic variance in a large set of cardiomyopathy genes and the occurrence of cancer therapy induced cardiomyopathy. So this paper is from co-corresponding authors, Dr Garcia-Pavia from hospital Universitario Puerta de Hierro from Madrid, and Dr Christine Seidman from Harvard Medical School in Boston, Massachusetts. The authors studied 213 patients with cancer therapy induced cardiomyopathy from three cohorts. The first retrospectively recruited adults with diverse cancers, the second prospectively phenotyped breast cancer patients. And then the third prospectively phenotyped children with acute myeloid leukemia. They showed an increased prevalence of rare variants in cardiomyopathy genes, particularly the truncating variants of the TTN gene in both adults and pediatric cancer patients with cancer therapy induced cardiomyopathy. They confirmed the human genetic data with experimental analyses showing that anthracyclines induced protracted left ventricular dysfunction in mice with truncating variants of TTN genes but not in the wild type mice.
Dr Greg Hundley Aha. So what are the clinical implications of this study, Carolyn?
Dr Carolyn Lam: Well, the findings show that variance in cardiomyopathy genes contribute to cancer therapy induced cardiomyopathy susceptibility among adult and pediatric cancer patients. And thus the identification of genetic risk factors really opens the door to new opportunities to define patients at high risk of cancer therapy induced cardiomyopathy and associated adverse outcomes.
I want to go onto the next paper because it's so related. It's another genetic paper. This time looking further at the truncating variants of the TTN genes and a very novel approach, they aim to assess a genomics first approach to assess the consequences of these TTN variants. So, this was from corresponding author Dr Zoltan Arany from Perelman School of Medicine in University of Pennsylvania where he and his colleagues reviewed whole exome sequence data for more than 71,000 individuals to identify anyone with truncating variants of TTN genes. They further selected individuals with these variants in exons highly expressed in the heart and using a linked electronic health record, they evaluated the associations of these truncating variants of TTN genes with the diagnosis and quantitative echocardiographic measures. They also reviewed data from the Jackson Heart study to validate specific analyses for individuals of African ancestry.
Dr Greg Hundley Interesting. So we're hearing a little bit about different ancestry and TTN genes. What did they find?
Dr Carolyn Lam: So, I should have first clarified that that first look was in individuals of European ancestry. And they found there that the individuals of European ancestry identified through this genomics VERSE approach had a much greater odds of developing dilated cardiomyopathy and had lower left ventricular function than their peers, whether or not a clinical diagnosis of dilated cardiomyopathy was present. They also found that the association of the TTN variants and dilated cardiomyopathy was much weaker in individuals of African ancestry. So in summary, truncating genetic variants of TTN had a measurable effect in large clinical populations with respect to both strong associations with cardiomyopathy and with associations with quantitative differences in cardiac structure and function. Given the caveat though, that these association appeared strongest in individuals of European ancestry. So Greg, what did you have?
Dr Greg Hundley Well, Carolyn, the overlap of inflammatory processes operating in atherosclerosis and the rich presence of macrophages within plaques make macrophages a strong candidate for therapeutic targeting in atherosclerosis. And so this study comes from Levent Akyürek at the Institute of Biomedicine and involves targeting filament A to reduce macrophage activity in atherosclerosis. So filament A is a large actin binding protein that has been implicated in atherosclerosis and this study tested the hypothesis that targeting filament A in macrophages would impair atherosclerosis in vivo in mice and the investigators evaluated the expression of filament A in human atherosclerotic plaques.
Dr Carolyn Lam: Huh, interesting. So what did it show?
Dr Greg Hundley: Well, in humans, expression of filament A is increased in macrophages and advanced atherosclerotic plaques of human carotid arteries. In mice, in the absence of filament A, macrophages displayed impaired migration, proliferation and lipid uptake and secreted lower levels of inflammatory IL 6, also lack of filament A and macrophages in vivo reduced aortic plaque size and atherogenic mice.
There were additional mechanistic findings and that the C terminal fragment of Filament A produced by calpain cleavage regulated IL 6 secretion in macrophages and treatment with calpeptin, which inhibits calpain cleavage, reduced aortic plaque size and atherogenic mice. And so therefore, filament A might serve as a prognostic biomarker and atherogenesis and perhaps targeting the C terminal proteolytic fragment of filament A could be a strategy to reduce inflammation and atherosclerotic plaque development. Carolyn, I've got another paper, but guess what? This one has our first quiz of the academic new year. This is a paper about Nexclin, and it discusses a new component of junctional membrane complexes required for cardiac T-tubule formation. The corresponding authors are led by professor Zhou Shen from the University of California, San Diego. So, Carolyn in this quiz, what is a T-tubule?
Dr Carolyn Lam: Greg, that is mean! T-Tubules, something inside the cell. Something to do with membranes folding over.
Dr Greg Hundley Yeah, you know this is one of those, it's not multiple choice. It's an open ended question. You need your little blue book. You've got to write the answer. So T, or transverse, tubules are extensions of the cell membrane that penetrate into the center of cardiac muscle cells and interact with the sarcoplasmic reticulum to facilitate calcium release and thus help modulate myocardial contraction. T-tubule uncoupling and remodeling are known features of heart failure.
Dr Carolyn Lam: Alright, so that's T-tubules. Guess what Greg, I'm going to ask you before you ask me. So, what's Nexilin?
Dr Greg Hundley I read the paper like a good student of the American Heart Association. This was answered by the investigative team of Chen and his associates. Nexilin has been identified as an actin binding protein and multiple mutations in the nexin gene are associated with cardiac diseases. In this study, Nexilin was required for initiation of T-tubule invagination and overall T-tubule formation, with a loss of next sullen leading to impaired calcium handling. Clinically, these results identified Nexilin as a new possible target for T-tubule remodeling and provide mechanistic insight into molecular pathways leading to cardiomyopathy in patients with mutations in Nexilin. So Carolyn, great job on our first quiz of the academic new year. And how about we move on to that featured discussion?
Dr Carolyn Lam: Absolutely.
Dr Greg Hundley Welcome everyone to our featured article discussion on this July 2nd and we are going to discuss with Dr Julian Gilmore from London, and our editor Dr Justin Grodin from Dallas, regarding amyloid. And Julian, I understand this particular study you have investigated a natural history of transthyretin amyloidosis cardiomyopathy. Can you tell us a little bit about transthyretin amyloid as opposed to light chain amyloid? And then also I think there's two types of transthyretin amyloid, both a hereditary and then a wild type.
Dr Julian Gilmore: Amyloidosis is a disorder of protein misfolding, and there are in fact many different proteins that can misfold and form amyloid fibrils. When they form fibrils they become insoluble and tend to build up and cause damage to whichever organ they're depositing in. Two of the proteins that form amyloid fibrils in humans in vivo are transthyretin, known as TTR for short, or immunoglobulin light chains, known as immunoglobulin light chains, and those two proteins cause transthyretin amyloidosis and AL amyloidosis or immunoglobulin light chain amyloidosis respectively. Those are the main two types of amyloid that affect the heart or cause a cardiomyopathy and they behave very differently in terms of their natural history in that AL amyloidosis is a very aggressive, rapidly fatal cardiomyopathy if untreated. Whereas cardiac transthyretin amyloidosis tends to be a more gradual albeit progressive cardiomyopathy.
Transthyretin amyloidosis, as you alluded to, can either be acquired, known as wild type or hereditary and in the hereditary version it's associated with mutations in the transthyretin gene of which there are more than 130 now that are recognized to cause disease. The wild type version of the disease, the non-hereditary version of the disease, is now an increasingly recognized cause of heart failure, mainly in older individuals and particularly older males. And the hereditary version essentially remains a rather rarer disease, although the mutation that is associated or it is associated with a risk of developing this disease occurs in certain populations and in particular occurs in 4% of people of African descent, as a particular genetic mutation that occurs in 4% of individuals of African descent. So and that is associated with risk of developing this hereditary transthyretin cardiomyopathy.
Dr Greg Hundley: And so, there's the UK National Amyloidosis Center. Tell us a little bit from that center, what did you do with this particular study in terms of its design and what were your results?
Dr Julian Gilmore: Essentially the UK National Amyloidosis Center is the single center in the UK, which is commissioned centrally to diagnose and type, stage, and provide treatment FYS for patients with amyloidosis. And that includes all parts of amyloidosis. We studied a large number of patients with cardiac transthyretin amyloidosis, so cardiac ATTR amyloidosis, who referred to our center and studied them longitudinally, if you like, over the course of many years. So this was a natural history study for a condition for which at the time of the onset of the study and until the end of the study there was no disease modifying treatment and essentially what we found is that there was a great delay in diagnosis amongst most patients diagnosed with the disease and in fact the median number of attendances in hospital for patients diagnosed with the disease before they were actually diagnosed with 17 which is quite amazing and unsurprisingly in a gradually progressive disease, by the time they were diagnosed, their quality of life was very poor.
We found that their quality of life symptoms gradually progressed and that they became more and more functionally impaired and had relatively poor survival with a median survival of somewhere in the region of five years. What we did find is that patients with a particular type of hereditary, ATTR amyloidosis, the type that I alluded to earlier, the mutation for which is present in 4% of people of African ancestry, he planted the V122I mutation. Patients carrying that particular mutation actually have more aggressive disease and survive for shorter than patients with the wild type disease.
So, 17 hospitalizations before diagnosis and the proceeding three years. Were there factors in your study that you could identify that we should now be looking for to try and make this diagnosis earlier?
Absolutely. So one of the reasons for not diagnosing the condition is basically the poor sensitivity and specificity of echocardiography, which is generally the first investigation that a cardiologist will request when a patient presents with symptoms of heart failure. There are some particular features on echocardiography that can provide clues such as strain measurement on tissue doppler imaging, where one can get a bullseye pattern, that's been reported in the literature. So there are particular features on echocardiography that one can look at to increase the chance of picking up this disease. And in particular the big increase in the number of diagnoses over recent years has been because of cardiac MRI scanning, which has become an increasingly used tool for the investigation of heart failure in which one gets a very characteristic picture of late gadolinium enhancement when it's performed in a patient with cardiac amyloidosis, which immediately triggers people to think, ah, here it is, we've got amyloid.
And the other sort of novel diagnostic technique as being bone scintigraphy. In the UK we use a bone tracer called DPD and in the US a bone tracer called PYP, and those bone tracers have exquisite sensitivity for cardiac amyloidosis. So if one injects these tracers in a patient with cardiac amyloidosis one gets cardiac uptake into the heart, which can't really be missed on a planar scan. So those two techniques basically, the increasing needs of cardiac MRI and the increasing use of bone scintigraphy to investigate patients with heart failure have resulted in a great increase in the number of diagnoses.
The last thing to say is that a huge proportion of patients with amyloid or transthyretin amyloid cardiomyopathy have actually had carpal tunnel syndrome previously. The median time from carpal tunnel syndrome to presentation with heart failure is about seven years, but that is another red flag, if you like, that ought to at least trigger a doctor to think could be amyloid. A thick walled heart in the context of someone whose had previous carpal tunnel syndrome. So there are a few clues there as to how one might make an earlier diagnosis, which is absolutely necessary given the nature of our data, sharing the delays that I outlined down here.
Dr Greg Hundley And Julian, last quick question before we get with Justin here. In your data, can you describe for us the importance of that earlier diagnosis related to long-term outcomes as opposed to the group that was diagnosed much later, you know, beyond your median. What was the difference in prognosis in those two groups?
Dr Julian Gilmore: There is no doubt that if patients are diagnosed earlier, they survived for longer, reflecting the natural history of the disease. So these patients, as I mentioned earlier, did not receive any disease modifying therapy and we did divide the patients into pre 2012, when patients were essentially diagnosed by endomyocardial biopsy, or the vast majority of them were diagnosed by endomyocardial biopsy, and post 2012 by which time most patients were diagnosed via an imaging, if you like, algorithm that we published in 2016 in the same journal in circulation. And the patients who were diagnosed earlier had significantly improved survival. Just corroborating really the fact that they were actually diagnosed earlier. What's particularly relevant there, is that the treatments that have been developed for this condition, and there are some recent new potential disease modifying treatments that have been developed, they find that things seem to slow progression of the disease rather than stop it or reverse it, so that if one can diagnose a patient early when their quality of life is still good and then slow progression, there's a high chance of improving quality of life quite substantially and obviously prolonging life.
Dr Greg Hundley Thank you so much, Julian. And Justin as the managing editor of this article, what struck you most in terms of its results and conclusions, and how we should manage patients today suspected of transthyretin amyloid?
Dr Justin Grodin: Well, I would say that really there are four things that in my opinion that were quite striking. The first at least as highlighted by Professor Gilmore is that the UK National Amyloid Center, they get the national case load. So this is unlike other cohorts and other centers across the world in that this is subject to less referral bias than others. So I think that's the first thing that's quite impressive. And I think Professor Gilmore really hit the nail on the head when he highlighted that this paper, that this analysis really underscores the importance of an early efficient diagnosis. And a lot of this is really through his seminal work in achieving a non-biopsy diagnosis of ATTR amyloidosis and his findings have been replicated in other cohorts as well. So I think those, I would like to say are really one and two.
And then number three, which is one that I don't think Dr Gillmor mentioned, I think he mentioned indirectly, but we were also struck by the prognostic importance or I should say the prognostic meaning of having the V122I mutation. So these are individuals like hereditary amyloidosis and they have a single mutation. This is the one that is prevalent, at least we think from population studies, in approximately 4% of the African or Afro-Caribbean population. And we really see unequivocally that the time from symptom onset to diagnosis was shorter and the prognosis was actually worse in comparison to other mutations or in individuals with wild-type amyloid. And this is an important finding really for two reasons. Number one, it is largely confirmatory from other studies, but it's important to note that those studies were subject to referral bias. And we could never ever successfully incorporate whether or not socioeconomic status had actually influenced the bad outcomes of these individuals.
And I would say that Professor Gilmore's findings are quite compelling in that regard. And then the second thing for this point is really this underscores I think the importance of genetic testing. I mean I think all the readers can take that message away. And then the fourth thing, which as Professor Gilmore alluded was the striking amounts of healthcare utilization, although it was in a minority, certainly quite compelling and really what it speaks to is multiple missed opportunities. Even in the UK where they have a centralized center of excellence, just like Professor Gilmore's, that there were delays in diagnosis and then when delayed these patients are quite ill. And I think I'm making all these points because at least in 2019, the regulatory environment about amyloidosis, specifically ATTR therapies. In The United States, it's actually changed. So a disease where we had therapies that might be off label or our therapies were largely symptomatic, where we managed the patient's signs and symptoms, we now actually have disease modifying therapies.
So, in the United States in 2018, there were two biological agents that actually silence the livers production of transthyretin or TTR and they were approved for hereditary ATTR polyneuropathy. But there is some suggestion from sub-studies that those will have the efficacy in cardiac amyloid. And then number two in the United States, we recently gained approval in May of a drug that actually stabilizes the transthyretin protein or tetramer. So in other words, just as Professor Gilmore had highlighted at the beginning of this call, it stabilizes the breaking up, if you will, of this protein, which is the rate limiting step of amyloid formation. So you take this pill and then the transthyretin molecule does not then deposit amyloid. So this is really exciting because professor Gilmore's cohort study really captures now at least the impact that these therapies might have, and in the United States and across the world and in the UK, these therapies are being studied for all types of ATTR amyloid and really they're on the horizon. So it's given us very deep insights into how these might impact our patient's lives with ATTR.
Dr Greg Hundley Julian, Justin, that was just such an impressive discussion of a very important topic and something that again, with echocardiography, we really need to start thinking about when perhaps we appreciate some LVH, diastolic dysfunction. We have apical sparing of systolic function, but abnormal basal systolic function. Could you just summarize one point, each of you, that we should be thinking about as we move forward and we're seeing patients in our clinic that might have this disorder.
Dr Justin Grodin: The first thing to say is that awareness is all important. You know, 25% of male individuals in autopsy studies over the age of 80 have ATTR amyloid deposits in their heart, and when one sees a thick walled heart in any situation, and particularly in an elderly individual, one needs to think, could this be, amyloid, that's the first thing. And the second thing I'd like to say is that if that thought occurs, which it should occur at a much earlier stage than it does probably in most cardiologists minds, then one should think about either a bone scan, which is a cheap, simple tests. The PYP scan in the US or DPD scan in the UK and or an MRI scan, which has a very characteristic picture in a patient with cardiac amyloidosis. So those would be my take home messages to try and improve early diagnosis.
You know, I'd like to dovetail what Professor Gilmore had said cause he just about took the words out of my mouth and I would like to emphasize the first point in that the diagnosis of AL, we mentioned earlier, or an ATTR amyloidosis, really necessitates a very, very high index of suspicion. What do I mean by that? When somebody has a thick heart muscle and it's not explained by something else, in other words, they don't have a lifetime history of high blood pressure and they don't have high blood pressure seeing you, or maybe they don't respond adequately to standard heart failure therapies when something is not fitting, it's always incumbent to the treating clinician to think amyloid.
I would also like to highlight some of the clues that Professor Gilmore had mentioned, that any individual with carpal tunnel syndrome or who might be hospitalized with heart failure, in other words, they have shortness of breath and swelling, and the squeeze of their heart is normal, or the ejection fraction is normal, that should increase your index of suspicion for amyloidosis. And then individuals that might've had lumbar canal surgery or really any issue impacting their tendons. And then they're now presenting with a thick heart muscle. That should be a clue. It doesn't necessarily mean it's diagnostic. In fact, the majority of those individuals might not have, or a large proportion, might not have ATTR amyloid, but it should certainly raise an eyebrow and then kind of allow the clinician to move forward with the evaluations that Professor Gilmore had mentioned.
Dr Greg Hundley Well, listeners, what a phenomenal discussion that we've had from Professor Julian Gilmore from London, and Dr Justin Grodin from Dallas, Texas, educating us on transthyretin amyloid and thinking about that early and being suspicious as we evaluate patients, particularly older individuals that are symptomatic with heart failure. Well, on behalf of Carolyn Lam, this is Greg Hundley. We look forward to seeing you next week. Have a great week.
Dr Carolyn Lam This program is copyright American Heart Association 2019
Dr Amit Khera: Welcome to Circulation On The Run. Our weekly podcast summary and backstage pass to the Journal. I'm Dr Amit Khera, associate editor and digital strategies editor from UT Southwestern Medical Center in Dallas, and I had the distinct privilege of standing in for Dr Carolyn Lam and Greg Hundley this week. Twice a year, we are very fortunate to have some unique podcasts when we don't have circulation issues, and in the past we've met with many fellows in training and heard about some interesting studies that they're doing. Today we have a very special podcast we have not done before, and that is one where we had the opportunity to learn about our Circulation Family of Journals, and more importantly to hear from the dynamic editors in chief of these various journals. I think you're really going to enjoy it, we'll walk through and hear from each one of them, hear about some of the innovative things that are happening, some of the future that they see for their journal in their field, and I really enjoyed it, and I'm sure you will as well. So, without further ado, we'll start with our first editor.
Dr Sunil Rao: I'm Sunil Rao. I'm an intervention cardiologist at Duke, and I'm the Editor-in-Chief for Circulation Cardiovascular Interventions, which is one of the daughter journals of the Circulation Family. We publish articles really related to the broad spectrum of interventional cardiology, from coronary interventions to peripheral arterial disease, and Endovascular interventions to structural heart disease interventions. We also published review articles in all of those areas, as well as any health policy or outcomes studies that are in that space.
Dr Amit Khera: Tell us what are some of the innovative things that your journal is doing this year.
Dr Sunil Rao: We're really excited about two things, one is our extremely successful Assistant Editor program that we launched last year at A.H.A. 2018. This is a program where we have five early career individuals that are within five years of completing their fellowship program who joined the editorial team at Circulation Cardiovascular interventions, and in that role they really learn a lot about the mechanics of how scientific publishing works, they commit to doing manuscript reviews, and receive feedback on improving their peer review process, and even independently handles some manuscripts as well, that are in their areas of interest. This is our way, I think, of encouraging the next generation to stay engaged with science, and with the scientific publishing process. It's been extremely successful. Assistant editors are part of our team for a two year term. So, in 2020, we will be selecting the next class of assistant editors, and after their term is ended, they join our editorial board as editorial board members. So, we're really excited about that, it's been an overall positive experience, for I think everybody involved. The second thing that we're really excited about is that we launched a social media presence for the journal, which it previously did not have. So, we have a very active Circulation Cardiovascular Interventions Twitter handle, I encourage all the listeners to join Twitter if you're not on Twitter, and if you are on Twitter please follow at Cirque intervened. It's " at C.I.R.C.I.N.T.V.". That is the official Twitter handle for our journal. Dave Fishman is our social media editor, and Chadi Alraies is our assistant social media editor, and we're not just tweeting out the articles, and providing summaries when the papers get published, we're holding Twitter journal clubs once a month ,and these have been extremely successful, it's an hour long Twitter journal club where the discussion gets very intense, and there's a lot of back and forth. We try to have the authors on as well, so that they can explain the rationale for their study, some of the challenges that they face when they are doing the study, and hopefully provide some implications for clinical practice, and what the next steps are. That's a way for us to engage our readership, it's almost a form of post publication peer review, which I think is becoming very popular. In addition, remember we don't have a print format of our journals, so this is a way to get the readership more engaged with the Web site, and to come to our website and learn what elsewhere publishing, and how they can get involve with the Journal as well, both as authors who submit their work, or if they want a peer review for us, please contact us and let us know.
Dr Amit Khera: I really love hearing about the Twitter journal club, I know that they are well received, and certainly getting a lot of traction. Tell us about what initiatives or topics you're most excited about this year, and maybe some things that are coming later in the year.
Dr Sunil Rao: We're really excited about the big areas in interventional cardiology, which are coronary physiology, we've published quite a few papers on looking at different physiological parameters, and how they can drive the appropriate use of PCI and how that affects outcomes. I think that's going to continue to be a huge topic over the next year, Certainly such a heart disease has exploded, and with the data on low risk patients undergoing TAVR, and having really good outcomes, we're seeing a lot more submissions in the low risk TAVR space, the other area that's really exploding right now is Mitral and Tricuspid Valve Interventions, one of the areas that I think has seen a tremendous amount of device innovation. So, we're seeing a lot of submissions from really high quality papers in that space, but I think it's also important to note, that unlike previous iterations of the Journal, we're actually having a review article, we're trying to have a review article every month on a major area that is burgeoning, so that the readership can understand the overall lay of the land, with respect to evidence, how that guy's clinical practice, and what's coming next. So, we've published quite a few review articles already, and there are more to come, and I think that's a really important way for the readership to keep current with what's going on in Interventional Cardiology.
Dr Amit Khera: What about the advancing aspects of your subspecialty? There's so much going on in interventional cardiology, it's a bit dizzying, just tell us a little bit about some of the ways that your journal's helping advance that mission, not just now but perhaps in the future.
Dr Sunil Rao: I think one of the challenges that we have at Interventional Cardiology, and maybe this is true across Cardiology, is that the evidence is developed very rapidly, and oftentimes it almost seems like the field is lurching back and forth in certain areas, a prime example of that is the drug coated balloon controversy for Peripheral Interventions. The Journal Of The American Heart Association published a meta-analysis, showing that there may be an association between the use of these devices and increased mortality, that has led to a lot of discussion in the interventional community, and quite frankly I think there's a fair amount of confusion out there about whether we should be using these devices, should we put a moratorium on these devices, is the signal real, if it is, what's the mechanism of death. So, a lot of conversation around that, in fact, it's led to what's going to be a focused FDA meeting in June, specifically on the drug coated balloon controversy. Where I see our journal playing a role is really in trying to, not only publish the latest science, which is rigorous in the field for controversial topics such as this, but also to help provide some context for that science, and I think our integrated strategy of original science review articles, and social media really helps us to communicate with the readership, and with the Interventional Cardiology community writ large, meaning not just physicians, but also Cath lab staff, nurses, noninvasive cardiologists who obviously have patients who are undergoing interventions, and even policymakers, to keep them abreast of what's going on, so that they can have the same level or base of knowledge, so that the conversation is on a level playing field.
Dr Amit Khera: Okay, well you heard it from Dr Sunil Rao. Thank you for your time.
Dr Kiran Musunuru: I'm Kiran Musunuru, I'm the outgoing Editor-in-Chief of Circulation Genomic and Precision Medicine. Let me start by saying a little bit about the content of the journal, it considers all types of articles related to, as the name implies, Genomic and Precision Medicine, and more specifically, Clinical Genetics, the molecular basis of complex cardiovascular disorders, considered at a variety of levels, that can include a lot of different, what we would call Omics Techniques, from Genomics to Transcriptomics, Proteomics, Metabolomics, Metagenomics, and, so forth. It also deals with big data applications, that includes Electronic Health Record Data, Patient generated data combined with any of the things I've already mentioned, Genome Wide Association Studies, Pharmacogenomics, Gene Therapy, Therapeutic Gene Editing, Systems Biology. So, it's a pretty comprehensive look at all the various topics that would fall under the rubric of Genomic and Precision Medicine.
Dr Amit Khera: Now, Dr Musunuru, you mentioned the outgoing Editor-in-Chief, let's introduce the incoming Editor-in-Chief, Thatcher Christopherson Semsarian.
Dr Chris Semsarian: I'm the incoming Editor-in-Chief. My name is Chris Semsarian, I'm a cardiologist at the Royal Prince Alfred Hospital in Sydney, Australia.
Dr Amit Khera: What are some of the innovations you and the Journal are doing this year, or, what are some of the things you see coming in the future?
Dr Kiran Musunuru: Something I'm very excited about, is that we are just starting a pilot project with the American Heart Association's Institute for Precision Cardiovascular Medicine. The institute has a very nice platform called the Precision Medicine platform, and, in brainstorming last year, we realized there was a very nice opportunity to try to create a new type of journal article. There's also a big move in science nowadays to improve transparency, and rigor, and reproducibility, especially in science. The idea being that ideally other investigators should be able to take one team's work, and be able to run through the entire analytical process, and reproduce the original findings, and perhaps even find ways to improve upon those original findings, and, so we realized working with the institute's Precision Medicine Platform, we had the opportunity to actually make a new type of article, we think of, as the paper of tomorrow, a virtual article. The idea would be, that we would have primary data on the Precision Medicine Platform, the analytical tools used to process the data would also be on the Precision Medicine Platform, the analytical plan, in the form of a so-called Jupiter notebook, that basically takes people step by step through exactly which tools were used in which order, in which way, with which parameters, would be on the Precision Medicine Platform, and then there would be some verbal explanation, some background, to explain the context of these analysis, and to really put it into perspective, as how it fits into the body of literature, and so the idea would be, this would live on the Precision Map Platform in a virtual format, and then anyone else who is interested in this work could come, and actually directly interact with the data, and the tools, and the analytical plan, and could actually rerun the entire papers work from scratch, thus reproducing it, and then could actually tweak the analytical plan, or install tools of their own, and be able to build upon the work that had already been done. It's a very different way of thinking about journal articles, more as living entities rather than static work that just lives on a page, and is there as reported, and then never has an opportunity to be fully produced or improved upon.
Dr Amit Khera: There's so much happening in the space of genomics, and obviously, we hear the word "Precision Medicine" so commonly. Tell us a bit about how your journal in specific is advancing the mission of your area.
Dr Kiran Musunuru: I'll say a little bit, and then maybe turn it over to Chris, give his perspective as the incoming Editor-in-Chief. I think it's a vibrant field, but it's also a very new field, it's evolving rapidly, and I think the Journal has a very important role to play, and not only reporting the results that are coming out of studies in this field, but actually having a role to play in helping to shape the field, helping to define the field, it's very exciting, it's very much in rapid evolution. Just ten years ago or so, when the Journal first started, we were just starting to see the first Genome Wide Association studies, and now we've gone so far beyond that.
Now, again, we're talking about these large bio banks, we're talking about Precision Medicine, we're talking about applying this information in health care, we're talking about combining all of these various streams of data and many levels to be able to do studies, that are, I would even say, exponentially advanced beyond what we able to do just ten years ago, and so, it's very exciting times for the journal, then maybe I can ask Chris to share his thoughts on that.
Dr Chris Semsarian: Yeah Kiran, I mean, it's a great honor system to follow in your amazing footsteps, and what you've done for the Journal, and as the incoming Editor-in-Chief, I really want to sort of try, and build on the platform that you've established over the last few years, and really, one of the areas that I'm particularly interested in is the area of Translation of Genomic Findings. I mean, ultimately what we do in our lives, as clinicians, is to help patients improve diagnosis, to improve the treatment of these patients, and to be able to do studies with very basic understanding of how our genomes work, and how Narcotic Genes interact, and translating those findings into these improved diagnostic approaches, and even in guiding management is really exciting, I think, in terms of clinical medicine, and improving patient care as we look ahead. I really want to be able to continue to publish really, state of the art, novel, innovative, research areas, that you've already covered, Kiran, which would lead to better care of our patients, who are ultimately the beneficiaries of this type of amazing work.
So, I'm really excited looking at the Journal, it's a tremendous area of interest and research, where there's twenty-two thousand genes approximately now genomes, and we really don't understand most of them in terms of their intricate function, and I figured it's a great time ahead, in terms of Precision Medicine.
Dr Amit Khera: Okay, well, that was Dr Kiran Musunuru, and Christopher Semsarian, we appreciate both of your time today for Circulation on the Run.
Dr Paul Wang: I'm Dr Paul Wang, I'm the Editor-in-Chief of Circulation Arrhythmia and Electrophysiology. Our Journal covers really the expanse of our field, going from basic mechanisms of arrhythmias, so very basic science work, to really clinical practice, clinical outcomes, to population based studies, and genetic based considerations in our field. So, we really feel we encompass the entire range, and there really isn't any topic within our area, that we don't feel is outside our realm.
Dr Amit Khera: I know there's so many innovative things you're doing, Dr Wang, with your journal. Why don't you tell us a little bit about your plans for this year.
Dr Paul Wang: We've been excited; our team has been at the Journal for two years now, and we focused on a number of different areas. So, I think one of our biggest advances, and we've tried to be more responsive to the authors, so we've really reduced the time to first decision very substantially, from over twenty days, to ten days or less, I think we hit a record of 7.8 days in the journal. So, really, we hope we're more responsive, we've involved the editorial board, we've substantially expanded it, so that more of our reviews of greater proportion going to our editorial board, which is a really fabulous, internationally recognized group, with really high quality reviews, so we've been very pleased, with both a level of science that we've received, as well as the level of the reviews that we have. One other area is, we really want to make sure that the reviewers, who do much of the heavy lifting, in addition to our editors for The Journal, and so we've established a new Reviewer Recognition Award System, they can be designated as silver, gold or platinum, and we've reached out to department chairs, or their deans, and recognizing that they won this prestigious award for their performance, and great work with the Journal, so there are a number of different things that, in fact, we think we've made some advances in, the other areas are really that of extending our reach, and so, one of the things we concentrated on, initially with the adding of podcasts, so we do that monthly.
All the articles are now available in review, and then what we're starting at our new initiatives is, we'll be starting a Twitter Journal Club. I've been recording at least two of our articles, as the interview with the authors, and then we're going to be having a journal club, in which we will have the opportunity for people around the world to comment, and have a discussion that will really be exciting, we think. So, there are a number of other areas that we're thinking about, in terms of that kind of work.
Dr Amit Khera: The field of Electrophysiology seems to be changing by the day, maybe you can tell us a little bit, about how the journal is advancing the mission of the field of electrophysiology.
Dr Paul Wang: So, one of the things that we focused on is the role the Journal can play, in terms of connecting with other elements of our field, and one of the ways that we've really concentrated on is, in particular, working closely with the American Heart Association, and its committees. We're related to a number of committees, but particularly, there is a committee on Electrocardiography, Electrophysiology, part of the Clinical Cardiology Council, and so, we work very closely with that group, and, in fact, we've invited that group to create proposals for a number of review articles, state-of-the-art reviews, that we hope will come out in the next year or so. The ways in which we can tie together our committees to AHA overall, I think, is really the direction we're looking for our journal, and we feel we can play a very novel, and innovative role in that regard. We, for example, also reached out to the American Heart Association funded researchers in our area, and invited them to participate in the journal, participate in our committees, become fellows or FAHA's of the American Heart Association, so we really want to create this family, a real community, and sense of community, that we hope will stem from the Journal. So, we're very excited about the future, and what we might be able to achieve together.
Dr Amit Khera: Thank you so much, Dr Paul Wang for your time today, and we appreciate your insights on Circulation, Arrhythmia and Electrophysiology.
Dr Nancy Sweitzer: Hi, I'm Nancy Sweitzer. I'm the Editor-in-Chief of the Journal Circulation Heart Failure. At Circ Heart Failure, we deal with all things related to heart failure. Heart failure is an expanding specialty, relatively new subspecialty in cardiology, and we're very interested in the physiology, and mechanisms of heart failure, as well as treatments of heart failure, and the innovative evolution of the specialty which includes Advanced Hemodynamics, Mechanical Circulatory Support, and transplant as therapies, as well as all Implanted Device Therapies, and new, and Innovative Pharmacologic, and Gene Therapies as well.
Dr Amit Khera: Tell us a bit about initiatives, or features in Circulation Heart Failure, that you're planning on tackling not only this year, but into the future.
Dr Nancy Sweitzer: The effort we're most excited about at Circulation Heart Failure has been ongoing now for a little over a year, but continues, and is really focused on the emerging scientists in the Heart Failure Space; we call it our "Featured Emerging Investigator Spotlight", and this spotlight focuses on authors of manuscripts, who are within ten years of their terminal training, and can take full responsibility for the content of a manuscript. When we publish a featured emerging investigator article, which we've done more than half of the months since launching the feature in late 2017, we schedule a Twitter Journal Club with that author, where we participate, over the course of several hours, in pretty intensive conversation, about not only the science, but career development in Heart Failure Space, the importance of mentoring, and sponsorship obstacles that people are facing in development as physician scientists or scientists, and insights they may have into fostering success in the Heart Failure Space. This has been a great feature, we launched it because we feel that the emerging scientists, in the Heart Failure Space, need a virtual community in those critical years, before you have a lot of resources to start traveling, and setting up a network that's based on personal interaction, and we felt that, the modern era of social media was perfect for this. We found our emerging investigators are getting to know one another, they participate in one another's Journal Clubs, the Journal Clubs are incredibly fun, and interactive and we're getting a lot of Twitter engagement from the Heart Failure Community, there's a lot of "Twitteratti" in Heart Failure that really are engaged, and engaged with the Journal, which has really been fun for all of us, I think, so that's the thing we're most excited about.
Dr Amit Khera: It's really wonderful to hear how you're spotlighting authors in creative ways. Tell us a bit about how your journal is advancing the mission of Heart Failure and Transplantation.
Dr Nancy Sweitzer: I see the journal as central to advancement of the subspecialty, as I mentioned earlier, Heart Failure is a relatively young subspecialty in the United States, we received a CGMC designation as a subspecialty just in 2008, just eleven years ago, and it's been a board certifiable subspecialty only since 2014. So, we're very young, and I think really developing into our own. We've seen tremendous growth in the number of people seeking subspecialty training in Advanced Heart Failure and Transplant Cardiology, and we are really enjoying helping the Journal evolve with the specialty, as it evolves, and that's happening very actively right now. So, I think what Heart Failure is in 2019 is different than what it was just five years ago in 2014. We're doing a lot more ,as I mentioned, Complex Chemo Dynamic Thinking, thinking about the path of physiology in our patients, and how we can target that effectively, not only with existing therapies, but with strategies, and, as I mentioned, the burgeoning growth of Mechanical Circulatory Support, and support devices, which the field has embraced quite actively, and The Journal is increasingly publishing content in these spaces, as well as the spaces of Advanced Heart Failure, but, I guess also, we're interested in every aspect of Heart Failure, from Complex Multidisciplinary Care Management, to Palliative Care, to the interaction of the heart with other organ systems, and Heart Failure such as the brain, we have a paper on Cognitive Function Abnormalities, and Heart Failure in this month's issue. So, the interaction with the brain, the kidney, the liver, many other organs, that are affected when the heart becomes quite ill with Advanced Heart Disease. So, basically we're interested in everything that touches Heart Failure Development Care, and treatment of patients with Heart Failure, and particularly we're interested in the newest and latest. We love publishing, and some of our highest impact papers in the last couple years have been new therapies, just being tested for the first time in patients with heart failure. Small studies that may not have large impact in terms of heart outcomes, but where we're learning about the pathophysiology of the disease, and new treatments, that's really exciting to us. We've published a couple of methods papers in the last year, really innovative models. One describing a model of pacing in mice, which has been a really challenging thing to do in Heart Failure, but several groups have now developed Tachycardia induced Cardiomyopathy models in mice, which is important for rapid discovery work, because mice have such a short reproductive span, and can be genetically altered, and then a recent publication on the methods paper, looking at a new initiative by the FDA, to potentially approve therapies based on patient reported outcomes, rather than just heart mortality and morbidity outcomes, so we're really excited about the innovations, and the Heart Failure Space, the work that describes where we're going as a field and as a profession. You'll see some features coming up in the journal, from opinion leaders across the globe on where this specialty sits in 2019, and where we, as the leaders in the field, can guide it as we move into our next decade, and I think that some of the most exciting work the journals doing.
Dr Amit Khera: Thank you, Dr Sweitzer. We really appreciate your time today for the podcast, and your insights on the Journal.
Dr Robert Gropler: Good afternoon, I'm Rob Gropler. I'm the Editor-in-Chief of Circulation Cardiovascular Imaging. It's one of the journals within the family of Circulation Journals, and our focus is really on being the most influential source of leading edge imaging sciences, as it relates to transforming cardiovascular care, so what that means is, that we're interested in all imaging studies that are applied to the care of the cardiovascular patient, and although our primary focus is really on clinicians, and researchers, but we also want to expand our viewership, if you will, to anyone who is interested in how imaging is used to understand Cardiovascular Medicine, and to treat patients with Cardiovascular Disease. So, we are edged in all forms of imaging, this can be from MR, to echo, to nuclear, to CPT, to optical imaging, it involves all types of disease, ranging from Congenital Heart Disease, up to diseases in the elderly, it also involves not just it is in humans, but also understanding disease in the preclinical space, particularly as it helps us understand new technologies that may ultimately reach human use, either for investigational purposes, or ultimately, to be used in the treatment of a patient with Cardiovascular Disease.
Dr Amit Khera: What are some innovative things you and the Journal are planning for this year?
Dr Robert Gropler: We're doing quite a few things. One of the first things we did, as you know, were relatively new, where we've only been an editorial team, if you will, for one year. One of the major efforts has been to increase our presence, in terms of digital media strategies, across the board. And so, this meant expand our Twitter presence, if you will. It also meant increasing our offerings in that digital space by, for example, having a journal club, what we would do is on a every other month basis, discuss a paper we published that's of significant interest via Twitter. And it would involve the authors, the associate editors who actually manage that study, as well as the editorialist who wrote about that study, and it leads to very unique insights into how that paper is being viewed by the scientific community at large, and also potentially how that information will be implemented in terms of transforming clinical care.
We've added what we call a teaching file. If you think about imagers, imagers learn by seeing images. And the more they can see images, put them in the context of clinical cases, the more they understand what an image means when they see it. So, what we do now is we accept a large number of what we call imaging cases. These are specific unique cases that have a history, and then a short write up about them.
And those are gathered each month, but then they're downloaded into a file. And then, anyone with access to the Journal can then look at, use to learn from, to potentially use for talks to enhance their own education the education of others. And we have found that to be, again, another offering that our readers particularly like.
Dr Amit Khera: And how do you see Circulation Cardiovascular Imaging advancing the mission of imaging, which seems to be ever-expanding, and ever-growing?
Dr Robert Gropler: We're really in the education business. And what that means is that we're educating at a multi-scale level. Just educating a practitioner on what technology can do, how it's helping cardiovascular medicine, yes, that's important. But what we're also doing, is we're educating the scientists as to here as some of the new findings that were coming out because of imaging. And then that, in turn, will help direct them or signal them as to where is the science leading them, and what should be their next steps?
We're also educating the general public as to what can imaging do, and how does imaging change cardiovascular medicine for the better, and what they can expect from that. And we're also educating the regulatory bodies, if you will, that determine what imaging can be done in the clinical environment and so on, and the importance of these imaging techniques.
So number one, I think we always have to maintain that focus, as to that's our goal. Now, that being said, I think the question becomes how do you convey that concept? And where we have to continually evolve.
And I think they were very smart years ago to make it a digital-only journal, as opposed to combined print and digital. So, I think that was actually very savvy. But the digital net component now has to expand. And that means our offerings have to reflect not just that people learn in different ways, that is, we have to have not just, if you will, a didactic or print equivalent component of a paper. But it also should be audio-based, such as this podcast. But they also need to be varied as in terms of the types of offerings, and their brevity or length, if you will.
Dr Amit Khera: Thank you, Dr Robert Gropler, the Editor-in-Chief of Circulation Imaging. We really appreciate your time today.
Dr Robert Gropler: Thank you very much. You have a great day.
Dr Amit Khera: Well, I'm sure you enjoyed this as I did. We really got incredible insight from the Editors-in-Chief of our Circulation family of journals. We learned so much about the broad array of subspecialties that they cover, and all the exciting and innovative things they're doing to really advance the missions of their fields, and also for the authors and for science.
Well, again, I'm Amit Khera, associate editor from UT Southwestern, Digital Strategies editor for Circulation. And next week, you'll have your usual hosts, Carolyn Lam and Greg Hundley.
Dr Carolyn Lam: This program is copyright American Heart Association 2019.
Dr Gregory Hundley: Welcome everyone to the June 18th edition of Circulation on the Run. I am Dr Greg Hundley, Professor of Internal Medicine and Director of the Pauley Heart Center at VCU Health in Richmond, Virginia.
In today's issue we're deviating from our common format due to some scheduling difficulties. So, rather than our traditional coffee chat in this program I'm going to have a large gulp of coffee and present results from several exciting papers. Then we'll turn over the second half of our program to Dr Carolyn Lam for our feature discussion.
Now, I promise this is a one-time deviation and we will return to our common chat format in early July. But, before I launch into my presentations I did want to introduce what will transpire with Carolyn. She will be discussing an exciting paper from the Adelaide Medical School at the University of Adelaide in Australia.
Some have wondered whether the persistence of a patent arterial venous fistula post-kidney transplant may contribute to ongoing maladaptive cardiovascular remodeling. To address this issue Carolyn will be discussing with authors whether ligation of this AV fistula may reverse this maladaptive remodeling. And like you, I'm excited to listen to that discussion. But before that let me review several of the other distinctive papers on this issue.
The first one is entitled “Individual Treatment Effect Estimation of Two Doses of Dabigatran on Stroke and Major Bleeding in Atrial Fibrillation.” They are the results from the RE-LY trial. The corresponding author is Professor Frank Visseren from the University Medical Center of Utrecht in Utrecht University.
The study emanates from the randomized evaluation of long-term anticoagulation therapy or the RE-LY trial. In which high dose dabigatran, that's 150 milligrams twice daily, was found more effective in prevention of ischemic stroke and systemic embolism than low dose dabigatran which is 110 milligrams twice daily.
But this occurred at that expense of an increased risk of gastrointestinal bleeds. Importantly however, the absolute treatment effect of dabigatran in both doses, likely differs between individuals. And therefore, individual treatment effect estimation has the potential to identify patients who have a favorable trade off and absolute benefit and harm from dabigatran compared with no treatment, and to select the optimal dose for each individual patient.
So in this study, the investigative team derived and validated a prediction model for ischemic stroke and systemic embolism and major bleeding in patients with atrial fibrillation from three treatment arms of the RE-LY study. They had 11,955 individuals in the derivation cohort and 6,158 in the validation cohort. And they evaluated the patient characteristics of sex, age, smoking, anti-platelet drugs, prior vascular disease, diabetes, blood pressure, estimated glomerular filtration rate, and hemoglobin.
Dr Gregory Hundley: Well, what were the results? Well the five-year absolute risk reduction, for ischemic stroke and systemic embolus minus the five-year absolute risk increase for major bleeding, when comparing the high to the low dose of dabigatran yielded a net benefit in 46% of patients. And therefore, the authors conclude that the absolute treatment benefits and harms of dabigatran in atrial fibrillation can be estimated based on readily available patient characteristics.
And perhaps down the road such treatment effect estimations can be used for shared decision making before starting dabigatran treatment and to determine its optimal dose of administration. Well, how 'bout that? And let's go on to the second paper entitled “Empagliflozin and the Risk of Heart Failure Hospitalization in Routine Clinical Care: A First Analysis from the Empagliflozin Comparative Effectiveness and Safety, or EMPRISE Study.
And the corresponding author for this study is Elisabetta Patorno from Brigham and Women's Hospital in the Harvard Medical School. So, as a background in a different study to this, the EMPA-REG OUTCOME trial showed that Empagliflozin an SGLT2 inhibitor was found to reduce the risk of hospitalization for heart failure by 35% on top of standard of care in patients with Type 2 diabetes and established cardiovascular disease.
Well, the current study, The Empagliflozin Comparative Effective and Safety or EMPRISE Study was designed to assess empagliflozin's effectiveness, safety, and health care utilization in routine care from the period of time between August of 2014 through September of 2019. And the author's report on the first interim analysis in which they investigated the risk of hospitalization for heart failure among Type 2 diabetic patients initiating empagliflozin vs. sitagliptin.
The investigators used two commercial and one federal Medicare claims data source from the U.S. and identified a one-to-one propensity score matched cohort of 16,443 pairs of Type 2 diabetes patients that were greater than 18 years of age initiating empagliflozin or sitagliptin. The average age of the participants was approximately 59 years.
And almost 54% of the participants were males and approximately 25% had records of existing cardiovascular disease. So compared to sitagliptin the initiation of empagliflozin decreased the hospitalization for heart failure risk by 50% over a mean follow-up of 5.3 months. And the results were consistent in patients with and without baseline cardiovascular disease for both the empagliflozin 10 milligram or 25 milligram daily dose. Or analysis comparing empagliflozin vs. dipeptidyl peptidase-4 inhibitor class all comers.
Thus, in conclusion, in this first interim analysis from EMPRISE, the investigative team showed that compared with sitagliptin the initiation of empagliflozin was associated with a decreased risk of hospitalization for heart failure among patients with Type 2 diabetes as treated in routine care with and without a history of cardiovascular disease.
Dr Gregory Hundley: Well, now we're going to turn our attention to red meat. And this next study was entitled, The Consumption of Meat, Fish, Dairy Products, Eggs, and Risk of Ischemic Heart Disease. It's a Perspective study of 7,198 incident cases among 409,885 participants in the Pan European Epic Cohort. And the corresponding author is Professor Timothy Key from The University of Oxford.
Some of the background here, met analysis of previous prospective studies have suggested that intake of processed meat maybe associated with a higher risk of ischemia heart disease whereas, unprocessed red meat might not. For dairy products and eggs, systematic reviews of prospective studies have reported no consistent evidence that higher intakes are associated with a higher risk of ischemic heart disease.
Other studies have shown that fatty fish consumption may reduce the risk of ischemic heart disease, it is a rich source of long chain N3 fatty acids. And meta-analysis has suggested even an inverse association between overall fish consumption and mortality from ischemic heart disease.
So, hear in this cohort: we're going to evaluate all of these. Accordingly Key, and his co-authors report the relationships of these foods with risk of ischemic heart disease in the European prospective investigation into cancer and nutrition, the EPIC study, and that again is a cohort of a half million men and women from nine European countries followed for 12 years to examine the association between the intake of animal foods and the occurrence of ischemic heart disease.
The author's found that higher consumption of red, unprocessed and processed meat was positively associated with the risk of ischemic heart disease. None of the other animal foods examined were positively associated with this risk. And intakes of fatty fish, yogurt, cheese and eggs were modestly, inversely associated with the risk.
In addition, the red and processed meat were associated with plasma non-HDL cholesterol and systolic blood pressure. And this finding is of interest as possibly these other variables could serve as mediator of the association between red or processed meat and future ischemic heart disease. It is important to note that while these results are of interest to those concerned with the future adverse cardiovascular effects related to the consumption of red meat, one cannot infer causality and other studies would need to be designed to address causal relationships.
The last paper that I'm going to present during the coffee gulp, emanates from the basic science arena. And it is entitled The “Shear-Induced CCN1 Promotion of Atheroprone Endothelial Phenotypes and Arthrosclerosis. And the corresponding author is Dr Fan-E Mo from the National Cheng Kung University College of Medicine.
Dr Gregory Hundley: The matricellular protein CCN1 has been implicated in arthrosclerosis based on its expression in arterial segments with evidence of arthrosclerosis. And this study evaluated the relationship between sheer stress, both laminar and oscillatory at the site of atherosclerotic liaisons and molecular markers of pathophysiologic process involved in the progression of arthrosclerosis.
The authors found that sheer induced CCN1 and its receptor integrin, alpha six, beta one, instigate atheroprone phenotypic changes in endothelial cells via activating NF kappa beta. Because the activation of NF kappa beta further up regulates the expression of CCN1, alpha six, and beta one, atheroprone flow creates a positive feedback to sustain atherogenesis.
In addition, disrupting CCN1, alpha 6 beta one engagement by a specific CCN1 mutation, or by a peptide antagonist unhindered atherogenesis in mice. So what are the clinical implications of these findings? That's something Carolyn would ask me. Well, it appears that CCN1 alpha 6 beta one engagement represents a novel therapeutic target for arthrosclerosis.
These data demonstrate a causative role of CCN1 in atherosclerosis via modulating endothelial phenotypes. And CCN1 binds to its receptor integrin alpha 6 beta one to activate NF kappa beta, thereby instigating a vicious cycle to persistently promote atherogenesis. Perhaps in the future T1 me medics may further be optimized to treat arthrosclerosis.
Well everyone, that concludes the first portion of this June 18 edition of Circulation on the Run and now it's time to move on to Carolyn's discussion of our featured paper.
Dr Carolyn Lam: Cardiovascular disease remains the major cause of death in kidney transplant recipients. And today's featured paper has important implications for the management of this cardiovascular risk following kidney transplantation. I'm so excited to be discussing it, and I'm going to let the corresponding author Dr Toby Coates from Royal Adelaide Hospital tell us all about it, and so happy to also welcome our editorialist Dr Patrick Mark from University of Glasgow.
Toby, could you please tell us what inspired you to do this remarkable study?
Dr Toby Coates: We're very interested in obviously our patients surviving as long as they possible can after kidney transplantation. And we noticed that many of them having had a successful kidney transplant, still had functioning AV fistulas. Now of course the AV fistula, is a connection between the artery and the vein that enabled us to access the circulation after hemodialysis. Which around the world is probably the most, is the most common form of dialysis practice performed.
So many of these patients sustained 20 years down the track after successful transplants still had these very large functioning left to right shunts, on the basis of their dialysis history. So we had a couple of patients who developed quite severe cardiac failure and we noticed that when we ligated the AV fistula, their back got dramatically better.
So, as a consequence of that, we went to look at the ligature and we couldn't find any randomized control trial that told us what the best thing was to do, post-transplant with these fistulas. So we decided that what we would do be use the state of the art cardiac magnetic resonance imaging, or cardiac MRI to assist the cardiac function with myocardium thickness in our patients and then randomize a group of stable transplant patients to ligation or not.
And then follow that up with cardiac MRI six months down the track to see what happened. And so that was the basis of the study that we performed. The first randomized controlled trial of the effect of ligation of the AV fistula on the left ventricular mass, that was the prominent one for trial.
Dr Carolyn Lam: You know, Toby, just to let you know right there, I thought it was so incredibly novel. So I'm a heart failure specialist and we know that shunts are associated with high output cardiac failure, and yet, I personally had never questioned this, so I thought this is incredibly novel and it's important. But please, tell us all about the results.
Dr Toby Coates: We were delighted to say that there was a very significant reduction in the left ventricle mass. In fact, the main decrease was 22.1 grams compared to the control arm in whom the cardiac mass actually went up 1.2 grams. So, then we mobilized the body surface area, the reduction of the left ventricular mass index dropped by 11.8 grams per metered square.
Now, this is quite remarkable for me doing the study because I've never seen an intervention, I've never seen an intervention where every single patient improved with the ligation, every single patient there was an improvement in the cardiac parameters. Never seen anything like it in the pre and post of the ventricular mass it really came down. So that was quite remarkable.
And the second thing that really impressed me at the time, was the improvement in the BMP's, and we measured the brain maturated peptide, and being a methodologist that's clearly something that's of interest to us and we saw a substantial reduction. It's statistically significant reduction in BMP as well.
The patient themselves, some of them recorded quite significant improvement in exercise tolerance afterwards. And we had, as I mentioned before in a couple of patients, not in the study but outside of the study, subsequently when they're presented with profound right heart failure, the ligation of the AV fistula made a huge difference to them symptomatically.
So that was sort of confirming all of the things that we thought along the way. Pleasingly we didn't see any change in kidney function. So, we were concerned that there might have been on the basis of some non-controlled studies in the past, that there might have been a deterioration in the estimated glomerular filtration rate, or eGFR. We didn't see that.
And we didn't see any significant change in the blood pressure either. Which is some of us have previously reported. Closing the fistula itself, is a very trivial procedure. It's usually done as an outpatient, so a day procedure. So it's not resulting in coming to the hospital. And the only complications, really were lots of local redness and some pain, potentially from the fistula where in the ligated.
So, we thought this was remarkable. An outpatient procedure that could significantly reduce the left ventricular mass by 22.1 grams over the six month period that was associated with minimal side effects and complications. And when you think about that, that's sort of equivalent really to taking an anti-hypertensive medication for six months. That magnitude of reduction with ventricular mass which clearly from the patient's point of view is much preferable to adding more medication to an already over-burdened tablet loading in your patients with kidney transplants. So we were very pleased with that result altogether.
Dr Carolyn Lam: Thank you Toby, and we in turn were very pleased to be publishing this in Circulation. Likewise, Patty, if I may, I love your editorial. First, let me tell everybody who's listening out there. Go pick up the editorial and look at the figure. It is so cool. It shows pros and cons of arterial venous fistula ligation in these patients. But could you please share some thoughts Patty? I mean you covered the perspective just so well.
Patrick Marks: I must give the credit to my co-author who actually drew the figure himself. So Chris Eaves rather myself. We were really impressed with the study and we're really delighted to write an editorial for it. It's just one of those studies that I have to say, you know, you kick yourself and you wish you'd done it. With all the world of observational data showing that creation of a fistula appears to be associated with an increase in LV mass obstruction by echo and angio and bicartic MR in smalls studies.
But it's taken a long stat to move from that to actually doing a randomized control of ligating the fistula in people with you know, stable functioning transplants. We were really, really impressed with Toby and his team for undertaking this study. And until we'd gone through the results, they're really very impressive.
The magnitude of reduction LV mass is very impressive and also the changing BMP was really nice to see. One of my comments of the study were, was interesting because as methodologists we are aware of the idea arteriovenous fistula as being the axis for dialysis. And we sometimes feel uncomfortable by ligating this because we know if the transplant was to fail, how much patients need a functioning fistula. And that's the one thing I'm still curious, like and I still offered some comments in the editorial were, that while there's doubt that the cardiovascular benefits demonstrated by Toby's study are really very impressive.
I wondered about the implications out with the study came down the line, you know would there be some of these patients whose kidney transplant function would decline? And there may be regret of losing the access. We mentioned there is some inconvenience, it is an operative procedure to loosen the fistula. So there are some things to think about in the study, but overall, I can't help saying just how impressed I am that they managed to do this trial in a proper randomized, controlled trial form. It's really, really impressive in using the cardiac MR endpoint is it seems quite a secure way of assessing this.
Dr Carolyn Lam: Those are great points, Patty. Toby, any response to that.
Dr Toby Coates: Look it's really very interesting as a transplant pathologist for the last 20 years, one of the biggest, I guess it's a bit of a misconception. When a fistula has been present for 10 or 15 years and still there to come back and try and reuse it for dialysis access after that period of time, in my experience anyway, also very difficult to reuse those fistulas and the surgeons end up having to create a new one anyway.
They frequently become quite aneurismal, they get very large and unsightly and the volume of the shunt is significant and often we find that as an access they don't work as well. So I personally don't have a huge concern about closing them. Now I agree with you, these patients were stable, longstanding and we assessed that the risk is, we need to go back onto hemodialysis was small.
But you are absolutely right, I mean, it is possible that something could have come out of the blue and maybe a patient would be disappointed that that access that they'd had for so many years was no longer available. So that is, the caveat on the study, but thankfully so far out, some of these patients five or six years down the track, we haven't had anybody need to go back on dialysis, so it's been good.
Dr Carolyn Lam: Yeah, it really says to me as well, that patient selection is important exactly like you emphasized, and you, in the editorial Patty. But from a cardiology standpoint, too, are there plans to perhaps do studies with hard, clinical endpoints? What do you think are the next steps? Maybe I'll let Toby go first, then Patty.
Dr Toby Coates: We think now with this study done, the next thing is to have a larger study with significant cardiovascular endpoints. Which I obviously would be cardiac failure and acute coronary events. So the two things that would seem in my mind, and I think that needs to be multi-centered, preferable international if we can.
And one of the really positive things about the highlight from the American Heart Association is that we've had people reach out to us from France and all around the globe saying that they'd be interested in participating, you know in a multi-centered trial. So, I think that's what we need to do, and clearly you don't it’ll have to be a constant endpoint, or not. I'd be interested in Patty's thoughts about that, right if you had some guidelines and some suggestions.
And then obviously would be randomized, controlled trial looking at those hard endpoints with probably some sidearms doing cardiac MRI as well, and potentially more heart functioning tests. So yes, I think this is just the beginning, we do need a hard endpoint trial to really nail this completely.
Patrick Marks: Yeah, I'll just come in there and just come on to that Toby. I completely concur with what you said. I think there's been quite a provocative editorial a few years back, and suggesting that while there's lots of studies in chronic kidney disease, end stage renal disease, kidney transplant patients avoid LV mass, really it hasn't yet been translated into actually leading studies in the integration of LV mass and end stage renal failure haven't really yet translated into mortality benefits.
And I think we need to move to a bigger study. It's really beautiful that you've been able to demonstrate LV mass falls naturally with ligation. And it's impressive that it just happens so consistently across your population in the intervention arm. But we need to move on to a longer trial with hard clinical endpoints. Certainly heart failure, certainly cardiovascular mortality, [be]cause there's plenty of reasons to believe that producing LV mass in these patients might have benefit both for heart failure, whether that's heart failure, heart injection fraction, or whatever, I'll leave that to Carolyn's judgment to help us with that.
But also, if we can reduce LV mass and then we may be able to reduce arrhythmia burden which again is when these things we worry about in end stage renal disease, again, your answer for that is, that in addition to the heart endpoints you should be able to also add in some patient afforded outcomes in a larger study. Or something like an exercise tolerance quota of quality of life.
All this has started has journey from the surrogate endpoint of left ventricular mass into a bigger outcome study and I can't wait to see how you get on with it.
Dr Carolyn Lam: I can't wait either. And I'm sure the audience is sharing all our enthusiasm as well. Thank you so much Toby and Patty. I really learned so much. You heard it right here on Circulation on the Run. Thank you for joining us this week. Don't forget to turn in again next week.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summery and backstage pass to the journal and it's editors. We're your co-hosts, I'm Doctor Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Gregory Hundley: And I'm Doctor Greg Hundley, Associate editor for Circulation and Director of the Pauley Heart Center at VCU of Health in Richmond, Virginia. Well Carolyn, in the second half of our feature we're going to discuss a randomized clinical trial in lower risked surgical patients related to, the five year clinical echocardiographic outcomes from aortic valve intervention. So Carolyn, do you want to go first this time and discuss on of your favorite papers?
Dr Carolyn Lam: Absolutely! So, are Cardiac Troponin T and I equivalent measures of cardiovascular risk in the general population? Well that's the question Doctor Paul Welsh and colleagues from University of Glasgow aimed to look at. They wanted to compare and contrast the associations of Cardiac Troponin T and Cardiac Troponin I with cardiovascular disease and non-cardiovascular disease outcomes, and also determine their genetic determinants in a genome wide association study involving more than nineteen-thousand, five hundred individuals in generation Scotland, Scottish family health study.
Dr Gregory Hundley: How about that. So this is kind of interesting. So most of us kind of use these two chests interchangeably Carolyn, and I think, I guess we'd consider them to be almost equivalent. So are you going to tell us that they are the same?
Dr Carolyn Lam: Ah-hah! So this is what the authors found. Both Cardiac Troponins T and I were strongly associated with cardiovascular risk, however, Cardiac Troponin I but not T was associated with both myocardial infarction and coronary heart disease. Both Cardiac Troponins I and T had strong associations with cardiovascular death and heart failure, however, Cardiac Troponin T, but not I was associated with non-cardiovascular disease death. They also identified five genetic loci in fifty-three individuals snips that had GWAS significant associations with Cardiac Troponin I and a different set of four loci of four snips for Cardiac Troponin T.
So, the upstream genetic causes of low-grade elevations of Cardiac Troponins I and Cardiac Troponin T appear to be distinct and their associations with outcomes also differ. Elevations of Cardiac Troponin I are more strongly associated with some cardiovascular disease outcomes whereas Cardiac Troponin T, is more strongly associated with the risk of non-cardiovascular disease death. These findings can help inform selection of an optimal Troponin essay for future clinical care and research in these settings.
Dr Gregory Hundley: Very good! So, does sound like there could be a little bit of a difference, depending upon what outcome you're looking for. So, Carolyn I'm going to discuss a paper from Doctor Alison Wright and colleagues at the University of Manchester, and it involves cardiovascular risk and risk factor management in type two diabetes.
So in this retrospective cohort study, using the clinical practice research data link, linked to hospital and death records for people in England, investigators identified 79,985 patients with incident type two diabetes, between the years 2006 and 2013, matched to three 386,547 patients without diabetes, and sex-stratified Cox models were used to assess cardiovascular risk.
Dr Carolyn Lam: Oh I'm dying to know, what did they find?
Dr Gregory Hundley: Well compared to women without type two diabetes mellitus, women with type two diabetes mellitus had a higher cardiovascular event risk than the adjusted hazard ratios 1.2, with similar corresponding data in men, so their hazard ratio is 1.1. And that lead to a nonsignificant relative risk in women with a risk ration of 1.07, however, some important sex differences in the management of risk factors were observed. Compared to men with type two diabetes, women with type two diabetes were more likely to be obese, hypertensive, and have hypercholesterolemia but were less likely to be described lipid lowering medication, ace inhibitors, especially if they had cardiovascular disease. So Carolyn, compared to men developing type two diabetes mellitus, women with type two diabetes mellitus do not have a significantly higher relative increase in cardiovascular risk, but, ongoing sex disparities in prescribing should prompt heightened efforts to improve the standard and equity of diabetes care in women as compared to men.
Dr Carolyn Lam: Nice Greg. Important message. My next one has an important message too. Now it goes to the pediatric population now. We know that brain injury, impaired brain growth, and long term neuro development problems are common in children with transposition of the great arteries. Now does the age at arterial switch operation predict these neuro developmental outcomes in infants with transposition of the great arteries or TGA?
Well Doctor Mike Seed from Hospital for Sick Children in Toronto, Canada and colleges addressed this question by imaging the brains of 45 infants with TGA, undergoing surgical repair, pre and post operatively using MRI. Their main finding was that surgery beyond two weeks of age is associated with impaired brain growth and slower language development in infants with TGA.
Dr Gregory Hundley: Wow Carolyn, this seems like, this could have really important clinical implications for the management of these patients.
Dr Carolyn Lam: Yeah, indeed. Expediting surgical repair could be neuro protective in newborns with Transposition. While the mechanisms underline this association are still unclear, extended periods of cyanosis and pulmonary over circulation maybe factors that inversely impact brain growth and subsequent neurodevelopment if the surgery's not done early. The timing of surgery may have an impact on neurodevelopment in other forms of congenital heart disease, too, therefore. So all of this is discussed in an editorial entitled Correction of TGA, "Sooner Rather than Later?", and this is by Doctors Rollins and Newburger, from Boston's Children's Hospital.
Dr Gregory Hundley: Fantastic Carolyn, well I'm going to discuss a paper from the World of Basic Science from the Ohio State University, Wexner Medical Center from Doctor Douglas Lewandowski. And it involves the preservation of Acyl-CoA and how that attenuates pathological and metabolic cardiac remodeling through selective lipid trafficking. So Carolyn, it has been shown that metabolic remodeling in heart failure contributes to dysfunctional lipid trafficking, and lipotoxicity. Acyl-Coenzyme A Synthase One, or ACLACSL1 facilitates long chain fatty acid uptake an activation with coenzyme A, mediating the fate of the long chain fatty acids. The authors tested wither cardiac Acyl coenzymes A synthase One over-expression aided long chain fatty acid oxidation and reduced lipotoxicity under the pathologic stress of transverse aortic constriction or TAC.
Dr Carolyn Lam: Interesting, I like that concept of metabolic remodeling. So what did they find?
Dr Gregory Hundley: So Carolyn, the studies were performed in both mice and in human subjects, and in mice at 14 weeks, TAC induced cardiac hypertrophy and disfunction was mitigated in MHCACSL1 hearts compared to nontransgenic hearts. This was manifest by retain greater rejection fraction, 65.8 percent versus the nontransgenic hearts of 45.9 percent. An improvement in diastolic E over E prime. Also, functional improvements were mediated by ACSL1 changes to cardiac long chain fatty acid trafficking. In humans, long chain Acyl-CoA was reduced in human failing myocardium and restored to control levels by mechanical unloading.
So, Carolyn, this is the first demonstration on reduced Acyl-Co-A in failing hearts of humans and mice, and suggest possible mechanisms for maintaining mitochondrial oxidative energy metabolism by restoring long chain Acyl-CoA through ASCL1 activation and mechanical unloading.
Dr Carolyn Lam: Awesome Greg! Thanks so much for sharing that paper. Let's go on to our feature discussion.
Dr Gregory Hundley: You bet.
Dr Carolyn Lam: Our feature discussion today is about transcatheter aortic-valve replacement. Could this be the new gold standard for the treatment of aortic stenosis? And yes, I am borrowing from the title of the editorial that accompanies our feature paper. With the editorialists right here with us, Dr Bernard Prendergast, from Saint Thomas' Hospital in London, and we are talking about the wonderful paper for the notion trial and that's a Nordic aortic valve intervention randomized clinical trial, and we're here with the first and corresponding author of that paper Dr Hans Gustav Thyregod from Copenhagen University Hospital, and we also have our associate editor Dr Dharam Kumbhani from UT Southwestern. So welcome gentlemen! And for a start could I ask Hans to please describe the results of the notion trial.
Dr Hans Thyregod: The notion trial as you said is the Nordic aortic valve intervention trial. Designed to compare transcatheter therapy and surgical therapy and patients with severe aortic valve stenosis, patients have to be thirteen years old or older and we didn't really specify any risk profile, as in previous trials. So all patients eligible for both procedures would be enrolled in the trial. And the main result of the trial was that we couldn't find a difference when looking at the composite outcome, which was all-cause mortality, stroke American infraction.
The primary outcome was after one year, in this paper it's up to five years and we could not see any difference. So the range was, in my estimate was 38 percent for transcatheter therapy versus 36.3 percent for surgery. And when looking at the different components of this composite outcome, all-cause mortality, stroke American infraction. We couldn't find any surgically significant difference for any of those outcomes either.
Dr Carolyn Lam: Wow, Bernard, could I ask you to place these results into context for us, I mean the notion trial is after all the first to compare TAVR and SAVR in patients with severe isolated valve stenosis at lower surgical risk, and really has the longest follow-up doesn't it? So please tell us, what are your thoughts?
Dr Bernard Prendergast: So this is yet another notch the remarkable success story of TAVI or TAVR, as you call it in the U.S. We pass our congratulations from the community to Dr Thyregod and the team in Copenhagen for such a ground-breaking study. The wider context is he say is the TAVR have demonstrated remarkable efficacy and safety, initially in operable and high-risk patients, but, more recently randomized control trials in intermediates and lower risk patients. And the important perspective of this study provides is the longer term follow up, because for a number of years we've perhaps considered TAVI or TAVR as a, let’s say a shorter-term treatment for patients in their eighty's and older, who perhaps have a shorter life expectancy. But what the five-year data demonstrates to us is that TAVI or TAVR is as good as surgery, at five years of follow up. With very reassuring outcomes, they maintain durability of the transcatheter heart valve, that's highlighted in the companion paper, which, is published very recently in JACC.
So really takes TAVI into a new territory, which is patients who have at least five years or longer to live and allows us to extend the indication for the procedure into younger patients. Alongside lower risk patients, who have supported by the recent landmark studies published in the New England Journal from Partner Three, and the Core Valve Low Risk trial. So, the information is very reassuring and it's another very positive notch in the journey of TAVI across the spectrum of surgical risk.
Dr Carolyn Lam: Thank you! Beautifully put and Dharam could I just ask you I mean what more do we need? Do you think this is guideline defining stuff now? Or do you have questions?
Dr Dharam Kumbhani: I really want to congratulate the investigators of the NOTION trial, as far as providing us with this longer term follow up in a lower risk population, and so, you know the field is moving incredibly, incredibly quickly and you know as we just mentioned TAVR has now gone from being something that's done in patients that are too high risk to level convention surgery, to now perhaps becoming either one of the main stream options, or the main stream option. And you know time will tell, so I think what this study really helps us is, provide us with a five-year time horizon on follow up, but, to be fair, you know this trial is very helpful in certain ways because it was designed a few years ago. You know it was done with the generation of a valve that is not used much right now for the most part, and you know so it's some of the things like pacemaker et cetera, may not translate to current practice.
Even though the clinical outcomes were similar, it's probably some issues with power as well, but, again not in a clinical way, but, just to kind of say that this trial definitely helps us in moving the field forward and it kind of adds to the growing body of literature that supports that. Going forward I guess one question I would have for this group is, you know as we think about TAVR and surgical aortic replacement, it would seem that we would need even longer term data, based off of detonators to be able to confidently tell patients, there are fairly similar therapies.
And then the other question is, this construct of surgical risk is that we applied telegraphically based on how the evolution of TAVR has occurred, but one wonder, you know with NOTION and other trials we should be thinking about this perhaps from an age perspective as a sort of NOTION trial—those would be my two comments.
Dr Bernard Prendergast: I think that's a very valuable comment, and of course there are other ongoing trials, which, will help to address many of these questions. One important deficit of notion is that it didn't enroll, for example, patients with bicuspid aortic valves. And we know that bicuspid aortic stenosis is far more common in younger patients. So, Hans a few comments regarding the protocol for notion two maybe helpful for our listeners.
Dr Hans Thyregod: Well this was mentioned, the follow up of five years is obviously not a very long time in younger patients with a lower risk profile. We are planning to follow these patients for at least 10 years. And the other comment about the risk profile of the risk certification of patients is also very interesting because the SDS and your scores have been developed for surgical patients and not for transcatheter patients. So we need a whole new transcatheter risk scoring system to help our team determining what treatment would be the best suited for each patient.
And as Dr Prendergast mentioned we are in Copenhagen, and Scandinavia conducting a NOTION II trial, which, will enroll patients younger than the previous low risk trials and also the notion trial. Which, at a mean age, at least for the patient of around 80 years and in notion two patients must be younger than 75 years old. And we are also including patients with bicuspid valve stenosis, and also patients which were not included in the NOTION I trial. Patients with a coronary artery disease, so these patients are obviously also a different patient category and will maybe require a different approach regarding the timing of the revascularization and so forth so there is more research to be done in those areas.
Dr Carolyn Lam: Well exciting. Thank you for sharing that Hans. Dharam could I ask you to just wrap us up with the take home message, it's for our audience right now.
Dr Dharam Kumbhani: For me one of the most interesting findings was that in five years, the clinical performance between TAVR and SAVR were similar, but, more importantly the valve performance, the hemodynamic performance was the same, and perhaps slightly better with the self-expanding design. They are so proud of the self-expanding design that was studied in the study. So that is helpful because as we discussed earlier, I think a lot of the controversy discussions centers around the long-term durability of TAVR compared with surgically aortic valve replacement, so that is a step in the right direction. The same investigators have published that hemodynamic performance elsewhere as well, sot that's I think the number one take home message that, that's very, very reassuring. The second thing is you know this study shows us it adds to the growing body of literature, in lower risk patients so all of this was not strictly a lower risk trial based on contemporary definition.
It was definitely a lower risk population and so, this is the largest pool of patients where they aortic stenosis about 50 percent will have low risk aortic stenosis, low surgical risk aortic stenosis and so this is very helpful in that space and then third you know that this is very exciting that NOTION investigators indeed are the low risk trial investigators, will be extending their follow up with 10 years. So I think in this next decade, most people expect as Dr Prendergast also mentioned, we'll see a gradual change perhaps in how patients with aortic stenosis manage. But, I will add a word of caution, I think in the current era, the way things stand right now, it's probably best in favor to appeal to what the guideline indicates. And for the low risk patients, surgical aorta valve replacement is still the center of choice.
Dr Carolyn Lam: Thank you so much Dharam and thank you Hans for the beautiful paper, and Bernard for that excellent editorial!
Thank you audience for joining us today, you've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: I'm Greg Hundley, Associate Editor for Circulation and Director of the Pauley Heart Center in Richmond, Virginia at VCU Health.
Dr Carolyn Lam: So Greg, ever wondered if prophylactic use of ICDs would help prevent sudden cardiac death in dialysis patients? Well, guess what? We're going to be discussing it in the feature discussion of the ICD II trial coming right up. First, I hear you've got a very interesting probabilistic paper.
Dr Greg Hundley: Yes. It's very sweet. This is from Renata Micha at Tusk University and it's examining the cost effectiveness of the US Food and Drug Administration added sugar labeling policy for improving diet and health. So Carolyn, in this study, investigators used a validated micro simulation US impact food policy model to estimate cardiovascular disease and type II diabetes mellitus cases averted, quality adjusted life years, policy costs, health care, informal care, and loss productivity in health related savings and cost effectiveness of two different policy scenarios.
First, the implementation of the US Food and Drug Administration added to your labeling policy or just the sugar label. And second, further accounting for corresponding industry reformulation the sugar label plus reformulation. The models used nationally represented demographic and dietary intake data from the national health and nutrition examinations survey and diseased data from the centers for disease control and preventive wonder data base and policy affects in diet disease effects from meta-analysis and policy and health related costs from established sources. Probabilistic sensitivity analysis accounted for model parameter uncertainties and population heterogeneity.
Dr Carolyn Lam: Sweet indeed, so tell us all about probabilistic analysis Greg.
Dr Greg Hundley: Okay Carolyn, so between 2018 and then forecasting out into the future, so this is probabilistic, in the year 2037. The sugar label would prevent 354,400 cardiovascular disease cases, and 599,300 diabetes mellitus cases, gain 727,000 quality adjusted life years, and save 31 Billion dollars in net health care costs. Or 61.9 Billion dollars in societal costs incorporating reduce loss productivity and informal care costs and similar findings were accomplished for the sugar label plus reformulation scenario, both scenarios were estimated with greater than 80% probability to be cost saving by the year 2023.
Thus, the results of this simulation exercises indicated that implementing the FDAs added sugar labeling policy could generate substantial health gains and cost savings for the US population particularly if the new label stimulates industry reformulation. The authors point out that the compliance date for updating the nutrition facts label including the added sugar perversion has been continuously delayed. And the authors believe, their findings highlight the need for timely implementation of this label so as to maximize health and economic gains.
An excellent editorial was written by Elizabeth Magnuson at Saint Luke's Mid America Heart Institute revealing the strengths of this work and explains some of the variants that could occur in the results based on assumptions that were used in the authors micro simulation model.
Dr Carolyn Lam: That is so interesting Greg, thanks. So from policy to guidelines and this time on cardiopulmonary resuscitation or CPR, now we know that an out of hospital cardiac arrest, chest compression only CPR has emerged as an alternative to the standard CPR where we use both chest compressions and rescue breathes. Since 2010, CPR guidelines recommend chest compression only CPR for both untrained bystanders and trained bystanders who are unwilling to preform rescue breaths.
The current study really aimed to describe the changes in the rate and type of CPR perform before the arrival of emergency medical services doing three consecutive guideline periods with gradual adoption of compression only CPR and this was in Sweden. Now these were authors led by Dr Hollenberg from The Center of Resuscitation Science, Karolinska Institute in Stockholm, Sweden and colleagues and basically, they study all bystander witness out of hospital cardiac arrest reported in the Swedish register for CPR from 2000 to 2017. They found that there was a six fold higher proportion of patients receiving compression only CPR and a concomitant almost double rate of CPR before emergency medical services arrival, and these changes occurred over time. Any type of CPR was associated with doubled survival rates in comparison with cases not receiving CPR, and this association was observed in all time periods studied. They also found a small but significantly higher chance of survival after CPR with compression and ventilation in comparison with compression only CPR.
Dr Greg Hundley: So Carolyn, does this mean we should go back to standard CPR?
Dr Carolyn Lam: Well, remember these we observational findings, albeit really amazingly done and nationwide. But the findings really support continuous endorsement of the compression only CPR as an option and that's because its associated with higher CPR rates and overall survival of the no CPR skill. The authors ended up calling for randomized controlled trials, which are really needed to answer the question of whether or not CPR with compression and ventilation is superior to compression only CPR, especially in cases where bystanders have had the previous CPR training. Now, this is discussion in a wonderful editorial by Drs. Hsu and Neumar from University of Michigan Medical School.
Dr Greg Hundley: Very nice, so you're going to tell us a little bit about troponin?
Dr Carolyn Lam: Well, the question is "Is Plasma Troponin I measured by the high sensitivity assay associated with incident cardiovascular disease in the community?" Well, Dr Ballantyne from Baylor College of Medicine and colleagues decided to answer this question by looking at the ARIC Study participants age 54 to 74 years without base line cardiovascular disease and what they found was that elevated high sensitivity troponin I was strongly associated with increased global cardiovascular disease incidents in this general population, and this was independent of traditional risk factors. They also found differences between black and white individuals and between men and women.
Dr Greg Hundley: What kind of differences?
Dr Carolyn Lam: Well high sensitivity troponin I had a stronger association with incident global cardiovascular disease events in white compares to black individuals and a stronger association with incident coronary heart disease in women than in men. The authors also did a comparative association of high sensitivity troponin I vs. troponin T, they found that the high sensitivity troponins I and T show only moderate correlation with each other but were complementary rather than redundant in risk assessment for incident cardiovascular events in individuals without known clinical cardiovascular disease at base line. The bottom line is, adding biomarkers to traditional risk prediction models presents a potentially effective approach for future risk prediction algorithms for cardiovascular disease in the general community.
Dr Greg Hundley: You know, think I might read that paper looking at that complimentary risk assessment. That sounds really interesting Carolyn. Well, I'm going to go back to the world of basic science and discuss a paper from Kun Wang discussing the long non encoding RNA regulation of cardiomyocyte proliferation and cardiac repair. Carolyn, post mitotic cardiomyocytes in the adult heart exit from the cell cycle and cease to proliferate, and that's the basis for their poor regenerative capacity and defective repair in response to say a myocardial infraction. Interestingly, the nonmammalian vertebrates such as our friend the zebra fish, their heart exhibits a robust capacity for regeneration. And it can efficiently regenerate its lost cardiac tissue throughout life due to this retain cardiomyocyte proliferation capability.
Dr Carolyn Lam: Interesting indeed Greg about our friend the zebra fish. So what did the authors find?
Dr Greg Hundley: Okay, in this study, Wang and associates investigated whether long non-encoding RNAs had a role in the regulation of cardiomyocyte proliferation and cardiac repair. Using bioinformatics and initial analysis, the identified a long coding RNA named Cardiomyocyte Proliferation Regulator or CPR that was comparatively higher in the adult heart as opposed to hearts in the fetal stage. The silencing of the Cardiomyocyte Proliferation Regulator or CPR significantly increased the cardiomyocyte proliferation in the postnatal in adult hearts, more over CPR deletion restored the heart function after myocardial injury which was evident from increased cardiomyocyte proliferation, improvement of myocardial function and reduce scar formation. Also, neonatal cardiomyocyte proliferation in cardiac regeneration where markedly suppressed in CPR overexpressing heart cells, therefore CPR acts as a negative regulator of cardiomyocyte proliferation and regeneration in fetal hearts.
So, Carolyn the conclusion of this paper is that the inactivation or silencing of CPR accelerates cardiomyocyte proliferation along with significant restoration of cardiac structure and function after myocardial injury in adult hearts. And as such, further studies may investigate whether the therapeutic inter fashion of CPR could be a useful strategy to trigger the expansion of cardiomyocyte populations and myocardial repair.
Dr Carolyn Lam: Nice Greg, so we've talked about CPR as in Cardiopulmonary Resuscitation to CPR as in Cardiomyocyte Proliferation Regulator, how about that? Well, that's as much as we go for now, let’s get to our feature discussion.
Dialysis patients are known to have a high mortality rate, a large proportion of which have been attributed to sudden cardiac death and yet compared to patients with heart failure, these patients with dialysis have been either excluded or only nominally enrolled in all previous trials of implantable defibrillators or ICDs. Now that's why our feature paper this week is so important, and it is the Cardioverter-Defibrillator in the prevention of sudden cardiac death in dialysis patients that prospective randomized controlled ICD to trial. So pleased to have with us, the corresponding author Dr Wouter Jukema from Leiden University Medical Center as well as associate editor Dr Mark Link from UT South Western to discuss this very important paper. Wouter, congratulations, this is a very difficult, very important to do the study though, could you tell us a bit about what you did and what you found?
Dr J. Wouter Jukema: Actually, you just referred to it as a very difficult study to perform and indeed it was. Many years ago, actually, twelve years ago, we noticed that now a lot of death in dialysis patients was attributed to sudden cardiac death, before we tried to make these type of patients better with all types of medications, but did not really work and suddenly the idea was, that came also from death certificates and death records that they have sudden cardiac death and we said we should monitor it and we should treat it in a prospective randomized study. We initiated the study after careful thoughts and we thought we would do it in 4-6 years but it took us 12. So it was quite an effort to set up this rightly and spread it around the Netherlands and activate a Nephrologist and a Cardiologist to take part in this prospective randomized controlled study in dialysis patients.
Of course, you can easily imagine that you could have great benefit from this ICD devise, but you could also easily imagine that you would have complications of the implication of the device. So explaining that we should show it out, I think was the most important job we had to do and think that was a great effort, and it was not easy to do.
Dr Carolyn Lam: And that in it of itself is very important observation.
Dr Mark Link: So you picked patients without doubts, which is great I mean this is a difficult study, but you also picked with an LDF greater than 35% and traditionally, ICDs are indicated for under 35%, can you give us a little explanation on why you chose the greater than 35% population?
Dr J. Wouter Jukema: Yeah, I think this is perhaps the most important remark on the study, because when we designed the study we had to choose at that time we had guidelines in general that under 35% of injection fraction you were entitled to receive an ICD, however of course almost never dialysis patients were included so there was no formal recommendation on that not to include them or not to exclude them, but dialysis patients have a death rate at that time to sudden cardiac death, anyway regardless of the injection fraction and we thought okay, the patient population that is first at high risk of sudden cardiac deaths so any dialysis patients but also they are entitled to have a meaningful extension of the lives because the prognosis of patients that are on dialysis with an injection fraction under 35% is in general so poor that it would be unfair to start there and most of the Nephrologists also would not allow it anyway, these patients are at the end of life and if you extended for two or three months its useless.
Anyway, so we thought we'd pick the high-risk population and we prove that there were still on high risk but when we could do something meaningful to extend their lives, so we thought we do not pick the worst patients we pick the patients that we think we can really help. We screened them well, we treated them well and we see if an ICD on the patient will benefit them. And that's why we picked the over 35% rage. You need another study to do below 35%, but I don't think that our results are substantiating such an effort.
Dr Mark Link: The population with EFs was 6-50%, which also has a high risk of sudden death in patients with dialysis but it’s still not looking with the population of less than 35%.
Dr J. Wouter Jukema: No, I completely agree, and we acknowledge that in the manuscript, it was always in the manuscript within the revision that was also pointed out to us that it should be more clearly acknowledged, why we choose this patient population and finally, we can of course not make a formal recommendation on dialysis patients with an injection fraction of less than 35%. You can extrapolate data but we have no formal prof of course for this type of population. I fully agree.
Dr Carolyn Lam: Before we go further, could you first describe, what did you find?
Dr J. Wouter Jukema: Basically, the conclusions are the prophylactic ICD therapy in patients on chronic dialysis with an injection fraction of 35% or higher was not associated with a reduced rate of sudden cardiac death nor of all cause of mortality and besides that the preference of sudden cardiac death in this type of patients on dialysis was actually significantly lower compared to its reports from literature, so that's what we very often see of course if you fill out a death certificate, you have to fill out a cause of death and of course in many patients the heart stops, and you say it's a sudden cardiac death. But that's not what this study actually showed and finally it's also no authority that this population was not too healthy to see any benefit, if you look at the results over the years, then you'll see that after five or six years more than half of the patients are dead anyway, but due to all kind of causes and not to a sudden cardiac death.
So, I think that this is from a pathophysiological background, this is also a very interesting study because we now have finally data, real data on sudden cardiac deaths in these types of patients.
Dr Carolyn Lam: Indeed, and Mark, I know that you invited the editorial from Rod Passman, just discussing why did we see the results that we did. Not quite what we expected I suppose, what do you think Mark?
Dr Mark Link: First, I want to congratulate Dr Jukema for finishing this study, this was a massive task and a difficult and long one. I think I was surprised, there has been reported to be a very high rate of sudden death in dialysis patients regardless of their LDF. The ICD is very good at preventing sudden deaths, but not good at preventing other types of deaths, so I would extrapolate to say, well you can prevent sudden death in dialysis patients, you should prolong their life and this study did not show that at all. And I was surprised, and it just goes to what Dr Jukema was telling us, that what's reported on a death certificate as sudden death is not necessarily sudden death and could be other types of death and at the end all death is sudden.
Dr J. Wouter Jukema: I fully agree with that remark because that makes is cumbersome to have the right interpretation of the data, so you have to feel like something and then finally your heart stops.
Dr Carolyn Lam: What seems that most of the reasoning seems to be maybe a lower rate of sudden cardiac death than we expected, but there were also other factors that were considered, for example, if you could clarify by dialysis did you mean both hemodialysis as well as peritoneal dialysis, do you think that made a difference? For example, do you think ICDs work differently in presence of uremic precipitant of arrhythmias vs. not and so on, what do you have to say about those factors?
Dr J. Wouter Jukema: We include on purpose both types of patients, the peritoneal dialysis and the hemodialysis patients because you could easily in-visit that there could be a difference, for instance to fluid or electrolyte sheaths that are more sudden in the hemodialysis patients than in peritoneal dialysis and we did a sub-analysis where we looked at both types, but the results are essentially the same, it doesn't seem to matter a great deal of what type of dialysis you have, the amount of sudden cardiac is lowered and expected. By the way occasionally, of course the ICD did work in sudden cardiac death, was aborted. So, it’s not that the apparatus doesn't function it does, it takes it properly and if functions properly. But finally, it doesn't prolong the life and you will die of something else, mostly infections in general well-being when finally, the nephrologist will say this is end of life you have to stop the dialysis procedures anyway.
Dr Carolyn Lam: Right, great points, now in the last few minutes, I'm dying to ask, what do you think of the next steps from here. Mark, what do you think first? And then perhaps I'll give the last word to Wouter?
Dr Mark Link: I'll start with a question to Wouter myself, the question is what are we going to do now with the individuals on dialysis that are under 35%? I think this study has pretty clearly said that were not going to extend our CDs to people on dialysis with greater than 35%. But we still have a population that currently fits indication for a ICD if their expected longevity is greater than a year. And currently those people are included in the guidelines for ICDs, I think this study gives us some pause about what to do with our population. And many of that population are getting our CDs and I'd be curious to what Dr Jukema thinks about that population and whether that population warrants some randomized trial or whether we should continue with our current guidelines that recommend implantation of an ICD in any individual less than 35%, as long as their expected life span is greater than a year.
Dr J. Wouter Jukema: I think these are excellent questions with excellent remarks, of course, finally, we do not know because we didn't investigate it, I can only imagine the difficulties we would have if we were to do a new additional trial with injection fractions patients less than 35%. I could tell you we had great great difficulty in persuading Nephrologists to take part in the study, because many of them were very reluctant, this is their principal, these are very ill patients, and a lot of them are more or less going towards the end of their lives so you cannot do this when we have Nephrologists telling us that they considered it an unethical study. A lot of them did not want to participate they said, "You shouldn't do this to this patient, they have troubles enough, they suffer from infections and all kinds of things."
Having said this, I do not advocate that you should never implant an ICD in a dialysis patient, I think in our study we also clearly show that in dialysis patients, implantation of an ICD is feasible within acceptable although better complication risk and infection risk, so if you have a patient on dialysis where you feel this patient has a good life expectancy, for instance, he already suffers an episode of arrhythmia, I think you are entitled to discuss this with the patient and have it a try, it might work and prolong their life. So I would not say never do it, I think our studies show that you can do it, yes, it sometimes works but do not expect too much of it. You will never hear me say that in general you should not do it, if you have a clear indication for it you may do it, secondary effect may require a good reason, but primary prophylactic indication, that's a difficult one I think and to do this study in patients that are even more ill, with injection fraction of less than 35%, I feel will be exceeding the difficult.
Dr Mark Link: One other comment I have is the issue of the SUBCU ICD I think changes the equation in a bit because the risk of infection is much lower with a SUBCU IDC in patients on dialysis, did you have any SUBCU ICDs in your study or was it all transvenous?
Dr J. Wouter Jukema: We don't have any data, when we designed and the developed study, the such a device was not even there so we couldn't do that, and during the study we did not adapt that but of course there is also no formal proof yet that it's a lot safer, a lot better, and once again this time of subcutaneous ICD I think you can do it at an acceptable complication rate. But it’s not effective enough, it's not that the patients were dying from infections of their ICD, they were dying of all kinds of infections and malignancies. Infections due to the ICD were facing procedures, real complications were rare.
Dr Carolyn Lam: Great! Thank you Wouter, thank you Mark, what an important study and what a lot of lessons that we learned here.
Thank you very much audience for listening as well, you've been listening to Circulation on the Run, don't forget to tune in again next week.
This program is copyright American Heart Association 2019
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and it's editors. We're your co-hosts, I'm Dr Carolyn Lam, associate editor from The National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor for Circulation and director of The Pauley Heart Center at VCU Health in Richmond, Virginia.
Dr Carolyn Lam: Guess what Greg? Right after this we have a double feature discussion. It is all about dapagliflozin with some really, really important self-analyses from the DECLARED-TIMI 58 trial and about heart failure in Type 2 Diabetes with dapagliflozin. But, all of that coming right up only after we have our chat. So Greg, what do you have for us today?
Dr Greg Hundley: My first article is going to be from Dr Mintu Turakhia at the VA Palo Alto healthcare system at Stanford University and is going to discuss the practice variation in anticoagulation prescription and outcomes after device-detected atrial fibrillation. It's a study that has insights from the VA Health Administration. This study evaluated the relationship between oral anticoagulant prescription practice variation in response to new device detected atrial fibrillation and the association to outcomes.
As you know Carolyn, there are no clearly defined thresholds of AF burden, for which to initiate oral anticoagulation.
Dr Carolyn Lam: Interesting, so what did they find, how did they do this?
Dr Greg Hundley: Carolyn, the investigators performed a retrospective cohort analysis using data from the Veterans Health Administration linked to remote monitoring data that included day level AF burden. They included patients with cardiac implantable electronic devices and remote monitoring from the years 2011 through 2014. A CHA2DS2-VASc score of greater or equal to 2, and no prior stroke or oral anticoagulant receipt in the preceding 2 years. They determined the proportion of patients prescribed oral anticoagulants within 90 days following new device-detected AFib across a range of AFib thresholds. Greater than or equal to 6 minutes, all the way up to greater than 24 hours. And they examined sight variation in oral anticoagulation prescription.
Dr Carolyn Lam: And so? What did they find?
Dr Greg Hundley: Well, you ask among 10,212 patients with defibrillators, proportion receiving oral anticoagulation varied based on device detected AF burden. For example, for those greater than or equal to 6 minutes, it was roughly 13% of individuals, for those greater than 24 hours, 27% of individuals received oral anticoagulants. Importantly, there was a substantial sight variation in oral anticoagulation prescription after device-detected atrial fibrillation, for example, greater than one hour. The median was 16%, but it ranged from as low as 3% up to highs of 67%. And so, in adjusted models, oral anticoagulant prescription after device-detected AFib of greater than 24 hours was associated with reduced stroke risk and has a ratio of 0.28, p-value's 0.02, although, the propensity adjusted model was significant when AFib lasted at least 6 minutes.
So, in conclusion, among veterans with implanted devices, device-detected atrial fibrillation is common. There is large practice variation in 90-day oral anticoagulation initiation after new device-detected AFib with low rates of treatment overall, even for episodes greater than 24 hours. Remember, we said that rate was 27%. The strongest association of oral anti-coagulation with reduction in stroke was observed after device-detected Afib of greater than 24 hours. And what this study shows, is that randomized trials are needed to perform these observational findings.
So, Carolyn, how about your next study?
Dr Carolyn Lam: Well, from anti-coagulants to anti-hypertensives. I'm going to tell you about the 6-month results if the RADIANCE Hypertension Solo Trial.
Dr Greg Hundley: Oh, so, what was the RADIANCE Hypertension Solo Trial? Can you remind us?
Dr Carolyn Lam: Glad you asked. So the trial was the one that demonstrated a greater reduction in daytime ambulatory systolic blood pressure at 2 months by endovascular ultrasound renal denervation compared with a sham procedure among patients who were not treated with anti-hypertensive medications. So the current paper, led by Michel Azizi from Université Paris-Descartes and colleagues, now report the 6-month results following the addition of a recommended, standardized, stepped-care anti-hypertensive treatment to the randomized endovascular procedure under continued blinding to the initial treatment.
Now, remember these were patients with uncontrolled combined systolic and diastolic hypertension who were initially off medications for two months following randomization. Now, between two and five months, if the monthly measured home blood pressure was more than 135/85, the stepped-care antihypertensive treatment approach was recommended and consisted of sequential addition of, for example, amlodipine 5mg a day, then a standard dose of an angiotensin-converting-enzyme inhibitor, or an ARB, and hydrochlorothiazide at 12.5mg a day, followed by sequential uptitration of the hydrochlorothiazide and amlodipine.
So, what did they find? At 6 months, 65% of the patients in the original renal denervation group were being treated by this stepped-care approach, versus 84.5 in the sham group. And the average number of antihypertension medications and defined-daily doses were all less in the renal denervation group than the sham group.
Now, despite less intensive antihypertensive treatment, the renal denervation group had reduced daytime ambulatory systolic blood pressure to a great extent than the sham group. Importantly, there were no major adverse events in either group through 6 months. The blood pressure lowering effect of endovascular ultrasound renal denervation was maintained at 6 months with less prescribed antihypertension medications compared with the sham control. And what this means is if safety is maintained in larger studies with longer follow-up, renal denervation could be a promising adjunct therapy for patients with hypertension.
Dr Greg Hundley: Wow, so we're getting back toward renal denervation? How about that?
Carolyn, my next paper jumps into the world of basic science. This is a study from Kari Alitalo at the University of Helsinki, and it involves endothelial cells and how they regulate physiological cardiomyocyte growth versus VEGFR2 mediated paracrine signaling. The study evaluates the role of bidirectional endothelial cells and cardiomyocyte cross-talk via cardiokine and angiocrine signaling as it pertains to the regulation of cardiac growth and homeostasis in pathological cardiac hypertrophy. The expansion of the cardiac vasculature to maintain adequate supply of oxygen and nutrients is a key determinant of whether the heart grows in a physiological compensated manner, or a pathological decompensated manner.
Understanding how an excess of angiogenesis induces cardiac hypertrophy and how endothelial cells regulate cardiomyocyte homeostasis, could provide novel therapeutic targets for heart failure.
Dr Carolyn Lam: Ah, this is something very close to my heart. So Greg tell us, how did they establish the link between the endothelial cells and cardiomyocytes?
Dr Greg Hundley: The investigators demonstrated that both endothelial cell deletion of vascular endothelial growth factor receptor 1 and AAV-mediated delivery of the VEGFR1's specific ligands, VEGF-B or BGIF, into the myocardium increased the coronary vasculature and induced cardiomyocyte hypertrophy in adult mice.
The resulting cardiac hypertrophy was a physiological as indicated by preserved cardiac function and exercise capacity and lack and pathological gene activation. Also, the investigators demonstrated that the reported changes were mediated by increased VEGF signaling via endothelial VEGFR2 and found that the notch and ERBb pathways are involved in transducing signals for endothelial cell cardiomyocyte cross-talk in response to angiogenesis.
So clinically, the relevance of the findings are highlighted nicely in an editorial by professor Issei Komuro at the University of Tokyo Hospital. First, he emphasizes that cross-talk between the endothelial cell VEGFR2 and cardiomyocyte ErbB signaling pathways coordinates cardiomyocyte hypertrophy with angiogenesis and contributes to physiological cardiac growth. And understanding whether factors could modify this process may impact the treatment down the road of pathologic hypertrophy.
Dr Carolyn Lam: Oh interesting! Well you know what, Greg, I've got a preclinical one for you too, and this time looking at the role of inflammation in atherosclerosis and specifically at the role of the adaptive immune response and T-cells.
So, Greg, let me remind you that when we looked at CANTOS and Canakinumab we were actually looking at the role of the innate immune response. And here is where I had planned this very nice, complicated quiz for you, Greg, about the innate versus the adaptive immune response in the various cells. Would you like to take the quiz?
Dr Greg Hundley: You know what? I think I'm going to pledge that I'm already going to get a D or an F, so why don't you enlighten us?
Dr Carolyn Lam: Now alright, remember that the CD4 T-cells are assumed to be activated by our antigens derived from modified proteins such as oxidized LDL, and these are presented via MHC class II molecules in the context of cytokine signaling, remember those? What I didn't realize is that it hadn't been assumed that atherosclerosis involves a loss of tolerance against these modified self-antigens, generated in response to hypercholesterolemia and that presentation of such antigens on these MHC class II cells, then lead to activation of proatherogenic Th1 cells. So, that was the assumptions, but this was really studied in detail by the authors, Dr Wigren from Scania University Hospital and Lund University in Sweden and their colleagues, who addressed the role of CD4 T-cells in a real novel, unconventional way. And they did this by crossing MHC class ii deficient mice with atherosclerosis-prone ApoE-deficient mice.
Now the result of these double deficient mice was almost complete void of CD4 T-cells. However, despite the lack of these T-cells and inflammation, these mice developed larger atherosclerotic lesions in the aortic root area of the heart than their ApoE-deficient counterparts. Cell transfer and blocking antibody studies also, then supported these findings and suggested that loss of regulatory T-cells is the most important cause of aggravated atherosclerosis in the double-deficient mice.
So, overall these observations demonstrate that deficiency of activation of the adaptive immune responses through MHC class ii is associated with increased development of atherosclerosis, and the findings have important implications for our understanding the possible risks and benefits of immunosuppressive therapy in patients with cardiovascular disease. Now this is discussed in a beautiful editorial by Dr Slütter and Kuiper and they are from Leiden, the Netherlands.
So, Greg, interesting stuff, huh?
Dr Greg Hundley: You bet! Let's go on and here a little bit more about diabetes.
Dr Carolyn Lam: And dapagliflozin coming right up.
Today's feature discussion is all about SGLT2 inhibitors both in heart failure and atherosclerotic disease. A huge discussion because we have two papers, and they're all coming from the DECLARE-TIMI 58 trial. I am so pleased to have the corresponding author, Dr Stephen Wiviott from the TIMI study group at Brigham Women's hospital in Boston, Massachusetts, as well as the first author of one of the papers, and that is Dr Eri Kato, who was at the TIMI study group and is now at Kyoto University, as well as the editorialist for these two papers, Dr Subodh Verma from University of Toronto, and our deputy editor, Dr Darren McGuire from UT Southwestern.
All-star cast, all-star papers. So, Steve, could you start by telling us about the DECLARE-TIMI 58 trial, just to set the background please?
Dr Stephen Wiviott: So DECLARE, for people who don't know, was a large, randomized trial of 17,000+ patients with diabetes, comparing the SGLT2 inhibitor dapagliflozin to placebo. And the patients could be enrolled if the patients had either an established cardiovascular disease, meaning secondary prevention, or simply risk factors for cardiovascular disease with primary prevention.
Patients that were treated with dapagliflozin or placebo were followed for a period of just over 4 years and there were co-primary endpoints. Those were cardiovascular death and hospitalization for heart failure, and the second co-primary endpoint was MACE, major adverse cardiovascular events, a combination of cardiovascular death, MI, or stroke.
And what we saw, initially, this was a safety trial to demonstrate the safety of this diabetes agent according to worldwide guidelines. We saw that there was certainly non-inferiority for MACE, so it was safe with regard to MACE, but we did see a statistically significant reduction in cardiovascular death and hospitalization for heart failure driven predominantly by a large reduction in hospitalization for heart failure, and we also saw consistent with the other SGLT2 inhibitors, a significant reduction in the progression of renal disease. And so we had the opportunity to follow up with a couple of important papers that were published in circulation.
Dr Carolyn Lam: Thanks, Steve. And at this point I would love to invite Eri to tell us, because we just heard that the heart failure hospitalization signal is very strong. What did you do in your analysis?
Dr Eri Kato: So previously, SGLT2 inhibitors including dapagliflozin have shown to reduce hospitalization for heart failure, now we wanted to take a step further and explore those who are at high risk. So, the aim of our study was to evaluate whether the clinical benefit of dapagliflozin is greater in patients with HFrEF, heart failure with reduced ejection fraction, compared with patients without HFrEF.
So, we used data from the DECLARE-TIMI 58, which you just heard, which included a broad spectrum of patients with Type 2 diabetes, and was also unique that it is the only SGLT trial to date that has detailed the information of these ejection fractions. So, for this study, for our study trying to find patients by the presence or absence of HFrEF, which was defined as having ejection fraction less than 45%, which is pre-specified ejection fraction couplings, and the key outcome in each was cardiovascular death or hospitalization for heart failure, its components, and of course, mortality. But we also additionally looked at MACE and renal composite endpoints.
There are several interesting findings. First, is that dapagliflozin reduced the risk of hospitalization for heart failure regardless of ejection fraction, including those with preserved ejection fraction.
Second, is we have observed lower rates of cardiovascular death in all-cause mortality with dapagliflozin in patients with HFrEF, but not in those without HFrEF.
So, in patients with HFrEF, there was a significant 45% reduction in cardiovascular death, and 41% reduction in all all-cause mortality with dapagliflozin. And I'd like to highlight that these were achieved on top of high-proportional use of conventional evidence-based heart failure therapies, and that it did not increase any adverse events.
And third, and finally, there were lower rates of renal composite endpoints with dapagliflozin regardless rejection fraction, and once again, it improves patients with preserved rejection fraction.
So, to summarize, our results showed a robust mortality benefit in patients with HFrEF, but also showed that dapagliflozin is beneficial in full spectrum patients with diabetes, regardless of ejection fraction.
Dr Carolyn Lam: Thank you Eri, that's beautifully summarized, but could I just clarify? These were patients not just with a reduced ejection fraction, but with heart failure? And how was that determined?
Dr Eri Kato: We collected data at the baseline and the heart failure was collected based on the medical record.
Dr Carolyn Lam: So, I just wanted to clarify that it wasn't just rEF, but HFrEF, but the HF part was a medical record. So, Darren, I know you thought a lot about this stuff, so what do you think? Is there still equipoise for these heart failure trials, or how do you think this adds?
Dr Darren McGuire: First, as deputy editor of Circulation, I'm thrilled that were attracting these excellent diabetes-related publications, we've had a track record of several years now of capturing many of the key analyses and certainly these two papers we're talking about today qualify among the very best we've had, and I've also had the privilege of working with these investigators on the executive committee at DECLARE. And to the investigators and the credit of the sponsor, we observed these heart failure signals in other trials as DECLARE was ongoing, and we actually made a modification during the trial to begin to collect as much as we could pre-randomization ejection fraction data. And we were able to capture on roughly one-third of the patients, pre-trial EF data and we took any way it was measured and any time of when it was measured, and there are some limitations to that, but this now represents the largest data set where we can stratify the outcomes by some measure of ejection fraction.
And I have to say I was really surprised by these results; that the cardiovascular death benefits were amplified in patients with heart failure with reduced ejection fraction, but not in those with heart failure with preserved ejection fraction, as these medications are relatively modest, diuretic agents I anticipated the opposite, honestly, that heart failure would preserve ejection fraction that is much more volume-sensitive may have incremental benefits from these medications.
So, I was surprised by this, it was a little bit upside-down from what I expected. I know Subodh and Carolyn you've both thought a lot about this as well, I'd be interested in your opinions. Did you expect that heart failure with reduced ejection fraction would drive these clinical results?
Dr Carolyn Lam: Subodh, I'm going to let you go first.
Dr Subodh Verma: First and foremost, I appreciate the opportunity the circulation gave both myself and Professor McMurray to write the editorial to these very important pre-specified analyses from DECLARE.
I actually see the results not only as interesting and tantalizing as you already discussed, but I actually see a lot of consistency between the two phenotypes, if I may, in that there is a heart failure signal or reduction in heart failure hospitalizations that appears to be consistent between the two groups, right? People with an EF of less than 45 with or without heart failure and then on the other side, people without reduced ejection fraction. They're both responsive in terms of reductions in heart failure hospitalization, so it brings into question that is this differences that we're seeing with respect to mortality, a reflection of a difference in phenotypic responsiveness to an SGLT2 inhibitor, or is this simply a reflection of increasing placebo event rates and a response based on baseline of entry in one group versus the other.
So, as has been nicely outlined by the authors, the placebo event rate for CB death and heart failure and the placebo group would have pass, if I may, was about 5 times lower than those with heart failure with reduced ejection fraction. And it might be that as we go up the pyramid of risk, whether that risk is defined based on a TIMI risk score, whether it's based on a post-MI versus stable CAV risk score, or whether it's defined based on GFR, or whether, finally, it's defined based on the event rates for CV death and heart failure, that the higher the event rate, the higher the probability of demonstrating a CV death benefit, but that old strategies are actually demonstrating a consistent benefit on the overall driver of that outcome, which in this case, is a reduction in heart failure.
So, that's what we sort of said in the editorial as well that we think that it may be a bit premature at this point to reach a conclusion that one group is responsive, and the other group is not responsive. But, as you rightfully said, Darren, it is entirely feasible through these analyses to hypothesize that one of the alternative hypotheses could be that there is a greater responsiveness in HFrEF compared to HFpEF. I actually don't understand the mechanisms of it, if that was the pieces I would have a difficult time explaining it based on the overall biology and sort of current understanding of these agents.
But, I would say let’s wait: dapa heart failure is just around the corner. That trial will enroll people with documented heart failure with reduced ejection fraction. I think 4,774 patients that are being randomized on top of base, on top of RNA, on top of MRA, etc. who still have heart failure and who have a BP that's elevated so the definitive proof for this, at least from a rough standpoint, will be forthcoming. And then there are numerous HFpEF studies that are ongoing. There's Emperor Preserve and there's Deliver, and they have characterized the HFpEF population with a little bit more granularity and clarity. And I think we will be able to then look at, specifically, is there a HFpEF group that has the same event rate for CV death and heart failure, and compare that population to a HFrEF group at the same level of risk and whether there is differences in the responsiveness to be definitive about whether this is a matter of risk, threshold, or whether this is a true representation phenotypically.
Dr Carolyn Lam: Subodh is a hard act to follow. So, I will answer your question directly, but maybe not with so many words, because it's already been said, Darren. And I'll just say I expected this benefit to be in both, I wouldn't have said one versus the other, but because we do know that in trials and with prospective studies that HFpEF outcomes are lower, especially mortality is lower, compared to HFrEF. I do wonder if it's a power issue, but the most important message--and this is coming from me also being on the steering on the committee of both DELIVER and EMPEROR Preserve--that please, this doesn't mean that we don't need the trials. I really really think that there's equipoise there still and we need to look at the DEDICATED HFpEF trials.
But, moving on from the concept of risk stratification, I would like to go on and talk about the next paper. About the DECLARE sub-study of those with a prior MI. So, Steve, could you tell us, why did you do this, and what did you find?
Dr Stephen Wiviott: I think that what we've seen as a pattern across the three SGLT2 inhibitor trials including CANVAS, EMPEROR, Outcome, and DECLARE, was that there seems to be, as Subodh has said, reductions that are relatively consistent in heart failure and renal outcomes. But there was what appears to be ischemic outcomes, the MACE outcomes, cardiovascular death, MI and stroke.
In fact, in a meta-analysis that we published at the same time as the primary paper for DECLARE, we demonstrated that there was an interaction between the primary prevention in the population, those without established cardiovascular disease, and the secondary prevention population as it relates to MACE, where the benefits for MACE seem to be in the secondary prevention population.
So, this was seen in DECLARE as well, and so we hypothesized that the population of patients who had myocardial infarction as their entering condition may be particularly at high risk for MACE and it may potentially be that that was driving the benefit. And so, what we did was we stratified the patients based on history of prior myocardial infarction versus none, turned out that there was about 3,500 patients in the trial who had had a prior myocardial infarction. As would be expected from what's known about the conditions, the event rates for those patients in the placebo arm were much higher, about 2.5 times higher than patients without myocardial infarction for MACE, also true for CV death and hospitalization for heart failure.
And then what we saw when we looked at the treatment outcomes was that there tended to be a greater reduction in MACE for patients with prior myocardial infarction. In fact, for the MACE outcome, we saw about a 16% reduction in MACE with patients with prior MI compared to reduction with patients without prior MI. And so, the combination of this higher risk, also a tendency towards a greater relative benefit lead to a much greater absolute benefit, where, in fact, we saw about a 2.5% reduction in MACE over the four-year period for patients with prior MI, compared to a 0% reduction for patients without prior MI.
And, in fact, when we broke this down to three groups: patients with prior MI, patients with atherosclerotic cardiovascular disease without prior MI, and then patients with no atherosclerotic vascular disease, essentially, we saw the same thing, which is that patients with MI were the ones who had the greatest benefit in terms of MACE. And this was almost entirely driven by reductions in myocardial infarction.
Now, I would say in contradistinction, as we look at heart failure reductions, the relative benefits for heart failure were similar among these groups, but because the risk was higher in the patients with prior MI, and of course the absolute benefits were greater in the MI population, and similar for renal outcome. So, I think that this sort of extends what we have previously known that patients with atherosclerotic cardiovascular disease were at higher risk intended to have greater benefit with the SGLT2 inhibitors on MACE events that the core of that appears to be those patients with myocardial infarction.
Dr Carolyn Lam: Thanks, Steve, that was just so clearly explained. Darren, in the last couple of minutes could I ask you to give us the take-home messages from these two studies, and maybe just, what next?
Dr Darren McGuire: I think the take-home message from these two studies in the context of the overall field of SGLT2 inhibitor data, I think the picture's becoming relatively clear and Subodh stated in eloquently before and is reviewed in the editorial is that I think across the board, and independent of how you define higher versus lower risk subsets, this class of medications in general and dapagliflozin, and these studies appear to have augmented benefit, the greater the risk. Whether that greater risk is defined by prior myocardial infarction, or heart failure with reduced ejection fraction, or decreased EGFR, these are all states where various sub studies have consistently shown across the three compounds where we have outcomes data that the treatment benefits are amplified in the higher risk patients.
And it's not just an absolute risk reduction that's augmented based on baseline risk, but there appears to be an interaction where the relative risk reduction is also amplified. And so, it's really a remarkable field and it's providing therapeutic options in these really high-risk subsets of patients where we've really been handicapped up until now with these antihyperglycemic therapies for type ii diabetes.
Dr Carolyn Lam: Thank you everybody for joining us today. This was truly a bonanza feature discussion, didn't I tell you?
You've been listening to Circulation on the Run, thank you for listening today and don't forget to tune in again next week.
This program is copyright American Heart Association 2019
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, Associate Editor of Circulation and Director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Well, Carolyn, our feature article is going to focus on trastuzumab-induced cardiac dysfunction in breast cancer patients. We will discuss with Stanford investigators their use of pluripotent stem cells that are differentiated to cardiomyocytes and subsequently exposed to toxins to determine an individual's susceptibility to cardio-toxicity from cancer treatment. But before we get to that, Carolyn, do you have a paper that you'd like to discuss?
Dr Carolyn Lam: Well, the first paper deals with cardiac biomarkers and asks the questions, can these biomarkers be useful for the diagnosis and risk stratification of syncope?" Now, this paper is from Dr Mueller and colleagues from University of Hospital Basel in Switzerland. They evaluated the diagnostic and prognostic accuracy of BNP, NT-proBNP, high-sensitivity cardiac troponin T, and high-sensitivity cardiac troponin I concentrations, alone and against the ones of clinical assessments in more than 1,500 patients presented with syncope to the emergency department in a prospective, diagnostic multi-center study. Now, cardiac syncope was adjudicated in 234 or 15% of patients. What they found was that the diagnostic accuracy from cardiac syncope, as quantified by the area under curve, was 0.77 to 0.78 for all four biomarkers. That was superior to that of the syncope-specific diagnostic score, EGSYS.
Now, combining the four biomarkers further improved diagnostic accuracy to an area under curve of 0.81. Furthermore, using the four biomarkers at cutoffs achieved predefined thresholds for sensitivity and specificity and allowed rule-in or rule-out of 30% of all patients. Finally, the biomarkers predicted adverse cardiac outcomes with moderate to good prognostic accuracy and better than some of the existing syncope risk-prediction scores.
Dr Greg Hundley: Very interesting, Carolyn. Do you think we can now use this clinically? Should we be drawing these biomarkers on patients with syncope?
Dr Carolyn Lam: These results really do imply that these biomarkers look like useful tools for the early rule-out and/or rule-in of cardiac syncope in the emergency department. After all, these biomarkers are readily available, inexpensive, and results of this study suggest that they have potential to simplify diagnosis and to risk stratify in challenging presentations. However, before embracing the concept of ordering cardiac biomarkers routinely for syncope presentation, we really need to read the editorial by Dr Sandhu and Sheldon, in which important perspectives are presented, such as considerations of the certainty of the diagnosis of syncope, the usefulness of the comparative scores, the timing of testing, the potential unintended adverse consequences of testing. These editorialists concluded that, although promising, further work is needed to determine how the use of cardiac biomarkers should be incorporated into a risk-stratification algorithm.
Dr Greg Hundley: Wow, Carolyn. It sounds like we'd get a lot out of that particular editorial. I'm going to switch over and talk about NT-proBNP in patients with pulmonary hypertension. This is a paper from Dr Kelly Chin from UT Southwestern, and the study evaluated the utility of end terminal pro BNP level thresholds and assessing prognosis in pulmonary hypotension using the GRIPHON study. So GRIPHON is a global double blind, randomized placebo control event driven phase 3 study which assesses the safety and efficacy or a Prostacyclin agonist that promotes pulmonary arterial vasodilation.
They performed the study in patients that were 18 to 75 years old with a diagnosis of idiopathic pulmonary hypertension, heritable hypertension or pulmonary hypertension associated with connective tissue disease, repaired congenital systemic pulmonary shunts, HIV infection, drug use or toxin exposure; and the diagnosis of pulmonary hypertension was confirmed by right heart catheterization and by a reduced 6-minute walk distance of 50 to 450 meters.
Eligible patients were permitted to take their other therapies including Endothelin receptor agonists and phosphodiesterase type-5 inhibitors. The patients were categorized into low, medium and high in terminal BNP level subgroups according to two thresholds. First, by just the tertiles within the study overall and the secondly by the ESC guideline cutoff ranges.
Dr Carolyn Lam: Nice, so what did they find Greg?
Dr Greg Hundley: Well first of all both thresholds either the tertile one of the ESC in follow-up NT-proBNP categories were highly prognostic for future morbidity and mortality. And their time dependent analysis the risk of experience a morbidity or mortality even was 92% and 83% lower in the treated patients with a low and medium NT Pro BNP level. And 90% and 56% lower in placebo treated patients with low and medium NT-proBNP levels. So both, whether you're taking that drug of not, the NT-proBNP levels were prognostically valuable. More pronounced treatment benefit of selexipag was seen in the medium and low proBNP groups. There was a positive value for the interaction term.
Dr Carolyn Lam: Wow, sounds like two really important findings.
Dr Greg Hundley: Yes, exactly Carolyn. So first, NT-proBNP levels are highly prognostic for pulmonary arterial hypertension progression. And having NT-proBNP in the low range, by improving to or maintaining low NT-proBNP levels is a clinically relevant treatment goal for those with pulmonary artery hypertension. And of course as we described this was a very diverse well represented group of many different types of patients with pulmonary hypertension. Then second, while selexipag the study drug was beneficial in all NT-proBNP categories, the treatment effect was greater in those with low and medium categories versus the very high. Suggesting that earlier selexipag treatment may be of greater benefit. But very interesting biomarker study that follows up on yours Carolyn.
Dr Carolyn Lam: Indeed!
Dr Greg Hundley: Carolyn what about your next paper?
Dr Carolyn Lam: Well I want to switch tracks now and talk about iron. And the question is, how does intravenous iron repletion augment exercise capacity in chronic heart failure? Even if hemoglobin doesn't change. So, first some background right, now, besides hemoglobin it's important to recognize that iron is an obligate component of the mitochondrial enzymes that generate cellular energy in the form of adenosine triphosphate and phosphocreatine. So dynamic phosphorous magnetic resonance spectroscopy is a noninvasive tool that can really quantify the in vivo muscle energetics by measuring the kinetics of phosphocreatine recovery after exertion. These authors use this technique, and these are Dr Okonko from King's College, London British Heart Foundation sender of excellence, school of cardiovascular medicine and sciences. The James Black Center in London and colleagues. And what they did was they tested the hypothesis that intravenous iron repletion in chronic heart failure would enhance skeletal muscle energetics as reflected by a shorter phosphocreatine recovery halftime on phosphorous magnetic resonance spectroscopy imagining of the skeletal muscles. And they looked at 40 patients with chronic heart failure with reduced deduction and iron deficiency in a randomized double blind placebo controlled ferric iron and heart failure trial.
Dr Greg Hundley: So, what did they find?
Dr Carolyn Lam: They found that a single total dose infusion of intravenous iron repleted iron stores and augmented skeletal muscle energetics at 2 weeks post infusion. Enhancements in the skeletal muscle energetics which implied better mitochondrial function were accompanies by improved symptoms despite no change in hemoglobin at 2 weeks. So, this trial really provides mechanistic support for iron repletion in patients with chronic heart failure and its very importantly discussed in an editorial by Peter van der Meer, Haye van der Wal, and Vojtech Melenovsky. And I really suggest that everybody read that.
Dr Greg Hundley: Well, I'm going to talk a little bit about dietary omega-6 fatty acids and the incidence of cardiovascular disease and mortality. And this paper is from Matti Marklund from the Georgia Institute for Global Health and the University of New South Wales in Sydney, Australia. The study focuses on linoleic acid which is an omega-6 polyunsaturated fatty acid that we get from pumpkin seeds, flax seeds, walnuts, soybean oil, canola oil and grapeseed. It's been associated with a decrease in cardiovascular risk, but others have worried about an effect of consumption mainly the downstream production of arachidonic acid which can give rise to eicosanoids that are both pro inflammatory and pro thrombotic.
And it's interesting Carolyn, several organizations suggest replacing saturated fat and carbohydrates with linoleic acid. So this study was really performed to address whether consumption of linoleic acid is associated with future cardiovascular events. In the study, investigators measured linoleic acid as well as arachidonic acid levels and from a global consortium across 30 perspective observational studies from 13 countries they performed multi variable adjusted associations of circulating an adipose tissue linoleic and arachidonic acid biomarkers with incident total cardiovascular disease and subtypes of cardiovascular disease including, coronary heart disease, ischemic stroke and cardiovascular mortality and this was all done as pre-specified analytic plan.
Dr Carolyn Lam: Wow, so what did they find?
Dr Greg Hundley: Well did I put you to sleep discussing all of that?
Dr Carolyn Lam: No! You have to tell me what they found. I'm seriously so interested in this topic because being vegetarian I actually get my source of omega fatty acids exactly from these sources.
Dr Greg Hundley: Okay, so Carolyn, higher levels of linoleic acid were associated with lower risk of total cardiovascular disease, ischemic stroke, cardiovascular mortality. While arachidonic acid was not associated with cardiovascular risks. And so, the clinical implications of the results support the potential benefits of main dietary omega- 6 fatty acid. That is linoleic acid for cardiovascular disease prevention. Now, while the trial is not randomized so we don't have definitive answers, the results do not support any theorized cardiovascular harms of consuming omega-6 fatty acids. And there is an excellent review on polyunsaturated versus saturated fat intake by Thomas Sanders from King's College, London as an editorial to this piece. So Carolyn I think we're safe right now in consuming linoleic acid. So how about a transition to our featured article and learn a little bit more about trastuzumab-induced cardiac dysfunction.
Dr Carolyn Lam: Absolutely!
Dr Greg Hundley: Great.
Welcome everybody, we have a fantastic paper to discuss. We're going to review human induced pluripotent stem cell derived cardiomyocytes and how they can be used to identify individuals at risk of trastuzumab-induced cardiac dysfunction after treatment for breast cancer. We have today Nazish Sayed and also Dr Joseph Wu, both from Stanford University in California.
Dr Joseph Wu: Thank you for inviting us.
Dr Nazish Sayed: Thank you.
Dr Greg Hundley: Nazish tell us a little bit about what are these human induced pluripotent stem cells and then also describe your experiment and what were your results?
Dr Nazish Sayed: So, induced pluripotent stem cells is about 10 years ago I knew technology where you can actually turn back the clock by you taking human fiber blast or blood cells and then you can test full reprogramming factors and turn back differentiated cells to pluripotent stem cells will mimic like catalytic stem cells. The catalytics include self-renewal, pluripotency and the most important that they can be differentiated to any cell type in the body. For example, cardiomyocytes or endothelial cells the neuron and kind of mimic these differentiated cells from the same individual from where the IPSCs were derived from.
So, what we did in our study is we used this platform to derive these pluripotent stem cells from patients and then differentiated them into a cardiomyocyte to understand what would these human cardiomyocytes behave in a dish when treated with a Herceptin or trastuzumab and then kind of determine the underlying mechanism for this cardiac dysfunction. It seemed really difficult to model trastuzumab and use cardiac dysfunction as a heart which is the receptor for the trastuzumab is expressed only in humans.
People have usually relied on animal model and for the first time what we did is we used these ideas of cardiomyocytes to model this dysfunction in a dish. Our results were pretty straightforward. We found that the IPSCs cardiomyocytes when treated with the chemotherapy agent showed cardiac dysfunction in the case of decrease contractility. The contraction velocity of these each individual cardiomyocytes is significantly reduced. More with this was also confirmed by having impaired calcium cycling which is very important for the contractility of these cardiomyocytes.
But I think the most important thing which we determined from the study is that individuals who are treated with trastuzumab have a metabolic impairment in these cardiomyocytes which is convenient but however have a severe impact on this contractility and calcium handling in these cardiomyocytes. And that was one of the gist of these papers to figure out the metabolic impairment could be a target where we can improve this cardiac dysfunction in these patients.
Dr Greg Hundley: And so, after you discovered this, I noticed you also did some work with AMPK activators and perhaps would reverse some of the dysfunction. Could you describe a little bit what are AMPK activators and then how did they reverse the dysfunction that you observed?
Dr Nazish Sayed: In our study we characterized these IPS cardiomyocytes from these individuals and then we ran a whole sequencing of them after treatment where trastuzumab to see which of the pathways which could be down regulated or dysfunction when compared to the control patients which are not treated with trastuzumab. And one of the most significant pathways which we found was in PK pathways which was down regulated in the trastuzumab treated IPSC cardiomyocytes. So knowing that the AMPK activators are used for metabolic diseases, for example being diabetes and metabolic dysfunction, we thought that this same thing could be used in a dish where we can take these AMPK activators and simultaneously cotreat cardiomyocytes with Herceptin or trastuzumab to see if we can rescue the phenotype and indeed you can see in our paper we used 4 different AMPK activators with metformin which is a commonly used diabetic drug. Showing the best rescue for that trastuzumab induced cardiac dysfunction.
Dr Greg Hundley: Very intriguing because it looks like you've been able to harvest cells from individuals and then pre-treat them, understand the mechanism of dysfunction, understand who's at risk of dysfunction and then offer therapeutic interventions to perhaps prevent that dysfunction in this patient population. Joe, turning to you now, this is really revolutionary technology it seems to me. Can you describe how long does this process take? Is this something that we see might come into clinical medicine soon?
Dr Joseph Wu: We're really excited about this technology that Nazish has described. I think as you know we've been working on this platform for the past 10+ years. In terms of the timeline, right now it takes us about a month to generate the induced pluripotent stem cells. It takes us another month to expand, propagate the IP itself. It takes us another month to generate the IPS cardiomyocytes. And it will take us probably another month to do all the phenotypic characterization in terms of using these IPS cardiomyocytes to expose them to various chemotherapy drugs and see how the chemotherapy drugs have an effect on these cardiomyocytes.
So, I would say the total timeline is 12 months at this moment. Is it possible that the timeline could be crunched, could be shrunk over time? Yes that's possible, I think the technology is improving month by month, week by week because there are many different labs trying to work on this platform trying to improve the whole process. But right now one of the limitations that as you pointed out is this 4 month time period. And also the cost that's associated with this. But we're hopeful that over time that both the time, the costs can go down so that we can offer this type of platform to help patients diagnosed with cancer, find out what kind of chemotherapy is safe to use, what kind of chemotherapy is not safe to use.
Dr Greg Hundley: So, we're working towards clinical applications but at this point in time it looks like a fantastic platform for understanding, diagnoses and understanding pathways that for patients particularly as they are treated for cancer will experience cardiovascular dysfunction. So, switching a little bit and asking a related question. Patients that receive trastuzumab often also receive doxorubicin. Especially the breast cancer patients. If you looked at this technology trying to understand, and certainly those more at risk for trastuzumab associated left ventricular dysfunction, are the patients that previously received doxorubicin. Have you and your group looked at patients that have also received doxorubicin and then went on to receive trastuzumab relative to those that received trastuzumab alone?
Dr Joseph Wu: I think for these two populations for this particular study, we tried to keep them clean. Meaning that we're looking mostly for trastuzumab treated patients, otherwise it's hard for us to piece out whether the toxicity was due to one medication or the other medication. But what you are asking is very important because as you pointed out many of these patients received both and I think for future studies we should be able to model both medications, meaning that take some IPS cardiomyocytes treated with doxorubicin, treated with Herceptin by itself and treated with both the medications.
In previous studies we have studied using IPS cardiomyocytes the effects of doxorubicin induced cardiac toxicity. In just the assessment, doxorubicin is a very common effective chemotherapy for breast cancer medications and just like Herceptin, the clinicians struggled with the issue, as we cannot predict which patient will develop toxicity. And then granted the doxorubicin induced toxicity has a slight different mechanism compared to perception induced mild cardiac dysfunction that this Nazish had mentioned about. But these are kind of the studies that we're very excited because now for the first time we have a way to model this. Otherwise they alternative would be not possible, for example it would not be possible for us to biopsy breast cancer patients woman's heart to study the cells.
Especially in the case of perception. The receptor that's being studied is not present in animal model cells. For example not present in mouse cardiomyocytes and therefore it would be very difficult to understand the mechanism and this is the reason why the patient specific and disease specific IPS cardiomyocytes become so useful.
Dr Greg Hundley: Do you find another emerging therapy in this entire realm is the immunotherapies? Do you think this technology will be applied to determine susceptibility to immune mediated toxicity?
Dr Joseph Wu: This is a very good question as well Greg. We've been thinking about studying that and as you know, it's a more complicated system because it involves patients’ immune response, the myocardial, to inflammatory infiltrates that happens. So we have a couple projects going on. One is to study direct effect of the immunotherapy on the cardiomyocytes and then the second angle is to take patients who are in full myocarditis and collect their patients urine samples, blood samples and to see if we could expose these IPS cardiomyocytes to the patients urine samples to see what is the effect. For these IPS cardiomyocytes for future studies we're also trying to make it more complicated by generating not just the cardiomyocytes by itself, but generating what we call engineered heart tissues. In which it's a chunk of human heart muscles that would have the patients cardiomyocytes, patients fibroblast, patients endothelial cells and expose them to the patients serum.
But that kind of study would take much longer period of time because the number of people who have these types of immunotherapy induced myocarditis it's relatively low compared to patients who have Herceptin or doxorubicin induced cardio toxicity. This is also part of the reason why we're very much interested in collaborating with big centers throughout the country like York Center to see if we could understand this process better as a team.
Dr Greg Hundley: Excellent. I want to thank both of you for this really elegant discussion and perfect work moving forward. In summary, you've illustrated an ability to withdraw human pluripotent stem cells, differentiate them to cardiomyocytes and then perform tests on them to forecast susceptibility to various treatments used commonly for women with breast cancer. And in this study identifying mechanisms for trastuzumab toxicity. And then perhaps therapeutic interventions using again human cells which has a marked leap as you've identified over doing mouse studies, particularly for studying trastuzumab when the receptors the HER2 receptors in mirroring models differ substantially to those in human subjects.
Dr Joseph Wu: Thank you Greg. And we want to also express our thanks to our collaborators, our colleagues who contributed to the study and most importantly to the patients who helped us with these studies.
Dr Greg Hundley: I want to thank both Nazish and Dr Wu from Stanford and Carolyn and I wish you the best for the coming week and we look forward to speaking with you again next week.
Dr Carolyn Lam: This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, Associate Editor of Circulation from the Pauley Heart Center at VCU Health in Richmond, Virginia.
Dr Carolyn Lam: Are NOACs, or non-vitamin K antagonist oral anticoagulants, safe and efficacious in patients with extremely high or very low body weight? Very interesting paper and discussion coming right up. Greg, I hear that you've got a couple of papers you'd like to highlight first.
Dr Greg Hundley: You bet, Carolyn. My two papers today both focus on ventricular dysrhythmia. The first one, from Yuki Komatsu from Tsukuba, Japan, researches the efficacy of catheter ablation of refractory ventricular fibrillation storm after myocardial infarction. VF storm attributed to focally triggered VF after MI is recognized as a distinctive, lethal, arrhythmogenic syndrome that differs from scar mediated monomorphic VT.
This study investigated the acute and long-term outcomes of catheter ablation for the treatment of last resort in a large series of consecutive patients with post-MI VF storm refractory to medical therapies. In the study, investigators enrolled 110 patients averaging about sixty-five years in age. Ninety-two were men, and their average ejection fraction was approximately 31%. VF storm occurred in the acute phase of MI, about four and a half days after MI-onset, during the index hospitalization in about 39% of the patients. It was sub-acute (that is greater than 1 week later) in 44% of patients. It was remote (greater than 6 months later) in 17% of patients. And the focal triggers were found to originate from the scar border zone in 80% of the individuals.
Dr Carolyn Lam: And what did the study show?
Dr Greg Hundley: So Carolyn, during in hospital stay after ablation, VF storm subsided in 84% of patients and overall, 27% of in-hospital deaths occurred. The duration from the VF occurrence to the ablation procedure was associated with in-hospital mortality, with a P-value of 0.008. During follow-up after discharge from the hospital, only one patient developed recurrent VF storm. Of note though, 36% of the patients died, with a median survival of 2.2 years. And the long-term mortality was associated with a low EF (less than 30%), New York Heart Association class greater than 3 Heart Failure, a history of atrial fibrillation or chronic kidney disease.
So in summary Carolyn, the results of this study show that in patients with MI presenting with focally-triggered VF storm, catheter ablation of the culprit triggers is life-saving and appears to be associated with short and long-term freedom from recurrent VF storm. The overall mortality for these patients is associated with the severity of their underlying cardiovascular disease, and those associated co-morbidities.
Now my next paper is from one of our associate editors, Sami Viskin from Tel Aviv University. He's looking at a new form of polymorphic VT. Now as we think about polymorphic VT, I always think about the long QT interval syndromes associated with Torsades de Pointes. We have specific management strategies for those long QT syndromes, but Carolyn, there's a second category of polymorphic VT that's not related to QT prolongation. This second category involves patients without structural heart disease, who have genetic disorders like Brugada or patients that may have experienced hypothermia. There is also a third category of individuals with structural heart disease, during acute ST elevation MI.
What Sami has discovered is there's now a fourth category of non-QT prolongation, which includes those with coronary artery disease but without evidence of ischemia.
Dr Carolyn Lam: So how did they show or find this fourth category?
Dr Greg Hundley: Well, this is a longitudinal cohort that he identified, and they basically followed forty-three individuals who developed polymorphic VT within days of an otherwise uncomplicated MI or coronary revascularization procedure. The in-hospital mortality was 17% with these patients with arrhythmic storm and the patients were treated with quinidine invariably survived to hospital discharge, just like the other categories of non-QT prolongation polymorphic VT.
During long term follow-up of five and a half years, 16% of patients discharged without quinidine developed recurrent polymorphic VT and there were no recurrent arrhythmias in those individuals that were receiving quinidine therapy long term.
So Carolyn, although quinidine therapy is usually considered contraindicated in patients with organic heart disease who develop ventricular arrhythmias, this therapy may be life-saving for patients with coronary disease developed arrhythmic storms due to polymorphic VT. Polymorphic VT storms may be a transient phenomenon. It's unclear for how long quinidine should be continued in these responsive patients.
Dr Carolyn Lam: Wow, neat! Well, for my two papers I'm going to start off with a basic paper and, in fact, a quiz for you this time, Greg! So, what do cilia have to do with the heart? All right, you get to ask me, do you remember what cilia are?
Dr Greg Hundley: Aren't cilia on prokaryotes? I mean, I think of bacteria.
Dr Carolyn Lam: All right, let me set us straight. The primary cilium is a cellular organelle and it's formed by a protrusion of the plasma membrane that functions as a signaling platform in eukaryotic cells and is found in many cells including neurons, pre-adipocytes and kidney tubular cells, where they have been reported to be involved in a variety of cellular functions such as proliferation, differentiation, cell cycle regulation as well as mechano-chemical sensing of diverse stimuli.
Now, the importance of these cilia is highlighted by the role in several diseases, known as ciliopathies. Polycystic kidney disease is one such disorder with, by the way, numerous cardiovascular manifestations. Whereas ciliated cells have been described in the developing heart, a role for primary cilia in the adult heart has not been reported. It was therefore the aim of these authors and those co-corresponding authors Dr Hill from UT Southwestern and Dr Lavandero from University of Chile, who aimed to identify cells in the adult heart harboring a primary cilium and to determine whether these primary cilia play a role in disease-related remodeling.
Dr Greg Hundley: Carolyn, this is so interesting. I had no idea about these cilia. So what did they find?
Dr Carolyn Lam: So, in a series of elegant experiments, these authors identified for the first-time primary cilia in mouse, rats, and human hearts, specifically and exclusively in cardiac fibroblasts. Now these ciliated fibroblasts were enriched in areas of myocardial injury. Transforming Growth Factor beta-1 signaling and SMAD3 activation were impaired in fibroblasts that were depleted of the primary cilium. Extra cellular matrix protein levels and contractile function were also impaired. And in vivo depletion of PC1 inactivated fibroblasts after myocardial infarction impaired the remodeling response.
Dr Greg Hundley: So how do we use this clinically, and what does it mean for us?
Dr Carolyn Lam: These findings point to a pivotal role of cilia and PC1 in disease related pathological cardiac remodeling and suggest that some cardiovascular manifestations of autosomal dominant polycystic kidney disease, for example, derive directly from myocardium autonomous abnormalities. The findings also uncover novel fibrosis regulators and raise the prospect that this pathway may emerge as a target with therapeutic relevance.
Dr Greg Hundley: Wow, very interesting!
Dr Carolyn Lam: Thanks! And the next paper is also very interesting, in dilated cardiomyopathy and providing insights in how specific viral function may be involved in the development of dilated cardiomyopathy. Looking at the Group B enteroviruses, which are a common cause of acute myocarditis and can be a precursor of chronic myocarditis and therefore dilated cardiomyopathy leading to heart transplantation. In fact, enterovirus-induced dilated cardiomyopathy represents a third of idiopathic dilated cardiomyopathy cases.
So these authors, led by corresponding author Dr Andreoletti from University of Reims, Champagne-Ardenne and Dr Semler from University of California, performed deep sequencing of viral RNA from cardiac tissue from patients with enterovirus related end stage dilated cardiomyopathy and then trans-factored viral RNA clones, mimicking the viral genomes found in patient tissues into primary human cardiac cells to assess their replication activities and impact on cardiomyocyte function.
They found that the major persistent viral forms are composed of B-type enteroviruses harboring 5' terminal deletion in their genomic RNAs. These viruses alone, or associated with full length populations of helper RNAs, could impair cardiomyocyte function by viral enterovirus proteinase 2A activities in these enterovirus-related dilated cardiomyopathy cases.
Dr Greg Hundley: Very interesting, Carolyn. So what are the clinical implications of this viral infection of the heart?
Dr Carolyn Lam: Well, the findings seem to imply that it would be important for us to develop specific inhibitors of enterovirus proteinase 2A activity that might prevent viral replication and inhibit the shut-off of host cell translation as well as the disruption of dystrophin.
Furthermore, in early diagnosed enterovirus induced dilated cardiomyopathy, the use of such protease inhibitors could potentially decrease and stop the chronic pathological process of dilated cardiomyopathy and therefore reduce the need for heart transplantation in this end-stage. Very interesting, but requires more work.
So, that wraps up our summaries Greg. Shall we move to our feature discussion?
Dr Greg Hundley: Absolutely.
Dr Greg Hundley: Today we have Renato Lopes from Duke University in Durham, North Carolina and Brian Olshansky, Professor Emeritus from Iowa now in clinical practice in Waterloo and Mason City, Iowa. We're going to talk about our non-vitamin K oral antagonists, or NOACs, safe and efficacious in patients in extremely high (greater than 120 kg) or extremely low (less than 60kg) of body weight.
Renato, welcome to our podcast in Circulation on the Run. Can you give us a little overview of your study, why you performed it and what results did you experience?
Dr Renato Lopes: The idea behind this study was to provide more data into the use of NOACs in these extreme body weight patients, where we don't have a lot of information. Some guidelines actually caution against the use of NOACs in patients with extreme body weight because of the lack of data.
We had the opportunity to look at the Aristotle database, which was a large, randomized trial comparing apixaban versus warfarin for patients with atrial fibrillation, over 18 000 patients. We took advantage of this database to try to look at the extreme body weight and how those patients at weight more than 120 kg, more than 140 kg and less than 60 kg, performed in terms of the treatment effect of apixaban versus warfarin. This was the rational, to try to provide more data so people could gain additional confidence in using apixaban in clinical practice in those extreme body weight patients.
What we showed was, in general the treatment effect of apixaban versus warfarin for the efficacy outcomes CHOKE, systemic embolism and all cause death and myocardial infarction was very consistent across the weight spectrum and preserved. Apixaban was superior to warfarin and this was consistent regardless of the weight category. For the low body weight patients less than 60 kg, we also found that apixaban results in terms if efficacy was preserved.
So, going out to the bleeding and safety endpoints, apixaban was safer than warfarin across different spectrums of weight. Surprisingly, in patients less than 60 kg we saw an even greater relative risk reduction in bleeding, in patients treated with apixaban compared to warfarin. The main message was for efficacy, apixaban was better than warfarin - the same results as the Aristotle main trial. For bleeding and safety endpoints, we also saw the same results and consistent results with apixaban- in particular with patients below 60 kg, which is always a concern that people might have in clinical practice. It seems that apixaban was even safer with an even greater treatment effect.
Dr Greg Hundley: Very nice. Can you tell us a little bit about some of the sites where you enrolled patients and did you identify any variation in age, sex or region specific factors? Were there any differences in your findings related to race?
Dr Renato Lopes: That is a very interesting question because we know that these variables play an important role in body weight. We enrolled patients from thirty-nine countries in Aristotle, in over a thousand sites all over the world. Interestingly, I can tell you that the heaviest weight we had in our study was 205 kg, a patient from the United States. The lightest weight that we had was 39 kg, from the Philippines. You lose trading the variation that regions of the world can play out and how patients can perform. We haven't seen any major difference in these analogies. There were prior analogies that look at different BMIs, and we know that the treatment effect might be attenuated depending on race and sex. In this analogy, we did not find any significant difference according to race, region of the world or even sex.
Dr Greg Hundley: Just getting back to your body weight measurement, you mentioned percentage of individuals were above 120 kg and briefly mentioned some were above 140 kg. What percentage of your study cohort was that extra-large size, above 140 kg? Do you think more work needs to be done in that area or do you think the results were sufficient for that very heavy body weight?
Dr Renato Lopes: This is a very important question. If we look at the breakdown, we had about 11% of the entire trial in the low spectrum of weight, less than 60 kg in weight - almost 2000 patients. A good number of patients. In extreme weight more than 120, we have about 980 patients. That was 5.5% of the overall trial. When you look at greater than 140 kg, we had 258 patients, 1.4% of the overall trial population and about 25% of this category greater than 120.
I think as we start getting greater than 140 kg, we had 258 patients. It is not a large number of patients. It is some information and it is good to have some data on these patients. Before that, we had no data on apixaban in this level of weight. What we are seeing is that above 140 kg, the death rate are very low. There is a trend to better bleeding endpoints and better bleeding profile with apixaban, similar to what we have seen in the entire spectrum of weight when we look at weight as a continuous variable. We also saw that trend in patients greater than 140 kg for bleeding. This is reassuring. I don't think we can say it is definitive, it is only 260 patients that we are talking about.
It is reassuring that we now have data in patients more than 140 and up to 205 kg, and we didn't seem to see any major concern or any difference in the curves in terms of the direction of efficacy and safety of apixaban. For the majority of patients it is reassuring and gives us extra confidence that the dose we use in clinical practice five milligrams twice daily should also work in those heavy weight and the heaviest body weight patients.
Dr Greg Hundley: Very good. Brian you've done an excellent editorial and I wonder if you could help us put this study in perspective with what we know about NOACs and managing patients with atrial fibrillation?
Dr Brian Olshansky: It really is a fascinating study. Obesity is as growing problem for us here in the mid-west and probably throughout the world. It effects a variety of things including drug pharmakinetics, volume of distribution, drug clearance etc. So knowing how NOACs work at the extremes of body weight, either the massively obese or the vanishingly frail, it becomes important to understand the safety and efficacy of the use of NOACs in these individuals. There are guidelines that caution us against use of NOACs at extremes of body weight, particularly those patients who are over the 120 kg mark. The one point I would like to make is, at least here in the mid-west, 120 kg is becoming almost the norm. We are having people that are becomingly massively obese and this is really the question then in my mind, is what to do with those patients who are over 140 kg or even way more than that. This gets to points that I would like to make about some the issues we need to consider about this study and where we are with our understanding about the use of NOACs in the extremes of body weight.
One thing to keep in mind is, in this analysis, this was a retrospective group analysis. That is one important point. We don't have prospective data that look at an entire large population, a very frail, a very low body weight population.
Another issue is that weight is not a static measure. We only have assessment at the baseline. Variability in weight or body mass index may be important in terms of its relationship to the development of atrial fibrillation and sequelae. The other issue here to consider is that there are comorbidities that are associated with those who are at the extremes of body weight and there was a significant variation in this study in age composition, sex dominance, the region of enrollment, the presence of comorbidities between the different weight groups that could contribute to results we have seen. Those with low body weight had more comorbidities and a higher mean CHADSVASC score, and had the biggest difference between apixaban and warfarin.
We have quite a bit to learn about how to understand these data, and when we consider the individuals who are over 140 kg, indeed there are concerns about the volume of distribution of a NOAC and its efficacy. We would like to rely on this data. The problem is that the number of individuals that are a part of this retrospective analysis at the very high body weight and very low body weights was a rather small number and so to project from that number, what we should do with all of our patients becomes somewhat of a concern.
Although these are interesting and provocative data, what we really need is to have some well-designed large prospective randomized controlled trials that specifically address those individuals at the extremes of body weight because this is becoming more and more of a problem as time goes on. We are seeing more individuals that are at the extremes of body weight. While I have not specifically noticed a difference in my own clinical practice, what we need is a better understanding about the dosing of and potential risks and benefits of the NOACs for the extremes of body weight.
Dr Greg Hundley: On behalf of Carolyn and myself, we really appreciate you listening. Have a great week. We look forward to seeing you next week.
Dr Carolyn Lam This program is Copyright American Heart Association 2019.
Dr Greg Hundley: And I'm Greg Hundley, Associate Editor as well, at Circulation, and Director of the Pauley Heart Center in Richmond, Virginia at BCU Health.
Dr Carolyn Lam: Now, we've heard of the PIONEER heart failure trial and that is a sacubitril/valsartan in acute decompensated heart failure. A very important trial, but was powered on the surrogate outcomes. Now, in today's issue though, we're going to hear a little bit more about the clinical outcomes from the PIONEER heart failure trial, a very important paper, a very important discussion coming right up. Greg, what paper do you have to start us off?
Dr Greg Hundley: Carolyn, I've got another favorite of our little discourse, your next Carolyn's Quiz. Except this time it's essay format, so it's open ended questions. And so here's my question to you. What paper addresses an important issue related to hookah inhalation. So Carolyn, do you know a little bit of the origins of hookah and then how does its use compare to e-cigarettes or conventional cigarettes?
Dr Carolyn Lam: Oh, okay. Well at least the quiz wasn't asking if I smoke hookah. Okay, so hookah, that water pipe smoking pipe, fun stuff. I think, is it a Middle Eastern origin? And frankly I don't know of any data to say whether it is better or worse than cigarette smoking.
Dr Greg Hundley: Yeah, you're exactly right. Hookah, it's a longstanding practice, primarily confined to men from the Middle East. But in the 1990s it was introduced with fruit flavored pre-packaged tobacco products and that ignited a sharp uptake of hookah smoking by young women and also men in the Middle East, and then a migration to our western culture. Now, believe it or not, in the United States and in the United Kingdom, hookah has a prevalence of 15% to 25% among university students. And today, twice as many secondary school children smoke hookah as they do cigarettes, and more adults have tried or currently use hookah than electronic cigarettes.
So, what does this article discuss? Well, it focuses on hookah inhalation byproducts, because the charcoal traditionally is used to heat the hookah tobacco in the water pipe, hookah smoke delivers tobacco toxicants and nicotine plus charcoal combustion products, not only carbon rich nanoparticles and oxidants that may destroy nitric oxide and impair endothelial function, but also large amounts of carbon monoxide, a putative vasodilator molecule that will dilate the arteries independent of endothelial dysfunction.
So, this study enrolled three groups of patients. First, there were 30 26-year-old hookah smokers. Second, there were 20 in which the flavored hookah tobacco product was heated electrically, not by the charcoal. And then finally, 15 age matched cigarette smokers who smoked one cigarette.
Dr Carolyn Lam: Wow, what was the result?
Dr Greg Hundley: Unfortunately, nicotine levels increased similarly with all types of smoking. Now, flow-mediated arterial dilation, a marker of endothelial function, did not become impaired after smoking charcoal heated hookah, but instead increased by about 43%. In contrast, flow-mediated arterial dilation decreased by 27% after smoking electrically heated hookah, compared to the decrease after cigarettes smoking. For hookah smokers, vasodilation increased 138% times more than in the other two groups. Therefore, the acute endothelial dysfunction was masked by those high levels of carbon monoxide that are generated from the charcoal. Remember, carbon monoxide is a very potent vasodilator.
What do we take away from this, Carolyn? With respect to large artery endothelial function, smoking hookah is not as harmless as discussed by an excellent editorial by Naomi Hamburg from the Whitaker Cardiovascular Institute at Boston University School of Medicine.
Dr Carolyn Lam: Oh wow.
Dr Greg Hundley: You know, importantly, the carbon monoxide is blocking our ability to appreciate endothelial dysfunction with traditional measures. So Carolyn, what about your article?
Dr Carolyn Lam: Going from smoking to exercise, this one looking at intensity of exercise that should be performed after heart transplantation. This is a study from Dr Nytrøen and colleagues from Oslo University Hospital in Norway, and they performed a multicenter prospective randomized controlled trial of 81 patients at a mean of 11 weeks only after a heart transplantation. And these patients were randomized to either nine months of high intensity training, which is a four by four minute intervals at 85% to 95% of peak effort, or to moderate intensity continuous training defined as 60% to 80% of peak effort. And the primary outcome was the effect of high versus moderate intensity exercise on the change in aerobic exercise capacity assessed as VO2 peak.
Dr Greg Hundley: So, what did they find here?
Dr Carolyn Lam: First, it's important to note that it is the first study to test this and to show that the effect of nine months of high intensity training in de novo recipients of heart transplants produced a clinically meaningful, significantly larger increase in peak VO2 and muscular exercise capacity compared to moderate intensity continuous training. Importantly, the study also showed that the approach was safe with high adherence and high completion rates. 96% of patients completed the study, during which time the exercise adherence for both groups was 81% and there were no serious exercise related adverse events.
Dr Greg Hundley: Wow. So it looks like we've been hearing about that in training and athletes. Are there any caveats?
Dr Carolyn Lam: Yeah, and that's an important question. High intensity training in this study required one to one interaction with physical therapists, and of course that's not feasible in most cardiac rehabilitation programs. It also requires motivated, medically stable patients who can maintain high exercise intensity ranges. So further research is really required to determine if these initial improvements at peak VO2 and muscular endurance persist in the long-term period post heart transplantation and, of course, whether they're associated with favorable clinical outcomes. All this is discussed in a beautiful editorial entitled "Can a Hit Result in a Home Run?" by Mark Haykowsky, Wesley Tucker, and Peter Brubaker.
Dr Greg Hundley: Carolyn, that's fantastic. In my next study, I'm going to switch over and discuss diabetes and the age of diagnosis of type two diabetes and its association with cardiovascular mortality and risk findings from the Swedish National Diabetes Registry. The study was conducted between 1998 and 2012 and the analysis cohort comprised 318,083 patients with type two diabetes mellitus matched with just under 1.6 million controls. Participants were followed for total mortality, cardiovascular mortality, coronary heart disease, acute myocardial infarction, stroke, heart failure, and atrial fibrillation.
Dr Carolyn Lam: Huge study. Important question. What did it show?
Dr Greg Hundley: Over a median follow up of about five and a half years, patients with type two diabetes diagnosed under the age of 40 years had the highest excess risk for the most common cardiovascular related outcomes. All risk attenuated progressively with each increasing decade. By the time type two diabetes was diagnosed at an age greater than 80 years, adjusted hazard ratios for cardiovascular disease and non-cardiovascular mortality were all less than one. In addition, survival for those diagnosed beyond 80 years was the same as controls, whereas it was more than a decade less when type two diabetes was diagnosed in adolescence.
Dr Carolyn Lam: Okay, so Greg, what does this mean for us clinically?
Dr Greg Hundley: The observations of this study amplify support for preventing and delaying type two diabetes onset in younger individuals and raises questions as to diagnostic strategies, as to whether we should even screen or implement management strategies for those individuals that are diagnosed with diabetes beyond the age of 80 years.
Dr Carolyn Lam: Interesting. Well, for my last paper, I have a basic science paper and this one really provides insights into endothelial dysfunction. It looks at
S-Adenosylhomocysteine, which is a precursor of homocysteine, and elevated levels of these are positively associated with the risk of cardiovascular disease and with development of atherosclerosis, but its role in endothelial dysfunction has been unclear. So authors Dr Ling from Sun Yat-sen University in Guangzhou, China and Dr Ke from Shenzhen Center of Disease Control and Prevention in Guangzhou, China, these co-corresponding authors and their colleagues performed a series of elegant mouse experiments and showed that the inhibition of S-Adenosylhomocysteine hydrolase resulted in elevated plasma levels of S-Adenosylhomocysteine, which then induced endothelial dysfunction via epigenetic upregulation of the p66Shc-mediated oxidative stress pathway.
Furthermore, plasma S-Adenosylhomocysteine levels were positively associated with oxidative stress levels and inversely associated with flow-mediated dilation and methylation of p66Shc promoters in patients with coronary artery disease and healthy controls. So, this study really provides a novel molecular insight into mechanisms by which this molecule, S-Adenosylhomocysteine, may be associated with endothelial injury and contribute to the development of atherosclerosis. So that brings us to the end of our summaries, Greg. Let's move on to our feature discussion.
Dr Greg Hundley: Welcome everyone to the second half of our presentation where we have an outstanding interview with David Morrow from Brigham and Women's Hospital and Dr Justin Ezekowitz from Edmonton to discuss a letter that we've received, "The clinical outcomes in patients with acute decompensated heart failure randomized to sacubitril/valsartan or enalapril in the PIONEER HF trial. David, can you remind us just a little bit about, first, your New England Journal study, and then how this letter adds to the prior findings?
Dr David Morrow: I think it's first worthwhile to place a little bit of context in that paradigm heart failure trial, which was a preceding trial in patients with chronic heart failure, who were ambulatory patients, who had to be tolerating a stable dose of an ACE inhibitor or an ARB, and could not have had a current acute decompensation of their heart failure, were randomized to sacubitril/valsartan versus enalapril with a significant reduction in major clinical cardiac events with sacubitril/valsartan. And that finding from that trial has led to changes in guidelines and clinical practice for patients with chronic heart failure with reduced ejection fraction.
But there were several important aspects that still left gaps for our clinical care, in that because of a run in period in that trial, so a period where patients had to tolerate sacubitril/valsartan, the stability of the patients that I just described, it often left practitioners in the position of caring for patients who might not meet those inclusion criteria, particularly those patients who are hospitalized where there is an opportunity, often, to update their care to be consistent with current standards and current guidelines. And so we designed the PIONEER heart failure trial with that in mind, to study specifically patients with acute decompensated heart failure, all patients with heart failure with reduced ejection fraction. And they were randomized within hospital initiation after an initial period of stabilization to either sacubitril/valsartan or enalapril in a double blind, double dummy design.
The primary endpoint for the PIONEER heart failure trial was a biomarker, so NT-proBNP, and we saw that there was a significantly greater reduction in
NT-proBNP by four to eight weeks as an average endpoint, by 29% more with the sacubitril/valsartan versus enalapril. And we also saw that the adverse events, the tolerability of the two regimens was similar and the event rates did not differ in the sacubitril/valsartan group.
And so that was the primary result of the trial that was published in the New England Journal of Medicine. We had, in addition, some exploratory clinical end points, one of which was a broad composite which included all-cause mortality, the need for an LVAD implantation, referral for transplantation, heart transplantation, as well as rehospitalization for heart failure. And so, what was new in the letter that we have published in Circulation, is that we specifically looked at the clinical end points and additional exploratory end points, looking at the harder composite of cardiovascular death and rehospitalization for heart failure. And we had particular interest in that because it's being used as a primary end point that was consistent with the paradigm heart failure trial that I described in chronic heart failure. That was really the reason for undertaking this additional analysis.
Dr Greg Hundley: So how did you define rehospitalization for heart failure and what did you find?
Dr David Morrow: Rehospitalization for heart failure, we actually used the same clinical endpoint committee as for the paradigm heart failure trial and used the same definition, which requires that patients had clinical evidence of heart failure, which could include both symptoms as well as biomarker values and evidence of congestion on physical exam. We needed graphic evidence of pulmonary edema. Together, they had to have a clinical presentation that was consistent with heart failure, and then also who have been hospitalized for the management of that decompensation.
And so what we found overall was that there was a significant reduction in cardiovascular death or heart failure with the sacubitril/valsartan over the eight week double blind study period, such that it was a 42% reduction in that end point and an absolute 6% reduction in cardiovascular death or rehospitalization for heart failure with sacubitril/valsartan compared with enalapril.
Dr Greg Hundley: And David, looking at these fantastic figures, for listeners, please take a look at this letter, it looks like the two groups separated early. Can you suggest a mechanism for why that might've occurred?
Dr David Morrow: We agree that it does appear that the separation begins early on. We did not have sufficient statistical power to test individual hypotheses much earlier time points, but the relative risk reduction appears homogeneous over that period. And when we look specifically at 30 days, for example, the relative risk reductions are comparable. So we do think that observation you just made is correct and consistent.
And I think that there's evidence of support for rather early effects on hemodynamic stress. So we have the primary end point with NT-proBNP where we saw that there was separation between the groups that was actually statistically significant on that continuous end point of a natriuretic peptide value already by one week of therapy, which was quite remarkable to us. We had planned as our primary end point the four to eight weeks period where we had expected, based on previous work, that there would likely be a reduction in this slightly different population. But in fact we saw those curves in NT-proBNP separate already by one week. We've also had subsequent work that we presented in abstract form looking at other biomarkers such as troponin and soluble SD2, so biomarkers of wall stress and myocardial injury, and also seeing reductions in those markers that appear also to occur early on.
Dr Carolyn Lam: Justin, can we bring you into this conversation here right now? What do you think are the clinical implications of this particular research letter and then perhaps of PIONEER in general?
Dr Justin Ezekowitz: Thanks Carolyn, and my compliments to Dr Morrow and the team for putting this together as a research letter because that's often a challenge to get to the core information from the study. And I would, again, draw the listeners to get a look at the figures that they put together and especially the way in which they separate early out. And we did ask to be cautious with statistical power about rehospitalization, but it's quite a driving factor for the overall end point and one that shouldn't be lost, because that has the biggest probably clinical implications, that the curves separate early between the groups on an ACE inhibitor versus to sacubitril/valsartan. And given they separate early, one of the clinical implications is, why wait? So why wait for when people have been outside the hospital to change the medication but instead use that as an opportunity when they're in front of you as a clinician to consider switching them over to a newer therapy and consider what they’ve been on from the majority of patients being on an ACE inhibitor or an ARB, but it is the right time when you have them in observation.
The second observation I would make from this study is that although this was done in high quality sites and sites that know how to do clinical research, but also those who take care of patients that are on high quality medications, the baseline medication rate use wasn't perfect. So there's dual opportunity for looking at the baseline medications, which was MRAs and beta blockers, and use it as opportunity and an implication to use all the best medications. And in this case sacubitril/valsartan would be an opportunity.
My final point would be, I think this study is critical from a clinician's perspective, as we've seen many biomarker-based studies where there's a reduction in the biomarker, but the clinical end point doesn't seem to change so NT-proBNP is great, but here is the judicated clinical endpoints. So for me, when I'm treating a patient, that means more to me than the lowering of a biomarker. We've seen other evidence where that doesn't always pan out, and so you are confident now that that is the case.
Dr Carolyn Lam: Well put, Justin. And you had a question, didn't you, for David?
Dr Justin Ezekowitz: Right. One of the questions I was trying to sort through, and we couldn't squeeze this fully into the research letter, was there were some patients who were randomized in the hospital but the overall PIONEER program allowed for up to 10 days, and when you look at the patients and when they were randomized and how they were cared for beginning of the hospital, end of the hostel, right after discharge, was there any difference that you saw across the spectrum of outcome?
Dr David Morrow: Actually, the study drug was initiated in hospital for all patients. We did provide up to 10 days while in hospital for the outer limits of recruitment into this study because we recognized that some hospitalizations for acute decompensated heart failure are quite lengthy, and we wanted to give sites the opportunity to recruit patients who took longer to stabilize in this study than others. So it was starting from 24 hours after hospital presentation up to 10 days as a maximum, but all patients were initiated in hospital.
The median turned out to be at 68 hours and at least three-quarters of patients were recruited and randomized within 98 hours. So the vast majority were early on. Overall, when we look at the consistency of the effects of the primary end points of the natriuretic peptide and a broader composite, we did not see any evidence of heterogeneity based on the timing of randomization relative to presentation. As you pointed out earlier, we have to recognize that the numbers do get smaller across that tier, particularly when we get out to the later window. Still. I would say that the primary results, almost in any trial you should always go by the primary result, and we did not see any heterogeneity to think that there was a different effect in those who were enrolled early or late.
Dr Carolyn Lam: David, can I just chime in and say again, congratulations on this great work. Can I go back to one of the points that Justin made a bit earlier? This being a research letter, could you maybe share with the audience a bit, what's it like to write and be constrained to such few words and a single figure?
Dr David Morrow: Well, as Dr Ezekowitz said, it does present a little bit of a challenge. You have to be very concise. We certainly were fortunate that we could leverage the primary publication for the majority of methods and other design elements that we didn't need to recapitulate. And so I think for, in particular, this type of research where there was something that we felt was quite important scientifically with potentially important clinical implications, but yet still was an additional exploratory end point that we could express concisely, the research letter was a very reasonable format to do that.
Dr Carolyn Lam: I couldn't agree more. But Justin, how about from the editor's point of view? Could you share about the research letter?
Dr Justin Ezekowitz: My compliments to Dr Morrow and his team, as I asked him a lot of questions that required both expanding on the things they had to say while constricting the number of words at the same time, and that's a huge challenge to get findings across. So they were able to meet that challenge. I think one of the key things was really honing down as to what the key messages are, as Dr Morrow just alluded to, you can refer to the main complication or a baseline trial publication for all the other details, but what were the core things that could be demonstrated in a publication that is of a limited number of words, tables, or figures. And I think that's the key is, what is the real hypothesis and question to be answered. And that's the way we focused on all the efforts. I did appreciate that it was not easy not to have a lengthy discussion. So we had a ... in the written discussion we have really just truncated this down to a few key sentences which summarize the overall study, so the reader could pick this up and know what the implications are without actually having to go into a lot of the detail that we've just been speaking about.
Dr Carolyn Lam: Ah, I love it. And thank you so much for this conversation too. That helps us go under the hood a little bit. I'm sure everyone who's listening just wants to pick this up now because it's so concise, so beautiful to read, and just look at the figure.
Thank you everyone for joining us today. Don't forget to tune in again next week to Circulation on the Run.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the Journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center, and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor as well, at Circulation, and director of the Pauley Heart Center in Richmond, Virginia at VCU Health. Carolyn, this issue, we've got a super-exciting interaction to follow related to SGL2 inhibitors on 24-hour ambulatory blood pressure in African-Americans, something used to treat diabetes, and maybe a positive effect on blood pressure, but more to come on that. Now, Carolyn, you're also planning to discuss some results from another SGL2 study.
Dr Carolyn Lam: You bet. This time, I'm taking you to Japan for the results of the SACRA study which stands for SGLT2 Inhibitor and Angiotensin Receptor Blocker Combination Therapy in Patients with Diabetes and Uncontrolled Nocturnal Hypertension and this is from Dr Kario and colleagues from Tochigi in Japan. It's a multi-centered, double-blind parallel study of 132 non-obese older adults with type 2 diabetes and uncontrolled nocturnal hypertension, receiving stable antihypertensive therapy, including angiotensin receptor blockers, who were then randomized to 12 weeks' treatment with empagliflozin 10 milligrams once daily or placebo. Clinic blood pressure was performed at baseline in weeks four, eight and 12. Twenty-four hour ambulatory blood pressure monitoring was performed at baseline and week 12 and morning home blood pressure was determined for five days before each visit. The primary efficacy endpoint was changed from baseline in nighttime blood pressure.
Dr Greg Hundley: So, what did they find, Carolyn?
Dr Carolyn Lam: Well, empagliflozin significantly reduced nighttime systolic blood pressure versus the baseline. The reductions in daytime 24-hour morning, home, and clinic systolic blood pressure at 12 weeks with empagliflozin was also greater than placebo. Between group differences in body weight and glycosylated hemoglobin reductions were significant, but small and the changes in antihypertensive medication during the study also did not differ significantly between the groups.
Dr Greg Hundley: Very good. Well, I'm going to switch gears and talk also on the same theme of sugar and diabetes and evaluate the long-term consumption of sugar-sweetened and artificially-sweetened beverages and the risk of mortality in U.S. adults. This is a study by Vasanti Malik from the Harvard School of Public Health. Now, as you know, in epidemiologic studies, intake of sugar-sweetened beverages has been associated with weight gain, a higher risk of type 2 diabetes, coronary heart disease and stroke, but to date, few studies have examined the association between sugar-sweetened beverages and intake and mortality. All right, Carolyn, I'm going to give you a quiz now. Here's the first question.
Dr Carolyn Lam: What?
Dr Greg Hundley That's right, sugar-sweetened beverages are the single largest source of added sugar in the U.S. diet, true or false?
Dr Carolyn Lam: I'm going to guess true.
Dr Greg Hundley: Okay, so all those consumption of sugar-sweetened beverages in the United States has decreased in the past decade. National survey data show a slight rebound in consumption in recent years among adults in many age groups. With the average equivalent being, multiple choice, 2%, 6.5% or 10% of our total energy requirements?
Dr Carolyn Lam: Oh, my goodness. One of the higher ones. I'm just going to go in the middle, 6.5.
Dr Greg Hundley: Excellent, good choice, you're a good multiple-choice taker, 6.5%. So, among younger adults, sugar-sweetened beverages contributed. They're a little bit higher, 9.3% of the daily calories in men and 8.2% in women in the United States. Now, how about other parts of the world, particularly developing countries? The intake of sugar-sweetened beverages, is it dropping, is it flat or is it rising dramatically?
Dr Carolyn Lam: Sorry, Greg, but that one's too easy. It's definitely rising.
Dr Greg Hundley: Yup, you got that right.
Dr Carolyn Lam: I live in those other developing countries, so I've seen so.
Dr Greg Hundley: And it's really thought due to widespread urbanization and beverage marketing. So, now we've got an alternative, artificially-sweetened beverages. And they're often suggested as alternatives to sugar-sweetened beverages and intake levels have increased of these alternative sweeteners in the United States. So, next question. Are the artificially sweetened beverages a better alternative to sugar--sweetened beverages in regard to cardiovascular or all-cause mortality?
Dr Carolyn Lam: Yikes. Okay, so Greg I'm afraid to guess on this one because I have to admit I sometimes, with a sweet tooth, like to take these alternative beverages. I think you're going to be telling us.
Dr Greg Hundley: Well, we don't know. Most of the data in this area is from research and comes from associative analyses utilizing longitudinal cohorts and some studies suggest yes, some studies, no. For example, one in the elderly suggested artificially-sweetened beverages, but not sugar-sweetened beverages were associated with adverse events, but critiques indicated that finding may have related to reverse causation because the elderly patients were switching from sugar-sweetened to artificially-sweetened beverages. So, where are we now? Well this study, in our Journal, examined the associations between the consumption of sugar-sweetened beverages and artificially-sweetened beverages with the risk of total and cause-specific mortality among 37,716 men from the Health Professionals Follow-up Study between 1986 and 2014 and 80,647 women from the Nurse's Health Study from 1980 to 2014, who were free from chronic diseases.
Dr Carolyn Lam: Wow, that's a huge combined cohort. So, come on, what were the results?
Dr Greg Hundley: So, the researchers found after adjusting for major diet and lifestyle factors, consumption of sugar-sweetened beverages was associated with a higher risk of total mortality and cardiovascular mortality and cancer mortality and, thus, the results provide further support for the recommendations and policies to limit intake of sugar-sweetened beverages and to consume artificially-sweetened beverages in moderation did improve overall health. Now, what were the results from artificially-sweetened beverages? Well, they were associated with total and cardiovascular disease mortality in the highest intake category only. So, those consuming large amounts of those daily, but only in the cohort of women from the Nurse's Health Study, not from the men in the Health Professionals Follow-up Study. Artificially-sweetened beverages were not associated with cancer mortality in either cohort.
So, moving forward, the positive association between high intake of artificially-sweetened beverages and total and cardiovascular disease mortality observed among women requires more study and further confirmation and also, we might consider that even though artificially-sweetened beverages could be used to replace sugar-sweetened beverages among habitual sugar-sweetened beverage consumers, higher consumption of the artificially-sweetened beverages would probably be discouraged. Finally, policies and recommendations should continue to call for reductions and limits on sugar-sweetened beverages intake and also address alternative beverage offerings with an emphasis on our favorite, water.
Dr Carolyn Lam: Sweet, Greg! Or maybe not so sweet. Oh, goodness. All right, well my paper deals with related, but not related perhaps, but talking about ketone body, 3-hydroxybutyrate and the cardiovascular effects of treatment with this ketone body in chronic heart failure and this is from corresponding author, Dr Nielsen from Aarhus University Hospital in Denmark and his colleagues. Now, they performed a series of studies. In the first 16 chronic HFrEF patients were randomized in a crossover design to three hours' infusion of 3-hydroxybutyrate or placebo and monitored invasively with a Swan-Ganz catheter and studied with echocardiography and they found that infusion of 3-hydroxybutyrate increased cardiac output by two liters per minute or 40% with an absolute improvement in left ventricular ejection fraction of 8%, and the observed defects were accompanied by vasodilation with a resultant stable systemic and pulmonary blood pressure.
Now, in the second part of the study, they studied eight HFrEF patients examined at increasing infusion rates of 3-hydroxybutyrate and they found a dose response relationship with a significant increase in cardiac output. And, finally, they studied 10 HFrEF patients and 10 age-matched volunteers, randomized in a crossover design to a three hour infusion of 3-hydroxybutyrate or placebo and they looked this time at myocardial external energy efficiency and oxygen consumption using 11-carbon acetate PET and what they found was 3-hydroxybutyrate increased oxygen consumption without altering myocardial external energy efficiency. The response did not differ between HFrEF and age-matched volunteers.
Dr Greg Hundley: Wow, Carolyn, there was a lot of data in that study. So, what's your main take home?
Dr Carolyn Lam: In summary, 3-hydroxybutyrate, this ketone body, demonstrated dose-dependent beneficial cardiac and hemodynamic effects in patients with heart failure reduced ejection fraction without deteriorating mechano-energetic coupling and without causing any safety issues. And what's significant is that this opens the door to modulating circulating 3-hydroxybutyrate as a novel treatment option in patients with heart failure.
Dr Greg Hundley: Right, Carolyn, so I've got an interesting study from the world of basic science that's looking at the role of potassium channels as novel molecular targets and bradyarrhythmia’s and even, perhaps, in atrial fibrillation. This is from Yoshihiro Asano from Osaka University in Japan. So, the acetylcholine activated potassium channel is expressed in the sinus node, atrium, and atrioventricular node and contributes to heart rate slowing triggered by the parasympathetic nervous system. So the potassium, activated potassium channel is a heterotetramer of 2 inwardly rectifying potassium channel proteins encoded by two genes, KCNJ3 and KCNJ5, respectively.
Dr Carolyn Lam: Okay, so what did this study show?
Dr Greg Hundley: What it showed is a selective potassium acetylcholine channel blocker effectively inhibited a mutant potassium channel and up-regulated heart rate and bradyarrhythmias using a zebra fish model. And this is really interesting, Carolyn, because two conclusions are worth considering. First, future studies could determine the prevalence of bradyarrhythmias associated with dysfunctional mutation in this potassium channel. And, second, results raise the possibility that pharmacologic blockade of this channel might serve as a therapy for increasing heart rate and be especially beneficial for bradyarrhythmias in patients with gain of function mutations in the channel and, therefore, genetic testing for KCNJ3 and KCNJ5 in patients with bradyarrhythmias may provide a drug treatment option in lieu of an invasive surgical implantation of a pacemaker.
Dr Carolyn Lam: Fascinating! Thanks, Greg. What a great issue and now onto an even greater feature discussion.
Dr Greg Hundley: Welcome, everybody, to the second part of this interview. We've got a very exciting paper to discuss with you. Remember this is our backstage pass to Circulation and we've got today, Keith Ferdinand from Tulane University in Louisiana and our Associate Editor, our hypertensive expert, Dr Wanpen Vongpatanasin from the University of Texas Southwestern Medical School in Dallas. We're going to be discussing the anti-hyperglycemic and blood pressure effects of empagliflozin in African-Americans with type two diabetes and hypertension. Keith, we're going to start with you. What was your hypothesis for this study? Who's the study population? Review a little bit about your design and, importantly, what were your results?
Dr Keith Ferdinand: Well, my hypothesis was that one of the new classes of medications, the SGLT2 inhibitors, which have a mild diuretic effect and a mild natriuretic effect, may have benefits in self-described African-Americans in not only controlling glucose, but also controlling hypertension. These medicines are approved, of course, as medications for type 2 diabetes, but we had seen in some earlier trials that did not include self-defined African-Americans, that there may be a blood pressure effect. We know that diabetes is higher in blacks, almost twice that seen in the general population and, of course, hypertension and uncontrolled hypertension is disproportionate. So, here's a medication that may be even more beneficial in that population and we wanted to study it.
Dr Greg Hundley: And tell us a little bit about who was in the study and what was your design?
Dr Keith Ferdinand: The design was to be a placebo-controlled randomized trial using empagliflozin starting at 10 milligrams and force-titrating to 25 milligrams versus placebo on the background of conventional anti-hypertensive agents. Everyone was on one or more anti-hypertensive agents. We used the gold standard for blood pressure control with 24-hour ambulatory blood pressure and that was the means by which patients entered the study, although the primary endpoint was changed in hemoglobin A1c, we actually designed and powered the study to see if there would be a change in blood pressure. Additionally, we looked for changes in weight, losing calories with the effects of the SGLT2 inhibitors with glycosuria has translated in some preliminary trials to weight loss. So, this was a study looking at a population. Most of them had diabetes for approximately nine to 10 years, 59 years of age, definite hypertension, obesity, a high risk population, to see if a new class of medications would be beneficial.
Dr Greg Hundley: And what did you find?
Dr Keith Ferdinand: Fortunately, we did find an effect. It did lower the primary endpoint of a change in hemoglobin A1c, but remember it was powered also by blood pressure effect and fortunately, we did see that both with the ambulatory and clinic blood pressure, both at 12 weeks and 24 weeks. The clinic blood pressure was a trend, but the ambulatory blood pressure was positive at 12 weeks and both had a strong difference in terms of confidence intervals for blood pressure lowering. About five millimeters of mercury at 12 weeks and up eight millimeters of mercury at 24 weeks for the change in ambulatory blood pressure which, in a large population would translate into a significant blood pressure lowering, the hemoglobin A1c reduction was also significant. But, although that was the primary endpoint, my concern is as a cardiologist and cardiovascular specialist.
Dr Greg Hundley: And what dose did you select? Did you have to up-titrate this at all and, finally, were there any side effects?
Dr Keith Ferdinand: You know, with the SGLT2 inhibitors, you have an effect both in terms of glycosuria, some osmotic diuresis and some natriuresis, and with the loss of body weight. But the change in body weight really wasn't that much, about 1.2 kilos and the change in blood pressure was discordant with the change in body weight. So, we think that the effects in blood pressure may be from extended diuretic effect, but it may also be from effects on endothelial function that are outside those significantly related to diuresis, per se. Because you're urinating glucose, glycosuria, you would expect the potential for superficial infections, mycotic infections and that was seen. The rates were not prohibitive and not dissimilar to what's been seen in other studies. So, overall, the drug was well-tolerated. It did not have any significant adverse effects outside of a few mycotic infections, which are basically superficial fungal infections and that's been seen in other uses of the SGLT2 inhibitors, but nothing that I think would be unusually disturbing in this population.
Dr Greg Hundley: Outstanding. So, Wanpen, going to switch over to you and ask you to help us put this in the context of treating African-American men, women with hypertension. How do we think about using this new finding? How would we integrate it with other therapies that these individuals already might be taking?
Dr Wanpen Vongpatanasin: Sure, so I think that this study is very intriguing and interesting that empagliflozin to me actually had more prominent benefit on lowering 24-hour blood pressure than the previous study that the true analysis showed the effects of 24-hour blood pressure is much less or almost half of four to five millimeters of mercury and that could be that this was not that significant in African-Americans and maybe this drug is particularly effective and, as you know, African-Americans tend to have more salt sensitive form of hypertension and I wonder if that could explain the results, but I think it's very encouraging because this drug class approved for treatment of diabetes and medication. African-American have higher blood pressures than other ethnic groups and having diabetes makes them prone to having more resistant hypertension. In this particular trial, almost 40% of the patients enrolled is already taking three or more antihypertensive medications, so adding this on top and having that benefit is as good as adding spironolactone, for example, and I didn't see from the manuscript, how many patients are taking spironolactone already, but I would be curious to see that, as well.
But I think that is something that physicians should think about and this drug is already FDA-approved for treating diabetes, so if you have a patient with difficult to control blood pressure and already needed something for diabetes, this could make a lot of sense to use it.
Dr Greg Hundley: Keith, do you have any thoughts on Wanpen's comment regarding the use of spironolactone in the study population?
Dr Keith Ferdinand: No, I don't have those specific data available at the time that we're speaking now, but that's certainly something that I will attempt to look at the database and get more information. But, I think Wanpen is absolutely right. If you look at some of the previous studies, for instance, EMPA-REG, the major outcomes trial that led to the indication of a decrease in cardiovascular death and heart failure, the blood pressure lowering wasn't that robust, maybe 4/2, but here we saw at week 24, 10 millimeters of mercury of blood pressure reduction and if you placebo subtract, which is what I mentioned in my first comments, you're talking about 8 to 8.5 millimeters of mercury reduction and that's a significant reduction, especially for ambulatory blood pressure measurement.
Dr Greg Hundley: Absolutely. So, I'm going to go with each of you separately, but taking this manuscript and this work that Keith, you've performed, we'll start with you. What do you think of the next steps in the research in this area, both from the perspective of using this family of agents in individuals with both diabetes and hypertension?
Dr Keith Ferdinand: What I would hope in the future is another outcome study is done with an SGLT2, any numbers of that class, that they particularly target enough African-Americans to see if this robust blood pressure reduction not only is found again, but also translates to decreased cardiovascular events. You know, NHLBI, for instance and ALLHAT, selectively over-represents African-Americans. They had 35% African-Americans in ALLHAT and the reason for that is you have a population that has a disproportionate degree of hypertension and a disproportionate degree of associated cardiovascular disease and renal disease, so you want to make sure that any medication that's been shown to be effective is effective in the higher risk population. So a future outcome study, regardless of whether they're renal-based or related to heart failure, I hope will target an increased population of blacks to see some of the robust reduction we have, translates in cardiovascular events.
My suspicion is that self-defined African-American versus a genetic factor, describes the phenotype of patients who tend to be more obese, have more salt sensitivity, perhaps subclinical kidney disease and will respond to a medication that has some diuretic natriuretic effects and effects with endothelial dysfunction and sympathetic discharge.
Dr Greg Hundley: Very good, well I heard sympathetic discharge. Wanpen, any comments there? That's your area.
Dr Wanpen Vongpatanasin: I think that definitely needs to be studied. To my knowledge, there was only one small study that published that tried to measure sympathetic nerve activity directly, but unfortunately that study after a very short-term treatment for like four or five days, so I’m sure that there will be more studies to come and also hope that the future study will shed light on any particular markers with surrogate that will identify patients that will respond better, for example, PATHWAY-2 trials that were done to test the effects of spironolactone on resistant hypertension they found that the lower the reading, the more likely you can have better response to Aldactone and I wonder if this might apply to empagliflozin and be something else. I think the fact that the blood pressures continued to decline from the week 12 to week 24 is very, very interesting when the body weight effect doesn't necessarily go down much further. This really tells us there's something else beyond weight and perhaps glucose that would explain this.
Dr Greg Hundley: Very good. Well, I certainly want to thank you both for this outstanding discussion. Keith, we want to thank you for bringing this manuscript to Circulation and identifying this new application for this therapy in African-Americans. Wanpen, thank you also for your time and comments.
On behalf of Carolyn and myself, we really appreciate you listening. Have a great week and we look forward to seeing you next week.
Dr Carolyn Lam: This program is a copyright of American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor as well at Circulation, and director of the Poly Heart Center in Richmond, Virginia, at VCU Health. Well, I'm going to talk about anti-hyperglycemic agents and look at a very important meta-analysis.
Dr Carolyn Lam: Those are the rage: GLP-1 receptor agonists and SGLT-2 inhibitors. But first, let's talk about psychosocial stress and cardiovascular health. So what is the joint impact of multiple stressors on racial or ethnic disparities in cardiovascular health?
Well, this question was tackled by Dr Albert, from University of California San Francisco Center for the Study of Adversity and Cardiovascular Disease and her colleagues. They basically studied more than 25,000 women participating in the women's health study follow-up cohort, and examined the relationship between cumulative psychosocial stress and ideal cardiovascular health as defined by the American Heart Association Strategic 2020 Goals.
As a reminder, this health metric includes smoking, BMI, physical activity, diet, blood pressure, total cholesterol and glucose, and higher levels indicate more ideal cardiovascular health and less cardiovascular risk.
So, they found that both cumulative psychosocial stress and ideal cardiovascular health varied by race or ethnicity. Mean cumulative psychosocial stress scores were higher in Hispanic, Black, and Asian women compared to white women, even after adjusting for age, socioeconomic status and psychological status such as depression and anxiety. The mean ideal cardiovascular health scores remained worse in blacks and better in Asians compared to whites, despite taking into account socioeconomic factors and cumulative psychosocial stress.
Dr Greg Hundley: So Carolyn, how should clinicians incorporate this information in what we do every day?
Dr Carolyn Lam: Although the cumulative psychological stress and socioeconomic status did not fully explain the racial or ethnic differences in ideal cardiovascular health that we saw, clinicians should be informed by these data that psychosocial stressors are social determinants of health that have different prevalence according to race and ethnicity. I think that's what we need to learn. And of course these data support the need for additional work that addresses the joint impact of multiple social determinants of health on cardiovascular disease and in diverse populations.
Dr Greg Hundley: Very good, Carolyn. That was really an interesting article. Well, I'm going to switch gears and talk about the role of red blood cells in promoting vascular calcification. My article is from Dimitrios Tziakas from the Department of Cardiology in Thrace, Alexandropoulos, in Greece.
Now, the presence of extravasated erythrocytes in human atherosclerotic lesions was described several years ago, but little is known about a possible active role of red blood cells during these cardiovascular disease processes. Clinical studies suggest that intraplaque hemorrhage may be associated with the progression of coronary, carotid, and atherosclerotic lesions and degenerative calcific aortic valve stenosis. So, in the present study, the authors examined the contribution of erythrocytes to vascular and valvular lesion progression, focusing on the effects of red blood cells on the osteoblastic transdifferentiation of smooth muscle cells in calcification.
Dr Carolyn Lam: Interesting. So, what did they find?
Dr Greg Hundley: So, lysed erythrocytes, and in particular their membrane faction, enhanced human and murine arterial smooth muscle cell mineralization and vascular aortic ring calcification. Red blood cell membranes injected in the vascular regions of atherosclerotic-prone mice also promoted calcification and red blood cells were found to co-localize with osteoblast like cells in human atherosclerotic plaques, stenotic aortic valves, and abdominal aortic aneurysms. And so, the study demonstrated that intra plaque hemorrhage promotes atherosclerotic and valvular lesion calcification and membranes of extravasated lysed red blood cells appeared to play an important role in the process. The investigators also showed a mechanism, that nitric oxide derived from erythrocyte endothelial nitric oxides synthase is involved, at least in part, in mediating the effects of red blood cells on vascular calcification.
Dr Carolyn Lam: Thanks, Greg. Now back to another, well, clinical paper with the next one asking, do mid-life biomarkers of heart and kidney damage associate with the level of and decline in physical capability with aging? Dr Kuh and colleagues from MRC Unit of Lifelong Health and Aging at University College London used data on 1,736 men and women from the oldest British birth cohort study. And, looked at their walking speed, chair rise speed, balance time, and grip strength. Assessed at ages 60 to 64 and 69 years. They tested the associations between Cystatin C, NT-proBNP, interleukin-6, and E-selectin all at ages 60 to 64 years with their performance at 69 years. And what they found was the lower levels of NT-proBNP in interleukin-6 in middle aged adults were independently associated with better physical capability up to nine years later. And all these associations were stronger than those observed for conventional risk factors: including lipids, blood pressure, and glycemia, and were not explained by the onset of cardio vascular and kidney disease or diabetes.
Dr Greg Hundley: Carolyn, is this saying we should now measure these biomarkers in mid-life?
Dr Carolyn Lam: Ah, before considering the use of NT-proBNP and IL-6 or interleukin-6 for risk stratification, we really do need further research to untangle whether these associations exist because the biomarkers are an integrated measure of accumulated exposures to stressors. Or, whether they are really capturing early an organ damage. Or, whether they are marking additional risk pathways. So, this and more is discussed in a great accompanying editorial entitled "Putting the Measurement of Physical Capacity in Older Adults in its Place". And that's by Dr Kritchevsky from Wake Forest School of Medicine.
Dr Greg Hundley: That's a favorite of my heart, Caroline. The old institution Wake Forest. But, I'm going to switch now and tell you a little bit about plasma ceramides and this is an article from Wei Zhao from the Department of Epidemiology in Population Health at Albert Einstein College of Medicine in Bronx, New York. The study evaluates the role of ceramides and what are those? Well, they're a class of bio-active lipids composed of sphingosines and fatty acids. And are involved in the development of cardiovascular disease. Elevated circulating levels of ceramides have been shown to be associated with increased risk of cardiovascular events, cardiovascular death, and even so, after adjusting for other cardiovascular disease risk factors. Now, interestingly, ceramide metabolism has long been noted to be closely related to HIV infection. But, the relationship has not been fully understood. HIV infected cells may cause enhancement of sphingomyelin volume breakdown and accumulation of intercellular ceramides, whereas intercellular accumulation is associated with enhanced replication of HIV.
So, what did this study do? They evaluated circulating levels of four ceramides species which have been investigated in previous studies of non-HIV populations. And were measured in 737 women and men, 520 HIV infected and 217 HIV uninfected from the Women's Intra-Agency HIV Study and the Multi-Center Aids Cohort Study. And they compared the relationships with the progression of carotid artery disease assessed by B-mode ultrasound over a seven year period.
Dr Carolyn Lam: Interesting approach. So, what did they find?
Dr Greg Hundley: Elevated ceramide levels were associated with anti-retroviral therapy use. Particularly, protease inhibitor use HIV infected individuals. All four ceramides were highly correlated with each other and significantly correlated with total cholesterol and LDL cholesterol. And of note, remember they were measuring four, but C16:0 and C24:1 ceramides rather that C22:0 and C24:0 ceramides were more closely correlated with specific modified activation and inflammation markers and, surface markers of CD4 t-cell activation. Elevated plasma levels of C16:0 and C24:1 ceramides were also associated with progression of carotid artery atherosclerosis. So, in summary, the results of this study provide new information on biological mechanisms that may involve the specific mono-site activation and inflammation beyond cardiovascular disease traditional risk factors like cholesterol levels. For the association between ceramides and CVD, particularly among individuals living with HIV infection.
Dr Carolyn Lam: Fascinating. Thanks, Greg. Now that sets us up for beautifully for our featured discussion.
Dr Greg Hundley: Welcome everyone, to our podcast. My name is Greg Hundley and we've got a very exciting paper for the second part of our program today. With us we have Dr Thomas Zelniker from Brigham and Women's Hospital. And then, also, a guest editor, Dr John McMurray from Glasgow, Scotland. We're going to be discussing a meta-analysis in type 2 diabetic patients. Thomas, can you tell us a little bit about the study population, your design, and what where the outcomes that you saw in this study.
Dr Thomas Zelniker: As you know, the last half decade, members of two drug classes, GLP1 receptor agonists and SGLT2 inhibitors, so our goal was to provide clear context by comparing or contrasting the benefit of these two drug classes, and in particular to investigate the potential heterogeneity in the treatment site between patients with and without atherosclerotic cardiovascular disease. For that reason, we performed meta-analysis of all randomized partially controlled cardiovascular outcome trials of GLP-1 receptor antagonists and SGLT-2 inhibitors. We included data from more than 77,000 patients, nearly 43,000 patients coming from the five GLP-1 receptor antagonist trials and approximately 34,000 patients coming from the three SGLT-2 inhibitor trials. We tried to compare patients with those with known established atherosclerotic cardiovascular disease with those that have multiple risk factors for but no evident ASCVD. And as you can see, our interests included MACE, or major atherosclerotic cardiovascular events, and its individual components, MI, stroke and cardiovascular death. And then we looked at hospitalization for heart failure and progression of kidney disease. The progression of kidney disease was defined as one of the broad composites consisting of new onset of macroalbuminuria, worsening of eGFR, end-stage kidney disease, or death due to renal cause. And then we also had a more narrow kidney outcome which excluded macroalbuminuria.
Dr Greg Hundley: Thomas, did you observe differences in the types of events between the two agents, as they would have impacted hospitalization for heart failure or the progression of renal disease?
Dr Thomas Zelniker: Right. So foremost both trial analyses reduced the risk of MACE, major atherosclerotic events, but the reduction of MACE was actually confined to those patients with atherosclerotic cardiovascular disease. We saw a 40% reduction in patients with known ASCVD, where neither of these groups reduced the risk of MACE in patients with only multiple risk factors but without ASCVD. Now, in terms of the individual components of MACE, both trial analyses reduced the risk of myocardial infarction cardiovascular death but only GLP-1 receptor agonist reduced the risk of stroke. In contrast, as SGLT-2 inhibitors vastly reduced the risk of hospitalization with heart failure by more than 30%, where there was only a non-significant 7% relative risk reduction with GLP-1 receptor antagonist.
GLP-1 receptor antagonists also reduced the broad kidney composite outcome. However, this effect was mainly driven by reduction macroalbuminuria. When excluding macroalbuminuria we found a non-significant relative risk reduction by 8% and this stands in contrast to a very robust relative risk reduction with SGLT-2 inhibitors of more than 45%.
Dr Greg Hundley: Thomas, you mentioned there was a difference in benefit for those with existing cardiovascular disease versus no-known cardiovascular disease upfront. What do you think the reason for that might be, and then did you have the same number of patients in the non-cardiovascular disease group? Did you have enough events in that group? And finally, do you think we might need to follow that patient population a little bit longer in time, to see those events as they didn't have pre-existing cardiovascular disease?
Dr Thomas Zelniker: These are fantastic points. I personally think it's biologically plausible that both drugs and receptors have the same benefit in both patient population to treatment effect may just require more time to become evident in patients with lower risk. You also mentioned a very good point, we had substantially more events in the patient cohort with ASCVD.
Dr Greg Hundley: Very good. So John, we want to turn to you now. Can you help us put those results of this study in perspective? Can you put this into context for us with other published reports using these particular ages?
Dr John McMurray: Certainly Greg, and I'd like to congratulate Thomas on what very important and very timely meta-analysis because, of course, what Thomas and his colleagues have done Greg, is to put all these studies together, to give us what meta-analysis does, which is much more power to look, for example, at components of composite outcomes, and we will in that way compare and contrast the differences and similarities between these two treatments. And as Thomas has mentioned, so interesting differences stand out but there are also some similarities that perhaps were not clear from the individual trials and I suppose the one that would perhaps stand out to me and might not have been realized by many of our readers, is myocardial infarction, that seems to be reduced to pretty much a similar extent by both GLP1 receptor antagonists and SGLT-2 inhibitors.
I think there had perhaps been a view out there from the individual trials, that maybe GLP-1 receptor antagonists have more effect on atherosclerotic events and SGLT-2 inhibitors more effect on heart failure and renal events and to some extent that's true, both agents seem to reduce myocardial infarction to approximately the same extent. Which in itself is interesting, perhaps raises some mechanistic questions. I mean, the differences that stood out is stroke is reduced by GLP-1 receptor antagonists but not by SGLT-2 inhibitors and conversely heart failure which is the opposite, which is by SGLT-2 inhibitors, but not by GLP-1 receptor antagonists in this meta-analysis.
So, I suppose, in summary what this tells us is that these drugs have complementary, perhaps additive cardiovascular benefits. Together, they potentially reduce the whole spectrum of the adverse cardiovascular events that occur in our patients with Type 2 diabetes, especially those who've got established cardiovascular disease.
Dr Greg Hundley: And so, just a last question here, for both Thomas and John, if you're considering in your practice, you have a diabetic patient that's not on these, one of these agents, and they have existing cardiovascular disease, how do you go about considering the addition or the switch to this type of medicine, and what practices do you use to effect that change?
Dr Thomas Zelniker: I guess, looking at patients, so we know that both drug classes have great benefits from MACE, right, but to people on antagonists having also reductions in stroke. So probably the associated risk is in the focus, I would probably rather go with the GLP-1 receptor antagonist. While looking at it from the heart failure perspective, or from the renal perspective, we see obviously bigger advantages attributed to inhibitors.
Dr Greg Hundley: And John, how about you?
Dr John McMurray: I would agree with Thomas' perspective, although I might add just a little caveat which is, of course, that the prevention of heart failure which is what, I think, the clear benefit of SGLT-2 inhibitors is, prevention of heart failure is different to the treatment of heart failure. So, patients at risk of heart failure sadly, an SGLT-2 inhibitor would make sense, but when it comes to patients with established heart failure event, of course we will get that answer because one of the great things about this recent incredible development of new therapies for diabetes, is that now there are now more studies underway including remarkable five trials in patients with different heart failure phenotypes, patients hospitalized, patients in the community, so we will learn a lot more about the use of these drugs, in particular cardiovascular populations.
Dr Greg Hundley: Excellent. I want to thank both Thomas Zelniker from Brigham and Women's Hospital and John McMurray, guest editor from Glasgow, Scotland for helping us work through this just fantastic meta-analysis study pointing us in a new direction for utilizing medications to treat diabetes and those that we see every day, with cardiovascular disease.
On behalf of Carolyn and myself, have a great week and we look forward to seeing you, next week.
Dr Carolyn Lam: This program is copyright American Heart Association, 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the Journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center in Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, also associate editor of Circulation and director of the Poly Heart Center at BCU Health in Richmond. Carolyn, we've got a really exciting interview to follow our coffee chat and it's evaluating individuals with low complexity congenital heart disease. We often think of those with high complexity congenital heart disease and looking at their cardiovascular events. We're going to hear a little bit about low complexity congenital heart disease.
Now you've got a paper you wanted to talk about first.
Dr Carolyn Lam: Absolutely. You've got to hang on for that because I'm going to delve into chromatin architecture in heart failure, and it's in this paper from corresponding author Dr Foo from Genome Institute of Singapore.
So, as background, the human genome actually folds in 3D to form thousands of chromatin loops within the nucleus encasing the genes and assists regulatory elements for accurate gene expression control. Now, these physical tethers of loops are anchored by the DNA binding protein CTCF, also known as the weaver of the genome and the cohesion ring complex. Now, the role of CTC in binding and changes in chromatin structure in heart failure are not well understood. Well, until today's paper.
What the author said is they undertook an independent analysis of chromatin organization with mouse pressure overload model of myocardial stress or transverse aortic constriction, and a cardiomyocyte specific knockout of CTCF. So, interestingly, they found that the cardiac chromatin architectural in adult terminally differentiated cardiomyocytes was unchanged in pressure overload from transverse aortic constriction. Now this was completely unlike the CTCF knockout model where they verified that there was generation of vast genome-wide loss of genomic insulation and near complete abolition of the CTCF chromatin loops.
Instead of chromatin rewiring on the scale of that knockout, the myocardial stress response appeared to proceed through enhancer H3K27 acetylation epigenetic changes and gene network co-regulation driven largely by fixed cardiac 3D chromatin architecture. In other words, a stable chromatin architecture really set the stage for accurate enhancer promoter interactions required for basal gene expression control and induction of the classical myocardial stress gene response.
Dr Greg Hundley: So Carolyn, are there therapeutic implications here for this?
Dr Carolyn Lam: Now of course, that was preclinical work, but it really opens the door to consider these epigenetic regulators that control disease expression changes and interacting gene sets in heart as potential future targets for novel heart failure therapy.
Dr Greg Hundley: Very interesting. So, I'm going to review and switch gears a little bit and focus on diabetic cardiomyopathy and mitochondria associated endoplasmic reticulin membranes. And this paper is from Shengnan Wu from the Center for Molecular and Translational Medicine at Georgia State University here in the US in Atlanta, Georgia. So as we all know, mitochondria are essential for cellular energy production, but when they're damaged, they become a major source of reactive oxygen species and pro-apoptotic factors. In particular, increasing evidence suggests that mitochondrial dysfunction is a central event in diabetic cardiomyopathy.
Well, the mitochondria and the endoplasmic reticulum are key players that regulate many cellular functions and their structural and functional interactions are essential for cellular homeostasis. The contact points, however, through which the endoplasmic reticulum communicates with mitochondria, they're known as mitochondria associated endoplasmic reticulum membranes, or MAMS. Importantly, MAMS play a pivotal role in calcium signaling, lipid transport, energy metabolism and cell survival, and they've been implicated in a variety of diseases, including Alzheimer's Disease, cancer, lysosomal storage diseases, diabetes, obesity induced mitochondrial dysfunction and other metabolic disorders.
But the role of these MAMS in the initiation and progression of Diabetic Cardiomyopathy is really unknown. So now, FUNDC1 is a highly conserved protein that's exclusively localized to the mitochondria. And this group had previously demonstrated that FUNDC1 was essential for maintaining the structure of MAMS and ensuring appropriate calcium transfer from the endoplasmic reticulum to the mitochondria normal hearts. Moreover, cardiac specific deletion of FUNDC1 induced cardiac dysfunction by inhibiting MAM formation.
Dr Carolyn Lam: Interesting. So that was their prior work? What did the current study show?
Dr Greg Hundley: Right, so what the investigator showed in this study is that high glucose driven inactivation of AMP-activated protein kinase increased FUNDC1 stability, but resulted in aberrant MAM formation, impaired mitochondrial calcium increase, mitochondria dysfunction and then cardiac dysfunction. And additionally, AMP-K activation reverses Diabetic Cardiomyopathy by suppressing high glucose induced MAM formation, mitochondrial calcium increase and mitochondrial dysfunction.
And interestingly, Metformin, an AMP-K activator, used exclusively for Type 2 Diabetes, might be effective in treating Diabetic Cardiomyopathy in individuals with Type 1 Diabetes. So a very interesting mechanistic study providing some information of how MAMS, mitochondrial function and endoplasmic reticulum could be important in understanding how to prevent Diabetic Cardiomyopathy.
Dr Carolyn Lam: Indeed. And you know, that last note that you made on Type 1 Diabetes, also links very well with the next paper that I chose. Which really asks the question, in Type 1 Diabetes, what are the relative prognostic importance and optimal levels of risk factors for mortality and cardiovascular outcomes? And this comes from Dr Rawshani and colleagues from the Swedish National Diabetes register who studied more than 32,600 patients with Type 1 Diabetes in their national observational cohort study from the Swedish National Diabetes register, with a mean follow-up of 10.4 years and a mean duration of diabetes of 17.9 years.
They found that the most important predictors for outcomes were HP-A1C, albuminuria, duration of diabetes, systolic blood pressure and low-density lipoprotein cholesterol, or LDL cholesterol. Now, the lower levels of HP-A1C, systolic blood pressure and LDL cholesterol than contemporary target levels were associated with lower risk for outcomes. Albuminuria was associated with a two to four times greater risk of cardiovascular disease and death. And each millimole increase of LDL cholesterol was associated with 35 to 50% higher risk for outcomes.
Dr Greg Hundley: Boy, Carolyn, those are interesting results. So, what do we take away from this in clinical management of patients?
Dr Carolyn Lam: The take home message is that in patients with Type 1 Diabetes, the strongest predictors for mortality and cardiovascular disease, with the exception of age, were mostly conventional and modifiable cardio-metabolic risk factors. And this in turn suggests that increased clinical focus on these risk factors, particularly in primary prevention, may result in the largest relative risk reduction for mortality and cardiovascular disease, even in Type 1 Diabetes. So, future clinical trials may be designed to test these findings.
Dr Greg Hundley: Very good. Well, Carolyn, my next paper, I'm going to talk about five year outcomes after off-pump versus on-pump coronary artery bypass grafting in those over the age of 75 years. And this paper comes from Anno Diegeler from Bad Neustadt in Germany. From June of 2008 to September of 2011, they evaluated a total of 2,539 patients that were 75 years or older, who had been randomly assigned to undergo off-pump or on-pump coronary artery bypass grafting across 12 centers in Germany.
And the primary outcome was all cause mortality at five years, and the secondary outcome included a composite of death, myocardial infarction and repeat revascularization. What did they show in this study? Well, after a median follow up of five years, the hazard ratio for off-pump versus on-pump coronary artery bypass grafting was 1.03, confidence interval 0.81 to 1.19, no difference. The composite outcome of death, myocardial infarction and repeat revascularization, the same. Hazard ratio 1.03, confidence interval 0.89 to 1.18, P-value 0.7.
So, first take-home message, no difference if you had your surgery off-pump or on-pump, if you're over the age of 75. Now, another outcome related to incomplete revascularization. And what was striking I this study is whether you underwent on-pump or off-pump bypass, if you were incompletely revascularized, that was associated with both the primary as well as the secondary outcomes. So, in elderly patients, in summary, greater than or equal to 75 years, the five year survival rates as well as the combined outcome of death, MI and repeat revascularization, was similar for on-pump versus off-pump CABG. And incomplete revascularization was associated with a lower five year survival rate, irrespective of the type of surgery that was performed.
Dr Carolyn Lam: Interesting. Beautifully summarized, Greg. Thank you.
Dr Greg Hundley: Absolutely. And let's head on to that featured article.
Well, welcome everyone to the second half of our program. We are very excited today to have Dr James Priest, from Stanford University School of Medicine. And also our associate editor Gerald Greil from University of Texas Southwestern School of Medicine in Dallas. And we're going to be discussing the article, Substantial Cardiovascular Morbidity in Adults with Lower Complexity Cardiovascular Disease.
So, James, first could you tell us a little bit about what constitutes low complexity congenital heart disease? And then a little bit about your study population, your design, and the results that you found with your study?
Dr James Priest: So, low complexity congenital heart disease really derives from definitions of congenital heart disease in adults that are grown up and have different complexity of lesions. And so high complexity congenital heart disease, you see things that, as people may remember, adult cardiologists may remember from their training. People remember from medical school, things like single ventricle disease, hypoplastic left heart, tetralogy of fallot, transposition of the great arteries. But, non-complex, so our low complexity disease, really constitutes a relatively simple malformation. Things like atrial septal defects, ventricular septal defects, patent ductus arteriosus. Things that are treatable with a single surgery.
You close the hole, you ligate the vessels, you dilate the valve, and the patient is affectively cured. So relatively low complexity diseases that can be treated with typically, a single surgery or minimal interventions to restore completely, or essentially normal, cardiovascular physiology.
So, the study was based upon a very large you know, volunteer data set, the UK Biobank. It comes from the United Kingdom where 500 thousand individuals enrolled, and from those individuals there is genetic information, medical histories dating back to the 1990s, self-reported history. A variety of functional and neuropsychiatric measures. And if you get a group of 500 thousand individuals from anywhere, there's going to be some congenital heart disease in there. And so, we looked to see what types of congenital heart disease were in there. And in fact, there was lower complexity individuals.
And because I spent some time on the research side of things with my adult colleagues, the first thing we looked at were from the common adult cardiovascular outcomes, things people write about in Circulation all the time. Coronary artery disease, atrial fibrillation, heart failure. We know these things are problems in adults with complex cardiovascular disease, but nobody had really looked for the most part in adults with low complexity or non-complex disease. And we were surprised to see such high event rates for these common adult cardiovascular conditions.
Dr Greg Hundley: So, what type of events did you appreciate in the population in follow up?
Dr James Priest: So, we really appreciated about a two-fold rate of let's say, acute coronary syndrome relative to the general population. Up to almost 13 fold risk of atrial fibrillation and heart failure, relative to the general population. So, really substantial and very impactful event rates.
Dr Greg Hundley: Very good. And so, just a couple points of clarification. Do you think that the events you observed, were they related to the congenital heart disease, per se? Or could it have been a result from the surgical procedure to treat that heart disease?
Dr James Priest: So, that's a great question. I think, in some ways, that's the fundamental question that the paper leads to. So, we thought of it in two different ways. You know, one, were these events, and they're perioperative events, for individuals receiving some type of care for their congenital heart disease, during their adulthood? And we performed a sensitivity analysis where we basically looked at those events and then looked for events occurring within a year of adult interventions. And we saw no difference in those event rates. So, they weren't perioperative or postoperative events in adults receiving adult congenital heart disease care.
The second part of the question is really more of an existential question in some ways. You know, is there some fundamental relationship between the care these people received as children? Or the genetic basis of congenital heart disease in the first place that is somehow put people at risk long term for adult cardiovascular disease, acquired adult cardiovascular disease? And I think there's indeed a lot of different ways to try and get at that question and explore that more, which we're currently working on.
Dr Greg Hundley: So, Gerald, I wanted to turn over to you now and, in your practice that encompasses those that are young adults that have this low complexity congenital heart disease, how do you manage them now? And how might the results of this study suggest, potentially, a different management strategy?
Dr Gerald Greil: Usually these patients, they're kind of thought to be cured or only needed minimal follow up in the past. So, if you take a patient with a VSD, rarely during childhood, young adult or even kind of in 20s and 30s, you have any major difficulties. And as a pediatric cardiologist, you rarely experience any major follow up problems with these patients. I think, particularly in the US, and I work actually for more than 10 years in the UK, the problem in the US is how can you organize follow up in these patients?
There're insurance issues, there're issues about moving into different areas, and since these patients were kind of labeled as being healthy and close to normal, they were lost for follow up, particularly in the US. I think this study raises some concerns, we should probably be more careful and cautious and follow these patients up kind of in a lifelong session. And take care of them. This is definitely something, which is a new finding, and what the cause is, how we are following up, that's the question. I guess it could be a good question for future studies.
Dr Greg Hundley: You mentioned future studies. Specifically, what type of future studies do you think we need to perform next? This shows us that the events are occurring, are we ready yet for randomized trials to perform prevention? Do we need studies that have more frequent observation? What are your thoughts there? And I'll get your answer and then we'll come back to James and get his thoughts on the same question.
Dr Gerald Greil: Yeah, I think the major thing is we need close follow up of these patients. And it will be a combined effort between pediatric and specialized adult cardiologists, with a special interest in patients with congenital heart disease. Once again, coming back to it, a closer follow up is a little bit dependent on the medical system, which you have. If you take Canada and the UK, it may be easier in these patients are under close follow up. And this allows large multicenter studies, large data bases like UK Bio Bank are kind of exemplary. And we should try to get something similar within the US or in other countries.
I think that's the lesson what we take from that, we need larger data bases, probably more granular than what we have right now. I mean, James probably can comment in a second about the shortcomings and what can be done better in the UK Bio Bank to allow more detailed conclusions than we have currently from his study.
Dr Greg Hundley: James?
Dr James Priest: I would agree with that. I think as a person who does not, clinically speaking, take care of adults with congenital heart disease, my colleagues and I, or I have the impression from my colleagues that for most of the time, in most of these patients in the Unites States adults who had VSD or ASD repair as a child, they were essentially said, oh, you're cured. And they perhaps had some follow up during childhood, but then were otherwise discharged to live the rest of their lives.
And so, in many cases I'd say the first step before performing any studies is to simply identify who these patients are, and figure out you know, what their risk factors otherwise for cardiovascular disease might be. Now, that being said, I think that was one of the powerful things about the UK Bio Bank study is that there's a large population in which all these traditional cardiovascular risk factors you know, obesity, lipid levels, hypertension, smoking status, all these things were uniformly measured in both the individuals with congenital heart disease, the adults with congenital heart disease. And of course the control population.
And so that allowed us to make some estimates about what proportion of disease was attributable to these traditional cardiovascular risk factors. And what was attributable to other factors related, potentially, to the congenital heart disease. But all those things being said, I think the first questions that I often to tend to receive about these studies from the pediatric cardiologists and the adult congenital heart disease doctors, reflects the sorts of data sets that we're used to looking at.
Well, what sort of an intervention did this person have? Did they have a ventriculostomy? When did they receive their diagnosis and their repair? Details of the surgical care and the perioperative of course, are not available in this data set because it's not a particularly pediatric cardiology focused data set. It's a broad population based data set. And so the relationship specifically the details of their perioperative care and diagnosis are not able to be attained. And so we'll need larger data sets that include that information to fully start to develop those sorts of relationships over time.
Dr Greg Hundley: So, we want to thank our lead author, Dr James Priest from Stanford University School of Medicine, and our associate editor, Gerald Greil from the University of Texas Southwestern Medical School in Dallas. And reviewing this very interesting article on lower complexity cardiovascular disease and its association with an increased risk of cardiovascular events. And thank you both so much for clarifying. It sounds like an opportunity to collect more data through registries, et cetera, that we may need to expand around the world.
Thank you everyone for listening to Circulation on the Run. Remember that's your back stage pass to our journal. And we'll see you next week.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, also associate editor from VCU Health Systems, the Poly Heart Center in Richmond, Virginia.
Dr Carolyn Lam: So arrhythmogenic cardiomyopathy that will make most of us think of right ventricular disease and fatty infiltration of the muscle, but could arrhythmogenic cardiomyopathy really be a bi-ventricular disease? Well you've got to stay tuned to find out more in a fantastic interview coming right up after our little coffee chat. So Greg, what are your picks this week?
Dr Greg Hundley: My first paper is from Chris Lim at NYU in New York. And it's looking at the relationship between Mediterranean diet, air pollution and cardiovascular events.
So, it's unknown whether usual individual dietary patterns can modify the association between long-term air pollution exposure and health outcomes. And so, in this large cohort with detailed diet information at the individual level, they had 548000 individuals across six states and two cities within the U.S. and a follow up period of 17 years. And that occurred between 1995 and 2011. And they evaluated whether a Mediterranean Diet modified the association between long-term exposure to ambient air pollution and then cardiovascular disease and mortality risk. And so, the average exposures to parts per billion and nitric oxide air pollution that the residential census track level were measured, and the investigators found that for the particulate matter there were elevated significant associations with cardiovascular disease. So, a hazard ratio of 1.13, ischemic heart disease similar hazard ratio and cerebrovascular disease with also a similar hazard ratio.
For the nitric oxide, there were also significant associations with cardiovascular disease, as well as ischemic heart disease. And then the analysis indicated that Mediterranean diet modified the relationships. Those with a higher Mediterranean diet score had significantly lower rates of air pollution related mortality. These results therefore indicate Carolyn, that Mediterranean diet reduce cardiovascular disease mortality related to long-term exposure to air pollutants in a large perspective, U.S. cohort. Can you believe increased consumption of foods rich in antioxidant compounds actually may aid in reducing the considerable disease burden associated with ambient air pollution?
Dr Carolyn Lam: Oh wow. That is hugely interesting. Gosh, what do we do about this clinically now?
Dr Greg Hundley: Remember, first of all, this is an associate study, so we can't infer cause effect. And what we need next are some more independent studies from other cities around the world, prospective cohorts, examinations of clinical outcomes and randomize interventions. And so, I think the results add to a growing body of literature suggesting that dietary patterns may help reduce cardiovascular events in these high air pollution exposure areas. And how does this work? Well, potentially through augmenting antioxidants and reducing oxidative stress.
Dr Carolyn Lam: That's really cool. So from one region, talking about air pollution to another region that often reports about air pollution and that's China. But this study from China is actually the largest registry study to evaluate sex related differences and hospital management and outcomes of patients with acute coronary syndrome in China.
This is from corresponding author Dr Zhao from Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease. With colleagues of the improving care for cardiovascular disease in China, Acute Coronary Syndrome project, which is an ongoing nationwide registry of the American Heart Association and the Chinese Society of Cardiology. So, the authors use data from this project and evaluate at sex differences in the acute management, medical therapies for secondary prevention and in hospital mortality in more than 82000 patients admitted for acute coronary syndrome in 192 hospitals across China from 2014 to 2018.
Dr Greg Hundley: What did they show in this study?
Dr Carolyn Lam: They showed that women hospitalized for acute coronary syndrome in China less frequently received acute treatments and strategies for secondary prevention and had a higher in hospital mortality rate than men. Now the observed sex differences in this in hospital mortality were likely due to older age, worse clinical profiles and fewer evidence base acute treatments provided to women. And that's because the sex differences were no longer observed after adjustment for these clinical characteristics and acute treatments.
What this all means though is specifically targeted quality improvement programs may be warranted to narrow these sex related disparities in patients with acute coronary syndrome in China.
Dr Greg Hundley: Very interesting. I'm going to take sort of the next paper and it's looking at a different aspect of acute myocardial infarction. And these papers from Yong Wang from the Division of Molecular and Translational Cardiology at Hannover Medical School in Hanover, Germany.
Now as we know, the heart can undergo deleterious changes and left ventricular geometry and function during that vulnerable period before scar formation has stabilized the infarct area. And so inflammatory cell trafficking from hematopoietic organs like the spleen to sites of tissue injury is coordinated by chemokine chemokine receptor networks. Therapeutically modulating these chemokine chemokine receptor interactions may promote infarct healing by limiting excessive inflammation induced tissue damage or by enhancing the recruitment of angiogenic cell populations to the infarct or the wound. Inflammatory cell trafficking after a myocardial infarction is controlled by a CXC motif chemokine ligand 12 or CXCL12 and its receptor CXC motif chemokine receptor 4. CXC receptor 4 antagonists, mobilize inflammatory cells and promote infarct repair. But the cellular mechanisms are unclear.
So, what do these investigators do? In mouse models, the investigators found that inflammatory cell trafficking between a hematopoietic organs and sites of tissue injury is controlled by CXCL12 and its receptor CXC receptor 4. And bolus injectives of a highly selected peptidic macrocycles CXC receptor 4 antagonist, enhanced tissue repair and functional recovery after re-perfused acute myocardial infarction in mice. And interestingly, the therapeutic effects require a dendritic cell priming and we're specifically mediated by t-regulator cells. Intermittent CXC R4 blockade mobilized the t-regulator cells from their splenic reservoir. Leading to their enhanced recruitment to the infarct region.
Dr Carolyn Lam: So bring it home for us, Greg. What does this mean clinically for MI management in humans?
Dr Greg Hundley: Right. Highlighting the translational potential. What we might infer is that CXC receptor 4 blockade reduces infarct volume and improved systolic function in a porcine close chest model of re-perfuse acute myocardial infarction.
And so, the results of both the mouse experiments and this sort of translational model in pigs should stimulate further research into therapeutic potential of CXC R4 blockade after MI and in other acute conditions were excessive, innate or adaptive immune responses cause immunopathology.
Dr Carolyn Lam: Fascinating. So from one preclinical paper to another, but this time focused on heart failure. And focus specifically on titin. Titin is this giant elastic protein that spans the half-sarcomere from the Z-disk to the M band, and it acts like a molecular spring and a mechanosensor that has been linked to striated muscle disease. Now the pathways that govern tight independent cardiac growth and contribute to disease are diverse and have been really difficult to dissect. And so corresponding author Dr Gotthardt, from Max Delbruck Center for Molecular Medicine and the German Center for Cardiovascular Research and his colleagues aimed to study titin deficiency versus titin dysfunction.
And how they did that is they generated and compared striatum muscles specific knockouts with progressive postnatal loss of the complete titin protein. And that's by removing Exxon 2. Or an M-band truncation that eliminates the proper structure and integration, but retains all the other functional domains. So they then evaluated cardiac function, cardiomyocytes mechanics, and the molecular basis of the phenotype. Now, what they found was that progressive depletion of titin led to sarcomere disassembly an atrophy in striated muscle. And in the complete knockout, remaining titin molecules had increased strain resulting in mechanically induce trophic signaling and eventual dilated cardiomyopathy.
On the other hand, the truncated titin helped maintain passive properties and thus reduced mechanically and do signaling. In other words, truncations versus loss of titin, differentially affected cardiac pathology with atrophy versus dilated cardiomyopathy respectively. And together, these findings really contribute to the molecular understanding of why titin mutations differentially affect cardiac growth and have implications importantly for genotype, phenotype relations that support a personalized approach to the diverse titinopathy.
Dr Greg Hundley: Interesting, Carolyn. All this information on titin. So why is it clinically important?
Dr Carolyn Lam: Well, first of all, tightened mutations are the most common genetic basis of heart disease and the findings are clinically relevant, as I said, for understanding the genotype phenotype relations at the Titin mutation. But understanding the integration of Titin based signaling and sarcomere biology could indeed help personalize diagnostics by improved clinical decisions and maybe identify suitable therapeutic targets for these titinopathy. But that of course requires much further work. Well that brings us to the end of our summaries. Let's go to our feature discussion.
Dr Greg Hundley: Welcome everyone to our second segment of our program. We're discussing an interesting paper today entitled Sudden Death and Left Ventricular Involvement in Arrhythmogenic Cardiomyopathy. And we want to welcome our coauthors Elijah Behr and Mary Sheppard from St George's University in London. And also, our own associate editor, Sami Viskin to discuss this paper. Mary, can you tell us a little bit about your study design here, the population and the hypothesis and some of your results?
Dr Mary Sheppard: I am a cardiac pathologist of 20 years and I have a special interest in sudden death. Over this time, I've established a national pathology database, where pathologists throughout the country when they have a sudden death, which is likely cardiac and non-ischemic, they will send the heart or tissue blocks insides to me for my opinion concerning the death. We have as a result developed a large number, over 5200 cases which has now built up to 6000. It's the largest pathological series in the world.
And I was also discovering the pathologists were either under or over diagnosing all types of cardiomyopathy but particularly ergogenic cardiomyopathy. And that is why with Chris Miles, our research fellow, we looked in detail at what I had diagnosed, or the pathologist as ergogenic cardiomyopathy and we actually honed are pathological diagnostic criteria for this very important entity. Establishing that left ventricular is five and ventricular and left and ventricular is the norm almost. That right or left ventricular is unusual by themselves and even in 20%, one in five, the heart can look macroscopically normal. So that histology is essential when you're making this diagnosis. You cannot make the diagnosis pathologically without histologically examining the heart.
Dr Greg Hundley: Very good, Mary. And did you also examine some genetic markers in some of the subsets of the patients? And how did you decide who those individuals would be that received the genetic analysis?
Dr Mary Sheppard: A small subset and I will hand over to Elijah Behr, my colleague concerning that.
Dr Elijah Behr: The genetic tissue is only available in a minority of cases. We've developed a pipeline now with the referring pathologists who are increasingly they're sending samples of spleen suitable for DNA extraction that allow us then to do a retrospective postmortem genetic testing or molecular autopsy. But unfortunately, in this particular series we only had a small proportion. I think there were roughly about 24 out of the 202 cases, so just over ten percent. And interestingly, while we didn't necessarily mirror the expected yield of genetic testing that is seen in clinical cases, where you may see about 40% carrying pathogenic variance. We certainly picked up some important pathogenic variance, particularly those that are often associated with highly penetrant and more severe disease. In particular TMEM43 and desmoplakin. These findings may reflect the small size of the sample, but it also may reflect where the greatest risk for sudden death from ergogenic cardiomyopathy lies.
Dr Greg Hundley: Elijah, getting back to some of the patients that experienced the sudden death in the study population Mary was referring to, were there characteristics that were associated with the sudden death? For example, those that might be related to gender or activity?
Dr Elijah Behr: So the majority of the cases were male. The majority has never had prior symptoms. These were unheralded deaths. The majority did not have a family history and I think the majority were addressed, but those that were athletes, we're much more likely to have died during exertion. So as we found with ergogenic cardiomyopathy in general and exertion is a trigger to sudden death. The risk was higher and compared to the athletes in death during exertion was associated with being younger as well. I think exertion and sports clearly play a role in ergogenic cardiomyopathy. It didn't appear to play a role in whether there was left ventricular involvement or not, but certainly a role at more severe presentation.
Dr Greg Hundley: Maybe both Mary and Elijah answering this. You found histopathological evidence of fibrosis and fatty infiltration. How extensive was that? And do you think that could be identified with a test like maybe magnetic resonance imaging?
Dr Mary Sheppard: Yes. Our diagnostic criteria which is illustrated in the addendum is that it was at least two blocks of tissue. We always look at 10 to 12 to 15 blocks of tissue from both right and left ventricle. And at least two of the blocks had to have fibrosis with fat in 20% of the area examined. We did not include inflammation because inflammation is, an important histological criterion in our experience. We were very precise about that because you need that much at least to make the diagnosis. A little bit of fibrosis or a little bit of fat is not sufficient by itself.
Dr Greg Hundley: When you mention a block, for us clinically, how much myocardium would that be? For example, on an imaging test like an echo or an MRI scan.
Dr Mary Sheppard: One to two centimeters squared.
Dr Greg Hundley: So quite a bit.
Dr Elijah Behr: You're looking at probably around two to four millimeters of potential depth of fibrosis. And what we've seen clinically in LV involvement of MRI scans is miss two epicardial late enhancement. Now the question is whether our scans are sensitive enough to pick that up? Given the technology available or a sense to the histopathology and I think that's why maybe some of the clinical studies have tended to miss the true proportion of left ventricular involvement. Because of the relative subtlety of the fibrosis compared to the technological ability to discriminate it. I mean certainly when you look at our cases that were diagnosed previously with cardiomyopathy, either they were arrhythmogenic or dilated, many did have imaging findings if MRI was performed, that would indicate or suggest some left ventricular involvement. But as you know, the task force criteria for arrhythmogenic cardiomyopathy having very much right ventricular focus. An LV imaging findings and LV ECG findings are just not part of those at the moment.
Dr Greg Hundley: Was there a particular location within the heart where there was a predilection toward the findings of fibrosis and fat?
Dr Mary Sheppard: In the posterior basal wall particularly, transmural involves going from the epicardium to the sub endocardium and also the interior walls of the left ventricular were the predilection areas.
Dr Elijah Behr: I think that's what we see on our MRI scans as well. When you look at these patients, that posterior basal area, is the one that tends to light up the most.
Dr Mary Sheppard: It is believed that increased stress in that area gives more damage because of the stretching away from the septum.
Dr Greg Hundley: Very interesting. So Elijah, you had mentioned task force criteria. I want to shift to Sami now and ask, Sami, can you help us put this in perspective relative to the existing task force criteria and then the findings in this study? And how that could lead to subsequent changes down the road?
Dr Sami Viskin: Okay, so it is difficult to place this in the context of the task force because mentioned by Elijah, the taskforce are focused on a disease that is believed to be in the right ventricle. And the study shows that many of the sudden death cases will involve the left ventricle. One of the most important messages of this paper is importance of her forensic examination. And importance of making it for anything examination in the center of expertise. We know of patients that will travel a thousand miles to undergo surgery or an ablation procedure, but families do not think that way when there is casualty or family dies. You may take a postmortem as a given, but in many countries, including my own, most cases of sudden death would not be followed by a post mortem and will not go into center of expertise. And you cannot overemphasize the importance of doing that because then you have to know what you are looking for in the remaining relatives is extremely important.
Dr Greg Hundley: Very good. How about from the perspective as an electrophysiologist? Does this impact in any way how you might evaluate a younger person with syncope?
Dr Sami Viskin: Well, it is difficult to conclude from this paper about how to evaluate patients with syncope because most of the cases in this series don't have symptoms at all. But this paper calls to very interesting investigations by Mario del Mar and others in New York. Looking about the electrophysiology consequences of a disease like right ventricle are like a bit mechanical in [inaudible 00:21:58] The tissues becomes editing the disease, the electrical properties how the patients in brugada can cause malfunction of this sodium channel and create a disease that is more like brugada and dysplasia at the beginning. So, the entire correlation between a morphologic disease and the metrical disease and we used to think they are two different things. And now we see that we can actually put them together and you can go through stages where one disease is before an electrical disease and only at later stages it becomes a morphological evident disease.
Dr Greg Hundley: A fantastic discussion on pathologic findings. Sami making the point that certainly in cases for young individuals having a postmortem examination performed at centers that have expertise such as what Mary's described, can be very important. And then Elijah, helping us to understand with arrhythmogenic cardiomyopathy, number one, findings are not, we shouldn't just be thinking about the right ventricle in isolation, but also the left ventricle. Fibro fatty infiltration, particularly in the posterior basal wall could be an important thing to look for, for those that are performing the magnetic resonance imaging exams. And then lastly, many of the patients in the study like this, the first presentation was of sudden death. And we need to be cognizant that this condition could be prevalent in the population and not necessarily appreciated by some of our current task force guidelines and examinations. So, what an outstanding discussion. And I think for today, we want to thank our authors and our associate editor and wish everyone a great week.
On behalf of Carolyn and myself, we look forward to seeing you next week. Thank you very much.
Dr Carolyn Lam: This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to The Journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center, and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, also associate editor in Richmond, Virginia at VCU Health.
Dr Carolyn Lam: So, PCI or no PCI for chronic total occlusion. That is a perennial question, and we have the results of the decision CTO trial reported in this week's Journal. In fact, we're going to discuss it right after our little chat here.
So, Greg, why don't you kick us off? What paper did you choose?
Dr Greg Hundley: Yeah, thanks so much Carolyn. My first paper is from Laura Benschop from the Department of Obstetrics and Gynecology at Erasmus Medical Center in Rotterdam, the Netherlands. It's going to focus on placental growth factor as an indicator of maternal cardiovascular risk after pregnancy.
So, as we all know, pregnancy is accompanied by extensive maternal hemodynamic changes that allow for proper placental implantation, growth, profusion, and fetal development and this process requires a tight balance between pro-angiogenic factors like placental growth factor, and anti-angiogenic factors like soluble FMS like tyrosine kinase factors. So, in response to stress, the syncytiotrophoblast will decrease the production of placental growth factor and women with reduced placental growth factor and increased FLT-1, are more at risk of a complicated pregnancy. For example, like preeclampsia and spontaneous preterm birth.
So, angiogenic placental growth factor concentrations can rise during pregnancy, peaking at the end of the mid-pregnancy. And low placental growth factor concentrations during pregnancy are associated with pregnancy complications with recognized later life cardiovascular risk. So here, the authors hypothesize that low placental growth factor concentrations, especially in mid pregnancy, identify not only a subset of women at risk for pregnancy complications, but also women with greater cardiovascular risk factor burden after pregnancy, regardless of their outcome.
So, among 5,529 women, the authors computed gestational age adjusted and mid-pregnancy placental growth factor concentrations and pregnancy complications, like preeclampsia, small for gestational age, spontaneous preterm birth, was obtained from hospital registries.
Dr Carolyn Lam: Cool, and what did they find?
Dr Greg Hundley: So six years after pregnancy, the authors found that women with mid pregnancy low placental growth factors, in the lowest quartile, had larger aortic diameters, left atrial diameters, and LV mass, and a higher systolic blood pressure by an average of 2.3 millimeters of mercury. High mid-pregnancy placental growth factor concentrations were the opposite. They were associated with smaller aortic diameters, smaller left atrial diameters, lower LV mass by 3.9 grams, and lower systolic blood pressure. And these differences persisted after exclusion of women with complicated pregnancies.
So, the results suggest that a woman's response to the cardiovascular changes of pregnancy, measured by pre-mid-pregnancy placental growth factor levels could provide insight into the path of physiological mechanisms leading to future cardiovascular disease in multiparous women.
Dr Carolyn Lam: Wow. That is really interesting. Well, the paper I chose really answers the question, are there racial differences in sudden cardiac death, and why? And this is from corresponding author Dr Guallar from Welch Center for Prevention, Epidemiology, and Clinical Research in Johns Hopkins Bloomberg School of Public Health and Colleagues.
What they did is they compared the lifetime cumulative risk of sudden cardiac death among blacks and whites in the atherosclerosis risk in community study, or ARIC. They evaluated the risk factors that may explain racial differences in sudden cardiac death risk in this general population.
What they found was that blacks had a much higher risk of sudden cardiac death in comparison with whites, with a sex adjusted hazards ratio of 2.12. Known factors explained 65% of the axis risk of sudden cardiac death in blacks compared to whites. The single most important factor explaining this difference was income, followed by education, hypertension, and diabetes. These racial differences were evident in both genders, but stronger in women than men.
Dr Greg Hundley: Hmm. So are there implications, and are there potential strategies that could help reduce this risk in African Americans?
Dr Carolyn Lam: Yeah, this is a really interesting study, and it really implies that efforts to reduce the sudden cardiac risk in blacks should perhaps focus on improving CPR outreach, medical care engagement in response to cardiac arrest, the quality of treatment in medical institutions in predominantly black neighborhoods, and factors such as that. Because remember the single most important factor explaining the difference was actually income and education.
Dr Greg Hundley: Oh, wow. Well, I'm going to switch gears a little bit here Carolyn, and we're going to talk about pulmonary hypertension. And this next paper is going to focus on pericytes. We'll learn a little bit about what pericytes are. So, the paper is from Vinicio de Jesus Perez, who's an assistant professor of medicine and pulmonary critical care at Stanford University Medical Center in California.
What are pericytes? So, pericytes are specialized perivascular cells embedded in the basement membrane of blood vessels, where in conjunction with neighboring and endothelial cells, they support vessel maturation and stability. In the lung, pericytes are mostly found associated with small precapillary arteries, the capillaries, and then those post capillary venules. And it's thought that pericytes are responsible for regulation of vasomotor tone and structural support of these micro-vessels. When the vessels become muscularized, pulmonary vascular resistance increases, resulting in pulmonary artery hypertension.
So recent studies have focused on pericytes in addition to pulmonary endothelial cells, smooth muscle cells, and fiberglass, but not much is known about the contribution of pulmonary pericytes to pulmonary arterial hypertension. Two genes are involved in Wnt planar cell polarity pathway that is responsible for coordinating complex cell movements during tissue morphogenesis. So, in this group, they have produced prior results that show that restoration of the Wnt planar cell polarity in pulmonary arterial hypertension, pericytes could partially restore recruitment to PNVECs and increase vessel stability.
Dr Carolyn Lam: Interesting, and so that was their past research, and what did the current paper show?
Dr Greg Hundley: Right. So Carolyn, what they found is that pulmonary microvascular endothelial cells isolated from pulmonary arterial hypertension patients, and endothelium from pulmonary arterial hypertension tissue have reduced expression of Wnt-5a. Healthy PMVECs produce and package Wnt-5a in the form of exosomes which regulate pericyte recruitment, motility, and polarity.
And so, the overall implication is that promising therapeutic strategies that help can restore the Wnt/PCP, or planar cell polarity pathway, and endothelial pericyte communication could help prevent micro-vessel loss in patients with pulmonary artery hypertension.
Dr Carolyn Lam: Thanks, Greg. So, I'm going to take us to the cath lab for this next paper. And it's the results of the CANTIC study, which aimed to answer the question, does intravenous P2Y12 inhibitor Cangrelor have a role in bridging the gap in platelet inhibition in patients with STEMI undergoing primary PCI. And this is from corresponding author Dr Angiolillo from the University of Florida College of Medicine Jacksonville and Colleagues.
Now, CANTIC was a prospective randomized double-blind placebo control parallel design investigation of the pharmacal dynamic effects of Cangrelor versus placebo in patients undergoing primary PCI, who were also treated with crushed Ticagrelor. So, after diagnostic angiography, patients were randomized to a blinded two-hour infusion of either Cangrelor or placebo. At the same time, 180 milligrams of crushed Ticagrelor was administered to both groups. Platelet reactivity was measured with Verify Now P2Y12 point of care testing, and with vasodilator-stimulated phosphoprotein, or VASP.
Dr Greg Hundley: So what did the trial show, Carolyn?
Dr Carolyn Lam: They found that addition of Cangrelor led to more prompt and potent platelet inhibitory effects, compared with crushed Ticagrelor alone in patients undergoing primary PCI. The significant differences were observed as early as five minutes post bolus administration, and persisted until the end of its two-hour infusion.
Furthermore, after discontinuation of Cangrelor or the placebo infusion, there were no differences in levels of platelet reactivity between groups. And this importantly rules out a drug/drug interaction when Cangrelor and Ticagrelor are concomitantly administered. This lack of drug-drug interaction is important, as it supports a more versatile use of Ticagrelor with respect to timing of its administration in patients treated concurrently with Cangrelor.
Overall, the results are reassuring and demonstrate reduced platelet reactivity, and no high on treatment platelet reactivity with Cangrelor in combination with Ticagrelor in primary PCI patients. Of course, the implications of these pharmacal dynamic findings really warrant investigation in an adequately powered clinical trial.
And that brings us to the end of our summaries. Let's go to our featured discussion.
So PCI, or no PCI for chronic total occlusion, that is a perennial question isn't it? Especially nowadays when procedural results for PCI and CTO have improved in recent years, and PCI strategies have moved towards more complete revascularization. Yet the evidence is clearly lagging behind for us to make decisions on this. And that's why we're so happy that our featured paper today is the DECISION-CTO trial from Korea, and so happy to have the first author, Dr Seung-Whan Lee from ASA Medical Center to tell us about this, as well as our associate editor, Dr Manos Brilakis from UT Southwestern.
So Dr Lee, could you tell us about the DECISION-CTO trial?
Dr Seung-Whan Lee: Yeah, in our trial our multicenter, randomized, noninferiority trial, PCI-eligible patients were assigned to receive either one of two strategies; PCI or no PCI or CTO. We did the option for PCI of the other. The primary endpoint as you know the composite outcome of deaths, myocardial infraction, stroke, or any revascularization. As related to quality of life was assessed up to three years. However, because of the slow recruitment, the trial was stopped before completion. We started 208 planned enrollments. For six years 834 patients there were randomly assigned to the CTO PCI versus no CTO PCI strategy.
Among the patients assigned to the no CTO PCI strategy, nearly 20 percent of patient cross over to the CTO PCI. That is our big limitation, as you know. Anyways, the primary end point was assessed per year, and then, finally, we founded the per year risk of the major adverse cardiac events there’s no difference in contributor composite outcome, MI, revascularization, and stroke.
However, in our trial, in some detail, in CTO PCI was success rate around 91 percent. However, complication is very low, .6 percent of patient is complication. Very surprisingly the coheir is up to the three, and no difference between CTO PCI versus no CTO PCI.
I think our main message is our patient is a relatively low-risk population, including the syntax score 20 and the score 22%. The majority of patient preserved LV function and single-vessel disease 25%. The relative low risk population CTO PCI versus no CTO PCI clinical outcome is no difference of the per year from the two groups.
I think that our trial is make the reposition with the medical law in the CTO patient. That’s my summary.
Dr Carolyn Lam: Thank you. Manos, could you maybe paint the background and let us know why this was so important for us to publish in Circulation? Why is it so difficult to do these trials?
Dr Manos Brilakis: This is the largest study on CTO PCI so congratulations on getting this accomplished. I know it was many years and a lot of effort.
I think a couple of things on the background. As Dr Lee said as well, CTO PCI success rates have been improved, and now at experienced centers you can get 85 to 90 percent success fairly consistently.
The complication rates are low. .5 to 3 percent is the average rate. We do have a tool right now. The procedure is mature, and it's time test in the randomized trials.
The question has always been for CTO PCI, "How does it help?" Does it improve symptoms? Does it improve the heart outcomes? Myocardial Infarction? This is what DECISION CTO was trying to answer.
Couple of I think limitations that we should take into account when interpreting the results. The first one is that these were notations with an isolated CTO, but a significant proportion had also multi-vessel disease. They were enrolled before treating the other vessels, which were subsequently treated.
Sometimes it's hard to know how much the residual ischemia or symptoms would be present after the other lesions were treated. That's one thing.
The second is that there was a significant crossover for about 1 in 5 patients that randomized to medical therapy immediately crossed over to the CTO PCI group. And that always uses the power and creates difficulty in interpreting the results.
In my mind, the question still remains, in low risk populations it's possible that CTO PCI doesn't improve symptoms, but the ones that were expected to improve, the heart outcomes dec-MI, would be the high-risk patients with significant ischemia. Ideally, studies in the future should actually look specifically at patients who have high ischemia, significant symptoms when looking at heart outcomes.
Dr Carolyn Lam: Dr Lee, I think you did mention as well in your manuscript that a viability test was not mandatory for patient enrollment. I mean, clearly it was such as work of labor enrolling such patients. If you put even more criteria it would have been impossible, I suppose. Do you have some thoughts there on maybe future studies?
Dr Seung-Whan Lee: Yeah, as you know, the currently ongoing CTO PCI process medical treatment is nobel CTO and ischemia CTO is assessed at the reduction of the ischemia burden in CTO PCI. I think there maybe two studies that give us some answer for the low level of the CTO PCI for the reduction of the ischemia.
So, I think the larger ischemic burden the patient is maybe high risk to make the however we don’t know exactly the cut off… ischemic burden in CTO patient. Usually instable angina any kind…coronary disease…3 years circulation showed more than 10 percent of ischemic burden is really predictive of future cardiac event. However, we don't know exactly the can be applied to CTO patient. We don't know exactly.
Dr Manos Brilakis: Can I ask Dr Lee a question regarding the study and his interpretation as well. Now the study was borrowed for hard end points dec MI. What his is perception, based on the DECISION CTO, and, of course, everything else in the literature and the CTO study with symptomatic benefit...Dr Lee, what is your conclusion about, or your kind of thoughts about, the effect of CTO PCI on improving symptoms, which is a more accepted indication for the procedure right now?
Dr Seung-Whan Lee: As you know, the university trials symptom assessment was done after the no CTO PCI. However, our trial is a pragmatic trial, initial approach to the CTO vessel and the vessels that is patient.
At this moment, I think the other vessel, other no CTO vessel intervention and OMT may improve the patient symptom and then CTO vessel is the intervention including the CI patient completely…improve the symptom status. However, analysis showed up to the 3 year, maybe no difference between two groups in the CTO PCI versus medical treatment.
Our trials of the CTO PCI symptom, we don't exactly the role of the after no CTO PCI. We don't know exactly the CTO based symptom assessment was not done, because of the symptom assessment was done before the intervention.
I think that our trials are more practical, because of the initial…multivessel… CTO. Our trials, maybe, completely vascularization including CTO and no CTO vessel revascularization without the CTO intervention. Sometimes the patient to complain of symptom multivessel with the CTO I think we can wait if we continue the patient symptom…
However, in this trial showed CTO specific intervention trial, because of the symptom assessment was done after no CTO vessel intervention. There is some improvement of the… receptor treatment satisfaction of the angina stability. I think that the CTO intervention is maybe reserved for the symptom control after the medical treatment failure of patient.
I fully agree the symptom control is possible with the CTO PCI.
Dr Manos Brilakis: Wonderful. Thank you. I think that's a critical differentiation that the DECISION CTO is not specific for CTO, but it's multi-vessel disease plus CTO. Thanks for clarifying. That's very important for the leaders and the entire community to understand that part.
One more question, if it's okay. I know that in Asian countries bypass patients are relatively less. I think in the U.S. 50 percent. Any comment on that? I know people get less bypass in Asia than they do in the United States. How may that affect the interpretation of the DECISION CTO?
Dr Seung-Whan Lee: Initially, I introduced my studies to our patients syntax score under 20. As you know, the U.S. Registry shows the syntax score more than I think the 20, and the tester score around 46. Quite different in population, because the risk factor is quite different. U.S. patient is hypertension and diabetic are more prevalent than the Asian patient. Bypass surgery is 40 percent in Asian patients. Bypass surgery is around 102 percent in CTO registry. Quite big difference of the base rank, risk factor, and morbidity.
I cannot apply to U.S. population exactly the same ... Not same situation. We cannot apply directly to the U.S. population. I fully agree with your suggestion, though. Lowest population is maybe ... Our trial is maybe lowest population. We agree.
Dr Carolyn Lam: I'm just learning so much listening to both of your interventionists. What do you think are the take-home messages from this? Maybe, could I start with Dr Lee, and then give Manos the last word?
Dr Seung-Whan Lee: CTO PCI critical outcome, it should be tested as a large random trial. Maybe Manos already mentioned about the high-risk population, because our population is the lowest population. However, in some large random trial with a high-risk population we have consider some random trial because they are not easy.
Maybe not easy to test in high-risk population. However, you must do that, because of the two established CTO PCI law in the current practice.
Dr Carolyn Lam: Manos?
Dr Manos Brilakis: Yeah, I would agree with that. I think the main conclusion regarding the field of CTO PCI is that still right now, the key indication remains symptom improvement. We do have the trials at this point showing that you do CTO PCI in terms of improving mortality. However, CTO PCI is a tool. It's a revascularization tool. Patients who have severe, complex, coronary disease, multi-vessel disease, may be best served with bypass in the first place. Those who have multi-vessel disease that's less complex and don't have significant symptoms after fixing the non-CTO lesions, then they may not benefit from CTO PCI as well. But those who have CTO lesions and have significant symptoms, this is the population for which I think there is general agreement, and I the decision that CTO is good with that, that those patients could benefit from CTO intervention.
Dr Carolyn Lam: Thank you so much for sharing your insights.
Thank you, listeners, for joining us today. You've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts, I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: I'm Greg Hundley, associated editor from the Pauley Heart Center at VCU Health Sciences in Richmond, Virginia.
Dr Carolyn Lam: A big number of acute ischemic stroke patients receiving endovascular therapy in the United States are receiving this therapy only after inter-hospital transfer. What are the temporal transient outcomes following this inter-hospital transfer? Very important discussion coming right up with our featured paper. But for now, sit back, relax with us. We're going to discuss a couple of papers that we found were interesting in this week's journal.
Dr Greg Hundley: Very good, so thanks Carolyn. I'll start off, and I'm going to talk a little bit about stress induced cardiomyopathy, and we also know it as takotsubo cardiomyopathy, looking at a paper from Dana Dawson from the University of Aberdeen in the United Kingdom. Takotsubo cardiomyopathy can result in a heart failure phenotype with a prognosis comparable to myocardial infarction.
In this study, the investigators hypothesize that inflammation is central to the pathophysiology in natural history of takotsubo cardiomyopathy. They prospectively recruited 55 patients with takotsubo cardiomyopathy, and 51 age, sex, and comorbidity match control subjects.
During the index event, and at five months of follow-up, the patients with takotsubo cardiomyopathy underwent a cardiac MRI study in which they looked at ultra-small, super paramagnetic particles of iron oxide, or USPIOs, enhancement for detection of inflammatory macrophages in the myocardium. What would the studies show? Patients with acute takotsubo cardiomyopathy had macrophage-mediated myocardial inflammation.
They also demonstrated modulation of peripheral monocyte subsets and increased systemic pro-inflammatory cytokines. This systemic inflammation persisted for five months, and then at that five-month time point, the cardiac MRI evidence of the macrophage presence was diminished.
Dr Carolyn Lam: Wow, Greg. So this is right up your wheelhouse, isn't it? Can you explain? What are the clinical implications of these MRI findings?
Dr Greg Hundley: It was really interesting. For the first time, they've linked an ongoing inflammatory process using the USPIO contrast agent with MRI actually going on or operative in the heart, and they associate that with systemic markers in the circulation.
They help us elucidate the mechanisms and the pathogenesis of takotsubo cardiomyopathy, and systemic and myocardial inflammation really may start to now serve as a therapeutic target for patients with acute takotsubo cardiomyopathy.
Dr Carolyn Lam: Very interesting. From stress-induced cardiomyopathy to early onset myocardial infarction. The first paper I chose really answers the question, "What is the relative prevalence and clinical importance of monogenic mutations, that is, a single mutation that significantly increases risk, versus a polygenic score, which really measures the cumulative impact of many common variants, in early onset myocardial infarction?"
The co-corresponding authors were Doctor Amit Khera and Sekar Kathiresan and both from Massachusetts General Hospital, and they performed deep coverage, whole genome sequencing of more than 2,000 patients from four racial subgroups hospitalized in the United States with early onset myocardial infarction defined as myocardial infarction before the age of 55 years, and compared this to 3,761 population base controls.
What they found was that a monogenic mutation related to familial hypercholesterolemia was identified in 1.7% of the patients, and associated with a 3.8-fold increased odd of myocardial infarction. In comparison, the high polygenic score, which was composed of 6.6 million common DNA variants and defined as the top 5% of the control population distribution, now, that was identified in 10 times as many patients, so 17% of patients, and associated with a similar 3.7-fold increased odds of myocardial infarction.
Dr Greg Hundley: Interesting. How do we apply this clinically, Carolyn?
Dr Carolyn Lam: These findings really lay the scientific foundation for the systematic identification of individuals born with a substantially increased risk of myocardial infarction. The important point is both familial hypercholesterol mutations and a high polygenic score are associated with more than three-fold increased odds of an early onset myocardial infarction.
However, the high polygenic score cannot be reliably identified on the basis of elevated LDL cholesterol, and yet has a 10-fold higher prevalence among patients presenting with early onset myocardial infarction. So very intriguing that both groups matter.
Dr Greg Hundley: Very good. My next paper is from Adrian Hobbs at the London School of Medicine, and is looking at the role of endothelial C type natriuretic peptide as a critical regulator of angiogenesis and vascular remodeling. We know that a central pathway coordinating both neovascularization and ischemic extremities in PAD is driven by vascular endothelial growth factor or VEGF-A4.
But preclinical studies and other large scale clinical trials have been disappointing because administering or using VEGF-A to promote angiogenesis or arteriogenesis in PAD really hasn't occurred. This group focused on endothelial-derived CMP. Why? Because it plays a fundamental role in regulating vascular homeostasis. It controls local blood flow and the resistance vasculature, and systemic blood pressure, and reduces the reactivity of leukocytes and platelets.
So, what were the results? Clinical vascular ischemia was associated with reduced levels of CMP and it's cognate NPR-C. Moreover, genetic and pharmacological inhibition of CNP and NPR-C reduced the angiogenic potential of the pulmonary microvascular endothelial cells and the human umbilical vein endothelial, and it isolated vessels ex vivo.
So, the study really defines a central pathophysiological role for endothelium-derived C type natriuretic peptide via activation of cognate natriuretic peptide receptor C in angiogenesis and in vascular remodeling. Moreover, the work demonstrates the therapeutic utility of pharmacologically targeting NPR-C to restore deficits in these processes following ischemia and injury.
Dr Carolyn Lam: Interesting, from new mechanisms and targets to good, old, major risk factors for coronary heart disease. Back to the basics but in a really, I think, nicely done paper from Dr Pencina and colleagues from Duke Clinical Research Institute.
Now, their objective in this next paper was to compare the associations of key, modifiable coronary heart disease risk factors with incident coronary heart disease events based on their prognostic performance, the attributable risk fractions and treatment benefits overall and by age.
And so really aiming at quantifying the importance of these major, modifiable risk factors for coronary heart disease. What they did is they used pool participant level data from four observational cohort studies sponsored by the NHLBI, and they created a cohort of more than 22,600 individuals ages 45 to 84 years old who are initially free of cardiovascular disease.
And these individuals were followed for 10 years from baseline evaluation and followed for incident coronary heart disease. They estimated that age, sex and race captured up to 80% of the prognostic performance of cardiovascular risk models. When we add either systolic blood pressure or non-HDL cholesterol, diabetes or smoking to model with the other risk factors, the prognostic performance, as measured by the C index, increased by only 0.004 to 0.013.
However, if you look at it from the attributable risk and absolute risk reduction standpoint, lowering the systolic blood pressure of all individuals to less than 130, or lowering LDL cholesterol by 30% would be expected to lower a baseline, 10-year coronary heart disease risk of 10% to 7% and 8% respectively.
Dr Greg Hundley: That's a lot of data, Carolyn. Help me synthesize all that.
Dr Carolyn Lam: This is a take-home message. Although the individual modifiable risk factors contribute only modestly to the overall model prognostic performance, when we eliminate or control these risk factors, they would actually lead to a substantial reduction in total population coronary heart disease.
That's because if we look at the attributable fraction and the absolute risk reductions, we see that they actually really matter. The take-home message too from Dr Pencina was that metrics used to judge the importance of these risk factors should therefore be tailored to the question being asked.
Dr Greg Hundley: Very good. That was a very nice summary, Carolyn.
Dr Carolyn Lam: Thanks. Let's move on now to our feature discussion, shall we?
Dr Greg Hundley: Very good.
Dr Carolyn Lam: Trials have established that endovascular thrombectomy dramatically reduces disability after acute ischemic stroke due to intracranial large vessel occlusion. In fact, guidelines almost immediately adopted endovascular thrombectomy as a standard of care. However, that has created some problems.
The main one being that hospitals equipped to carry out this procedure are largely limited to tertiary centers in urban areas. This is, of course, important because that means that patients may need to be transferred from another center to receive such treatment.
Today's feature paper discusses this very issue, a terribly important one, and I'm so pleased to have the author with us, Dr Shreyansh Shah from Duke University Medical Center. We have our editorialist, Dr James Grotta who's director of the Mobile Stroke Unit project at Memorial Herman Hospital.
And we have an associate editor, Dr Graeme Hankey from University of Western Australia. So, such an important topic. I think Shrey, could you just jump right in and tell us what your study showed.
Dr Shreyansh Shah: I'm very excited to present findings of our study, and as a Carolyn mentioned, this study is going to have a very important implication in our country here in US on the creation of systems of stroke. I think the findings are already applicable to other countries also where we are seeing endovascular care getting more and more used.
As Carolyn was talking, endovascular treatment is very important and lifesaving measure. But unfortunately, it is not available at every hospital. Patients are often transferred across different hospital or institution before they can receive this endovascular care.
What we did in our project was we looked at the data from the hospital that's participating in Get With The Guidelines®® Stroke, which is a quality improvement program here in US. It looked at the endovascular thrombectomy used especially in relation to inter-hospital transfer.
What we found was big proportion of patients receiving endovascular care, up to about 43% to 45% of patients, were getting the care after transferring across different hospital. The outcomes in this patient were worse compared to the patient who were receiving endovascular care if they had come directly to the hospital.
While there was no difference in mortality between these two groups, the endovascular care, after inter-hospital transfer, resulted in a higher rate of symptomatic ICH, patients are less likely to be discharged to home, which is the preferred outcome. And patient was also less likely to be able to ambulate independently prior to the hospital discharge.
There was also delay in endovascular care initiation for patient who received this after inter-hospital transfer. I think this particular study highlights the magnitude of this problem, and that's why it's going to be important for people who are studying systems of care. The fact that about 45% of patient had to get inter-hospital transfer before endovascular care tells us that we still need to take significant steps in increasing access to this lifesaving therapy.
Dr Carolyn Lam: Thank you and indeed James, I really love the editorial you wrote that accompanied this. I mean you highlighted its importance, and you also noted that what was unusual about the paper was that even after controlling for the delay in initiating endovascular thrombectomy, there was still worse outcomes in the patients who were transferred. Could you share some thoughts?
Dr James Grotta: It is a very timely issue. Now that we have a very effective treatment, the big challenge we have is getting it to the patients as fast as possible. Right now, our system, as is pointed out, means shuffling patients from one hospital to another.
I think that clearly with stroke treatment, any sort of stroke treatment, the faster we deliver it, the better. Other studies have shown that transferring patients is associated with a delay of treatment, and this study showed the same thing.
There was a substantial delay in getting the patients treated if they required a transfer. And as you pointed out, however, this did not explain the entire or was not at least the entire explanation for the worst outcome. So, it is a little bit of a mystery.
I do know from personal experience that transferring patients from hospital to hospital, it's not exactly a black hole, but you lose control of the patient when they're being transferred. These are patients who have large artery occlusions. That means they have their middle cerebral artery is blocked.
And so, the area of brain that's affected is in a very tenuous shape. So, any drop-in oxygen concentration from breathing problems or of any drop-in blood pressure might further worsen the stroke. So, this could happen in transit. So, it's possible that in the process of transfer, these sorts of things happen.
I do think that we do have to be a little bit careful in that by remembering that this was not a randomized comparison, so patients that were treated directly and those that were transferred were not randomized. And so, although they appear to be balanced in a lot of the important variables like their stroke severity, there may be other things that we can't account for that could explain some of the worst outcomes.
I'd like to ask Dr Shah whether he identified any things in ... well, he and his co-authors think might have contributed to some of the worst outcomes.
Dr Shreyansh Shah: To answer Dr Grotta's question about what other factors may have played a role in the worst outcome that we saw in patients who were getting inter-hospital transfer, I think as we correctly pointed out, transferring this very sick patient is very tricky. As we know, the hemodynamic instability or variability plays an important role in outcomes of stroke patient.
And it is very likely that during the transfer process, there is not adequate control of their blood pressure variability, their oxygen saturation, and this ends up affecting their brain leading to worst outcome. The other possibilities also, as Dr Grotta was explaining, this is not a randomized control trial.
And although we balance for number of important factors that can affect stroke outcome, there might be a selection bias in transferring patient who are more sicker and also patients who received thrombolysis with TPA but did not improve, while the patient who were directly arriving to the hospitals and getting endovascular care, they received the TPA.
It is possible that they started to improve and still received a thrombectomy at the same time. So that group may have been more favorable in that respect, which could have also played a role in better outcomes with patient who are directly arriving.
Dr Carolyn Lam: Interesting. And, you know, with the mention of TPA, I really have to bring James back. I loved your mention about potential solution using mobile stroke units. And since you direct one of them, could you tell us what you meant there?
Dr James Grotta: Yes, of course, I have to state at the outset that I have a little bit of a bias about mobile strokes, and so I do it every day. What a mobile stroke unit is, for those who don't know, it's basically taking the emergency department to the patient.
It's an ambulance with a CT scanner on board and the ability to treat with TPA in the field. But in addition, it's also the CT scanner. We can do CT angio and identify large vessel occlusions on the mobile stroke unit, not to mention the fact that you have a vascular neurologist either in-person or by telemedicine examining the patient.
So clinically, you can make the determination also much more accurately than any sort of pre-hospital stroke scale, whether the patient has a large artery occlusion. That way, you don't have to take the patient to the nearest hospital. You can bypass the nearest hospital, take them right to the thrombectomy center, therefore, avoiding the transfer process.
We've been implementing this in Houston, and there are now about 30 mobile stroke units around the world. The innovation actually started in Germany by Dr Fassbender about a decade ago in Hamburg, Germany. We are conducting a randomized trial, comparing mobile stroke unit care to standard management to see how much better outcomes occur as a result of this faster treatment.
We obviously can treat patients with TPA faster. For example, a similar study from the Get With The Guidelines® a few years ago showed that only 1% of patients treated with TPA in emergency departments get treated within the first hour after symptom onset simply because it takes an hour in the emergency room itself to do the evaluation of the patient and get them treated.
Whereas on our mobile stroke unit, at least a third and probably 40% of the patients we're treating with TPA, we can get treated within that first hour where there may be an exponential better benefit. But we don't yet know really how much that translates to better benefit, and also, of course, mobile stroke units are more intensive in terms of the amount of facilities on board and costs.
So, we need to look at the cost-effectiveness. If it produces only a marginal reduction in disability but costs a fortune, then it's not worth it. But in fact, in our experience, it's pretty practical. We can cover almost the entire City of Houston, which is the fourth largest city in the country, with one mobile stroke unit. When it's well-integrated, it requires careful integration with the fire department and other hospitals in the city.
Dr Shreyansh Shah: At those two conferences, I came across a very interesting talk from Dr Grotta's group about rendezvous with the EMS which allows extending their coverage area significantly. I think we definitely need more and more innovative solutions like this where we can identify patients by their origin, whether they have large vessel occlusion or not, and then triage them appropriately at the centers that can perform endovascular therapy. So as a result, we can provide them earlier therapy and hopefully, it will lead to better outcome.
Dr Carolyn Lam: Thank you Shrey and James for these incredible insights. Now, Graeme, I want you to have the last word and reflections from down under.
Dr Graeme Hankey: Firstly, just to congratulate Dr Shrey and colleagues on this terrific study that reports a contemporary United States experience, a very broad one across the country, really highlighting how since 2012, until a year ago, there's been a six-fold increase in the number of patients being transferred for endovascular therapy.
And we're all experiencing that around the world. And moreover, since the DAWN trial and the DEFUSE trial were published just over a year ago, which is when this study stopped, there's been an expansion of the window from six hours out to 24 hours.
So, in the last year, which this study doesn't cover, we've seen an exponential increase in the number of people being transferred from rural and remote areas who have had a stroke up to 24 hours ago being considered for endovascular therapy if their CT angiogram at the base hospital shows a large vessel occlusion.
This is likely to be not only internally valid, but externally valid to all of us around the world. It reflects our experience of this avalanche of cases coming. And it's provided a lot of challenges for those who are trying to deliver the service at the tertiary referral center.
And it highlights that nearly half of the cases who are having endovascular therapy are coming from external sites. As Jim has really highlighted in his editorial, it challenges us to reassess the current practice of inter-hospital transfer.
Dr Carolyn Lam: Thank you so much for publishing this paper with us and the editorial. And listeners, don't forget to tune in again next week. This program is copyright American Heart Association, 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to The Journal and it's editors. We're your co-hosts. I'm Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, also Associate Editor from the Pauley Heart Center in Richmond, Virginia, VCU Health Sciences.
Dr Carolyn Lam: How well are we doing with guideline-directed stroke prevention therapy in atrial fibrillation? Well, there are going to be very important results that you need to hear about from Get With the Guidelines Atrial Fibrillation. That's our feature paper coming right up in a future discussion. But first, you've got Greg and I discussing really important papers that we've spotted in The Journal. Greg.
Dr Greg Hundley: Absolutely, Carolyn. And my favorite kind of follows from that 'cause it's really about left atrial electromechanical remodeling following two years of high intensity exercise training in sedentary middle-aged adults, kind of like me. The studies from Ben Levine at University of Texas Southwestern Medical Center in Dallas. So, what he's driving at here are moderate-intensity exercises associated with a decrease in incidents of atrial fibrillation. However, extensive training in competitive athletes is associated with an increased atrial fibrillation risk.
So, in this study, they're looking at the effects of 24 months of high-intensity exercise training on left atrial mechanical as well as electrical remodeling in sedentary, healthy, middle-aged adults. So, he had 61 individuals, their average age was 53.5 years, quite young, who were randomized to 10 months of exercise training followed by 14 months of maintenance exercise and some stretching or stretching and balance control. He also had another group of 14 master's athletes that were added for a comparison and he looked at three of the echocardiograms to assess left atrial and left ventricular volumes and also had signal average EKG's for filtered P-wave durations and atrial light potentials. He made assessments at baseline, so before everyone started, and 10 and 24 months.
Dr Carolyn Lam: Hold on, hold on. Let's really understand here how much exercise were these sedentary middle-aged adults subjected to.
Dr Greg Hundley: So, let's talk about that because that was very interesting because a lot of us are out there exercising. So briefly the way he started this, there was an initial phase that was comprised of six months of regressive training during which an increase in the frequency, the duration, and the intensity of exercise, including two high-intensity aerobic interval sessions per week that were prescribed to peak training load. The peak training load included five to six hours of exercise per week that included two interval sessions, at least one being an hour-long session, and then two 30-minute sessions.
Once you got that peak training load, that was sustained for four months and then he made these 10-month measurements as part of his study design. Now following that phase, a 14-month sort of a continuation, all of the 24 months, a 14-month period of maintenance exercise was completed where the frequency of high-intensity intervals was reduced to once per week plus continuous training all the way to that 24-month time point. And during the maintenance phase, participants performed a total of about three hours a week of aerobic exercise.
Dr Carolyn Lam: Well, don't keep us in suspense now. What did the study show?
Dr Greg Hundley: So at the 24 month time point of high-intensity exercise, it led to a disproportionate dilation of the left atrium compared to the left ventricle. So, mechanical changes, but no electrical remodeling was seen. And interesting, and remember he had that comparison cohort with master's athletes. Those participants randomized exercise training demonstrated lower absolute left atrial and left ventricular volumes, but a similar left atrial to left ventricular ratio after 24 months of exercise training.
So, what's going on here, if you're middle-aged or young, some of us like to think, and you start one of these aggressive training sessions, you do have some changes mechanically in the shaping of your left atrium and left ventricle, but they're concordant, but no electrical remodeling that was observed in this situation. So, how do those elite athletes develop atrial fibrillation in the electrical remodeling? Don't know. It may be they need a longer duration of exercise. Maybe they start at a different time point because these are relatively sedentary individuals, and maybe their training regimen is very different.
So, more research is needed, but it was interesting that these middle-aged folks that start with this little bit more aggressive regimen really didn't develop the electrical remodeling. So, Carolyn, you've got a couple of papers that are sort of tied together.
Dr Carolyn Lam: Indeed. A couple of papers centered on lipoprotein little A. Now, we know that lipoprotein little A levels predict the risk of myocardial infarction and this has been shown in populations of European ancestry, however there's very little data available in other ethnic groups. And so, this was addressed by Dr Paré from McMaster University and the Interheart Investigators who looked at more than 6000 cases of first myocardial infarction and more than 6800 controls, all from the Interheart study, and were stratified by ethnicity and included African, American, Chinese, European, Latin American, South Asian, and Southeast Asian ancestries.
Lipoprotein little A concentration was measured in each participant, first using an SA that was insensitive to iso-form size and then iso-form size itself was also assessed by Western Blot in a subset of more than 4200 participants. So, what they found was that lipoprotein little A concentration and iso-form size varied markedly among the ethnic groups. Africans had the highest concentrations with the smallest iso-form size whereas Chinese had the lowest concentrations with the largest iso-form size.
Furthermore, higher lipoprotein little A concentrations were associated with an increased risk of myocardial infarction and carried an especially high population burden in South Asians and Latin Americans. And a high concentration above 15 milligrams per deciliter was associated with significantly increased risk of myocardial infarction in all populations except Arabs and Africans. The iso-form size, on the other hand, was inversely associated with lipoprotein little A concentrations and did not significantly contribute to the risk.
Dr Greg Hundley: So, Carolyn, how do we use this clinically? I mean, do we measure this in folks?
Dr Carolyn Lam: Yeah. So, there are two take-home messages. I think one is about the monitoring or measuring and it supports a clinical use of the actual lipoprotein A concentration rather than iso-form size as a marker of myocardial infarction in this ethnically diverse population. But this is, other than Africans and Arabs where, remember that cut off did not seem to associate with a risk of MI's in these two ethnicities. The second take-home is that the effects of clinical interventions that reduce lipoprotein A should be investigated especially in South Asians and Latin Americans where the population attributable risk is really high. And that actually brings me to the second study.
So, we've always been looking for intervention that can reduce lipoprotein A and this current paper is really interesting 'cause it talks about insights from the Fourier trial. So, we may finally have a therapy that can reduce it. Dr O'Donoghue from the TIMI study group and Brigham and Women's Hospital in Boston, Massachusetts and colleagues looked at the relationship between lipoprotein A levels, PCSK9 inhibition, and cardiovascular risk in the Fourier trial, which you remember is a randomized trial of Evolocumab versus placebo in patients with established atherosclerotic cardiovascular disease.
So, they found that patients with a higher concentration of lipoprotein little A were at increased risk of coronary events independent of the LDL concentration. And individuals with a higher baseline LP little A concentration tended to have a greater relative and absolute coronary risk reduction with Evolocumab and therefore a lower number needed to treat. It was as low as four T for individuals with a lipoprotein A above the median versus 105 number needed to treat for those at or below a lipoprotein A level below the median.
Dr Greg Hundley: So should we start checking this in all our patients now, these lipoprotein little A levels?
Dr Carolyn Lam: Yeah. So, this issue was discussed beautifully in a company editorial by Dr Thanassoulis from McGill University Health Center. And here he mentions that there remains tremendous clinical inertia honestly for the measurement of lipoprotein A in North America and in fact, worldwide. For this to be successful, we really need to be proactively screening our patients with myocardial infarction and stroke and especially those with premature events or a family history. And particular attention will need to be made on screening individuals with recurrent events despite adequate lipid or LDL lowering who frequently may still have high lipoprotein little A. It's encouraging to know that the most recent version of the US Lipid Guidelines has newly recommended LP little A measurements in select individuals as a risk enhancer and so this should further raise awareness of lipoprotein little A as a risk marker.
Finally, the editorialist mentioned that common misconception that we have a lack of therapeutic options to lower high LP little A. Still, we need to remember that these individuals may obtain significant benefit from more aggressive lifestyle modifications. And now we have these results of this trial that suggest that PCSK9 may be one of the few drugs that can lower lipoprotein little A. And so, the editorialist actually ended with targeting therapy for lipoprotein A is around the corner and a test of this hypothesis is really imminent, so we should watch this space.
Dr Greg Hundley: Yeah, so it sounds like another wonderment of PCSK9 inhibitors.
Dr Carolyn Lam: Yeah.
Dr Greg Hundley: Well Carolyn, let me jump in and finish our chat here talking about iron. This particular paper is from Dr Jean-Sébastien Silvestre from Paris, France, and he's looking at the iron regulator Hepcidin. So, we know that iron deficiency is frequent in patients with coronary artery disease and increases morbidity in those with high risk profiles such as those with diabetes and anemia and then conversely, excess iron is also detrimental to cardiac function. We see this with iron overload cardiomyopathies and as a major co-morbidity in patients with genetic hemochromatosis.
So, among the multiple regulators of iron homeostasis is Hepcidin. It plays an instrumental role in fine-tuning systemic iron trafficking by modulating the transfer of dietary, recycled, and stored iron from intracellular compartments to extracellular fluids. Hepcidin is a catatonic peptide hormone. It's produced primarily by hepatocytes, but also, it's produced in macrophages. So, given the role of Hepcidin to locally regulate cardiac function and that inflammation guides cardiac remodeling after acute MI, the investigators hypothesized that inflammatory macrophages may control cardiac repair through a Hepcidin-dependent mechanism. And until now, the role of Hepcidin in some other cardiac diseases challenged by inflammation hasn't really been explored.
Dr Carolyn Lam: Huh, interesting. So, what did they find?
Dr Greg Hundley: Great question and let's lead to the main results of this study. The hormone Hepcidin, they found, was produced by a distinct sub-population of inflammatory cardiac macrophages residing in infarcted heart tissue and the deletion of Hepcidin in macrophages improved tissue remodeling and stimulated cardiomyocyte renewal in both, just as our wonderful basic science studies have, in both adult mice with myocardial infarction, neonatal animals with apical resection and also in human subjects. And so, this study provided novel insights into the complex roles of the immune response during cardiac repair following MI and suggests and deleterious role for the macrophage-derived Hepcidin in cardiac repair.
Interesting, Carolyn. Another role for iron in acute MI and more research to come.
Dr Carolyn Lam: Indeed. Well, thanks Greg. Let's move on to our feature discussion, shall we?
For our feature discussion today, we are talking about the first results from the Get With the Guidelines atrial fibrillation. That is huge, and I have none other than the first author, Dr Jonathan Piccini from Duke Clinical Research Institute, as well as Dr William Lewis from Case Western Reserve University here to discuss these really important results, so listen up. I think to start with it is such an honor to have you with us, Bill. I mean, as Chair of the Get With the Guidelines atrial fibrillation work group, could you give us a background on how did this start? How far has it come?
Dr William Lewis: The Get With the Guidelines program started in 2000. Greg Fonarow figured out that if we put in place mechanisms to improve adherence, that we could get people on appropriate therapies. In 2012, there was some focus on atrial fibrillation and I had been participating in the program since 2004 and I kept telling them that A-fib was a big, big problem. And in 2012, they said, "Let's do this," so we built this program to try to improve adherence in atrial fibrillation. Get With the Guidelines is a national, hospital-based, quality improvement program that improves adherence to guidelines over time and it has been very successful at doing that.
So, by 2013 we were ready to start enrolling patients and we started getting patients in the database and we're now up to about 162 hospitals nationwide, in the United States, and we've enrolled about 75000 patients in the program. So, it's been very successful from that standpoint.
Dr Carolyn Lam: Congratulation. And today we're actually going to be talking about that very question you asked. Adherence. How well are we adhering to guideline-directed stroke prevention therapy for atrial fibrillation? Jonathan, wanna share the key results?
Dr Jonathan Piccini: I think you're getting exactly to the point of what was the rationale for this study and I think most individuals that are familiar with the field and atrial fibrillation and also clinicians across the world who are treating patients with atrial fibrillation know that most large reports, most nationwide studies have shown that adherence for oral anticoagulation to prevent stroke in patients with atrial fibrillation usually ranges in the 50, 60, 70 percent range at best. And there's been some notable publications in the past several years from nationwide registries that have shown rates as low as 50 percent or lower in high-risk patients. So, one of the main goals of the program, as Bill articulated, was to try and improve the use of oral anticoagulation in patients who had a guideline recommendation. So, patients who had a CHA2DS2-VASc score of two and higher with atrial fibrillation.
And so, looking at over 30000 admissions between 2013 and 2017 and the guidelines A-fib program, we saw that just under 60 percent of patients who had known AF at the time of admission were on oral anticoagulation. And not surprisingly, the patients who were on oral anticoagulation had lower rates of stroke during their hospitalization. But the major finding from the program was that in this quality improvement program, the program was able to improve adherence to oral anticoagulation at discharge from 60 percent to admission all the way up to 93.5 percent in the overall cohort. And if you looked at results over time, adherence improved from 80 percent at discharge all the way to 96 percent and those improvements were sustained in follow up as well.
Dr Carolyn Lam: Could you tell us, what do you think are the key elements that help this improvement? Is it just because there's a program and people know they're being watched? Is it that there was a change? I mean, when you say oral anticoagulants I bet you mean both Warfarin and the newer oral anticoagulants, so how much did that help? What do you think is the key ingredient here?
Dr Jonathan Piccini: It was several things. Having visited several of these hospitals and spoken with them about the impact of the program, I think you can't emphasize enough that if you don't measure something, you can't really expect to improve it. So, just the fact that hospitals were having systematic data on their atrial fibrillation patients at discharge illustrating who was and who was not getting oral anticoagulation makes a big difference. Between the program itself and the conferences affiliated with the program and teaching sessions affiliated with the program, there's a heavy emphasis on education of the importance of guideline recommended treatments for atrial fibrillation, so that's a second component.
And then there's an iterative relationship between the sites and the American Heart Association where improvements in the rates of oral anticoagulation are recognized and celebrated. And I think it's not any one thing, in my opinion. I think it's all of those things taken together. And again, Bill, who's been with the program since its inception probably has additional thoughts on that as well.
Dr Carolyn Lam: Bill, did you expect such remarkable results?
Dr William Lewis: No. I actually didn't expect 96, but in a previous study where we were looking at patients who had had a stroke in the stroke database, we were able to achieve 93 percent adherence. And so, 96 is remarkable and it's the highest number that's ever been seen in any A-fib program. I was going to mention about the idea of what makes the special sauce, if you will, and I think John put forth a number of items. I think, again, celebrating success, those kinds of things, but I think that docs, by their very nature, are very competitive and when you get a data report that says you're doing x percent and somebody else is doing y percent and their percentage is higher, you tend to get motivated to actually do better. And so, we provide these reports in the program to hospitals so that they can measure their success against other institutions.
Dr Carolyn Lam: That's such a good idea. And, you know, I practice here in Asia and there aren't these very massive programs that are accepted in many places. So, what do you think is the generalizability of something like this?
Dr Jonathan Piccini: That's such a critical question because a limitation is that these are hospitals that are saying voluntarily, "We want to commit to the program because we think quality care for atrial fibrillation patients is important." And so, you could argue that, well, these results really don't generalize to your run of the mill hospital in different parts of the world. And I think while that's a limitation, it's also a call for what the next steps are. So, having visited many of these hospitals, these are real hospitals of brick and mortar that face many of the same challenges other health systems and hospitals across the world do and I think the key message is that a hospital that implements these types of interventions is very likely to see the same improvement with their patients. And so, I think that's a very important message and a very positive message for patients all over the US and all over the world.
Dr William Lewis: I agree. I think it's, not turn-key, it's much more generalizable than we had ever expected. So, community hospitals do this. The American Heart Association is using other Get With the Guidelines programs in China. I think that there is a lot that has to do with the support that's provided by the program and the tools that are made available to them to be able to make it so that you can recreate it in a hospital. I agree, it is more difficult in some hospitals than others.
Dr Carolyn Lam: John, before we end, what are the take-home messages for clinicians listening out there?
Dr Jonathan Piccini: I'd have two messages. The first message is that this study shows that with some assistance any healthcare system or hospital can achieve optimal adherence to these medications for their patients and thus in so doing achieve a significant benefit for the public health. And the second message I would have, which isn't necessarily specifically related to the paper, but I think it's equally important, that this is just the beginning for the American Heart Association and the Heart Rhythm Society Get With the Guidelines A-fib registry. Though stroke prevention is obviously just one of many different aspects of quality care for atrial fibrillation and so keep an eye out 'cause you'll be seeing a lot of studies coming out about how Get With the Guidelines A-fib is better informing care and treatment for atrial fibrillation across many different therapy domains, including catheter ablation and rate control and other interventions for rhythm control. And again, on behalf of all the co-authors and the American Heart Association, the Heart Rhythm Society sponsors, we really appreciate to have the opportunity to talk about the program.
Dr Carolyn Lam: Thank you so much for sharing that with us.
Audience, you heard it right here on Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor and director of the Pauley Heart Center at VCU Health, in Richmond, Virginia.
Dr Carolyn Lam: So Greg, are ARNI's now going to be used for functional, mitral regurgitation and heart failure? Well, we're going to be chatting all about that with our feature paper, coming right up after these summaries.
Greg, you've got a biggie to start with, haven't you?
Dr Greg Hundley: Oh yes, Carolyn, I'm really excited about this paper. The senior author Wanpen Vongpatanasin from University of Texas Southwestern Medical Center in Dallas and looking at high phosphate diets and their relationship to exercise intolerance. I really felt this was an exceptional study and combining that key that we have, for basic science papers and translation, where we're looking at data from both human and basic science, in both in a single manuscript.
So, this study focuses on inorganic phosphates and they are present in 40-70 percent of the foods, really as a preservative enhancer, in western diets. We see it in colas, meats, dry food mixes, bakery products.
For the human subject component of this study, the investigators examine the relationship between physical inactivity, assessed with ActiGraphs that were worn, and serum phosphate levels. They also obtained MRI measures of cardiac function and participants were recruited from the Dallas Heart Study too.
In animals, they looked at the direct effects of dietary, inorganic phosphate on exercise capacity, oxygen uptake, serum non-esterified fatty acids, and glucose was measured during exercise treadmill tests in mice fed either high inorganic phosphate diets or normal in-organic phosphate diets. And they were on that for 12 weeks.
To determine the direct effect of phosphate on muscle metabolism and expression of genes involved in fatty acid metabolism, additional studies in the differentiated myotubes were conducted after subjecting those cells to media with high or low phosphate conditions.
Dr Carolyn Lam: So, what did the study show?
Dr Greg Hundley: In the human part, among 1603 participants, higher serum in-organic phosphate was independently associated with reduced time spent in moderate to vigorous physical activity and increased sedentary time. And interestingly, there was no association between serum phosphate levels and left ventricular ejection fraction or volumes.
In the animal studies, mechanistic insight was obtained. Compared to controlled diets, consumption of high phosphate diet for 12 weeks did not alter body weight or left ventricular function, thereby confirming what we saw in the human subjects, but reduced maximal oxygen uptake, treadmill duration, spontaneous locomotor activity, fat oxidation, fatty acid levels, and led to down-regulations of genes involved in fatty acid synthesis.
So, the take-home on this is that the results of this study demonstrate a detrimental effect of dietary, phosphate excess on skeletal muscle, fatty acid metabolism, and exercise capacity, which is independent of obesity and cardiac contractile function.
And as such, dietary in-organic phosphate may represent a novel and modifiable target to reduce physical inactivity associated with the western diet. I think, Carolyn, we're going to see a large number of epidemiologic studies that are going to really look at this as something we might be able to modify in our diet to help impact some of these sedentary lifestyles and the harmful cardiovascular effects that we find associated with that lifestyle.
Dr Carolyn Lam: Yikes. Remind me again, so phosphates in colas, meats, dried food mixes, and bakery products and so on, the preservative. Wow, you're right; big paper.
Dr Greg Hundley: It's amazing. It's in 40-70 percent of the food products here in the United States. So, wow. Something really striking. So Carolyn, how about one of the papers that you liked?
Dr Carolyn Lam: Moving to related cardio metabolic disease, we know that patients with type 2 diabetes and prevalent atherosclerotic cardiovascular disease, there is a tenfold variation in future cardiovascular risk in these patients. The current paper actually analyzes data from EMPA-REG OUTCOME where the authors, led by David Fitchett from St. Michael's Hospital in Toronto, sought to investigate whether the beneficial effects of Empagliflozin, observed in the EMPA-REG OUTCOME trial, varied across the spectrum of baseline, cardiovascular risk.
What they found was that in patients with type 2 diabetes and atherosclerotic cardiovascular disease, the relative reductions in risk of cardiovascular death, all-cause mortality, 3-point MACE, and heart failure hospitalizations with Empagliflozin versus placebo, were consistent in patients with and without a prior, myocardial infarction, with and without a prior stroke, and across sub-groups by the 10-point TIMI Risk Score for secondary prevention at baseline.
Dr Greg Hundley: Does this suggest, Carolyn, that we use these inhibitors in all patients with type 2 diabetes?
Dr Carolyn Lam: Remember the EMPA-REG OUTCOME; all patients had established atherosclerotic cardiovascular disease. This paper really adds to the understanding of the gradient of risk within these patients who had atherosclerotic cardiovascular disease and says Empagliflozin could be beneficial. But remember, there are patients with type 2 diabetes without established, cardiovascular disease and I think there's still equipoise in this primary prevention population.
Dr Greg Hundley: That was great, Carolyn. Now I'm going to grab another sip of coffee and go onto my next paper.
Dr Carolyn Lam: Sure, as long as it's not cola. No phosphates.
Dr Greg Hundley: Right, thank you very much, Carolyn. I'm going to talk about screening for small and medium abdominal aortic aneurysms. This particular study comes from the surveillance of the National Health Service screening program by Dr Earnshaw. Basically, population screening for abdominal, aortic aneurysms has been shown to reduce AAA-related mortality by up to 50%. Most men who screen positive have a AAA below 5.5 centimeters in diameter, and that's really our current referral threshold for treatment. When they have smaller diameter aneurysms they're entered into an ultrasound surveillance program.
In this study, the investigators looked and reviewed those that had small, 3-4.4 centimeter diameter aneurysms or medium ,4.5 up to 5.4 centimeter aneurysms, and they were followed. They were looking at the risk of rupture in these under surveillance.
They had a total of 18,652 men and the risk of rupture overall per annum was 0.03% for men with small, abdominal aortic aneurysms and 0.28% for medium size. That was just below the threshold for the 5-5.4 centimeters, which was 0.4% over time. The risk of abdominal aortic aneurysm surveillance is below .5% per year and that is just below our current referral threshold for surgery, which is 5.5 centimeters.
This is a study that really confirms, Carolyn, that the target mark or diameter that we've selected is appropriate.
Dr Carolyn Lam: Nice. These just confirm the current guidelines?
Dr Greg Hundley: Yeah, they do and Gil Upchurch from University of Florida, a surgeon, had a very nice editorial. The point he wants to make is yep, diameter of 5.5 is the threshold, but a couple key points. As patients are coming in for these visits, we need to continue to emphasize to them other factors related to growth of abdominal aortic aneurysms and their rupture. So, tobacco cessation, treatment of your lipids, management of your hypertension.
The other point that he makes, is we really don't need to be operating on those individuals with an abdominal aortic aneurysm diameter of less than 5.5 centimeters. He makes an argument here that's in some countries with fee-for-service reimbursement, up to 30% of AAA repairs are for aneurysms less than this diameter of 5.5 centimeters. This over utilization of resources can add considerable costs to the healthcare system for managing this condition and is unlikely to increase the overall survival of these patients.
A nice study confirming that what we're doing, really in terms of size and diameter, is correct, but also emphasizing this patient population often has a lot of other cardiovascular co-morbidities that we need to aggressively manage. How about your next paper?
Dr Carolyn Lam: From one very clinically, applicable paper to another. This one answers the question, what's the optimal duration of emergency department and post-emergency department rhythm monitoring among patients with syncope. And the authors, led by Dr Thiruganasambandamoorthy and his colleagues from the Ottawa Hospital Research Institute, prospectively studied adults presenting within 24 hours of syncope at six emergency departments. They collected baseline characteristics, the time of syncope, the time of emergency department arrival, and the Canadian Syncope Risk Score, risk category. They followed subjects for 30 days and adjudicated the primary outcome, which was serious arrhythmic conditions and that includes arrhythmias or interventions for arrhythmias and unexplained death.
Their results showed that the overall arrhythmia risk, and the risk after two hours of emergency department arrival from Canadian Syncope Risk Score, low-risk patients, was indeed very low. Similarly, the overall risk and after six hours of emergency department arrival for medium and high-risk patients was moderate and high, respectively. No low-risk patients suffered ventricular arrhythmia or unexplained death and most of the arrhythmias among the non-low-risk patients occurred within 15 days of the index syncope.
Dr Greg Hundley: Carolyn, what's the take home message here?
Dr Carolyn Lam: The results really support brief monitoring in the emergency department for two hours for Canadian Syncope Risk Score low-risk patients, and six hours for medium and high risk patients followed by selective admissions and the results also support a 15-day outpatient monitoring for medium-risk patients at a selected threshold and for all high-risk patients. So very practical advice.
Dr Greg Hundley: Very good. Until next week, I'm going to watch out for phosphates.
Dr Carolyn Lam: Indeed, and let's go on now to our featured discussion.
For today's featured paper, we are discussing the results of the PRIME Study and that is Angiotensin Receptor Neprilysin Inhibitor, or ARNIs, for functional mitral regurgitation. A terribly interesting study. So pleased to have with us an author Dr Sung-Hee Shin from Inha University Medical center in Incheon, Korea as well as our associate editor Dr Victoria Delgado from University of Leiden in the Netherlands.
Sung-Hee, what an interesting study. ARNI or Entresto for functional mitral regurgitation. Could you tell us what inspired this study and what did you find?
Dr Sung-Hee Shin: Our study was the designed to tell if ARNI or functional mitral regurgitation because secondary functional mitral regurgitation was developed as a result of a reduced function. Guideline-directed medical therapy for heart failure would be a mainstay for a therapy.
But despite use of the traditional drugs such as BETA blocker, ACE inhibitor or angiotensin receptor blockers, you know that the functional mitral regurgitation may be common and significant in the person having this functional mitral regurgitation would be related to increased morbidity and mortality.
So, that trial showed that trans-catheter mitral valve repair effectively reduced the function mitral patient and resulted in lower rate of heart related mortality among patients with heart failure and function mitral regurgitation.
In our blind trial, we also tried to tell whether an ARNI is more effective in improving function mitral regurgitation and randomly assigned 118 patients with heart failure and chronic secondary function mitral regurgitation lasting more than six months despite medical therapy and ejection fraction between 25% and 50% to receive either sacubitril/valsartan or valsartan in addition to standard medical therapy for heart failure.
What happened with that change of mitral regurgitation after 12 months which was assessed by means of transthoracic area ways echo. What we observed was that transthoracic area as well as the volume of mitral regurgitation saw a decrease much more effective in the sacubitril/valsartan group than valsartan group.
We also looked at the various other measures of the left ventricle remodeling and showed that the valsartan group had smaller left ventricle volume at 12 months and had a greater reduction of end-diastolic volume index.
Also, among the completers ARNI, for the reduced left ventricle volume and the yearly time than the control group. So, what we think is that these factors might contribute to greater reduction of function mitral regurgitation in patients in the sacubitril/valsartan group.
But our study was a mechanism study, but it was not designed to see outcomes. So further research and data would be necessary to check is this transthoracic echo end point can translate into better outcome in this population.
Dr Carolyn Lam: Sung-Hee, this is just so interesting to have hypothesized this about functional mitral regurgitation. And not only that, I mean, to my mind, this is the largest echo-based studies of patients before and after Entresto that I can think of. It's nice to know, on top of knowing in paradigm that we can improve outcomes in heart failure reduced ejection fraction, that we now can look at the heart and see what happens in so many dimensions.
Victoria, were you surprised by these results? And do you agree with the mechanisms that Sung-Hee suggested?
Dr Victoria Delgado: I think that this study is very important because in the field of functional mitral regurgitation, there is still a lack of consensus on how to treat these patients, which are very challenging.
If the patient needs revascularization they will be referred for certain. But it still should be CBR mitral regurgitation and moderate and mile mitral regurgitation are not considered.
I think that we discuss often which is the optimal medical therapy or the guidelines based medical therapy but it's not really consensus because the studies before have not been like this one. That large in order to answer a specifically that question.
I think that this article brings an important message and brings more evidence to our field that there is not that much data. So, I think it's very important for that research, in particularly after the research of the co-op and the mitral trial where it seems that the selection of patients is very important in order to identify the patients that will really benefit from those therapies.
Dr Carolyn Lam: That's such a good point. Going to that selection of patients, Sung-He, you mentioned very carefully the ejection fractions that you allowed up to 50% in these patients. Could you explain how you reasoned the selection of this patient cohort?
Dr Sung-Hee Shin: The reason why we chose the patients we did, the range of ejection fraction condition, was that we thought the reversibility of the left ventricle mortality and function mitral regurgitation might be more pronounced in these patients.
When we considered the fraction condition in mitral regurgitation with ejection fraction used under [inaudible 00:18:17] LV dysfunction, our inclusive criteria of ejection fraction between 25 to 50% might correspond to ejection fraction of 20 to 40% in patients with mitral regurgitation.
We concluded that if a patient had ejection fraction less than 25% because the reversibility of mortality and function mitral regurgitation might be smaller when all the LV dilation is too extreme and advanced heart failure is already established.
So, I just thing how it can be provided to the patient who have functional mitral regurgitation associated with too extreme LV dilation and LV ejection fraction too.
Dr Victoria Delgado: I think, Carolyn, it's a very good point what she explained because we are used to select patients based on ejection fraction, in particularly patients with functional mitral regurgitation, ejection fraction is rather misleading because actually it's just a change of volume in the ventricles emptying in a low pressure chamber which is the left atrium.
The moment that you correct that in mitral regurgitation sometimes then you face, or you see, the true ejection fraction of that ventricle. And if we wait too long, we may end up with ventricles that they don't have any more resource in order to improve ejection fraction after repair of the mitral valve.
So, I think that this study is important to also realize that concept. That ejection fraction in patients with functional mitral regurgitation may not be the most accurate parameter to assess the function of that ventricle.
Dr Carolyn Lam: Yeah. Exactly. And I thought that was a very clever part of the design. I'm glad you explained it and also so glad, Victoria, you invited the editorial by Dr Mullens, who also commented on that. So, just for the audience to understand that ejection fraction up to 50% was included and ejection fraction less than 25% was excluded.
So also, again, very consistent to your prior point, Victoria.
Could I ask you, I think Dr Mullens also spent quite some time talking about the potential mechanisms. What's your take of this Victoria? ARNI for functional regurgitation. How come?
Dr Victoria Delgado: For me, I'm much more from the side of the imaging point of view. When we have patients with functional mitral regurgitation I always try to see which is the capability that that ventricle has to recover.
Actually, first is always medical therapy, but we know that the [inaudible 00:20:59] only, for example, we just reduced the mitral regurgitation, but they don't really improve the function of that ventricle, while if you reduce the loading conditions of the ventricle in terms of blood pressure as well and favoring remodeling of the left ventricle, you can improve the condition of the mitral valve and reduce the mitral regurgitation.
How valsartan plus sacubitril works differently than valsartan alone that I don't think that I have enough knowledge to explain why but it could be that in a way there is more effective with sacubitril on top of valsartan can improve the loading conditions of the ventricle and improve the, or facilitate, the reversing of morbidity of that ventricle, reducing the mitral regurgitation and that, by itself, could also lead to reversing morbidity.
Like a little bit cardiac resynchronization we'd do, for example, in patients with an ejection fraction below 35% and based on the EEG you have the synchronous fraction of the papillary muscle or the walls of the ventricle which could lead to the mitral regurgitation at the moment that you resynchronize that mitral regurgitation can produce, you reduce part of the volume of the load of the ventricle and that can favor that reversing morbidity.
So, I think that this study raises a lot of questions and I think that further research is needed in order to confirm or to know more how these treatments work.
Dr Carolyn Lam: Goodness, that was so beautifully explained and in fact, many clues from Sung-Hee's study and the reversal of left ventricle end diastolic volume index greater with those treated with ARNI, the LA size and so on.
But maybe I should ask you, Sung-Hee, in line with what Victoria said, what are the next steps? Do you already know what are the next studies that you're going to be looking at in PRIME?
Dr Sung-Hee Shin: We're considering mark of monitoring such as NT pro-BNP or using auto imaging models such as echo and cardiac MRI to look at the change of mitral valve regurgitation in more detail.
This kind of study might be very helpful in understanding [inaudible 00:23:15] ARNI in functional mitral patient.
Dr Carolyn Lam: Yes, that's clever, too. And Victoria, before we end could you maybe give us some take home messages?
Dr Victoria Delgado: I think that the take home message from this study is that when we have patients with functional mitral regurgitation, we need to think what we can offer to them. Not consider mitral regurgitation just as a base standard. That it's going to respond only to diuretics. No. We need to do something on that left ventricle to help it to improve the function and to avoid the progress to more reduced function.
It's very important to understand the mechanism of the mitral regurgitation and to use the guidelines based medical therapy trying to go step by step in order to optimize the medication of that patient and later on, see all the potential treatments that are available right now such as cardiac synchronization therapy, which we should not forget, and then surgery if the patient needs catheterization and if the patient needs the benefit from mitral valve plasty or eventually, for example, trans catheter mitral valve therapies.
But we should avoid that the patient goes further down into heart failure with very dilated ventricles and very poor function because then probably we may face a point of no return.
Dr Carolyn Lam: Thank you so much, Victoria. Both you and Sung-Hee mentioned this is a mechanistic study. So many insights. But it's not saying that everybody with functional mitral regurgitation has to be treated this way now. It's calling for more work and it's certainly very, very important study.
Thank you listeners, for listening today as well. You've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association, 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm doctor Carolyn Lam, associate editor from the National Heart Center, and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor from the Pauley Heart Center at VCU Health in Richmond, Virginia.
Dr Carolyn Lam: Have you heard of long non-coding RNAs? Well, they are definitely the hot topic and our feature paper today discusses the first demonstration of the importance of a linked RNA in atherosclerotic lesions not just in mice but also in humans. You have to listen on, it's coming up right after our copy chat.
Greg, what are your picks upon the journal this week?
Dr Greg Hundley: The first paper I wanted to discuss comes from France, and it's basically looking at ambulance density and outcomes after out of hospital cardiac arrest from Florence Dumas from Hôpital Cochin in Paris, France. This manuscript addresses the geographic disparities and survivorship of out of hospital cardiac arrest and the relevance of the patients characteristics versus whether ambulances are equipped with those trained in basic or advanced cardiac life support. So, what they did they had nineteen neighborhoods in Paris, and the number of BLS trained versus ALS ambulances was collected, and the authors assessed that respective associations of socio-economic characteristics of the patient population and the ambulance resources of these neighborhoods and compared those with successful return of spontaneous circulation or risk as the primary end point and then survival of out of hospital discharge as the second end-point.
So, they had 80754 non-traumatic out of hospital cardiac arrests across the Paris area. 42% at ROSK 9% head survival at discharge, and after accounting for the patient's socio-economic status, greater than one and a half advanced cardiac life support ambulances per neighborhood and greater than 4 basic cardiac support basic life support units per neighborhood were associated with ROSK, but only the 1.5 ALS units per neighborhood were associated with survival.
Dr Carolyn Lam: Oh, interesting Greg. So does this we need more advanced life support units?
Dr Greg Hundley: So, Paul Dorian from St. Micheal's Hospital in Toronto, Canada wrote an excellent editorial, and one point he made related to these ALS units is that it was really a very small 1.3 adjusted odd ratio for survival to hospital discharge, and it's important to note that although the increase in survival was associated with more ALS units, there were many other variables that were likely important and not recorded in this study. For example, including the time to collapse, to calling for EMS, the time from the call to the deployment of that ALS unit to the scene, the time from collapse to the defibrillation, the total "no flow time" sort of in quotation, which is the total duration of collapse until CPR is started and so I think one of the points in this observational study is there could've been many differences that would've associated with the findings, interesting findings how about one of the papers that you liked?
Dr Carolyn Lam: So, the paper that I selected here is a first time that a targeted anti-inflammatory therapy has been shown to reduce hospitalization for heart failure and at-risk patients. So, you know that some clinical inflammation associates with an increased risk of heart failure and associates with the worst prognosis in patients with heart failure, and yet, so far, treatments specifically directed at reducing inflammation in patients with heart failure have not been shown to improve clinical outcomes. That's why today's paper is so special and it's from Dr Everett and colleagues from Brigham and Women's Hospital Harvard Medical School in Boston, and basically, the authors looked at CANTOS and tested the hypothesis that the interleukin -1β inhibitor can canakinumab would prevent heart failure hospitalizations and the composite of heart failure hospitalizations on heart failure related mortality in the CANTOS trial.
Now, remember the CANTOS trial randomized more than 10 000 patients with a prior myocardial infarction and with high sensitivity C-reactive proteins at least two or greater, and they were randomized to canakinumab 50, 150, and 300 mg or placebos. Now, before randomization, these participated were asked if they had a history of heart failure and 22% said yes so the current paper actually looks at this stratification of patients who said they had heart failure, and during a meeting follow-up of 3.7 years, 385 patients had a new heart failure hospitalization event. Now, here's the key: the authors found a dose dependent reduction in the risk of hospitalization for heart failure as well as the composite of hospitalization for heart failure or heart failure related mortality among those allocated to Canakinumab.
Dr Greg Hundley: So, how does this differ from prior attempts targeting inflammation and heart failure? I mean is this ready for prime time thing?
Dr Carolyn Lam: So, we have to bear a few things in mind here you know. CANTOS was different from a previously published randomized controlled trials, which were basically neutral and that was like of infliximab and etanercept so the drug in CANTOS targets interleukin-1 beta whereas the prior ones targeted the TNF-alpha, and also very importantly, CANTOS did not specifically enroll patients with an established heart failure only. CANTOS patients had to have a history of myocardial infarction and there was no data on their ejection fraction or natriuretic peptides at the time of randomization nor at the time of heart failure hospitalization. So, by the way, we don't know whether there's a differentially effect on hep pef versus hep-ref. So, again difference from the heart failure focused trial previously that used an anti-inflammatory agents.
The other thing: although there was a dose dependent reduction in the risk of hospitalization for heart failure no single dose of Canakinumab compared to the placebo had a statistically significant reduction in the risk of heart failure hospitalization. Only the trend was statistically significant so all in all, this was a pre-specified aim of CANTOS to look at heart failure, the data presented here should really be considered hypothesis generally, but really quite promising. And what about you Greg? What's your other paper?
Dr Greg Hundley: We're going to switch gears a little bit and shift over to the Jackson heart study. The large longitudinal cohort from Jackson, Mississippi that's recruited to follow for cardiovascular events, and it's an area of the United States where we have some of the highest cardiovascular disease event rates really across the nation so this study focuses on sleep apnea and is the Jackson's heart sleep study. It's a sub-study of this larger Jackson's heart study that involves 913 patients, and the investigators were looking at the association between sleep apnea and blood pressure control among those of a Black race. So, Dayna Johnson of Emerald University is the first author on the paper. What's nice about this sub-study, this sleep sub-study is that there are objective measures using an in-home type III sleep apnea study. They had clinical blood pressure measurements and then anthropometry as opposed to questionnaire derived data that may have been performed in the larger cohort.
And the study determined these associations between moderate or severe obstructed sleep apnea with controlled, uncontrolled and resistant hypertension. So the analytic sample of the individuals with hypertension was 664, and they had an average age of about 64 years. They were predominately women 69%, obese 58%, College-educated at 51%. Among the sample, about a quarter had obstructive sleep apnea, which was untreated and unrecognized in 94% of the participants. That's an interesting point, just right there.
Overall, 48% of the participants had uncontrolled hypertension and 14% had resistant hypertension. So, multiple medications, often four and still unable to control the blood pressure. So the findings participants with moderate or severe obstructive sleep apnea had 2 times higher odds' ratio of resistant hypertension.
Dr Carolyn Lam: Whoa Greg, that's a huge risk and very important finding. I mean if sleep apnea could be modifiable risk factor perhaps for very important issue among African Americans resistant hypertension. What do you think about clinical implication?
Dr Greg Hundley: One of the things to be considering now is what are we going to do about that cause as you know CPAP is really the preferred treatment for resistant hypertension, but it's efficacy hasn't been really that well studied in African Americans and CPAP tolerance is low so this study highlights for us potentially new mechanisms for resistant hypertension, but we still got to be thinking about what would be our next therapeutic intervention for this particular patient population. And what about your next study?
Dr Carolyn Lam: The next study is about Impella support for acute myocardial infarction complicated by cardiogenic shock. Now, we use it all the time, but did you know that to date, there is no large randomized study actually comparing the use of Impella to other contemporary cardiac support devices and medical treatment in stem related cardiogenic shock. So, Dirk Westermann and colleagues from University Heart Center in Hamburg tried to address this knowledge gap by using a multi-national database of patients with acute myocardial infarction complicated by cardiogenic shock and treated with the Impella device and compared in a matched fashion their outcomes to patients from the IABP Shock II trial, which you would recall is a randomized trial which demonstrated similar outcomes between IABP and medical treatment in myocardial infarction in cardiogenic shock.
So, they looked at 237 matched-pairs so remember this was pairs from this registry of acute myocardial infarction with shock and using an Impella matched with IABP shock patients and what they found was that there was no significant difference in 30-day all-cause mortality. Instead, severe or life-threatening bleeding and peripheral vascular complications occurred significantly more often in the Impella group when they limited the analysis to the IABP treated group as controlled versus Impella that was still the same results.
Dr Greg Hundley: So, Carolyn, there are trying to match patient population from two different studies and they may have confounders in there that we can't account for so why we not able to produce large randomized trials of Impella devices in studies of patients with acute myocardial infarction?
Dr Carolyn Lam: The rate of acute myocardial infarction complicated by cardiogenic shock has really declined in the past decade. Furthermore, clinical signs of shock really appear in half to three quarter of cases several hours after hospital admission so making randomization before primary PCI of the AMI really very difficult. And finally, many interventional cardiologists believe that there's equipoise that has already been reached on the use of these cardiac assistive devices in patients with cardiogenic shock and this was from registry data, and so if interventionists believe this then they also believe its unethical to randomize these patients in trials. Still, I think that current study to date really causes us to pause and to acknowledge that we really need to evaluate this better and prospective randomize trials of Impella treatment are warranted.
Let's now go to our featured discussion, shall we?
For our featured paper discussion today, we are talking about a basic science paper, and we have none other than the best of the best Dr Charles Lowenstein, our associate editor from University of Rochester Medical Center joining us as well as the first author of a really fantastic paper on long non-coding RNA in a specific type involved in arthrosclerosis and plaque formation. This first author is Sebastian Creamer from Goethe University in Frankfurt.
Charlie, could you start us off by telling us what is a long non-coding RNA? We've heard a lot about this in recent times. What's the big deal about them?
Dr Charlie Lowenstein: So in the last decade, scientists have learned that your genome, your DNA inside you, every cell codes about 20,000 genes and those 20000 genes encode proteins, but there are another 20000 genes that encode RNA only, RNA that never turns into protein that leaves RNA are an amazing diversity of different kinds of RNA really short micro RNA, longer RNA that defends the host from viruses and long non-coding RNA that have a huge variety of effects regulating genes, turning genes on and off in proliferation and cell growth and inflammation so long non-coding RNAs are increasingly appreciated as an important part of the genome.
Dr Carolyn Lam: What a perfect set up with that. Sebastian, could you tell us about your study please?
Dr Sebastian Creamer: Our laboratory was interested in non-coding RNAs for some time and previously, we've found that this specific non-coding RNA MALAT1 regulates endothelial cell functions and because we were interested in analyzing this particular RNA in the disease setting it shows at a risk growth so it's because also we saw that when it's regulated by flow and end of previous cells and so we cross MALAT1 deficient mice to Apoe mice and set them on a high fat diet and analyzed and subtracted in both groups. And while we only saw a modest increase in plaque size in MALAT1 deficient mice, we could appreciate a higher amount of inflammatory cells in plaque of aortic roots in those mice, which let us hypothesize that inflammatory responses was appreciated and is a very important contributor to arthrosclerosis in MALAT1 deficient mice. And to test this, we decided to transplant MALAT1 deficient bone marrow in Apoe knockout mice with MALAT1 and interestingly, we saw that now plaques were significantly larger than compared to mice who received controlled MALAT1 white cell bone marrow, and also inflammatory cells were more prominent in those mice.
Dr Greg Hundley: Sebastian, this is Greg Hundley. You also did some experiments in human subjects. Could you tell us a little bit about those too?
Dr Sebastian Creamer: So, because we saw this interesting phenotype, we were very much interested if this also translates into the human setting. Luckily, we got a really nice collaboration receding in Stockholm access to high impact material from patients with arthrosclerosis and what we could see here that MALAT1 expression was down regulated in patients with arthrosclerosis and it also correlated with disease progression. Moreover, in another collaboration, we consolidated those findings with experiments, which showed that human cells have less MALAT1 compared to normal vasculature.
Dr Carolyn Lam: It all sounds so sensible and logical and so on but let me just frame this for our audience. This is actually the first time that it's been demonstrated. The importance of long non-coding RNA in arthrosclerosis. Charlie, could you tell us a little bit about how significant these findings are?
Dr Charlie Lowenstein: Sure. So, I'm really interested in the final figure in this paper because there are lots of interesting human data, showing that MALAT1 expressed more in normal than atherosclerotic arteries and also that MALAT1 expression is correlated with fewer major adverse cardiac events so the whole story is a very nice story saying that the expression of this anti-inflammatory link RNA not only has an effect in mice but it can be extended into the human field of arthrosclerosis and inflammation. It's particularly important because there's a lot of attention in the last decade that inflammation drives atherosclerosis, and in light of CANTO trial showing that anti-inflammatory therapy can actually decrease atherosclerosis and decrease cardiovascular events in humans. This is important cause it shows another pathway, which regulates inflammation. Not only in mice, but also in humans, and in the human atherosclerotic setting.
Dr Carolyn Lam: Amazing. Sebastian, what are the next steps? How far are we away from clinical applications here? What are the next steps to get it in the clinic?
Dr Sebastian Creamer: So, the very difficult thing is that MALAT1 is down-regulated in atherosclerosis and also therapeutic approaches is very difficult in such a complicated disease like atherosclerosis to actually increase the expression of such a long non-coding RNA. What we are currently working on is to decipher more than the clinical malade-1 is actually influencing atherosclerosis so we have lots of hints or some evidence that adhesion of inflammatory substances altered and the bone marrow activity, which is very important in atherosclerosis and also in other cardiovascular diseases like myocardial infarction is altered so we think that malade-1 might actually influence the resolution of inflammation and when it's lacking, inflammation can be resolved. So, we are now putting somewhat mechanistic studies and finally, we hope that we can find another downstream target like micron AB, we talked about in our paper, which we can directly target in the future.
Dr Charlie Lowenstein: So, I agree with Sebastian. I think MALAT1 is going to turn out as one of those major link RNAs that controls inflammation possibly controlling the way in which the bone marrow reacts to systemic inflammation and produces cells and then have those cells home in on various inflammatory targets so I think this is an important observation that's going to have not only implications for atherosclerosis but also for other inflammatory diseases.
Dr Carolyn Lam: Excellent. If you don't mind, I would love to switch tracks a little bit. We find it that very special and we can discuss basic papers with people who can explain it so well because we understand that there's so much work that goes in to these papers and so on. Charlie, could you take behind the scenes a little bit with the editors and tell us what is it that circulation looks for in basic science papers that makes us published?
Dr Charlie Lowenstein: We get a lot of really good basic science papers, and it's a challenge for the associate editors, and the editors to figure out what's right for circulation and let me use this manuscript as a great example because this is a terrific paper. So, this paper is divided into four sections, and these sections are what we look for in any basic science paper that's going to reach an audience of clinicians who are interested in pathways and therapeutics so this paper has a section on mice. There's a gene in mice that's important then the paper delves into cells what's happening with cells and then a little bit of mechanisms and genes and proteins and then this paper takes the observation back into humans and shows that there's some human and clinical relevance so this is not only a great paper, but it is a classic example of what the associate editors are looking for in a basic science paper that's targeted towards clinicians.
Dr Charlie Lowenstein: There's some in vivo work with mice, there's some mechanistic work then they take it back to the humans. Plus, of course like anything that comes into circulation, it's going to be novel, interesting and has some important relevance to human cardiovascular disease. This paper that we're discussing is a great example of a paper that we love to publish in a circulation and it's a real tribute to Dr Dimmeler and her team and to Sebastian that they put this paper together and submitted it to us.
Dr Carolyn Lam: Thank you audience for joining Greg and I today. You've been listening to circulation on the run. Don't forget to tune in again next week.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor and director of the Pauley Heart Center from VCU Health in Richmond, Virginia.
Dr Carolyn Lam: So, Greg, are we any closer to the holy grail of safe ED discharge for acute heart failure based on a risk score? Well, we're going to be discussing that coming right up after Greg and I share about the papers that we'd like to discuss today. Lovely issue, isn't it?
Dr Greg Hundley: Yup, and time to get your coffee and bring it up. My first paper, Carolyn, is from Michael Chu from London Health Sciences Center, and is really investigating the surgical management of thoracic aortic disease, and looking at the impact of gender or sex related differences. Sex related differences have not been thoroughly studied. This group looked at a total of 1653 patients, 30% were women, who underwent thoracic aortic surgery with hypothermic circulatory arrest between the years of 2002 and 2017 across Canada in 10 institutions.
Well, women underwent less aortic root reconstruction, including aortic root replacement, Ross procedures, or valve sparing root operations. But, even with less invasive, the women experienced higher rates of mortality, 11% versus 7%, stroke, and that composite of the thoracic surgeons' adverse events. On multi variable analysis, female sex or women was an independent predictor of overall mortality, stroke, and those comorbidities.
Dr Carolyn Lam: Greg, you know how much I love these papers, so I'm going to repeat that. You're saying the women received less ominous procedures and yet had worse outcomes, and this was independent of the clinical covariances, right?
Dr Greg Hundley: Absolutely. Putting all this together, women underwent thoracic aortic surgery a little bit older, and with larger index aortic aneurysm size than men. Intraoperatively, women undergo fewer concomitant procedures, such as the aortic root repairs, and things that you just mentioned. But nevertheless, women experience significantly worse outcomes identified as an independent predictor of mortality, stroke, and that composite endpoint for mortality, morbidity, after multi variable analysis.
What should we think about this? Well, sex specific considerations are important when considering thoracic aortic surgery and future research should focus on the development of a personalized approach to thoracic aortic surgery with respect to gender. For example, utilization of maybe lower size thresholds for women for aortic aneurysms should be considered, and for earlier interventions, and improved outcomes.
Carolyn, tell me about one of your papers.
Dr Carolyn Lam: All right, so I chose a paper looking at the stroke outcomes in the COMPASS trial. Now, let's remind everybody that the COMPASS trial, where patients with stable coronary artery disease or peripheral artery disease, and randomly assigned to receive aspirin 100 milligrams daily, rivaroxaban five milligrams twice daily, or the combination of rivaroxaban 2.5 milligrams twice daily plus aspirin. Patients requiring anticoagulation with a stroke within a month had a previous lacunar stroke or intracerebral hemorrhage were excluded.
Now, in the current paper, and this is from Dr Sharma from Population Health Research Institute, and their colleagues, basically they looked at a detailed analysis of the stroke by type, predictors, and anti-thrombotic effects in the key subgroups. They found that the combination of low dose rivaroxaban and aspirin prevented stroke and disabling stroke better than aspirin in patients without atrial fibrillation and with stable vascular disease, and without an increasing risk of hemorrhagic stroke; which is really important. This effect was consistent across subgroups of baseline risk, and particularly marked in those with a history of previous stroke.
Dr Greg Hundley: Carolyn, what about that rivaroxaban five milligrams twice daily alone?
Dr Carolyn Lam: There was no significant difference in the occurrence of stroke in the rivaroxaban alone group compared with aspirin. But all of this simply says perhaps low dose rivaroxaban and aspirin may be a really important new anti-thrombotic option for primary and secondary stroke prevention in patients with clinical stable atherosclerosis.
Dr Greg Hundley: Very interesting. I'm going to follow your lead and go into another sort of anticoagulant-related topic on iliofemoral deep vein thrombosis. This paper is by Suresh Vedantham from the Washington University of St. Louis.
Let's talk about just what is the definition? This is a DVT that involves the iliac and/or the common femoral vein with or without involvement of additional veins. It basically obstructs the outflow of the veins. These patients are phenotypically distinct from patients with cath or femoral popliteal DVT because that totally obstructs flow, and they have more frequent recurrence of venous thromboembolic events, and more frequent post-thrombotic syndrome. Well, that's a horrible condition because of that obstruction, it leads to calf muscle dysfunction, edema, subcutaneous fibrosis, tissue hypoxia, and ulceration.
Dr Carolyn Lam: Great background. What did this study show?
Dr Greg Hundley: This is a sub-study of the ATTRACT trial. The ATTRACT trial basically is looking at anticoagulation plus perhaps mechanical intervention, or direct catheter directed thrombolysis therapy versus just anticoagulation alone. This sub-study is 391 patients with acute DVT involving just the iliac or the common femoral veins, and following these individuals for 24 months to compare short and long-term outcomes.
What did the study show? Well, this interventional group did have a reduction in leg pain and swelling, and improvement in quality of life related to that lower extremity. But, no overall difference in overall quality of life, and very importantly, no difference in the occurrence of this post thrombotic syndrome.
Dr Carolyn Lam: That's kind of disappointing. I understand that the ATTRACT study is not the first to look at this, though. That was in an editorial discussing this. Could you tell us about that?
Dr Greg Hundley: Yeah, Carolyn. Jay Giri from University of Pennsylvania just had an incredible editorial. I think if you have an opportunity, listeners, to take a look at that, I highly recommend it. He reminded us of the CaVenT trial, which is basically performed as an open label randomized control trial of 209 patients across 20 hospitals in Norway.
What was different in the CaVenT trial is that at 24 months of follow up, the intervention with thrombolysis and systemic anticoagulation improved iliofemoral patency. It reduced the incidence of this post thrombotic syndrome. In ATTRACT, in this sub-study, it was intravenous thrombolysis, systemic anticoagulation, and mechanical intervention on the vein versus in the other study from Norway, CaVenT, just the inter vein thrombolysis and the systemic anticoagulation.
What Dr Giri points out is that maybe something related to intervention in that vein when you're stripping out thrombus, et cetera, are we damaging the veins in the vessel that prevents reflux, et cetera?
I think really moving forward, you're going to have to personalize this decision in individual patients until we have more data on this subject.
Dr Carolyn Lam: Great learning. I learned a lot from this next paper, too, because I actually chose a basic science paper. This is a paper that uncovers a new fine tuning factor that modulates myocardial infarction induced inflammation. That is a small GTPase called RhoE.
In this study, Drs Chang from Texas A&M University College of Medicine, and Song from Fuwai Hospital in Beijing used three genetic mouse model lines. Those are the global knockout, the cardiomyocyte specific RhoE heterozygous mouse, and the cardiomyocyte specific RhoE over expression mouse. With this combination, they showed that RhoE deficiency causes excessive inflammatory response in infarct animal heart, resulting in enlarged heart, decreased contractility, and increased mortality. The mechanism is that RhoE binds to P65 and P50, which impedes their dimerization and blocks these two proteins from nuclear translocation. Now, over expression of cardiac RhoE inhibits NF-κB, restrains post MI inflammation, and improves cardiac function and survival.
Importantly as you always say, Greg, there is human data. They found that the expression of RhoE was elevated in the infarct patient heart and that patients with a higher expression of RhoE exhibited a better prognosis and better cardiac function recovery.
Dr Greg Hundley: Carolyn, tell me a little bit about the clinical significance of this.
Dr Carolyn Lam: You just wanted to ask me a tough question. I can see it on your face. Basically, I think this is really exciting because RhoE may serve as a new potential biomarker for the assessment of myocardial infarction in patients, and manipulation of RhoE could be a potential therapeutic approach for MI. There.
Dr Greg Hundley: Very good.
Dr Carolyn Lam: That's all the time we have for our little discussion here. Now, let's go onto the feature paper. ...
Over 80% of emergency department patients with acute heart failure are admitted to the hospital. Now, contrast this with the fact that over 80% of all emergency department visits result in discharge. So, why is that many other emergency department based cardiovascular disease processes like for acute coronary syndrome have evolved from high rates of admission to timely and safe discharge whereas decision making in acute heart failure has not experienced a similar evolution. Do we need perhaps a better acute heart failure prognostic score that's validated?
Well, guess what? We're going to talk about this right now in our feature discussion, and a beautiful feature paper that we're so proud to have the corresponding author, Dr Douglas Lee from University of Toronto right here to discuss; along with the managing editor, Dr Justin Ezekowitz, who's associate editor from University of Alberta, and the editorialist, Dr Sean Collins from Vanderbilt University Medical Center. Welcome everyone, and Doug, please, could you just start by telling us about this great paper?
Dr Douglas Lee: We validated, and it's a tool, decision making tool, for acute heart failure patients in the emergency department. We, in this study, wanted to prospectively validate a decision making prognostic tool called the Emergency Heart Failure Mortality Risk Grade, or EHFMRG for short, to see how well it performed in the real world busy emergency department hospital setting.
We studied just under 2,000 patients who came to emergency departments at multiple centers, and asked physicians to rate their prognostic estimation of what's going to happen to that patient in the next seven days. We compared that with the EHFMRG model, which predicts outcomes of seven days and 30 days. We were very careful to ask physicians to provide their prognostic estimates. This is their intuitive guesstimation of the risk of the patient before calculating the score because we didn't want the physicians to be influenced by the score.
What we found was that when we looked at how well physicians' estimates performed, they actually performed quite well. The c-statistic for physician estimated risk was around .7, which is a reasonable discrimination. However, the physicians' estimates were not as good as the EHFMRG risk score, which had a C greater than .8. The mathematical model seemed to do better in terms of predicting what's going to happen to the patient than physicians' estimates.
Interestingly, when we combined the physicians' estimates with the EHFMRG risk score, the c-statistic improved by another 1%, so there's some additive value of having both factors combined.
The other interesting finding was that patients in the lowest risk groups had 0% mortality at seven days, and 0% mortality at 30 days. We may be able to identify, using the score, patients who have a very low risk of events in that seven to 30 day period after emergency department presentation.
Dr Carolyn Lam: Thanks so much, Doug. I have to tell you, I am a fan of the EHFMRG score. In fact, we're trying to study how well it performs in our local situation even here in Singapore.
Justin, you've been thinking a lot about this. I would love for you to share the reactions that we got when we discussed this among the editors.
Dr Justin Ezekowitz: We had a lot of good discussion about this from a number of different aspects. First, it's an in-practice assessment, a physician-based risk assessment, as we survey hundreds of physicians in the ER, which is a busy environment, and get these types of information. That's a very unique piece of this study where, in addition to the just under 2,000 patients and collecting the other data in a robust way, this really does have a potential to contribute to the literature.
A lot of the discussion was about how data rich this is, and that this is an area where unlike acute cardiovascular disease where there are good risk assessment tools and other therapies, it's a really need of a scoring system that was well validated, can be replicated, and both in clinical practice as well as in selective cohorts. Doug, my congrats to your and the other parts of the team that's helped put this together.
One of the questions that came up when we were discussing it was the risk textiles and buckets were very important for people to think about the very low risk, as you mentioned, 0% all the way up through much higher percents for seven day mortality, but how discrepant the risk was of the physicians versus the mathematical model; and a very good reminder of the inaccuracy of sometimes our assessments of risk in practice, especially in acute care.
I wonder if you could comment on what your fence was from the physicians who participated in the study, and then the data of those, the most striking findings of that piece about where physicians make judgements on risk in for that seven-day mortality. Just any comments you may have?
Dr Douglas Lee: We didn't know what to expect because there haven’t been many studies of this type before. What we found in our study was that physicians tended to overestimate the risk of lower risk patients. They thought bad things would happen to healthier patients, just to put it very simply. Physicians also underestimated the risk of the highest risk patients. They thought that the highest risk patients would do well.
We were surprised about that finding, but also, we were not surprised in the fact that it seems to explain some of our earlier findings that in our earlier work, we found that low risk patients are hospitalized, and we think it's probably that physicians are admitting those patients because they want to ensure that they're making a safe decision; and no harm will fall in the patient. Maybe physicians are erring on the side of admitting those patients, even though they know they're a little bit low risk.
At the other extreme, physicians underestimated risk in the highest risk patients. We think it might explain the observation that we made previously that sometimes high risk patients are discharged home, and they die at home after discharge. That may be because patients who look well to physicians, I think there's great value in the clinical experience of a seasoned physician looking at a patient and knowing that, that patient is sick or not sick. But in certain cases, patients may look relatively well, but their numbers would indicate that they're actually higher risk. I think it's that group where we found they're higher risk, but physicians thought that they were healthier than they were. It seems physicians' estimations really have great value, but it seems that they can be improved.
Dr Carolyn Lam: Sean, you discussed this beautifully in your editorial. Share with us your thoughts, and especially thoughts on the question you posed: are we any closer to the holy grail of safe emergency department discharge based on acute heart failure risk rules?
Dr Sean Collins: Doug, kudos to you. Nearly 2,000 patients, nine different hospitals, prospective data collection, as Justin said. I don't think this can be overstated. From a data cleaning perspective, this is truly a labor of love, and to get this done, congratulations to you and your team.
I think the most interesting part of this is this exact disconnect of patients look well who are high risk, and patients may look a little bit unwell who may be low risk, ironically. That's where a risk tool is much needed, as Carolyn said in her introduction to sort of change the dynamic of 80 to 90% of patients are admitted to the hospital. If we even chipped away at 10 to 15% to able to be discharged, it would be a huge win for partly for management for an emergency department perspective.
I think that the importantly, the next steps will be now looking at implementing this in some sort of a randomized manner, somewhat like what you did with asking physicians gestalt about what their level of risk is, but really finding out how does a physician gestalt when it comes to nuance and heart failure. A relative amount of congestion, even when the tool says the patient may be low risk, can they go home? I think that will be the crucial next step to find out how much does this augment and/or detract from physician decision making? We have a long way to go, as Carolyn said. It's just the complete opposite at almost every other disease process, including chest pain, from a discharge perspective. Even a little bit improvement would be great, so I'm looking forward to seeing the next steps, and I'm wondering what your thoughts are about the next steps, Doug.
Dr Douglas Lee: There's actually great value in physicians' clinical judgment. It's been, I think relatively understudied. I'm hopeful that future studies where decision tools or prognostic tools are validated, we can see more potentially, more comparisons with clinicians because we don't have a real great understanding, I think, of how doctors think, especially in an acute setting. More research in this area, I think would be really helpful, especially as we ... As more and more clinical decision tools being published, it would be great to see how well they hold up against good clinician judgment.
In terms of next steps and implementation, when we talk to our emergency colleagues, they have brought up an issue about it's great that patients are low risk, and that we could potentially discharge them from hospital; but where is the receptor to take that patient and to care for that patient once they've left the hospital? Are they going to get good care once they leave the hospital? Are there structures in place?
We're now embarking on testing this in the clinical trial where we will be comparing two strategies. The first strategy will be using the risk score at a hospital-wide level, and then discharging home patients who are in the lower risk categories, and having them follow up, and receive their care in a rapid ambulatory follow up clinic within two to three days after discharge from the emergency. This will be compared to the control, which is not using the risk score, and having usual follow up care. This trial is called the Comparison of Outcomes and Access to Heart Failure Trial, or the COAHFT trial. It is currently ongoing.
Dr Sean Collins: Great point, Doug. As Carolyn suggested with chest pain and heart failure as the interesting dichotomy is that unlike chest pain, when we safely rule somebody out and send them home, we're sort of done with that acute episode. Heart failure, it doesn't end. We've found that they're safe enough to go home, but now they need great collaboration and outpatient support with their heart failure provider, which may be as equally heavy lift as externally validating the EHFMRG score. You bring up a great point, which is we need to have outpatient follow up and collaboration for this to be successful. Thanks.
Dr Carolyn Lam: Awesome comments, guys. Could I switch tracks a bit and maybe just ask Justin to round up by sharing? Circulation, we get a lot of papers about risk scores and so on. There's a bit of fatigue, I think, about scores in all kinds of things. Now, could you maybe tell us, Justin, what makes us look at a paper twice, and in fact, feature this one with a good editorial? I mean it's clearly very clinically applicable. Could you share some thoughts there?
Dr Justin Ezekowitz: Yes, that's a great point. The things that make a risk score like this kind of elevated into kind of a circulation level of manuscript is A) the data quality has to be excellent. There has to be lots of completeness of data, but also capture of elements that we think are quite important. Two, the data science about how it's analyzed and put together, and interpreted, it has to be to the bar that we feel would be robust, and be able ... if somebody could repeat it and replicate it without an obvious challenge to the quality.
The third, I think is the clinical applicability. It's okay to write a data model and come up with all these great risk scores, but if they haven't been thought through about how either a patient will be seeing this, or clinicians behave, or the environment that it has to be deployed in that, that isn't necessarily going to be something that is going to be implemented. Then, the question is: why would somebody do the study in the first place?
Now, it's okay if somebody's forward thinking and saying, 'Look, EMRs are coming, or other EHRs around, so this could be implemented if there was enough impetuous and it's a good enough quality.' That's actually okay, but in the reverse where if you try to implement a model that is too complex, and it's in a hand-off to the environment, it just won't work. We just want to make sure people have thought that next knowledge translation and dissemination approach through.
The final part is things that have a very local impact are, that are very unique to the environment they're in, such as it only would work in your hometown or your own country because of some environment, that's okay. But under that, the much more global focus that, that is, it could be picked up and trans located to any major city, providence, state, or country, because vis vises are global. Those things have a much greater impact because the circulation leadership is global. The patients are global. The clinicians who care for them are also global. People are all looking for very similar situations and can adapt to their own environments.
Dr Carolyn Lam: Awesome, Justin. I don't think any of us could have said it better. Those are the reasons that we're so grateful that you publish with us, Doug. Thank you so much, Sean, for your excellent editorial, too.
Thank you, listeners, for joining us today. You've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and it's editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore. And I am so privileged to be joined by Senior Associate Editors whom I respect and admire so much. And they are Dr Biykem Bozkurt from Baylor College of Medicine and Dr Sana Al-Khatib from Duke University. And we have three woman discussing the Go Red for Women issue. Yes!
The current issue is the third Go Red for Women issue and boy, is it a bonanza issue. It tackles a wide spectrum of topics relating to cardiovascular disease in women, including prevention, risk stratification, myocardial infarction, pregnancy, heart failure, cardiac arrest, sudden cardiac death, and in so many wonderful formats; from original papers to systematic reviews, state-of-the-art papers, in-depth reviews, a research letter, and even frame of reference papers.
So, let’s get digging into this issue, shall we? And Biykem, we could start with you because I'd like to start with three original papers that really set the scene. The first discussed temporal changes and the very contemporary data from 2001 to 2016, describing cardiovascular risk factors and their treatment. And then the second focuses on young females with acute myocardial infarction. And the third on older women. Could you take us through these papers Biykem?
Dr Biykem Bozkurt: Lets first start looking at the sex differences through the Anne Haines Survey which enrolled more than 35000 patients. And they examined the trend all the way back from 2000 to 2016. Now the good news is the improvement in hypertension diabetes hyperlipidemia in woman were similar to men. So that's the good news. But BMI increased more in women than in men and overall, the ability to control blood pressure and diabetes hyperlipidemia appear to be a little bit better for women than in men.
But the concerning trend becomes apparent when we look at another paper that examined the twenty-year trend in young adults. Now, the first message is, and this is important for both genders, the proportion of the hospitalizations that are attributable to young patients, and young patients are defined as ages between 35 and 54 in this study, and this study was from Erik, increased from 1995 to 2014. So young patients appear to be having more in life compared to before, compared to 1990s and the 2000s. And that was actually partly due to the increasing prevalence of comorbidities, such as hypertension diabetes among young patients.
Now, interestingly among young patients, young women presenting with [inaudible] had a lower likelihood of receiving guideline directed therapy which, of course, sound familiar to our audience because we have the disparities of lower treatments and lower access to care in women with MI presentation compared to men. And unfortunately, again this will sound like the former news, the pre-hospital mortality was quite high in young women and has declined less in young women, compared to men.
So, the Erik study highlights the disparity for young women compared to young men. And then we have to recognize that most young patients in my hospitalization attributed to young patients is increasing. So this is probably a population that we need to be aware of. Regarding the older patients, there is a publication from the Opach Study looking at the sedentary behavior and cardiovascular disease in older women. And they looked at more than 5500 patients aged between 63 and all the way up until 97. And they looked at sedentary time and they looked at the duration of sedentary time all the way over eleven hours in some of the patients. And of course the higher the sedentary time was, the worse the cardiovascular disease risk was amongst the older women. So now we are recognizing that among older women, the post-menopausal or elderly women, the risk of cardiovascular disease rises with sedentary lifestyle.
And I think these three papers highlight the overall trend that we tend to see, maybe, better emphasis for comorbidity control. But at the same time we are now starting to recognize that in younger patients, especially in younger women the risk of MI is on the rise. And in older women, activity and remaining active and not having too much sedentary time are important to prevent cardiovascular disease.
Dr Carolyn Lam: Oh, Biykem, thank you for framing that so beautifully. So some good news, some bad news, and certainly some things we should be looking out for. You know, in another patient group that we always need to touch on when we talk about the Go Red for Women issue is pregnant women, or post-pregnancy. Could you comment, perhaps, on the systematic review that we have?
Dr Biykem Bozkurt: This is a very comprehensive, systematic review looking at the cardiovascular disease morbidity and mortality in women with a history of pregnancy complications. And they provide detailed systematic review and method analysis. It's becoming more apparent that the spectrum of cardiovascular disease ranges all the way from preeclampsia to arrythmia to pericardial myopathy. And we're recognizing this continuum both in the peripartum period, at the same time as the future risk. So those with preeclampsia and premature birth and delivery are associated with lifetime risk of cardiovascular disease. So, I think this paper is providing the right overview and a very comprehensive meta-analysis recognizing that pregnancy led to complications and morbidity and mortality in women.
Dr Carolyn Lam: Indeed. And it does just add so nicely to this issue, you know? Letting us know that we should watch out for the young women. We should watch out for the sedentary older women. And we should watch out for women with a history of pregnancy complications. But let’s switch tracks now. Sana, there was an amazing autopsy paper, actually, relating to sudden death in women. And as well as another original paper focusing on out of hospital cardiac arrest that is really very interesting. Would you like to tell us about those two?
Dr Sana Al-Khatib: Oh absolutely. I would love to. As someone who has devoted her life to the study of sudden cardiac death and you know, identifying factors, prevention. I really like that the paper looking at the risk of cardiac death in women and men. This study, Carolyn, was conducting in Finland, and the aim of the study was to determine autopsy findings and causes of death among women in a large population of sudden cardiac death.
They also were able to classify some EKG characteristics in men and women cardiac death victims. That really added helpful information. To do that, they systematically collected clinical and autopsy data from sudden cardiac death victims in Northern Finland between 1998 and 2017. So they actually had data on close to 5870 SCD victims. The findings were very interesting because they found that victims were significantly older than that. You know, so when they provided the median age it was 70 years for women versus 63 for men. So that was a significant difference there. And when they looked at the most frequently identified cause of death, they found that it was ischemic heart disease in both factions. Seventy two percent in women verses seventy six percent among men. And what was really striking about this was that the seventy two percent presence among women was higher than what had been reported in other theories.
They also reported that women were more likely to have lung ischemic cause of sudden cardiac death than men. It commented on the fact that primary myocardiac fibrosis was more likely to be found in woman victims rather than in men. And then they were able to identify some EKG factors stating that, in general, women were more likely to have a prior normal EKG than men. But that it increased the marker for sudden cardiac death with the presence of MDH with the polarization changes that were more commonly seen in women.
So, I thought that the findings were really interesting. They sure to be advance the field.
Dr Carolyn Lam: I couldn't agree more. Sex differences in sudden cardiac death. I don't think many people could tell you they knew much about it at all before this paper. And what about at a hospital cardiac arrest?
Dr Sana Al-Khatib: So, the other paper, which was really interesting, was a study that really looked at the public perception on why women receive less bystander CPR than men in out of hospital cardiac arrest. And this was an observation that was made a long time ago, Carolyn. So what's interesting for these investigators to be able to shed some light on this observation. What they did was they conducted a national survey of members of the public. And they were able to get 548 people to respond. Not a very high response rate, but pretty good for getting qualitative research studies. About fifty percent of the responders were women, so it was important to note that. And there was a good geographic distribution of the people; this was done in the U.S. And after they corrected their data, and they analyzed their data, the major thing emerged in terms of why the public perceived that women received less bystander CPR. The findings were really interesting.
The first finding was that people were concerned about being accused of sexual assault if they were to do CPR on the woman, which was interesting. Some actually were concerned that women were too weak or too frail. If they were to ever do CPR, might they cause any bone fractures, any injuries to the woman because they're more fragile, so to speak, than men. And their last theme was misperceptions about women in medical distress. What that meant was they felt that, well, you know, are women actually victims of sudden cardiac death? Yes, definitely, women can have sudden cardiac arrest and some people said, "Well, sometimes women can be overly dramatic and so maybe those presentations were not real presentations of sudden cardiac arrest," which I thought was really interesting.
I felt these were really interesting insights into why women don't receive CPR as much as men, and hopefully future interventions can be targeting these misconceptions or these concerns that the public has about doing CPR on women.
Dr Carolyn Lam: Isn't that so intriguing. The misconception that women are either too shy, too frail, or too dramatic. Oh my goodness. Anyway, that was all the original papers, which were fantastic. But I have to admit that one of the things that I love most about the Go Red for Women issues is that it talks about women in cardiology. And Biykem, you've always been such a huge mentor to me. And what I love about this issue is that there are a few papers, aren't there, that actually focus on the importance of this mentorship. Could you tell us about that?
Dr Biykem Bozkurt: It's a very important concept that I think is underlying a few papers in our issue. The first one is women in cardiology and perhaps the lack of increase in the representation of women in cardiology. Even though women make up about half of our medical graduates, among practicing cardiologists women comprise less than about twelve to fifteen percent of the population. That perhaps disparity hasn't changed in the last two decades. We tend to sometimes compare our profession to the surgical field, and I think gender inequality appears to be a little bit similar to general surgery and orthopedic.
But the paper by Ziman underlines the following: Even though our gender inequality is similar to the surgical field, to look at the temporal trends there has been a significant rise in female representation in general surgery. And actually, among medical trainees, about one third of the medical trainees, not fifty percent like us, one third of the medical trainees are in surgical fields after they go to medical school. But the female representation has been steadily increasing in the surgical fields; about three-fold out of cardiology. Whereas female representation cardiology has the main slot, so the surgical fields are doing a better job in either welcoming, supporting, and mentoring their female trainees than the cardiology field.
This is an important concept for us to recognize, and usually the disparity reasons are perceived to be gender and lifestyle and/or personal preferences. That doesn't appear to be the case. Perhaps the better role models and better mentorship could eliminate this disparity and this is underlined in the Olmein Mein paper by Ziman.
Another paper by Sharon Hunt also underlines this concept. She portrays the woman needed in cardiac transplantation from a historical and personal perspective, and underlines the following: We tend to have a large number of woman leaders in advance heart failure and cardiac transplantation. And part of this may be attributed to the fact that women have been part of the fabric, part of the readership, part of the group that has developed the field and has been practicing. And thus, there has not been a nation or incorporation of the women in the field. And thus, since they've been involved in the practice from the beginning, they have been seen as a natural partner. Even though cardiac transplantation is quite demanding, requires bedside presence, and hours which are usually used as a reason for women not to go into certain fields, such as interventional. In transplant, we don't seem to have that much disparity for women. Women tend to select this field on one of the reasons in Sharon Hunt's piece is identified as being part of the team from the beginning, and having good role models and mentors.
And finally, there is a research letter that identifies if the corresponding author is a female author. There is a large representation of co-authors. This is a very interesting finding by Ouyang stating that even though the female to male senior authorship rates have not been different over the years, if the senior author or the corresponding author is a female there tends to be a higher number of co-authors. This may suggest that female corresponding authors are able to mentor or include their partners or team members. Or vice versa, female co-authors may feel more invited and incorporated as a team. So, this paper also underlines that women in leadership positions connected to cardiology may serve as positive role models to recruit and retain talented junior female investigators.
Dr Carolyn Lam: Ah, indeed, indeed, indeed. So many topics that come close to my own heart. But Sana, among the numerous other papers here, we have two state of the art papers, two in-depth reviews, there are three frame of reference papers. Which one, or ones, stood out to you?
Dr San Al-Khatib: One important paper, Carolyn, you certainly mentioned is an online paper that was titled "Why are Young Black Women as High Risk for Cardiovascular Disease". I personally like this paper a lot because it highlights such an important issue that has great impact on public health. And sometimes the population of young black women may go unrecognized in terms of their risk of cardiovascular disease and what have you. So really the On My Mind paper tackles what are these things that are driving the worsening cardiovascular disease trends in this patient population. And what can we do about it? And they talk about how the awareness of heart disease and the leading cause of death among these women is actually more among black patients. And so, they talk about the need to really implement multi-level strategies to try to address this, raise awareness, identify disparities in care. They even also call for really investing in black women scientists.
And so, this was such a really good paper and I'm sure that the readers will enjoy it as much as I have.
Dr Carolyn Lam: Oh, thank you so much for that, Sana. That really, really makes for such a rich issue with such a lot of different papers. We're running out of time, so we don't even have the opportunity to really discuss, but I want to mention these so that the listeners will look out for them. Beyond the papers we've already discussed, we have state-of-the-art papers on cardiovascular care in women veterans and the management of cardiovascular disease in women with breast cancer. We even have two in-depth reviews. One on sex differences in advance heart failure therapies and a second on the role of breast arterial calcification in cardiovascular risk stratification in women. And finally, there's a research letter on the size of thoracic aortic aneurysms in women. So many papers, such a beautiful, beautiful issue. I just want to thank you both Sana and Biykem for leading this beautiful Go Red for Women issue.
Thank you, listeners, for joining us today. You've been listening to Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Greg Hundley: And I'm Dr Greg Hundley, director of the Pauley Heart Center from VCU Health in Richmond, Virginia.
Dr Carolyn Lam: Is income volatility a new cardiovascular risk factor? You have to stay tuned to hear all about that. But for now, join Greg and I over a nice little coffee chat, because we're picking up the journal right here and I'm going to tell you about our two top picks this week. Greg, you go.
Dr Greg Hundley: Well my top picks, Carolyn, is really pertaining to senescence and senescent cardiomyocytes. Remember that? Senescence is a situation where there's a mismatch between energy demand and supply and so that facilitates the cells transitioning toward failure. They lose their ability to function. In other parts of the body, they lose their ability to divide.
And these investigators assessed altered calcium transfer from sarcoplasmic reticulum to the mitochondria, because that's being casually linked to the pathophysiology of aging in heart failure. Because the advanced glycation end products or AGEs accumulate through life, the authors thought that maybe this intracellular glycation would be occurring in aged cardiomyocytes and their impact on the sarcoplasmic reticulum and mitochondria. So, their study, they investigated both mice and humans and the found that ryanodine receptor glycation was associated with more pronounced calcium leak in mice and also interfibrillar mitochondria directly exposed to sarcoplasmic calcium release from aging mice had increased calcium content, compared to those with younger ones.
Now we're starting to implicate a mechanism by where senescence could be important in these mice. But of course, in Circulation in these wonderful basic science papers that we have, they also cover a translational human component. And what these group found is that there were higher levels of advanced glycation end products and reduced glyoxalase 1 activity present in left atrial appendages, from those patients that underwent surgery greater than 75-years-of-age, compared to individuals that were younger. And also, elderly patients exhibited hyper glycation and increased mitochondrial calcium content that was associated with reduced myocardial aerobic capacity due to less respiring mitochondria.
Dr Carolyn Lam: Wow Greg, that was a huge summary and how nice to link aging or senescence with AGE or advanced glycation end products. Seriously, that was new to me. Okay look, bring it home. What are the clinical implications?
Dr Greg Hundley: What these investigators have done is now identified a previously unknown pathophysiological mechanism that may facilitate the transition from healthy, towards failing cardiomyocytes and the implication is that if you could disrupt that process, maybe you could halt the aging of cardiomyocytes. You got to be careful though I think with senescence, just as we know from the general literature. Senescence is a defense mechanism in cancer therapy, but it's a protagonist if you will, in aging. More to come in this field, but very exciting research.
So Carolyn, tell me about your first paper.
Dr Carolyn Lam: Happily, Greg. I'm going to take us to the cath lab and talk about functional assessment of epicardial coronary artery disease. This paper from Dr Koo and colleagues of Seoul National University Hospital, is the first to validate the physiological relevance and prognostic implication of all available novel resting pressure derived indices of coronary stenosis. This includes indices like resting full cycle ratio or RFR and diastolic pressure ratio or DPR, and they compared this to instantaneous wave free ratio or IFR and fractional flow ratio or FFR.
What they looked at was more than a thousand vessels in 435 patients and showed that all the resting ... Just the resting. Not hyperemic but resting pressure divide indices, closely correlated with each other and showed excellent agreement and the same discriminatory ability for no FFR. All the indices also showed a similar pattern of changes to different anatomical and hemodynamic stenosis severity, regardless of the target vessels and importantly showed similar diagnostic performance for myocardial ischemia, defined by gold standard PET derived CFR and hyperemic myocardial blood flow.
And finally, they showed that all these indices showed significant association with the two year vessel oriented composite clinical outcomes.
Dr Greg Hundley: So, do we still need to do adenosine infusions in the cath lab?
Dr Carolyn Lam: That's exactly what they're trying to drive at, because the major advantage of these resting indices, for example RFR over IFR, is that IFR doesn't require identification of a specific landmark or a specific time point during diastole. They may be simpler to perform and this first study showing their physiologic relevance and prognostic implication may enhance adoption of invasive physiologic assessment in daily clinical practice, which we know is important and a clinical benefit.
Dr Greg Hundley: Excellent. I tell you, it would sure save time if we could use indices like that.
Let me tell you about my next paper. This is from Renato Lopes, from Duke University Medical Center, in Durham. Also, one of your affiliates. In all of our cardiovascular/metabolic clinical trials today, cardiovascular death is a very important outcome. But what happens when, in doing a study like that and you have an undetermined cause of death, the US Food & Drug Administration Guidance indicates that deaths due to undetermined causes should be rare in well-run clinical trials.
And so what this group did is they looked at 127,049 enrolled participants from nine trials and they looked at how deaths were adjudicated. And across nine clinical cardiovascular trials, in different therapeutic areas, the proportions of deaths adjudicated as related to undetermined cause ranged from 7-to-22% and overall, had an average of 16%. Interestingly, in multi-variable analysis, death due to undetermined cause, was associated with the therapeutic area and the year of publication of the study, and then also several patient factors including: gender, age, the region of enrollment, and time from enrollment to death.
Dr Carolyn Lam: Gosh, this is so enlightening. Greg, having been on CECs and struggle with the adjudication, I really like this paper as well. But please, tell us all, why should we be concerned about this?
Dr Greg Hundley: Great question, Carolyn. First we might think about, if you're reading a study, the proportion of deaths due to undetermined cause should really fall within this range. And have a mean of maybe 16%. Second, what if there are higher rates due to undetermined cause? Well, that may indicate there are issues with the trial quality. And then finally, researchers, whenever they're doing a study, should really report on the proportion of deaths where cause was unable to be determined.
And there was a great editorialist, David Morrow, from Brigham and Women's Hospital, and really pointed out, you've got a couple factors here that lead to why there's undetermined cause of death. Maybe the documents are missing, or you're in a clinical situation where a subject lives alone, found dead, there's no autopsy. Uncertain duration. Sometimes there are limits on the study personnel; their ability to actually go out and acquire the data so that the team, like what you're on, can actually adjudicate the information. And a point that's made is really ... He used the word, doggedness, but with which he consistently worked toward and tried to get those medical records and pursue them, because that is very important.
When we think, well what's the importance of a study like this? It's valuable to those that perform studies, because as we're working with our study coordinators, we need to make that information known to them. If we don't collect the exact cause of death in these important cardiovascular interventional studies, we may end up with an improper result. And also, for the investigative team. A really important study I think, providing guidance for the first time now about what we should expect in undetermined cause of death, when we're looking at cardiovascular trials.
Dr Carolyn Lam: Indeed, and from talking about doing the trials to talking about a very important trial, I want to take you to The Partner 2 Trials and talk about the cost-effectiveness of Transcatheter Aortic Valve Replacement, or TAVR, compared to surgical aortic valve replacement, in patients at intermediate surgical risk.
Now we already know that TAVR is cost-effective, although not cost-saving. But cost-effective compared to surgical aortic valve replacement in those at high surgical risk. But this paper refers to intermediate surgical risk. And the analysis is from Dr Cohen and colleagues from Saint Luke's Mid-America Heart Institute, and it's an analysis of the Partner 2A Randomized Trial and the SAPIEN 3 Intermediate Risk Registry.
In summary, they found that TAVR was projected to lower total costs by $8,000.00 to $10,000.00. And to increase quality adjusted survival by 0.15 to 0.27 years, compared to surgical aortic valve replacement over a lifetime horizon.
Dr Greg Hundley: Wow! Carolyn, I've got two questions for you. First of all, how does TAVR save those costs? And number two, was this true for everyone? Were there any caveats or special subgroups that this was really applied to?
Dr Carolyn Lam: The cost savings in a TAVR cohort looked like they were driven by both a shorter length of stay during the index hospitalization, as well, as less resource utilization during follow-up. And that would be in the form of fewer hospital days, as well as fewer rehabilitation and skilled nursing facility days.
As for the caveats, you see that the authors did acknowledge that the long-term durability of the valves involved like the SAPIEN XT and the SAPIEN 3 valves is still unknown, and so lifetime costs associated with TAVR, may be higher than we assumed, owing to the need of more frequent repeat valve procedures for example.
Now if though, the long-term data demonstrate comparable late mortality with TAVR, and the surgical aortic valve replacement, these findings are really significant, because they suggest that TAVR may become the preferred treatment strategy for patient populations. Not only based on clinical outcomes, but even based on economic considerations.
Dr Greg Hundley: It looks like that long-term information is going to be really critical here, so we'll look for more in this area.
Dr Carolyn Lam: For sure. Wish we could keep chatting, but I think we need to move to the featured discussion.
Dr Greg Hundley: And now to the very fun segment of our discussion this week at Circulation on the Run. This is Greg Hundley, from VCU Health. Director of The Pauley Heart Center. And today we have a fantastic paper from Adina Zeki Al Hazzouri from Miami, transitioning to Columbia University. And also, our Associate Editor, Dharam Kumbhani from the University of Texas, Southwestern.
Today's paper, Adina is going to discuss is, Associations of Income Volatility with Incident Cardiovascular Disease and All-Cause Mortality in a US Cohort. And what she's done is worked with the Coronary Artery Risk Development in Young Adult Study, we also know that as, CARDIA. And it's really a prospective cohort conducted in urban centers, in Birmingham, Alabama, Chicago, Illinois, Minneapolis, Minnesota, and Oakland, California. The goal here was to asses a block of individuals, younger, aged 23-35 years, identified in the time window of 1990-to-2005 and then followed subsequently to look at income volatility.
Adina, we're so excited to have you here. And can you tell us a little bit more about your study.
Dr Adina Zeki Al Hazzouri: Sure, the motivation for the study is the fact that we know that income volatility is on the rise. And what I mean by, income volatility, is the sudden and unpredictable change in income. And in the health researcher, we actually do not know as much, what is the effect or the influence of income volatility on health outcomes, and it is really common, most of us do experience these sudden or unpredictable changes in income. Whether they're little dips or little jumps in income. So they are really common, and I think it's really important to try to understand what would be their effect on health outcomes.
We were really interested in specifically understanding their effect on all-cause mortality and incidents of cardiovascular disease events, so we took advantage of an ongoing perspective cohort study. The cardio study that you just mentioned. And what is really nice about this study is they were really relatively young back in 1990 when we first had the measure of income. They were between ages 23-and-35. And they were followed for over 20-years, so we had repeatedly over 10-years, or 15-years, repeated measures of income. And then we were able then to look in the subsequent 10-years for incident events, cardiovascular events and all-cause mortality, and what is also interesting in this study is that these individuals, given that their age range, so that they are in the peak of their working years, which makes it even more interesting in terms of applicability and inference of those findings that we're making in this study.
We looked at, as I said, income volatility and we defined it basically as what is the standard deviation of these percent changes in income that you experience between the different visits in the study, which were on average, five years apart. And once we defined that, then we looked at it with outcome and what we really found was that those who experienced high volatility had around a two-fold increased risk of cardiovascular disease, as well as all-cause mortality.
We also looked at another measure of income volatility which is the number of income drops, so how many times you've dropped significantly, which we defined as a drop of more than 25%. And that is lower than your average income throughout the study period. And we found similar results.
Dr Greg Hundley: Adina, what could be the cause of this? What do you think as an investigative group, is the mechanism behind this finding?
Dr Adina Zeki Al Hazzouri: There could be various mechanisms playing roles here. Stress is obviously one of the important mechanisms. If you think about the instability of income, that instability in income could result in daily stresses, maybe inability to pay for bills. Also, that resulting in inflammation in all the stress pathway.
Also, you could think potentially having this instability could also maybe hinder access to care, maybe coping mechanisms related to stress could alter adherence to treatment. Whether maybe someone has to take daily medications, having those dips or changes, sudden changes in income, could alter your adherence to those medications and then subsequently influence your risk for cardiovascular disease.
Also, you could think access to health insurance. The social support, though it's not very well evidenced, but maybe if you've had always stable income, or low income, you're more likely to have more resilience. However, when you have these unpredictable changes, or sudden changes in income, you may not have that coping mechanism or support ready for you to deal with those sudden changes.
These are some of the pathways that we think of that could potentially be playing a key role here.
Dr Greg Hundley: Very good. Now let's turn to Dharam, our Associate Editor, from University Texas, Southwestern. Dharam, boy, surprising findings. A young cohort. I mean, they were 23-to-35 and in the next 10-years of their life they start to experience hard cardiovascular events. I mean, fatal and non-fatal myocardial infarction, and also, all-cause mortality. How do you put this in perspective, related to the workforce, and what do you think this means for this young population moving forward?
Dr Dharam Kumbhani: At the outset we obviously want to congratulate Adina and her group, for this really, very interesting study in cardiovascular EPY and broadly intersects in health economics and health policy, as well for obvious reasons.
Very interesting construct as you pointed out and what does this mean for younger subjects who experience these income volatility very early in their life. I think, just like any other EPY study, I think the perspective is helpful, because although the hazard ratio for these income volatility is two or higher, the absolute incidents rates are, again putting that in perspective is important, and so the absolute incident rates for example is somewhere between two-to-five, per 1,000 persons. So overall that impact, that's just helpful to understand what effects this would have.
Hopefully, that helps. But obviously, very interesting analysis and brings up a lot of questions. I think one thing I may add to what was just mentioned is ... And this was highlighted very nicely by the editorialist, Dr Spatz, and her colleague from Yale. About how this is globally in the financial toxicity space, and there are a number of these indicators that are now being carefully studied like in this study, such as wealth shock and as I said, financial toxicity. And how they actually have an impact on cardiovascular outcomes.
One of the feelings when you read a paper like this or when you read studies like this, and in fact this was one of our initial concerns as well, is to what extent you may have a component, or significant component of reverse causality. Your, "Patients who are sicker in some way," or have those culpabilities, be the ones that have these events is their relationship with other socio-economic indicators such as employment and how that would affect income volatility as well.
I think the authors have done a really terrific job responding to that. And again, it shows an association obviously we know that, that doesn't imply that it's cause[owed], but it's a very interesting association. And that it's helpful to speculate both on the mechanisms, which were just outlined, and also what this means from a health policy standpoint. What that would mean for researchers in the cardiology community, or policy makers, things like that. So I think this is a very nice analysis and definitely brings up a lot of discussion points.
Dr Greg Hundley: And a very important paper on multiple fronts. One, we've identified an issue in young, healthy individuals that could significantly contribute to adverse cardiovascular events. And then number two, I really liked your point on how this could impact public health policy, and maybe even how we need to think about reducing stress and how we design aspects of the workforce moving forward, so individuals don't suffer from these conditions.
I want to thank, Adina Zeki Al Hazzouri, from Columbia. And our Associate Editor, Dharam Kumbhani, for these excellent comments. We look forward to seeing you next week.
Dr Carolyn Lam: This program is copyright, American Heart Association, 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, from National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Greg Hundley, associate editor for circulation from VCU Health Systems in Richmond, Virginia.
Dr Carolyn Lam: What does cardiac autoimmunity, glycemic control, and cardiovascular disease risk and Type I diabetes have in common? Well, you've got to wait for our feature discussion. This one's such a hot one, don't you agree, Greg? We could hardly finish talking.
Dr Greg Hundley: Absolutely, and Myra, you're just going to love listening to her.
Dr Carolyn Lam: Yep, but stay tuned. First, we're going to discuss a couple of papers each. Greg.
Dr Greg Hundley: Thanks Carolyn. So, the first paper I've got is from Professor Van Rein at Leiden University Medical Center. And basically he's getting at the issue of bleeding in patients with atrial fibrillation. So this is a retrospective cohort that evaluates different anticoagulation strategies for atrial fibrillation. They examined 272,315 patients that had a median age of 75 years and followed them longitudinally over time. These individuals experience 31,459 major bleeding events, and what he did is he evaluated whether they were not taking anticoagulant therapy, whether they were on a vitamin K antagonist, a DOAC, antiplatelet therapies, and then all combinations of the above, including single, double and triple therapy.
What he observed is relative to taking a vitamin K antagonist alone. The hazard ratios range from 1.13 to 3.73 in those that were receiving dual antiplatelet therapy of vitamin K antagonist plus antiplatelet therapy, a DOAC plus antiplatelet therapy, and then of course triple therapy, which had that highest hazard ratio.
Dr Carolyn Lam: But were there particular combinations within these groups that had particularly high bleeding risk?
Dr Greg Hundley: Well, yeah, Carolyn. As we might expect, triple therapy was the worst, but those that were receiving triple therapy, there were two subgroups that were particularly susceptible to having a bleeding episode. First, those that were greater than 90 years of age, and second, those that had CHADS-VASc 2 scores greater than six. Of course, these are very complicated patients, often particularly that latter group. So there are clinical implications. I mean, clearly, this isn't a randomized trial, but what we should take away from this is that if we have one of those two patient groups, age greater than 90, CHADS-VASc score greater than six, that we ought to minimize the time that those individuals are on that triple therapy.
Dr Carolyn Lam: Talk about and bleeding, I've got a paper, and it's on the performance of the ABC scores for assessing the risk of stroke and systemic embolism or bleeding in patients with atrial fibrillation. This is a study that actually looked at the performance of these scores in an external cohort, which actually hasn't really been done. Now, as a reminder, the ABC score is actually the age biomarker clinical history stroke score, which helps to estimate the risk of stroke or systemic embolism. The ABC bleeding risk score incorporates biomarkers along with the clinical variables to estimate the risk of bleeding.
All of these were tested in the ENGAGE AF-TIMI 48 trial, which was that multinational randomized trial of the oral factor Xa inhibitor edoxaban in patients with atrial fibrillation and a CHADS-VASc 2 score of two and above. Now, this was from Dr Morrow and the TIMI study group in the Brigham and Women's Hospital, Harvard Medical School in Boston, Massachusetts. Basically what they found was that the ABC stroke and ABC bleeding risk scores performed well in stratifying the risk for stroke or systemic embolic events or major bleeding in this multinational trial.
Compared to the CHADS-VASc score, the ABC stroke score provided both correct upward and downward reclassification of the stroke systemic embolism risk. Compared with the HAS-BLED score, the ABC bleeding score resulted in a predominantly correct downward reclassification of the bleeding risk.
Dr Greg Hundley: So, this new ABC score, do we integrate it with HAS-BLED? Do we integrate it with CHADS-VASc 2? How do we use this clinically?
Dr Carolyn Lam: So first of all, there are some important remaining unanswered questions, and this was really nicely discussed in an accompanying editorial by Dr Hylek from Boston University School of Medicine. Among this, first of all, the ABC scores need to be validated in patients outside of a clinical trial. Remember, this was a clinical trial cohort. Then there are questions about the timing of measurements of the score, the different settings, hospital and otherwise. Do these scores perform equally well across different vascular beds and in diverse patient populations at the same thresholds used?
So, all these things still need to be addressed. And really, in Dr Hylek's words, the work has just begun.
Dr Greg Hundley: This is an issue with the theme that might be bleeding, and I'm going to talk about a study from Professor Huisman from Leiden University again, and this is the RE-VERSE AD study. Again, patients that are receiving dabigatran and that may have a GI bleed or patients that are on this therapy and unexpectedly need an emergent surgical procedure, this investigative team evaluated the utility of idarucizumab on reversing that anticoagulant dabigatran. So what did they do? They administered 2.5 milligrams of idarucizumab twice separated by 15 minutes.
And again, the study population was uncontrolled GI bleeding or those in need of an emergent procedure. The types of GI bleeds that were involved in this study, a third were upper GI bleeds, a third lower, and then a third, it was either unknown, or there was a mixture of both upper GI or lower GI bleeding. So how do we know that dabigatran is effective? We use a DTT time, and 98% of those with an elevated diluted thrombin time had that reduced after receiving these two twin 2.5 milligram doses at a time point of four hours after administration.
Dr Carolyn Lam: Okay, but were there any complications?
Dr Greg Hundley: Yeah, there were. So first of all, something to think about is that this is a high-risk group. In this study, 14.6% of the cohort actually later died either from the bleeding or what have you. Then another thing we need to be thinking about is when we reversed this anticoagulant, do patients experience thrombotic events? So what this group reported is 4.4% did within 30 days. What were those? Myocardial infarction, deep venous thrombosis, and subsequent PE. Then also at the 30-day time point, one patient experienced an ischemic event.
Another question is once you've administered this, you've gone through the procedure. You stopped the GI bleeding, or you've had the surgery. In this particular study, 66% of those individuals had restarted their DOAC. Those events occurred on top of that. So, interesting information. Looking at administration of idarucizumab, and we'll be using this I think frequently as DOACs are used more frequently in the population, particularly dabigatran, so some important data in guiding us on what we might expect when we administer this therapy.
Dr Carolyn Lam: I think going back to atrial fibrillation though, this is my other selected paper, and it's actually results from the GARFIELD-AF Registry. It's from Dr Bassand from University of Besançon in France, and colleagues, and basically, they looked at the early risks of death, stroke, systemic embolism and major bleeding in patients with newly diagnosed atrial fibrillation in the GARFIELD-AF Registry. They basically found that the rates of all three major clinical events was significantly higher during the first month than in the subsequent period set following up to 12 months.
The leading causes of early death were heart failure, sudden death, acute coronary syndromes, infection or sepsis, and respiratory failure.
Dr Greg Hundley: So, what's the take-home message here?
Dr Carolyn Lam: This is observational, so the key thing to understand here, it's a registry. It's observational. We can't really tell chicken from egg with regards to its newly diagnosed AF verses events, which comes first, which causes what. But nonetheless, the increased hazards of an early event and especially cardiovascular mortality in these newly diagnosed AF patients really point to the importance of comprehensive care for such patients and really should alert physicians to detect warning signs of possible early mortality in these newly diagnosed patients.
Dr Greg Hundley: Very good, Carolyn.
Dr Carolyn Lam: I think that wraps it up. Let's hop to our feature discussion, shall we? I'm so super excited about today's feature paper because it may explain that strong link between hyperglycemia and cardiovascular disease in type one diabetes and all by revealing a potential novel pathway that may have been hiding in plain sight. And yes, I'm stealing the words of editorialists and our associate editor, Dr Naveed Sattar from University of Glasgow, and we're all so pleased to have with us the corresponding author of today's feature paper, Dr Myra Lipes from Joslin Diabetes Center in Boston, Massachusetts. Myra, start us off by telling us a little bit about your study please.
Dr Myra Lipes: Sure. So we were interested in examining the role of whether chronic hyperglycemia could trigger cardiac autoimmunity in type one diabetes, because chronic hyperglycemia is associated with subclinical myocardial damage, and we had actually previously observed just unexpectedly in a young adult cohort that ... Actually from Italy, where unexpectedly, we noticed that patients with the poorest glycemic control expressed cardiac antibodies. There's a lot of interesting people who are autoimmune-proned may overreact to injury of certain tissues.
So, type one diabetes, it's a classical autoimmune disorder. So we examined, really tested this hypothesis, in stored samples from the DCCT/EDIC study, and this is a very landmark study where patients were randomized to tight glycemic control, intensive glycemic control. Then another group had just conventional control, and this was done over an average of six and a half years. So during this time, the samples were stored. Every year samples were stored from participants, and this was quite a rich data set that is publicly available. So we studied the development of autoimmunity in two groups that had very distinct separations of the A1C level.
We specifically excluded people who developed kidney disease or cardiovascular disease events during the study. So this is a cohort that had relatively recent onset type one diabetes. They're relatively healthy, and again, groups were matched with cardiovascular risk factors at the beginning and the end of this DCCT period. And of course with our studies, we've also looked genetically because your HLA immune response genes can influence susceptibility to autoimmunity.
These patients were actually matched in HLA genotypes. So what we found was that patients with poor glycemic control, there was expression over time. You could see a time course relationship between expression of antibodies over time on the levels of the antibodies that were different in the two A1C groups. The number of antibodies were different in that with the high group expressing more antibodies, more different types of antibodies. These are antibodies ... might say antibodies as like proteins in the blood, and they're actually directed against parts of the myocytes, the myofibrillar complex, and a major target is cardiac myosin heavy chain.
We saw the different parts of the myosin heavy chain retarded, and the presence of two or more antibodies, different types of antibodies, different regions of the myosin to different isoforms. Also, we saw antibodies, the troponin, troponin I. So the number of antibodies with different ... with almost a complete absence of antibodies in a tightly controlled group. I might mention the A1C average was 6.5%, so this is a very tightly controlled group whereas the poorly controlled group is at the opposite extreme, the average A1C during DCCT. The mean updated A1C was about 10%.
So, it was a very clean group, two different groups, and we could see that the number of the types, the number over time, very different in the two groups. In fact the profiles of these antibodies were almost very similar to patients with Chagas cardiomyopathy. That was our positive control group. Chagas cardiomyopathy is possibility to be a form of chronic myocarditis directed against cardiac myosin. So the profiles are almost indistinguishable. So on one hand, you have relatively healthy patients with type one before glycemic control, and that was very unexpected that this would look pretty similar.
But very interestingly, and I might say unexpectedly, we saw ... It was very clear that the people with the highest titers of antibody and the most different types of antibodies, particularly two or more, were subsequently ... We noticed that those patients were at high risk for developing CVD events. And that's while the number of events was slow, we noticed that all the patients, some 60%, had two or more antibodies and developed cardiovascular events. Perhaps one more striking example is a single patient in the study could die of cardiovascular death, had a positivity for all five antibodies at highest titer.
Then we looked at coronary calcification just to measure subclinical atherosclerosis. We noticed that the same numbers, two or more, and also the same antibody specificities that were the highest predictors of CVD events were also predictive of coronary ... had detectable coronary calcification. In addition, we looked at the levels trying to find mechanistically what could explain the link between cardiac autoimmunity and an increased risk for atherosclerosis. We looked at CRP, high sensitivity CRP levels.
Again, these were measured about a decade after the antibody samples were obtained, and we saw that the positivity for multiple antibodies was also associated with markedly elevated ... subsequently elevated high sensitivity CRP levels with levels of six versus something like 1.4 in a group with one or less antibody. So these were very intriguing findings, suggesting a role for autoimmune pathways as a susceptibility to cardiovascular disease in type one diabetes.
Dr Greg Hundley: Myra, that was absolutely incredible description of the study and all the particulars of the findings. I wonder if I could ask both you and Naveed, where do you see the next steps moving forward with this research in the future? Number one. And number two, is this in any way can be used to segregate patients that may need, for example, really aggressive glucose control with an insulin pump or something of that nature?
Naveed Sattar: I think we left this study as beautifully described as you see by Dr Lipes. I think the context ... We looked at this from editorial perspective ... is that most people don't realize if you have a middle-aged person with type one, their hazard ratio for cardiovascular risk is about somewhere between four to six fold for men and women respectively, which is much higher than type two. It's often thought that it's the area under the curve for hyperglycemia. But what this paper throws up is actually maybe there's another pathway, which we just didn't understand that this wasn't a permanent autoimmunity closing subclinical myocardial disease and inflammations.
But potentially, for me though, there's a saying in British that one swallow does not make a summer. So, it would be nice for other groups to replicate this. I think the findings are, as they stand in isolation, fantastically well done. But it would be lovely if other groups had accessible samples, and I knew of several groups that have up towards tens of thousands of samples, maybe even not 10,000. Certainly 10,000 or so plus or minus samples for type and prospective outcomes to potentially validate the findings and extend them.
And really, if the antibodies do help protect people at higher risk in a meaningful way and improve beyond what we can already do, then you're right. Absolutely. If we can pick up early people who are going to have substantially higher risk, you would want to potentially improve glycemic control, potentially pumps, CGM, closed-loop systems or more intensive statins or lower blood pressure targets or other types of antihyperglycemic agents, which seem to be being tested in type one as well. So that's really one example.
And for me, the other thing would be really nice is to pull up any inflammation. Is this high systemic inflammation? Is it IL-6 level? Is it something else? What about troponin and BNP levels, et cetera. I'd be interested to hear what Dr Lipes thinks and how do you think to take it forward as well.
Dr Myra Lipes: So, this is something Dr Sattar said and I completely agree. Actually, right now, we're looking at the DCCT cohort as a whole for already. It's relatively small compared to the population-based studies. But there's 1,400 patients, and the subjects had CMR studies that were published in Circulation. So we're going to actually study next whether we see CMR evidence of systolic dysfunction and looking at the broader DCCT cohort. So, those studies are underway. But of course the ultimate test would be looking at if there were samples available from the Swedish NDRs, Scottish registry.
I think it's something that's not often done prospectively. So that would be incredibly exciting, and that's the important thing. I'd say with type one diabetes, for screening for type one diabetes, the use of autoantibodies and particularly two or more different types of islet autoantibodies, and this is just putting things in a broader context, is the entry criteria for type one diabetes prevention trials and something cardiologists wouldn't be aware of but this particular thing. So in decades, people, researchers, in the field has spent decades optimizing islet antibody assays.
So by analogy, it would be really important to standardize assays so that they can be done in Sweden and Scotland and so that other groups could confirm this, and I'm confident that this could be done, since the setting up of our assays was really built on the experience of people of developing standardized assays and rigorous cutoff points for antibody positivity. So it would be really important to work internationally to try to tap into this.
Dr Carolyn Lam: Oh, my goodness. Myra, Naveed, these are such insightful comments. I think as Greg said earlier, I think we could go on forever discussing this paper, but I'm so sorry. Our time is up. Before we go though, I must point all readers to look at figure five of this marvelous paper. It puts together the whole schema of how autoantibodies can play a role both in myocardial and atherosclerotic cardiovascular disease and type one diabetes.
Thank you so much. Greg and I loved having you. Listeners, don't forget to tune in again next week.
This program is copyright American Heart Association 2019.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the Journal and its editors. We're your co-hosts of Circulation on the Run. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I am Greg Hundley, also associate editor from VCU Health Systems in Richmond, Virginia.
Dr Carolyn Lam: So, have you ever wondered in patients with atrial fibrillation and stable coronary artery disease beyond a year of coronary stenting, can you safely just continue on oral anticoagulation without antiplatelet therapy? Well, if you've ever wondered that ... I sure have. I'm sure you have too, Greg. Our feature paper this week does discuss this, so you have to stay tuned. But for now, Greg, what are your picks from this week's issue?
Dr Greg Hundley: I've got a couple to discuss. The first is Patrick Hsieh from Taipei, Taiwan, and really is evaluating the gut microbiota and how that affects cardiac repair after myocardial infarction. I mean, who would've thought to chase an idea like this? But what this investigative team did is they had mice, so this was a basic science experiment, and they treated them seven days prior to ligation of their left anterior descending artery that would induce a myocardial infarction. They treated them seven days prior with ampicillin, metronidazole, neomycin, and vancomycin. What were they trying to do? Totally obliterate any bacterial load within their GI system. Then, they ligated that coronary artery, and at 21 days, they looked at histopathologically what was happening.
And you know what they found? Those where they wiped out the bacterial load, they had increased cardiovascular events. And importantly, myocardial rupture was very high in this group of mice. Also those mice, they had reduced heart rate, and mechanistically what had occurred is there was a reduction in our immune monocytes that were trying to infiltrate the peri-infarct. They weren't there. They were not in those peri-infarct zones. And so, the thought here is that removal of the favorable microbiota in the gut can actually be harmful in the setting of myocardial infarction.
Dr Carolyn Lam: Fascinating. So, microbiome as our pals. But wait a minute. I mean, how can you say it's from elimination of the microbiome versus some kind of effect of the antibiotics itself?
Dr Greg Hundley: Yeah, that's a great question, Carolyn. The way they did this is they took another group of animals, and they supplemented them with lactobacillus probiotic, like the stuff we get in the grocery store. And those animals, they did not suffer any of the adverse cardiovascular effects. So, it really points to an important role of our gut microbiota. You know, and what do they do? They basically ferment these carbohydrates that we ingest, and produce short chain fatty acids that are a substrate for these mononuclear cells to help infiltrate those infarct zones. So, really exciting basic science question that this group examined.
Dr Carolyn Lam: I love that you picked a basic science paper, and I love that you made even me understand it so well. Okay, but what I have is a clinical trial. So, it's the REDUCE-MVI trial, which is the first randomized trial comparing maintenance treatment with ticagrelor or prasugrel after a primary PCI. So, this is from Dr van Royen and colleagues. They're from Radboud University Medical Center in the Netherlands. Basically, they figured that despite successful restoration of epicardial vessel patency with primary PCI, coronary microvascular injury does occur in a large proportion of STEMI patients, and of course, adversely affects outcomes. Now, ticagrelor has been reported to increase plasma adenosine levels, which may have a protective effect on the microcirculation. So, the authors randomize 110 STEMI patients following revascularization to maintenance therapy with ticagrelor versus prasugrel, with the primary outcome being microvascular injury at one month as determined by the index of microcirculatory resistance in the infarct related artery.
What they found was that there was no difference in the extent of microvascular injury and in the extent of infarct size by cardiac MRI at one month after the primary PCI. The attributed pleiotropic benefits of ticagrelor through the adenosine metabolism pathway actually could not be confirmed in the STEMI population, as plasma adenosine levels were actually not increased in the patients treated with ticagrelor.
Dr Greg Hundley: So, what does this mean for the use of adenosine and its role?
Dr Carolyn Lam: I suppose you're also asking, you know, is the adenosine hypothesis really out here? This is a study that really suggests we have to question it, but there are some limitations that we perhaps should keep in mind when we think about this. So first, before primary PCI, all patients were loaded with ticagrelor because this was standard of care in the participating centers. That, of course, could have modified microvascular injury already at the index event. Now, a second important thing is that the study may have been underpowered. There was a greater than anticipated variability in that primary outcome of index on microcirculatory resistance.
The relatively low rates of risk factors, the small infarct size, the preserved ejection fraction could all have influenced this IMR values, as well as the potential effects of the pharmacological intervention. And furthermore, the natural recovery of microvascular dysfunction over time may have diluted the positive effects. And of course, selection bias is inevitable in a trial. And so, you know, although this really questions the adenosine hypothesis, there are still caveats to these results.
Dr Greg Hundley: Very good. So, Carolyn, I've got another study to sort of go over, and this is from Dan Modin from the University of Copenhagen. And it's really addressing this issue. We all in the fall, do we all get our flu shots? And could that be helpful in patients with heart failure? You know, the ACC, the AHA, and the ESC all suggest flu shots, but there's actually no guideline to recommend. So, what did these investigators do? They looked in Denmark, and from the period of January of 2003 to June of 2015, they identified 134,048 subjects. And they looked at the vaccination status for those with a diagnosis of heart failure that were greater than 18 years in age. 55% percent of these were men. And then, they also looked at ICD-10 codes for cardiovascular events.
Now, they examine the dates of when you had your vaccination, how frequently, what were your comorbidities cardiovascular-wise, medication use, etc. And what they observed is that those individuals that had more than one vaccination ... So, basically annual vaccinations for a three year period, they had an 18% reduction in all death, and a 19% reduction in cardiovascular death.
Dr Carolyn Lam: So, is this all heart failure patients? Are there specific subgroups that we should be targeting?
Dr Greg Hundley: At our institution, they really get on us. If we don't have our flu shots in September, I mean, they threaten to withhold everything, or maybe October. Well, interesting that you asked that question. Those individuals that had flu shots in the September to October window did much better than those individuals that had their vaccination November, December, or actually later in January. And the second group that benefited were the individuals that actually had annual vaccinations. So, if periodically you say, "Oh, I'm going to get it this year, but then I'm not going to get it two years from now." Not so good. It was those individuals that had those vaccinations annually.
Dr Carolyn Lam: You know, Greg, it's making me question too, because here I am in a tropical island. We actually don't have seasons. So, what does that mean for us? That's one thing. And then, do we need even randomized trials now?
Dr Greg Hundley: Yeah, I think you're right there, Carolyn, because first of all, you know the investigators targeted this because 50% of heart failure exacerbations are actually triggered by some sort of respiratory infection. So, that was kind of the thought behind this. But we do have to be careful about looking at this longitudinal data and making predictions or developing guidelines. A couple of reasons why. It could be that those that come in for annual vaccinations at the time points, well, maybe they also come in for more frequent heart failure visits with their doctor. So, it's not cause and effect.
And in fact, there was another study, Get with the Guidelines heart failure study, and it actually showed no association. So, more work really needs to be done in this area. And just to point out quickly, there is a current randomized trial going on called Invested, and it's looking at different types of vaccinations, trivalent versus quadrivalent. They're underway in those with heart failure. And so, there's a lot more work in this area. But it was interesting getting it that old "get your flu shot," and it looks like at least longitudinally in cohort studies could be beneficial. And if you are going to do it, do it every year and get that September, October. So, Carolyn, what about your next paper?
Dr Carolyn Lam: So, Greg, my second paper is another trial. It's the radio sound hypertension trial, this time focusing on renal denervation. In fact, it's the first trial to compare three different techniques and technologies for catheter-based renal denervation. It's from Dr Lurz from Heart Center Leipzig in Germany. And what they did is, they randomized 120 patients with resistant hypertension to three arms. Either one, radiofrequency, renal denervation of the main renal arteries. Two, radiofrequency renal denervation of the main renal arteries and the side branches and accessories. Or three, an endovascular ultrasound-based renal denervation of the main renal artery. The primary endpoint was change in systolic daytime ambulatory blood pressure at three months. In the end, endovascular ultrasound-based renal denervation was the winner over radiofrequency ablation of the main arteries, with or without ablation of the side branches.
Dr Greg Hundley: Carolyn, does this mean that renal denervation is coming back? Are we going to actually start thinking about this as a viable option to treat those with longstanding hypertension?
Dr Carolyn Lam: Greg, this was exactly addressed by an editorialist, Dr Ram from UT Southwestern and Apollo Hospitals and Apollo Medical College in India. Beautiful editorial. Basically, even with the publication of these new data, it is difficult to predict whether renal denervation is firmly back on track. You see, some caveats should be mentioned, including that in this trial, only patients with large renal arteries were chosen for this study. And patient enrollment was rather selective.
For example, out of 1,884 patients screened, only 120 patients met the inclusion criteria. And then, importantly, in a few patients, the reduction in systolic blood pressure was really impressive, close to 40 millimeters mercury. But the majority of responders had a more modest effect, and in about 30%, there was no change in blood pressure.
So, one of the ultimate things we need to learn to do is to identify the so-called hyper-responders from the non-responders. So, lots more work needs to be done in renal denervation.
That brings us to a close of our little chat. Can't wait for our feature discussion coming right up.
Our feature paper today deals with a very important topic in a very frequently encountered group of patients. And they're the ones with concomitant stable coronary artery disease and atrial fibrillation. You see, these are patients at high risk of both ischemic and bleeding events, and therefore, it's critical to identify the right antithrombotic regimen with the optimal benefit ratio, since this is going to be lifelong therapy. Now, interestingly, despite recommendations in the guidelines and consensus documents, there has been no randomized controlled trial evaluating oral anticoagulation with and without antiplatelet therapy in patients with atrial fibrillation and stable coronary artery disease beyond one year of coronary stenting. I mean, Greg, I didn't even realize that we didn't have a randomized control trial. Did you?
Dr Greg Hundley: Absolutely, Carolyn. And, you know, this is an important issue, because we have a lot of patients coming to the cath lab that have atrial fibrillation, and what is going to be the recommended anticoagulant and antiplatelet combination? And so, it's really time for a randomized trial.
Dr Carolyn Lam: I know, and luckily for us, that's exactly what this issue's feature paper does. And I'm so pleased to welcome to the show Dr Satoshi Shizuta from Kyoto University Graduate School of Medicine, Japan, as well as associate editor Dr Shinya Goto from Tokai University in Japan. We're so proud to be publishing the OAC-ALONE trial, even though we understand it was a difficult trial. Tell us, what were the results?
Dr Satoshi Shizuta: As you know, the results were somewhat inconclusive because of pretty much a combination of patient enrollment. Initially, we scheduled to enroll 2,000 patients during 12 months, but patient enrollment speed was extremely slow, much slower than expected. So, we extended the patient enrollment period from 12 months to 38 months. But finally, we could only enroll 696 patients, about one-third of the initially planned patients. The result was around 50% rate of primary end point during 2.5 years of follow up. And the hazard ratio of [inaudible 00:15:01] strategy, as compared with OAC plus APT was 1.16 with a 95 confidence interval of 0.79 to 1.72.
So, in conclusion, our study failed to establish no inferiority of OAC-ALONE to combination therapy of OAC plus antiplatelet therapy in patients with AF and stable coronary artery disease beyond one year after stenting in terms of primary endpoint of death, MI, or stroke. So, this study was underpowered and inconclusive. So, future larger studies require to establish the optimal antithrombotic regimen in this same patient population.
Dr Carolyn Lam: Thanks so much. Shinya, you've been thinking about this, too, and the performance of such a difficult trial. Did you have anything to add or to ask?
Dr Shinya Goto: So, first of all, I would to congratulate Satoshi and the group. They have completed a very interesting randomizing trial. As Greg mentioned, there is two kind of patient who lead to coronary artery disease and atrial fibrillation, especially after, you know, one year after stenting. So, taking a look at coronary artery disease with atrial fibrillation, we don't have the established standard of care yet. So, Satoshi know, it is a long-time study. So, I understand the rich colored nature of the patient in this kind of trial. So, what is the most difficult point increased to encourage the patient in this long-term trial?
Dr Satoshi Shizuta: We think that difficulty reflects substantial reluctance of most cardiologists to withdraw antiplatelet therapy, single antiplatelet therapy from stented patients, even the patients treated with oral anticoagulation for atrial fibrillation. So, that is the most important point.
Dr Shinya Goto: You have already showed in this paper myocardial infarction recurrence of stents thrombosis. Not a huge problem in this kind of patient population, you know? Stroke is a bigger problem, mortality, not including cardiovascular is also the problem. So, you have suggested, you have a strong kind of mind, is it? And single antiplatelet therapy necessary after stenting. Your results are underpowered but still suggest how always you know would be enough in stable CAD patients with atrial fibrillation.
I would congratulate you again.
Dr Satoshi Shizuta: Thank you.
Dr Greg Hundley: Satoshi, I have a quick question. So, in the randomization process, how can you achieve the physicians managing the patients to administer the anticoagulant therapy to guideline levels, particularly when they are also prescribed antiplatelet therapy? I noticed that in the editorial on this manuscript that was a concern, and suggesting that in future studies that the therapy really be defined, and not so much open label administration at the discretion of the prescribing physician. What are your thoughts on that?
Dr Satoshi Shizuta: I agree with you, but in this kind of study, randomizing whether or not to withdraw a drug is very difficult to conduct. Financial support is limited, and in such situation, double blind placebo controlled trial is very difficult to conduct. As you know, several years ago, a loose trial was published in the Lancet. And also in the loose trial, the study design was open level, and also in the PCI and [inaudible 00:19:48], I think the study design was not blinded but open. In this paper figure two, our control level was set as a dependent based on the Japanese guidelines. In the Japanese guidelines, target IR was set as 1.6 to 2.6, a little bit lower than Western golden standard for elderly patients older than 50 years. And same 2.0 to 3.0 in patients younger than 70 years.
And in that criteria, as you can see, if you get 2A of paper, the therapeutic range was extremely high. 76% in the OAC-ALONE group, and also 73% in the OAC plus APD group. We can clearly understand that the intensity of oral anticoagulation was different between the two groups. Most of the OAC-ALONE group, OAC was controlled with ionine level higher than 2.0. On the other hand, in the OAC plus APD group, the ionine level was mostly controlled between 1.6 to 2.2 or .5 or so. So, this is a great big limitation of the study. But even in this limitation, the bleeding events, there was numerical excess in the OAC plus APD group. And, regarding the TEMI major bleeding, there was a trend toward increased major bleeding in the OAC plus APD group. If the intensity of OAC was the same, of course, I am convinced that even in this underpowered sample five, the major bleeding will be statistically higher in the OAC plus APD group.
Dr Carolyn Lam: Thank you so much Satoshi for really taking us under the hood, and showing us all the myriad of considerations that occurred to perform this trial.
This is Greg and Carolyn. Thank you for joining us on Circulation on the Run. Don't forget to tune in again next week.
This program is copyright American Heart Association 2019.