Dr. Carolyn L.: 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. On our podcast today we are discussing the role of diastolic stress testing and the evaluation of heart failure with preserved dejection fraction, a really hot topic indeed, but first here's your summary of this week's issue.
The first study tackles the obesity paradox in cardiac surgery, where morbidity and mortality are lower in obese patients. This study sought to ask the question, "Is this due to reverse epidemiology, bias, or confounding?" To answer this question, Dr. Maris Kelko and colleagues from University Leicester in United Kingdom used two separate analysis. One, registry data from the National Adult Cardiac Surgery Registry and two, a systematic review in meta-analysis of studies. Of more than 400,000 patients in the cohort study and more than 550,000 patients in the systematic review, the authors found a U shape association between mortality and body mass index classes, where lower mortality was observed in overweight and obese class one and two patients, relative to normal weight patients, and mortality was increased in underweight individuals.
Now, the obesity paradox has been attributed to reverse epidemiology where the survival benefit associated with obesity is thought to actually reflect worse outcomes in the underweight patients who also had frailty, cachexia, or severe chronic disease. However, in the current study, counter to the reverse epidemiology hypothesis, the protective effects of obesity were less in patients with chronic renal, lung, or cardiac disease and greater in older patients as well as in those with complications of obesity, such as metabolic syndrome and atherosclerosis. Furthermore, adjustments for important confounders did not alter the results. The authors therefore concluded that obesity is associated with lower risks after cardiac surgery with consistent effects noted in multiple analysis even after attempting to address residual confounding and reverse causation.
The authors even went as far as to suggest that their findings do not support common practice where weight loss is recommended prior to surgery or where very obese patients are refused surgery in the morbidly obese. These provocative findings are discussed in an accompanying editorial by Doctor's Carnethon and Kahn from Northwestern University. While the editorialists agree that this well-designed study highlights an important knowledge gap, they pointed out that the obese class two patients had nearly five times greater risk for deep sternal wound infection and 25% higher likelihood of needing renal replacement therapy.
In such patients additional intervention in the perioperative period may still be indicated and include weight loss recommendations and postoperative surveillance for complications. Thus, a more cautious final recommendation may be for future studies to prospectively assess weight loss interventions prior to elective surgery in the context of overall surgical risk as assessed by the EuroSCORE or STS models.
The next paper describes mechanistic studies showing for the first time that nucleoside diphosphate kinase suppresses cyclic-AMP formation in human heart failure. In this paper by First Authors, Dr. Abu Taha and Hagemann, corresponding authors Dr.'s Tobref and Weilend from the Heidelberg University in Germany, the authors performed biochemical studies of nucleoside diphosphate kinase and G Protein signaling in human and rat tissue samples, assessed the functional impact of nucleoside diphosphate kinase C on cyclic-AMP levels and contractility and isolated red cardiomyocytes and determined that in vitro effects of these nucleoside diphosphate kinases on contractility in zebra, fish and mice.
They identified nucleoside diphosphate kinase as the critical isoform for the regulation of G Protein function and cyclic-AMP levels in the heart with important consequences for cardiac contractility. The increased nucleoside diphosphate kinase membrane content in human heart failure could potentially counteract a fading beta adrenoceptor response in the early stages of heart failure by increasing the amount of G Alpha stimulatory proteins in the plasma membrane. However, by switching from stimulatory to G Alpha inhibitory to activation, nucleoside diphosphate kinase may play a role in heart failure progression by reducing cyclic-AMP levels, typical for end-stage human heart failure.
The study, therefore contributes to a better understanding of the molecular processes, underlying alter G Protein signaling in heart failure, and may help to develop new heart failure therapies.
The next study tested the hypothesis, that high intensity interval training is superior to moderate continuous training in reversing cardiac remodeling and increasing aerobic capacity in patients with heart failure and reduced ejection fraction.
Doctor Ellingson and colleagues from the Norwegian University of Science and Technology, performed a multicenter trial, comparing twelve weeks of supervised interventions of high-intensity interval training at 90 to 95% maximal heart rate, moderate continuous training at 60 to 70% maximal heart rate, or a recommendation of regular exercise in 261 patients with heart failure and ejection fraction less than 35%, in New York Heart Association class II or III status.
The primary end point of change in left ventricular end-diastolic diameter from baseline to twelve weeks was not different between the high-intensity and moderate continuous groups. There was also no difference between the high-intensity and moderate groups in peak oxygen uptake, although both were superior to the recommendation for regular exercise. None of these changes were maintained at follow up after 52 weeks. Serious adverse events were not statistically different. However, training records showed that 51% of patients exercised below the prescribed target, during supervised high-intensity interval training, and 80% above the recommended target in those with moderate continuous training. Given that high-intensity interval training was not superior to moderate continuous training, in reversing remodeling or improving secondary end points, and considering that adherence to the prescribed exercise intensity based on heart rate was difficult to achieve even in the supervised setting.
The authors concluded that moderate continuous training remains the standard exercise modality for patients with chronic heart failure.
The final paper tells us, that brain emboli after left ventricular endocardial ablation may be more common than we knew. First author Doctor Whitman, corresponding author Doctor Marcus and colleagues from University of California studied eighteen consecutive patients, scheduled for ventricular tachycardia or premature ventricular contraction ablation, over a nine month period. Twelve patients undergoing left ventricular ablation were compared to a control group of six patients, undergoing right ventricular ablation only. Heparin was administrated with a goal activated clotting time of 300 to 400 seconds for all left ventricular procedures. Pre impulse procedural brain magnetic resonance imaging was performed on each patient within a week of the ablation procedure. The authors found that seven of the twelve patients, or 58% undergoing left ventricular ablation, experienced a total of sixteen cerebral emboli, compared with none among patients undergoing right ventricular ablation. Seven of the eleven patients undergoing a retrograde approach to the left ventricle, developed at least one new brain lesion. Thus, more than half of patients undergoing routine left ventricular ablation procedures, experienced new brain emboli after the procedure, even in the absence of clinically apparent stroke.
Future research is critical to understanding the long-term consequences of these lesions and to determine optimal strategies to avoid them. This is further discussed in an editorial entitled "The Sound of Silence". How much noise should we make about post ablation silence strokes? By Doctor Z and Vora from Stanford University. Well, those were your summaries, now for our featured discussion.
I am so thrilled to have with me two special guests to discuss the topic of the diagnosis of heart failure preserved ejection fraction or HFpEF. As you all know, that's my favorite topic and I have favorite people with me today. First, the corresponding author of our feature paper, Doctor Barry Borlaug from Mayo Clinic, Rochester, Minnesota. And, for the first time on the podcast, Doctor Mark Drazner, Senior Associate Editor from UT Southwestern. So, welcome Barry and Mark.
Barry Borlaug: Thank you Carolyn.
Mark Drazner: Thank you, great to be here.
Dr. Carolyn L.: So, Barry, you talked about the role of stress diastolic testing, shall I call it, in the diagnosis of HFpEF in your paper. Could you tell us why you looked at it and what you found?
Barry Borlaug: Sure, Carolyn. When you have dyspnea and fatigue and you got a low EF, it's pretty easy to make the diagnosis of heart failure reduced EF, but we've been struggling for years with making the diagnosis of dyspnea, whether it's HFpEF or not in people with normal ejection fraction. And that's because physical and laboratory and clinical signs of high filling pressures and congestion, are either difficult to see or only present during stress, like physical exercise, in patients. So that's really what motivated us to pursue this study.
We took patients, that were referred to our cath lab for invasive hemodynamic exercise testing, so we directly measured filling pressures, PA pressures and cardiac output reserve, to get a gold standard assessment, whether people have heart failure or not. And then we performed simultaneous echocardiography and blood testing to measure NT-proBNP levels, and then we just looked at what we could figure out. Can you accurately discern HFpEF patients from patients without cardiac dyspnea, using these non invasive estimates.
We saw that a lot of people, with, for example, NT-proBNP levels that are low enough to be where most would consider HFpEF excluded, actually had HFpEF. And we saw that there were modest correlations between non-invasive echocardiographic estimates of filling pressures, specifically the E to E Prime ratio, and directly measured left heart filling pressures. But when we applied the criteria that had been initially proposed, we saw poor sensitivity to make the diagnosis with exercise. And this was largely related to the difficulty with getting all of the different echocardiographic indices, that are currently examined as part of the diastolic stress testing non-invasively. Next, we looked at just adding the exercise E to E Prime, which is an estimate of filling pressures, and when we used the cut-point, that's already been proposed, according to contemporary data, we found that this substantially improved the sensitivity to identify HFpEF, but there was a bit of a trade-off in that specificity decrease.
Dr. Carolyn L.: That's so cool. So let me summarize some of these take-home messages here. First of all, using just rest echo. I was really impressed to see that rest echo indices alone only identifies a third to maybe up to 60% of the patients you found with invasively proven HFpEF. So, we may be specific, but we're really missing quite a number of patients. And then if you exercise them, what your data is really showing is that it's better to exercise them and use this data for the negative predictive value, isn't that what you're saying?
Barry Borlaug: You know, the exercise is really the gold standard, so it gives you both, the negative and positive. With the echocardiography, relying on the exercise E to E Prime ratio, that was really helping us, as you say, Carolyn, with the higher negative predictive value. So most people, that had HFpEF, in this series, where we could get adequate, highly controlled environments, adequate diagnostic echocardiographic data, most people that ended up having HFpEF fit those criteria, we could see an elevation in this E to E Prime on exercise, so it did provide good negative predictive value.
Dr. Carolyn L.: These are just such important data, because I think we're all still struggling with how to make this diagnosis of HFpEF. Mark, could you just share some thoughts on whether you think this is going to really change practice, even change guidelines?
Mark Drazner: I think, if you read this paper, you would recognize it, that it's certainly a critical question that we're all facing, how to make the diagnosis of HFpEF. And all of their guidelines that have been advocated, there really wasn't much data, and these really are the best data out there. So, certainly, it's [inaudible 00:15:41] me a direction of changing practices. Barry says, certainly, the approach will need to be validated, I think, before it reaches high level guidelines, but certainly I think it's a step in the right direction, and points the way towards the future in terms of improving our ability to diagnose HFpEF. And really, that's why both reviewers and [inaudible 00:15:59] this is such an important paper.
Dr. Carolyn L.: Right. Barry, I have a quick question for you though. Doing exercise echo, not easy. E to E Primes are all over the place usually. How easy was it? How feasible was this test?
Barry Borlaug: So, first I'd like to say that we have outstanding, very well-trained, very highly skilled research scenographers, here at Mayo doing this. In very controlled environment, we're providing plenty of time for them to obtain images and that's going to be a question moving forward, because not everybody in clinical practice has that capability. But with that said, in this very controlled environments, skilled scenographers, we were able to measure the exercise data during low level exercise about 85 to 90% of the time and at peak exercise about 75 to 80% of the time. So, it's fairly feasible, but even in this best case scenario, we can't get it on everybody.
Mark Drazner: Even in the [inaudible 00:19:49] echo lab, the recommended approach by the ASE with the four measures. How many times they were not able to acquire all those images, are necessary for those four techniques and so, here you have a [inaudible 00:20:03] of AS echo lab not being able to do that, and being transparent about that, and [inaudible 00:20:08] to the community, saying that, although these are ideal measures, even the [inaudible 00:20:12] perhaps you can't acquire them. I think that was another important point that came out of this and then lead to the focus on the E to E Prime.
Barry Borlaug: I couldn't agree more. You got one of the world renowned labs, very skilled scenographers doing imaging, and we're still not able to get it all in each patient, and that just points to the difficulty of getting really high quality diagnostic images, and a lot of time you need the next level test, when that happens. And invasive exercise testing is really that test, the gold standard.
Mark Drazner: When you get echos from the outside and you look at the E to E Primes, are you confident that the data, that's generally acquired, is gonna be acceptable for this [inaudible 00:20:50]?
Barry Borlaug: Yes and no, I mean I'm always a little bit concerned, but it's not just being a control freak, you know, wanting to see everything, but I think that if it's a still frame doppler, tissue doppler spectrum, you can see that the sample volume is in the right place, and it's really unequivocally normal or abnormal, I feel pretty good about that. Not as good as when they get a full dedicated study here.
Mark Drazner: Of course, the gold standard is also difficult. The invasive measurement.
Barry Borlaug: Yes it is, I didn't [inaudible 00:21:18] that, but we've been doing a lot of invasive exercise tests for the last ten years now. And we do like 250 a year here, so we're really quite [inaudible 00:21:28] but we have all hands on deck in the lab. We have a couple technicians running gas samples around, all over the place. Somebody is on the medgraphics card, measuring oxygen consumption. We've got a nurse in there, that's helping out, so it's complicated, and of course we're using the micromanometer catheters for the pressure assessments, because you get so much more artifacts from width and under damping and over damping with the pressure tracing, so that's also not easy to do if you say.
Mark Drazner: So maybe for practicing cardiologists it's gonna be hard to duplicate that and perhaps spend the energy in terms of doing the exercise echo techniques off the speed, for example. Perhaps, it's another message.
Barry Borlaug: I would agree completely. And I think that again, when you do that, if you do a really high quality exercise echo and it's still not quite definitive, then you can refer on to a center that does have that capability, because obviously it's just reality, not everybody is going to be able to do this. Not every place has the size and resources to be able to do these really advanced tasks.
Dr. Carolyn L.: And do you apply exercise echo now in making your diagnosis? How do you use this data, for yourself, clinically?
Barry Borlaug: We started to think about this, and I think that the best case scenario where the people, that really have an intermediate pretest probability, based on their clinical characteristics. Somebody has jugular distension and a very high NT-proBNP level, and edema, you really don't need further testing, you know that that's going to be HFpEF. And if somebody has no risk factors, and everything is stone cold normal, they don't.
But in some of these people that have some signals, but they don't quite meet criteria, we are doing this, again, if they have adequate echocardiographic images at rest. And then we're looking really carefully at the exercise echocardiography data, one concern from this data, I want to make sure people are very circumspect and really critically looking at the quality of their data, because we shouldn't over-interpret equivocal findings. And as you said earlier, E to E Primes can be all over the map, they're very difficult to obtain during exercise. But I think that if everything looks very high quality and is definitely abnormal or definitely normal, that can be helpful. More so, if it's normal. We did see more false positive, so if it is abnormal, we did suggest that you may want to perform further confirmatory testing, because of the higher false positive rate with exercise echo.
I would say for the listeners, they should take a look at his figure six, which really is a nice diagnostic algorithm, where Barry shows, or advocates, for taking patients with intermediate probability and then using this to restratify that, using [inaudible 00:19:40] approach. I know that, that figure resonated with the editors and the reviewers dramatically, so I'd encourage listeners to take a look at that.
Dr. Carolyn L.: Listeners, you heard it right. [inaudible 00:22:36] Circulation on the Run. Don't forget to tell all your friends about this podcast and tune in next week.
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. I am so excited to be discussing the diabetic HFpEF or heart failure with a preserved ejection fraction phenotype, with world experts and new insights from the I-PRESERVE Trial. That will just be in a moment and here are your summaries first.
The first paper in this issue is a systematic review and meta-analysis of risk factors for Co-Arctation of the Aorta on pre-natal ultrasound. In this paper by first author Dr. Familiari and corresponding author Dr. D'Antonio and colleagues from Arctic University of Norway, the authors performed a systematic review of 12 studies on 922 fetuses with echo-cardiography, and found that those with a post-natal diagnosis of co arctation had significant differences in several cardiac morphological parameters compared to cases without co arctation. The presence of a co arctation shelf, or hypoplastic arch, was associated with a significantly increased risk of co arctation. Furthermore, they reported multi-parametric diagnostic models that were associated with an increased detection rate. Thus, this paper tells us that assessment of left inflow and outflow tracts prenatally may help in stratifying the risk of co arctation.
The next paper reports pre-clinical data that truly represents a paradigm shift in our understanding of vascular resident endothelial progenitors in tissue regeneration. In this paper by first author Dr. Patel, corresponding author Dr. [Cossroterrani 00:02:00], and authors from Royal Brisbane and Women's Hospital in Australia, the authors studied protein expression levels of common endothelial markers in mice using flow cytometry. They discovered an endovascular progenitor cell in vivo that is present in normal endothelium in the aorta and lungs and activated in vessel walls during various endogenic situations, such as in the placenta, skin wound healing, and tumors. They further define at a molecular level an entirely novel endothelial hierarchy from an endovascular progenitor cell to a mature different-shaded endothelial cell via complete RNA sequencing. They further clarify the linage of endothelial progenitors in their origin by using bone marrow transplantation and vascular-specific, lineage-tracing mouse models, showing that the endovascular progenitor cells were derived neither from bone marrow nor from hematopoietic progenitors. This discovery of an endovascular progenitor cell will have significant implications for the development of endothelial progenitors as a cell therapy.
The next paper addresses the chicken or egg question regarding the association between obesity and atrial fibrillation, and this is done using Mendelian randomization to define a causal association between body mass index and atrial fibrillation. In this study by Dr. Chatterjee and colleagues from Massachusetts General Hospital, the authors looked at more than 50,000 European individuals without atrial fibrillation at baseline and showed that genetic variance associated with increasing body mass index were significantly associated with an increased risk of atrial fibrillation. The association between genetically determined obesity and atrial fibrillation persisted even after adjustment for traditional atrial fibrillation risk factors, such as hypertension, diabetes, coronary artery disease, and heart failure. Taken together, these data are consistent with a causal association between increasing body mass index and incident atrial fibrillation. These findings therefore support the primordial prevention of obesity as a significant public health target to combat the expanding global burden of atrial fibrillation.
The last paper provides contemporary estimates of the stroke burden in China, a country which bears the biggest stroke burden in the world. In this paper by doctors Wang and Fagen from the Capital Medical University in Beijing, China and Auckland University of Technology in New Zealand, and colleagues, the authors reported results of a nationally represented door-to-door survey conducted in 2013 in 155 urban and rural centers in 31 provinces in China, totaling 480,687 adults. They found that the age standardized prevalence was 1,115 per 100,000 people, incidence rate was 247 per 100,000 person years, and mortality rates were 115 per 100,000 person years. The stroke prevalence estimates in 2013 were greater than those reported in China three decades ago, especially among the rural residents. Finally there was a north to south gradient of stroke in China, with the greatest burden observed in the northern and central regions. Well, that wraps it up for our summaries. Now for our discussion.
For our featured discussion today, we are talking about my favorite topic and of course that is HFpEF, or heart failure with preserved ejection fraction, and I am so thrilled to have with us today Dr. John McMurray from University of Glasgow, who's the corresponding author of our featured paper referring to diabetes in patients with HFpEF and really talking about the novel results from the I-PRESERVE Trial. Welcome, John!
John McMurray: Thank you Carolyn, it's always a pleasure to speak to you.
Carolyn Lam: Oh, I have been waiting for this one, and I'm so excited I don't know where to begin, but how about with this? Diabetes and HFpEF, first of all, haven't we spoken to death about co-morbidities in HFpEF? And secondly, what makes this paper special? Because we've heard about diabetes and HFpEF from CHARM, from DIG, from Relax, so tell us: why the interest in diabetes and HFpEF?
John McMurray: Sure, Carolyn. I think you and I have been interested in diabetes and heart failure, that terrible combination, for a long time. But I think there's a lot more interest in it today because, of course, we've had several new clinical trials with interventions to lower blood glucose that have showed both beneficial and potentially harmful effects on the development of heart failure. But really what these trials have highlighted is just how common heart failure is as a complication of diabetes. And we strongly suspect, though we don't know for sure of course, but we strongly suspect that most of that heart failure developing amongst patients with diabetes is probably heart failure with preserved ejection fractions. So, I think the context currently is that what's different about our study compared to the ones that you mentioned is that in I-PRESERVE we measured a number of things that were not available in, particularly, the large clinical trials previously. So, in I-PRESERVE we measured natriuretic peptides, we looked at health-related quality of life, and maybe most importantly of all we had a large echo-cardiographic sub study. So I-PRESERVE is quite different than DIG-Preserved and CHARM-Preserved, and of course a lot larger than the RELAX HFpEF study.
Carolyn Lam: I was the associate editor managing your paper and I was so excited about this that I invited an editorial as well by Brian Lindman, and he's got this beautiful table that summarizes what your study really adds to the literature, and I think it's so critical. Could you start by summarizing? What are the main findings?
John McMurray: Well, I-PRESERVE, as you know, was a trial of just over 4,000 individuals with HFpEF defined clinically and with an ejection fraction of 45% or above. There was actually a trial comparing the angiotensin receptor-blocker [inaudible 00:09:17] placebo, though in fact there is no difference in morbidity and mortality between those two treatment groups. So we've looked, as you said, at the patients who had diabetes and compared those to the patients who didn't have diabetes. I think there was some very interesting novel information; if you look at the two subsets of patients, they actually don't differ in terms of age and sex and, importantly, in left ventricular ejection fraction.
But there are other differences that you would expect; for example, many more of the patients with diabetes were obese. But interestingly, and despite that, the patients with diabetes had higher, significantly higher, NT-proBNP levels. So as you know, obesity tends to be associated with lower rather than higher natriuretic peptide levels, so here we were finding higher natriuretic peptide levels in a subset of patients who were actually, by and large, more obese. And there was no difference in other things that might have accounted for that difference; natriuretic peptides, for example, there was no difference in the proportion of patients who had atrial fibrillation.
So that was important, and that's also important when we come to think of outcomes because of course the previous studies reporting worse outcomes in patients with diabetes had not adjusted for natriuretic peptides because they by and large weren't available in the large prior trials. So that, of course, could have accounted for some of the worse outcome.
Some of the other things, features, maybe to pick out in terms of baseline characteristics ... one was that these patients had many more features of congestion, so patients with diabetes had more edema, more often had a raised jugular venous pressure and so on, and that's interesting given some of the recent clinical trial data that we might come back to. And even though the [inaudible 00:11:22] class distribution was not different between patients with diabetes and those without, what was very different was health-related quality of life, which was much worse in patients with diabetes than those without. Now you could if you chose to, Carolyn, look at that as saying that physicians weren't assessing worse functional status or symptomatic status in the patients with diabetes, but the patients were certainly self-reporting a much worse health-related quality of life.
So those were the, sort of, clinical characteristic differences. We did, as I said, have an echo-cardiographic sub study. There were 745 patients in total in the trial who had a detailed echo study, and there were perhaps more modest differences than I might have expected (and I'd be interested in your opinion about this) in patients with diabetes. So they had a somewhat greater, statistically significantly greater left ventricular mass, they had increased early diastolic mitral inflow velocity through E, they certainly had increased E over E prime increased left atrial areas, so there was some left ventricular remodeling and there was some evidence of increased left ventricular filling pressure, maybe diastolic disfunction. But the differences were not very striking; they were there, and as I said previously, ejection fraction (which most of us regard as perhaps not a very good measure of systolic function) was similar between the two groups. We didn't look at more sophisticated and [inaudible 00:13:09] measures of systolic functions so those could have been different, we just don't know.
So that's the baseline clinical features and baseline echo-cardiographic findings. And then, of course, we followed these patients for a median of just over four years and what we found was that the cardiovascular and all cause mortality was about twice as high in patients with diabetes as in those without. And if you adjust for conventional clinical variables, including NT-proBNP, which is individually the most powerful predictor of outcome, you only very slightly attenuate that greater risk associated with diabetes. The risk of heart failure and hospitalization was also about doubled in an unadjusted analysis, but that was more attenuated in the adjusted analysis. But you've also got to remember that, of course, the patients with diabetes were not surviving as long, so the very fact that they had a substantially higher risk of heart failure and hospitalization despite a shortened longevity is important.
Then lastly, again I think a fairly unique aspect of this study was that we then added the echo-cardiographic findings into the multi-variable model [inaudible 00:14:33] because it was only a subset of patients in which we had echo-cardiographic measurements. The statistical reliability of this is not as robust as in the main model, but what we saw was that there was more attenuation of the risk associated with diabetes when you added in the remodeling and diastolic dysfunction findings that we saw in the echo-cardiographic sub study. So that's a summary, I think, of the key points.
Carolyn Lam: John, I was really impressed and struck by the consistency of the message, which is what I really appreciated. What you added to the field was this consistent message that the diabetic HFpEF just had more signs of fluid overload in general, be it clinical, be it by NT-proBNP, be it by echo. And I thought that was something you said it was a moderate difference by echo; it was enough to be convincing to me, and I really appreciated that. The fact that adding the echo findings attenuated the significance ... you know we went back and forth about that quite a bit together, didn't we?
John McMurray: We did.
Carolyn Lam: I think at the end it is consistent, it is useful information. It tells me that perhaps some of these outcomes are mediated by this access fluid, to me, at least part of it. And I think that is how we ended up expressing it in the final paper.
John McMurray: I think you are absolutely spot on, Carolyn, because I don't think I had anticipated that the features of congestion would be so different. And you are correct in that, of course, correlates very well with natriuretic peptides, with the left atrial enlargement and so on.
And then of course (and this is clearly extrapolation) but then of course it makes one wonder about some of the trials with diabetes drugs that we've seen. The TZDs, glycosomes, which calls a little bit of fluid retention, of course precipitating heart failure, and then the opposite recently with the SGLT2 inhibitors which of course are diuretics, and those drugs preventing the development of heart failure.
And it does make me wonder if the diabetic phenotype maybe was a little bit of renal dysfunction, some subtle renal dysfunction, is a sodium and water avid phenotype state and that it doesn't take very much to tip those patients into frank heart failure and perhaps we need to think (and I think you might have been alluding to it) think about insuring that we adequately diurese these patients given that in this study where people were supposed to be optimally treated, clearly there was still a lot of evidence of residual fluid overload.
Carolyn Lam: I absolutely agree, and yes you read my mind that I was going to allude to the implications for therapies that have a diuretic effect, you know, like the SGLP2 inhibitors and in fact this was discussed in Brian Lindman's editorial, which is a must read.
Just another question though. What do you think of peripheral mechanisms contributing to all this?
John McMurray: Yeah, obviously there is the kidney aspect that we saw a relatively small difference in estimated GFR. Of course that only tells you one aspect of renal function and the nephron in diabetes may well be sodium avid maybe more likely to retain water. So certainly the kidney as a peripheral mechanism might be very important.
And then of course the blood vessels, I mean there's no question that patients with diabetes have more abnormal endothelial function probably have got enhanced vascular stiffness. And of course we know from a long time ago at least in HFrEF (I'm not so sure about HFpEF) but in HFrEF there's evidence that some of the vascular stiffness you see in patients with HFrEF is actually due to sodium in the vessel wall and there's some beautiful old-style clinical physiology experiments showing that if you diurese patients with HFrEF you restore vasodilation you restore basal motor responsiveness. It could also be true in HFpEF though of course patients with HFpEF and many other reasons to have vascular stiffness.
So yes, peripheral mechanisms may well be important. Your humoral abnormalities may be more pronounced in patients with HFpEF and diabetes compared to those without diabetes. We don't know because I'm not sure that's been measured very often. Certainly natriuretic peptides are, but what about things like the angiotensin system and arginine/vasopressin and the sympathetic nervous system. You know, there's still so much to study looking at patients with heart failure with and without diabetes because they're really quite distinct. And whatever's going on it makes a big difference the way those patients feel, what they can do, and what happens to them.
Carolyn Lam: Yeah, and your study really establishes that. Congratulations once again John, it's just been such a delight chatting with you.
John McMurray: Likewise, Carolyn.
Carolyn Lam: Listeners, you heard it right here on Circulation on the Run. Don't forget to tell all your friends about this podcast and turn in next week!
Dr. 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. Our podcast is taking us to Japan today where we will be talking about aspirin for primary prevention in patients with diabetes. First, here's your summary of this week's issue.
The first study provides insight into the development of neurologic injury in patients with single ventricles undergoing staged surgical reconstruction. In this paper by Dr. Fogel and colleagues from the Children's Hospital of Philadelphia, the authors recognize that single ventricle patients experience greater survival with staged surgical procedures culminating in the Fontan operation, but experience high rates of brain injury and adverse neurodevelopmental outcome. They therefore studied 168 single ventricle patients with MRI scans immediately prior to bi-directional Glenn, prior to the Fontan, and then three to nine months after the Fontan reconstruction. They found that significant brain abnormalities were frequently present in these patients and that the detection of these lesions increased as children progressed through staged surgical reconstruction. In addition, there was an inverse association of various indices of cerebral blood flow with these brain lesions. This study therefore suggests that measurement of cerebral blood flow and identification of brain abnormalities may enhance recognition of single ventricle patients at risk for poor outcomes, and possibly facilitate early intervention.
The next paper uncovers a unique mechanism underlying arrhythmogenesis and suggests that the anti-epileptic drug valproic acid may possibly be repurposed for anti-arrhythmic applications. In this paper by first authors Dr. Chowdhury and Liu and corresponding author Dr. Wang and colleagues from University of Manchester UK. The authors used mouse models and human induced pluripotent stem cells derived cardiomyocytes to discover a new mechanism linking mitogen activated kinase-kinase 7 deficiency with increased arrhythmia vulnerability in pathologically remodeled hearts. Mechanistically, mitogen activated kinase-kinase-7 deficiency in the hypertrophied hearts left histone deacetylase-2 unphosphorylated, and filamin A accumulated in the nucleus, which then formed an association with kruppel-like factor 4 preventing its transcriptional regulation. Diminished potassium channel reserve caused repolarization delays resulting in ventricular arrhythmias, and the histone deacetylase-2 inhibitor, valproic acid restored potassium channel expression abolishing the ventricular arrhythmias. This study therefore provides exciting insights in developing a new class of anti-arrhythmics specifically targeting signal transduction cascades to replenish repolarization reserve, all for the treatment of ventricular arrhythmias.
Does the Mediterranean diet improve HDL function in high risk individuals? Well, the next paper by first author Dr. Hernaiz, corresponding author Dr. Fito and colleagues from Hospital Del Mar Medical Research Institute in Barcelona, Spain addresses this questions. The authors looked at a large sample of 296 volunteers from the PREDIMED study and compared the effects of two traditional Mediterranean diets, one enriched with virgin olive oil, and the other with nuts to a low-fat control diet. They looked at the effects of these diets on the role of HDL particles on reverse cholesterol transport, HDL antioxidant properties, and HDL vasodilatory capacity after one year of dietary intervention. They found that both Mediterranean diets increased cholesterol efflux capacity and improved HDL oxidative status relative to the baseline. In particular, the Mediterranean diet enriched with virgin olive oil decreased cholesterol ester transfer protein activity, and increased HDL ability to esterify cholesterol, paraoxonase-1, arylesterase activity, and HDL vasodilatory capacity. They therefore concluded that adherence to a traditional Mediterranean diet, particularly when enriched with virgin olive oil, improves HDL function in humans.
The final study tells us that among hospitalized medically ill patients, extended duration Betrixaban reduces the risk of stroke compared to standard dose enoxaparin. In this retrospective sub-study of the APEX trial, Dr. Gibson and colleagues from Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, Massachusetts randomized 7,513 hospitalized acutely ill patients in a double-dummy, double-blind fashion to either extended duration of the oral Factor Xa inhibitor Betrixaban at 80 mg once daily for 35 to 42 days, or standard dose subcutaneous enoxaparin at 40 mg once daily for 10 days all for venous thromboprophylaxis. They found that the extended duration Betrixaban compared with enoxaparin reduced all cause stroke by almost one half with a relative risk of 0.56 equivalent to an absolute risk reduction of 0.43 percent and number needed to treat of 232. The effect of Betrixaban on stroke was explained by a reduction in ischemic stroke with no difference in hemorrhagic stroke. The reduction in ischemic stroke was confined to patients hospitalized with acute heart failure or non-cardioembolic ischemic stroke.
This paper is accompanied by an editorial by Drs. Quinlan, Eikelboom, and Hart in which they articulate three reasons that they think these results are important. First, the results demonstrated an unexpectedly high rate of new or recurrent ischemic stroke during the first three months in hospitalized medical patients receiving standard enoxaparin prophylaxis, the rate being even higher in patients presenting with heart failure or ischemic stroke. Secondly, the data demonstrated for the first time that a NOAC reduces the risk of ischemic strokes in patients without known atrial fibrillation. Thirdly, the effects of Betrixaban on stroke were dose dependent, all of the benefits were seen in those who received the 80 mg dose, whereas the 40 mg dose did not provide advantages compared with enoxaparin or placebo. While these results are encouraging, the editorialists also warn that these are based on a post-hoc analysis and should be considered hypothesis generating.
Well, that brings it to the end of our summaries. Now for our feature discussion.
Today our feature discussion focuses on the exciting 10-year follow up results of the Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes, or JPAD trial. I am simply delighted to have with me first and corresponding author Dr. Yoshihiko Saito from Nara Medical University, Japan. As well as a familiar voice on this podcast, Dr. Shinya Goto associate editor of Circulation from Tokai University in Japan. Welcome gentlemen!
Dr. Goto: I am very pleased to have this opportunity. I am always enjoy listening your podcast, and this is very interesting topic of aspirin in prevention cardiovascular event in patients with diabetes, type II diabetes.
Dr. Lam: I couldn't agree more, because the burden of cardiovascular disease globally is actually shifting to Asia, and the burden of diabetes especially, is one of the fastest growing in Asia. So a very, highly relevant topic indeed. Could I start, Yoshi, by asking you: these are the 10 year follow up results, what inspired you to take a re-look at the original JPAD results and to report this 10 year result?
Dr. Saito: The American guidelines said that low-dose aspirin is recommended to the type II diabetes patient for the primary prevention of cardiovascular events who are older than 30 years old, and who are not contraindicated to aspirin. That meant that almost all type II diabetes patients were recommended to low dose aspirin. However, at that time there was no direct [inaudible 00:09:49] evidence for it. So we connected the prospective randomized control trial that examined the effects of the low dose aspirin on primary prevention of cardiovascular events in type II diabetes patients without preexisting cardiovascular disease. The name of this trial, JPAD trial, that stand for the Japanese Primary Prevention of Atherosclerosis with aspirin in Diabetes. We enrolled 2,539 patients who were assigned to the low dose asprin group or the no aspirin group. So we followed them with a median follow up period of 4.4 years.
The results of the original JPAD trial were that low dose aspirin reduced CV events by about 20%, but the reduction could not reach statistical significance. So I don't know the exact reason, but one is the reason is low statistical power, because event rate was about one-third of the anticipated. Another reason is that low dose aspirin really could not reduce cardiovascular events. So we decided the extension of the follow up of the JPAD trial to elucidate the efficacy and safety of long term therapy with low dose aspirin in type II diabetes patients. This extension study was named the JPAD 2 study. We followed them up to the median follow up period of more than 10 years.
In this time the JPAD trial study, we analyzed the patients in a pod protocol method because the randomized control trial was ended after 2008. Finally, we analyzed the 992 patients in the aspirin group, and 1,168 patients in the no aspirin group who retained the original allocations throughout the study period. The primary endpoint were composite endpoint of cardiovascular events including sudden cardiac death, the fatal and the non-fatal coronary artery disease, fatal and non-fatal stroke, peripheral vascular disease, and aortic dissection. This end point is the same as the original JPAD trial. The main results are the primary endpoints, 15.2% of patients occurred primary endpoints in aspirin group, and 14.2% in the no aspirin group occurred in the primary endpoints. So the primary endpoints rate is singular in both groups, with the hazard ratio is 1.14 with a 95% CI is 0.91 to 1.42 with a p value of 0.2 by log-rank test. So the low dose aspirin therapy could not reduce cardiovascular events in the type II diabetes mellitus.
We also analyzed these data by intention to treat analysis, the results is singular. Again, the low dose aspirin therapy could not reduce the cardiovascular event in type II diabetes mellitus. However, I was told the hemorrhagic events, total hemorrhagic events was singular in both groups, but gastrointestinal bleeding of about 2% in the aspirin group but only 0.9% in no aspirin group. That means our gastrointestinal bleeding is doubled in the aspirin group compared with no aspirin group. This is the main outcome of the JPAD and JPAD-2 trials.
Dr. Lam: Thank you so much Yoshi, and really congratulations on such a tremendous effort. I completely applaud the idea of looking at the 10 year follow up trying to address the issue of whether or not it was a lack of power that limited JPAD-1, but what you found really reinforced what you found in JPAD-1, which is low dose aspirin did not reduce cardiovascular events in the diabetic group. They're still huge numbers, I'm so impressed that 85% of the treatment assignment was retained. Then furthermore you even showed increased gastrointestinal bleeding with aspirin. So really remarkable results. Can I just ask, are you surprised by the results, and how do you reconcile it with what was found in the general population studies like the Physician Health Study, or the US Preventive Services Task Force, where they really seem to say that primary prevention aspirin works in the general population when your risk is a certain amount?
Dr. Saito: I think that we studied only the type II diabetes patients, so it is not clear that our results are applied to the general population, but our results is very much similar to the current European guidelines and American guidelines.
Dr. Lam: That's a very interesting point about diabetic versus non-diabetic population and the utility of low dose aspirin. Shinya, you brought this up before. What do you think?
Dr. Goto: For the primary prevention population cohort study, aspirin demonstrated 25% reduction of cardiovascular event. We are not recommending aspirin for primary prevention due to the balance of bleeding and cardiovascular protection, absolute risk. In Yoshi's paper, in patients with type II diabetes aspirin evened that [inaudible 00:16:13], and that is very important message he had shown in this long term outcome randomized trial.
Dr. Lam: Do you think that there are some pathophysiologic differences when you study a diabetic versus non-diabetic population?
Dr. Goto: Yes, that is a very important topic, and we have very nice review paper by Dr. Domenico and Fiorito. In patients with diabetes the platelet time over becomes relatively rapid as compared to general population. New platelets come to blood and COX-1 inhibition by aspirin cannot reach to enough level in diabetes patient. Still, this [inaudible 00:16:57] hypothesis, very interesting hypothesis.
Dr. Saito: I think so, I think so. That review that proposed the same concept, their higher dose of aspirin as possibly effective for diabetic patient.
Dr. Lam: That's interesting. Are you planning any future studies Yoshi?
Dr. Saito: Yeah, maybe two times study.
Dr. Goto: But anyway, the event rate is currently very low than the old [inaudible 00:17:28]. So the sample size should be huge. Huge sample size is needed for the primary prevention setting to analyze the effect of aspirin, so the number needed to treat in the primary prevention setting is more than 1000. If diabetes patient, aspirin is resistant to aspirin so the number needed to treat is getting larger. So the sample size is getting larger and larger. That is not practical to perform that clinical trial.
Dr. Lam: That's a very good point that the contemporary trials like yours are really challenged by the low event rates because of improved preventive treatment across the board like high dose statins, like very, very low LDL targets, and so on. That's a good point. Actually, could I ask both of you gentlemen, and maybe Shinya you can start, can you let us know what is it like to perform such a large rigorous clinical trial in Japan? It must be a lot of effort. Could you give us an idea?
Dr. Goto: In Japan, medical care system is a little bit different from the U.S. Every patient covered by the homogeneous health care system so it means it is rather difficult to conduct a clinical trial. I appreciate the effort by Professor Saito, Yoshi, it is extremely difficult to conduct the study. Japan is relatively small island, patient stick to the clinic so the long term follow up with relatively low follow up can be expected. [inaudible 00:19:15] number of patients is a challenge, and Yoshi did succeed it. We can do that and due to the baseline therapy is quite homogenous, impact of the clinical care like this has very strong impact.
Dr. Lam: Exactly, and I share your congratulations once again to Yoshi for really tremendous effort, important results. Thank you so much Shinya for helping with this paper, and for really highlighting how really important it is. Did anyone have anything else to add?
Dr. Saito: Yes, I have one thinking, in respect to the Japanese clinical trials. I think the Japanese evidence, as derived from Japanese clinical studies is getting better and better in quality. Almost all Japanese clinical trials enrolled only Japanese patients, so the way the Japanese not so good at to organize the international clinical trial because of the, one is the language problem, and the other is funding problem. In Japanese funding agency, the AMED, that is similar to the NIH in United States, but AMED is not so strong as NIH so that they cannot give a bigger budget to the Japanese clinicians. That is another problem to organize a big clinical trial. The funding [inaudible 00:20:49] apprenticeship without holding investigators are very, very important to be better clinical situation in Japan, I think so.
Dr. Lam: Thank you for listening to Circulation on the Run, don't forget to tune in 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 Centre and Duke-National University of Singapore.
Today is special, special, special because here with me is the editor of special populations and that is Dr. Sharon Reimold from UT Southwestern, who is the editor handling the special issue for Go Red For Women.
Dr Sharon Reimold: Thank you, Carolyn. I'm happy to be here.
Dr Carolyn Lam: This is so cool. Just us ladies chatting about issues that we need to be talking about.
Now first of all, this is the first time that Circulation is doing a focus issue for Go Red for Women. Could you tell us a little bit more about that?
Dr Sharon Reimold: Sure. The Go Red for Issue campaign has been around for many years. The editorial staff realized that we really hadn't had an entire issue devoted to cardiovascular issues in women. We decided several months ago to try to make this a reality and asked for submissions of articles and we’re delighted to see the interest that our cardiologists across the country had, as well as across the world, in submitting their research for consideration in this issue.
Dr Carolyn Lam: I know. There are seven original papers. There are review papers. There are research letters. It's an amazing issue.
Dr Sharon Reimold: We had hoped to focus on a lot of different areas in which heart care in women is influenced. We're really quite delighted that we had papers on pregnancy, papers related to strategies to get women involved in trials. We were able to look at novel risk factors in women, and also, have an excellent review about arrhythmias in women versus men that I think everyone will want to take in.
Dr Carolyn Lam: Yeah. Congratulations once again right off, but let's jump straight into this set of twin papers that deal with post MI outcomes and sex differences. There've been quite a number of publications on this. What makes these two papers special?
Dr Sharon Reimold: I think these papers are special because they're trying to think more deeply into why women tend to get re-hospitalized after a heart attack more often and what are the reasons that they're getting readmitted.
For instance, it seems that women, as we know, may get a variety of different symptoms that are their equivalent or anginal equivalent after they've been in the hospital and also before they were in the hospital. I, personally, suspect that when somebody comes to the hospital with chest discomfort and they've recently had a heart attack, then often times, they get readmitted and re-hospitalized.
These papers are starting to look at mechanisms, why this happens. I think this will be the bridge to the point where we figure out what can we about this, to hopefully, make men and women more equal in this regard.
Dr Carolyn Lam: That's so true and well put. I also found very, very interesting and important that paper that really highlighted the importance of coronary flow reserve and microvascular ischemia, not just obstructive disease. Can you say a few words about that paper?
Dr Sharon Reimold: Sure. It's been known for a long time that if you perform catheterizations on men versus women with similar presentation ... Women may not have as much obstructive disease. This particular manuscript explores coronary flow reserve and identifies this as being part of the difference between men and women in that regard. That, obviously, could have important implications for the clinical care of these patients.
Dr Carolyn Lam: I like that. All these papers really took what we may have known a bit before, but took them to a deeper level and in a very novel way. So important. You mentioned some of the novel aspects that were also explored in the issue, the pregnancy related factors, in fact, novel risk factors that we should be taking note of in women. Do you want to comment on a few highlights?
Dr Sharon Reimold: The relationship of pregnancy complications to long term, both maternal and offspring health has been around for a while, but really, we don't know very much about it. We, certainly, have known previously that women with preeclampsia, or those who have significant hypertension, or diabetes in pregnancy may have later problems when they are in middle age or older.
What we are learning from some of these new entries into the research domain is that women who have premature labor and delivery are also at risk for having complications, and this sort of fits in the middle. It's not just preeclampsia, or hypertension, or diabetes. It's that you delivered earlier. Then moreover, we have a couple of research focused letters that describe arrhythmias in pregnancy and what happens to those women during pregnancy. I think we all have seen young women come in and have symptoms, but we really don't know what their outcome has been because any single physician probably just sees a few of them. This highlights arrhythmias as a issue in that population.
We also looked at other articles that focused on other risk factors for heart disease, ranging from breast arterial calcification to traditional biomarkers that we may be drawing in hospital, BMP, troponin, and such. There's a nice manuscript that focuses on hormone changes in women and how they're associated with development of cardiovascular disease. So a fairly broad look at a variety of different risk factors that we don't think about when we're simply asking, "How old are you? What's your blood pressure? What's your diet? Do you have diabetes, and do you have lipid disorders?"
What I would hope that we would get out of this is to open all of our minds and our approaches to patients to think about asking about their pregnancies, did they have any complications, figuring out if they have any hormonal issues, and then being free to consider whether or not the woman that you have in front of you actually has obstructive disease or perhaps has issues with abnormal flow reserve.
Dr Carolyn Lam: Exactly. I would, actually, add to that, also, looking at our commonly used cardio metabolic biomarkers with the lens of realizing that there are important sex differences in all these biomarkers. That was a very nice paper, corresponding author, Dr. James de Lemos. All these papers are just so practical.
I'm actually going to switch tracks now, Sharon, because I really want to talk about this final paper. All I need to do is read the title of the editorial and it’ll be self-evident. "Women are less likely than men to be full professors in cardiology. Why does this happen and how can we fix it?" I love that you invited this editorial. Could you tell us a bit about the paper that sparked this editorial and your thoughts on this?
Dr Sharon Reimold: Yes. The original article has as its first author, Dr. David Blumenthal. It's an article that's one of a series of manuscripts that looked at academic cardiologists and looked at faculty rank where they were able to gather data on sex differences, clinical productivity, research funding, publications, et cetera. They have looked at other disciplines other than cardiology, but this particular manuscript focuses on cardiologists. What it demonstrates is that we are getting, perhaps, a little bit more women in at the assistant professor level, but there’s still a significant lag at the full professor level.
In fact, in many centers if you query development offices, there's probably at least a seven year lag between women and men in terms of making it through the whole spectrum. While perhaps, this is not new conceptually, I think it does quantitate it for us and it highlights the concept that this is an issue now, similarly to what it was 25 years ago when I was a cardiology fellow.
The interesting compliment to this is the editorial by Dr. Karns and Dr. Bairey Merz which tries to go into why does this happen and how can we fix it. They took a very academic approach to their editorial in terms of looking at data and then talk about implicit bias and how even a very small degree of implicit bias will cause men to be promoted, perhaps more in a faster manner than in women, and also bring up some things we don't even think about. One of the best ones was the concept that you advertise for a new position as a cardiologist. If you advertise for someone and you list the skills you want and what you want to build, then that's a more gender neutral way to approach a job. If you advertise for a dynamic, outgoing, I don’t know, vigorous sort of person, and there are ads out there that read like that, you are, inadvertently, advertising for a man, most of the time.
Dr Carolyn Lam: Male characteristics.
Dr Sharon Reimold: Yeah. They talk about that. Then they obviously end up with how can we fix it? I think that's a real challenge.
There are some data within the field of literature for development that suggest that mentoring and coaching are important, but that they don't necessarily push people up the ladder very rapidly. There are some places, for instance, our University of Texas system now that is very interested in the concept of sponsorship. That someone sponsors another individual, could be male or female, to get involved and pushes them ahead, not pulls them, so that they have opportunities for faster career development and success. In any event, I think this compliment of paper and editorial really highlights an issue that, while not necessarily affecting female patients, certainly affects cardiology as a destination career.
Dr Carolyn Lam: I agree. I think part of the how to fix it is simply by being aware and acknowledge the issue. That is exactly what we’re doing in these papers. I love that they are academically written. Like you said, you read a lot about these gender biases in the popular press, but it's so refreshing to see it addressed in an editorial, in a beautiful paper, in circulation.
Sharon, congratulations on just this excellent, excellent issue. Is there anything else you may want to highlight about the issue?
Dr Sharon Reimold: I think that's the major thing. I think we moved a long way from the beginning of Go Red For Women as a campaign where we really wanted patients to be aware that hypertension or elevated cholesterol levels were an important issue. I think now is a time where we move forward. We’ll learn more about differences between men and women and we figure out how we can treat or account for these differences as we strive to make health care for all and cardiovascular care for all improve over time.
Dr Carolyn Lam: Thanks Sharon. Everyone of you listening to this, go pick up this issue. I'm sure we've peaked your interest.
Thank you for listening to Circulation On The Run. Don't forget to tune in next week.