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. Our feature paper this week tells us more about aortic wall inflammation, and how this predicts abdominal aortic aneurysm expansion, as well as need for surgical repair. Much more, right after these summaries.
Our first original paper sheds light on a novel mechanism for adult cardiac regeneration. This is a paper from first authors Drs. Wang, and Lee, and corresponding authors Dr. Chen, Houser, and Dr. Jeng from Third Military Medical University from Chongqing, China.
In an elegant series of experiments using mouse models, the authors showed that mature adult cardiomyocytes could re-enter the cell cycle and form new cardiomyocytes though a three-step process: of dedifferentiation, proliferation, and redifferentiation. Intercellular calcium signals from neighboring functioning cardiomyocytes through gap junction induce the redifferentiation process. Furthermore, they showed that this mechanism contributed to new cardiomyocyte formation in post MI hearts in mammals. In summary, this study contributes to our understanding of adult cardiac regeneration and could lead to novel strategies to repair the injured heart.
The next paper provides mechanistic data that may explain why thrombotic complications are more prevalent in patients with diabetes, and why some anti-platelet drugs may have limited efficacy in patients with diabetes. In this paper by first author, Dr. Hu, corresponding author Dr. Ding, and colleagues from Fudan University in Shanghai, China, the authors show that platelets of patients with Type 2 diabetes express high levels of activated P2Y12 receptor.
The P2Y12 inverse agonist inhibited P2Y12 activity of platelets from diabetic patients and rats, more than Cangrelore, leading to a stronger in-vivo antithrombotic effect in thrombosis rat models with diabetes. Increased platelets P2Y12 receptor expression in diabetes was mediated by a high-glucose reactive oxygen species, NF-kappaB pathway. In summary, platelet P2Y12 receptor expression was shown to be significantly increased, and the receptor was constitutively activated in Type 2 diabetic patients, which contributed to platelet hyperactivity, and limited anti-platelet drug efficacy in Type 2 diabetes.
The next paper tells us that the majority of cardiovascular disease events are now occurring amongst adults with a systolic and diastolic blood pressure of less than 140 over 90 millimeters mercury. Prior data have shown us that the majority of incident cardiovascular disease events occurred among U.S. adults with higher systolic and diastolic blood pressures of above 140 over 90. However, over the past several decades, blood pressure has declined and hypertension control has improved. Thus, in the current study, Dr. Tajeu and colleagues from Temple University College of Public Health in Philadelphia estimated the percentage of incident cardiovascular disease events that occur at blood pressures below 140-90 in a pooled analysis of three contemporary U.S. cohorts: the Reasons for Geographic and Racial Differences in Stroke, or, REGARDS study, the Multi-Ethnic Study of Atherosclerosis, or MESA study, and the Jackson Heart study.
In these three U.S. cohorts that enrolled after 2000, more than 60% of incident cardiovascular disease events occurred among participants with blood pressures below 140 over 90 millimeters mercury. In the 2001 to 2008 National Health and Nutritional Examination survey mortality follow-up study, 58% of cardiovascular disease stats occurred in U.S. adults with blood pressures below 140 over 90. Among participants taking anti-hypertensive medication, with blood pressures below 140 over 90, only one-third of those who are eligible for starting treatment were taking one, and approximately 20% met the SPRINT eligibility criteria.
In conclusion, while higher blood pressure levels are associated with increased cardiovascular disease risk, in the modern era the majority of incident cardiovascular disease events occur in U.S. adults with blood pressure below 140 over 90. Although absolute risk and cost effectiveness should still be considered, additional cardiovascular disease risk reduction measures for adults with blood pressure less than 140 over 90, and at high risk for cardiovascular disease, may be warranted.
Well, that brings us to the end of our summaries. Now, for our feature discussion.
Dr. Carolyn Lam: On today's podcast discussion, we will be talking about aortic wall inflammation as a possible functional, or biological, imaging bio-marker that may add to the usual structural measurements of size that we use to predict abdominal aortic aneurysm expansion and rupture. Now, to discuss this very important paper, we have the corresponding author, representing the MA3RS study investigators, Professor David Newby from the Center for Cardiovascular Science in Edinburgh, as well as a familiar voice now, Dr. Joshua Beckman, associate editor from Vanderbilt University. Welcome, gentlemen.
Professor David Newby: Hi, there.
Dr. Joshua Beckman: So great to be here again, thanks for having me.
Dr. Carolyn Lam: So great that you're back again, Josh! But David, let's start with you. Could you just summarize what this trial was about and your main findings?
Professor David Newby: Sure, so this was a major clinical trial that we undertook in the U.K. and Scotland. We approached patients who were in a surveillance program who had an abdominal aortic aneurysm, and we asked the question, "Is there anything we can do better than just serial ultrasound measurements that currently are stunned to this care?" So, in Edinburgh, we developed a technique using ultrasmall, superparamagnetic particles of iron oxide, which is a bit of a powerful ... so we shortened that to USPIOs; these are really small iron particles that are so small they can cross vascular spaces and they get gobbled up by tissue resident macrophages, and then causes a signal that we can detect on magnetic residents' scanning MRI.
So we were really asking the question, "Can we do better than ultrasound by using what we call USPIO-enhanced MRI?"
Dr. Carolyn Lam: So a biological or functional imaging parameter versus just structural. And so, what were your main findings?
Professor David Newby: We recruited around 361 patients and ultimately 341 went into the trial because of various exclusions, et cetera. And we followed these patients up for, on average, around three years. And so we were following it up every six months with ultrasound, with other various assessments, and ultimately what we found was that the USPIO-enhanced magnetic residents' scan was positive in around half of patients, and in those patients that took up the USPIOs in their abdominal aortic aneurysm wall, those patients, their aneurysms expanded quicker. So rate of expansion was higher, and they went on the have the primary event of either elective repair, or rupture. And, don't forget, that the clinicians who were looking after these patients, they didn't know the results of the MRI so it didn't influence their clinical minds, when this was completely independent of the clinical team.
So, for the first time, we demonstrated that imaging or tracking macrophages in the abdominal aortic wall could, indeed, predict both disease progression and clinical outcome.
Dr. Carolyn Lam: And Josh, you know, no one can say it better than you: could you just describe what we discussed as the editors about the significance of such a finding?
Dr. Joshua Beckman: I think there's a few things to take home from these three that are really incredible. First, David, were you surprised at the concordance between the USPIO-enhanced imaging and smoking, or was that something that you expected?
Professor David Newby: That was a big surprise. That was, actually, as we discussed in the manuscript, quite an interesting finding, and as always with an interesting find, we dig around in the background, and it actually gets more and more exciting and plausible because of the mechanistic work that we'd seen in the pre-clinical science that preceded our trial. So yes, it was a surprise, but actually the more we got into it, the more it made sense.
Dr. Joshua Beckman: One of the other things that I think is really important to talk about is how you get this study done, and one of the things I found incredibly impressive ... I am unaware of any other multi-sensor MRI study like this. How did you organize this amongst the different institutions?
Professor David Newby: It can be a bit of a challenge. So I've done quite a few multi-sensor trials in Scotland, and imaging trials, and the community in Scotland actually is very, very supportive and we got a good network of folks. So the three centers are actually two imaging centers: one in Edinburgh one in Glasgow, a further recruitment center in a city just in the center of Scotland, Sterling. And the patients ... we were able to obviously make sure the scanners did the same protocols; fortunately, they were the same scanner, make and model. So that all obviously helped, but we had a lot of inundation, phantom work, to make sure both centers got things right.
But there was a huge motivation to get this done, and I'm indebted to Charles Riditi and Colin Barrie in Glasgow for doing the, and supporting the, imaging work, and also a medical physicist here in Edinburgh, Scott Semple, who'd done a lot of the work to get this to happen. So there's a teamwork in Scotland and the NHS, where the access to patients are in the screening program as well, which made recruitment really well and very efficient. And we started exactly to target, which is pretty unusual in clinical trials, often takes longer to recruit patients, but it was a great team effort. The imaging quality, we checked, verified, centrally read, and it was really good to see it delivered in that way.
Dr. Joshua Beckman: Do you think that agent, the iron oxide particles, is going to be the contrast agent, I guess, of the future, or do you think because it is now so consistent with smoking, it's gonna be more of an investigational tool?
Professor David Newby: So there's a couple of things to say here on ferumoxital, which is the USPIO we used. It's currently licensed in the U.S. for the treatment of anemia and chronic renal failure, but it can also be used as an imaging agent and actually this, I think increasingly, might have a role; not just in aneurysms, but elsewhere. So the first thing you can do is actually do angiography with this agent. [Obviously gadolinium is getting a lot of press at the moment, with problems with warnings coming out, of residual brain deposition, and so on. With the USPIOs, you can use this in renal failure patients, so again, another contraindication for us to concern about: NSF in renal failure patients. So actually, for angiography, I think it's going to have an increasing role.
For imaging of inflammation, we've previously demonstrated that you can track inflammation post-myocardial infarction, so you can see air is lighting up following myocardial infarction. We have some papers out on that, and I think, if you are in the business of looking at cellular inflammation, macrophage trafficking, then this technique really can be helpful.
When we come to aneurysm studies, I think it is less clear because ultimately, doing a quick ultrasound, in fact can give you the information together with all of the clinical risk factors, like smoking, and you get to the same end point without doing the MRI. Then, clearly, it's not going to be that impactful. Having said that, I think sometimes we will have patients who've got all this information and we're not sure which way to go. So I think it could be used as an almost umpire test, if you're not sure whether to proceed with surgery or not. And I think, also, if we discover new agents that are anti-inflammatory that may impact on disease progression, with a normal therapy, then clearly this might be a good buyer market to use in future therapeutic trials.
Dr. Joshua Beckman: Yeah, I actually see a huge potential for the testing of new agents, to see whether or not it reduces the inflammation that's associated. I'm gonna ask you a theoretical question, if that's okay with you. Part of the inflammatory process in the aneurysm is based on oxidative stress, but I've always wondered if you provide more oxygen, which may enhance the oxidative stress reaction, are you actually worsening the reaction at the time you're doing the study? Is that possible, or am I just concerned about nothing and making it up?
Professor David Newby: Well, obviously your [inaudible 00:13:19] stressors is important in all of cardiovascular disease, and if you increase oxygen supply, maybe you indeed induce more oxidative stress. In the context of an aneurysm, often there's quite an hypoxic state in the aneurysm wall, because obviously the intraluminal thrombus can buffer the wall itself from it, obviously the vasovasorum come in, but they may not be as efficient in doing that. Some of the areas that we're seeing light up probably are quite hypoxic, so they'll be in an oxygen-deprived state. So I think that needs to be put in the balance, too, and there has been some suggestion that iron particles can increase oxidative stress, and it has been suggested maybe harmful; we've not seen that, we've had absolutely no adverse reactions at all in all of our patients. We had one patient whose blood pressure fell a little bit, but we didn't have to medically intervene at all, so it was just observed and it passed; of course it might be due to many things.
We've also studied this in patients with myocardial infarctions, I've said, also bypass surgery, people who've had bypass surgery. We've also published on using these agents there, and again, we've seen absolutely no adverse reactions. And you would've thought, in the context of those situations, if you were going to see an adverse effect you would've seen it behind.
Dr. Carolyn Lam: David, I've got a question for you. I think you mentioned, a little bit earlier, that end of the day this enhanced MRI did not improve the risk stratification beyond the current predictors of clinical outcome in abdominal aortic aneurysms, but what are the next steps for you?
Professor David Newby: There's a couple of things, which we've been thinking through. Firstly, I think the primary end point of the trial was mostly driven by repair, and when we looked at the emergent events, so dying, and rupturing, the signal got stronger and very close to statistical significance. And obviously when you've got a population of patients whose elective surgeries mostly dominated by the ultrasound scan decision, therefore makes it difficult to prove, on top of that, the MRI will have value. So it's quite high, and on a difficult bar to cross, so some of the thoughts we've had are thinking about predicting rupture, rather than repair. And there will also be potential for actually doing a trial, where we actually base decisions on the aneurysm, and if you've got an intermediate category of patient, where you're not sure which way to go, those patients you then do use as an arbiter, and that might have, therefore, proof or value for it.
And the final area that we're probably thinking about exploring is, "Okay, paths for macrophages." Is there other pathophysiological processes that we might want to explore with other agents, that might predict aneurysm growth and rupture even stronger, and macrophage inflammation? So those are some of the thoughts that we've had about where the next steps will be.
Dr. Joshua Beckman: This is an incredible amount of work and I always think it's important to make clear to everybody who's listening to this podcast that, even though we may not all do the same kinds of research, it needs to be made clear that having a multi-sensor study in this topic, with this technique, is incredibly impressive. And the physiology that was brought forth, in addition to the clinical stuff that we just heard about, I think is what makes this worthy of a podcast.
Dr. Newby, thanks so much for participating.
Professor David Newby: Thank you so much, that's very kind. And just to reiterate, it has been a long journey and a huge effort, but we're reaping the rewards now, and it's nice to see the data being published in circulation.
Dr. Carolyn Lam: Gentlemen, it has been so wonderful having you here to discuss this. Thank you so much for your time.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. And Dr. Carolyn Lam, Associate Editor from the National Heart Center, and Duke National University at Singapore.
What is the effect of obesity and underweight status on perioperative outcomes of congenital heart operations?
Our feature paper this week sheds light from the Society of Thoracic Surgeons Database. More soon, right after these summaries.
The first original paper highlights the role of micro RNAs in metabolic remodeling and heart failure. As a reminder, micro RNAs are small, noncoding RNAs important in post transcriptional modification and influencing many cellular processes simultaneously.
First author, Dr. Heggermont, corresponding author, Dr. Heymans, and colleagues from Maastricht University in the Netherlands use mice subjected to pressure overload by means of endotension to infusion or transverse aortic constriction. They show that micro RNA 146A was up regulated in whole-heart tissues in these murine pressure overload models, as well in left ventricular biopsies of aortic stenosis patients. Over expression of micro RNA 146A in cardio cardiomyocytes provoked cardiac hypertrophy and left ventricular dysfunction in vivo, whereas genetic knockdown or pharmacological blockade of micro RNA 146A blunted the hypertrophic response and attenuated cardiac dysfunction in Vivo.
Mechanistically, micro RNA 146A reduced its target dihydrolipoyl succinyltransferase or DLST, a mitochondrial protein that functions as a TCA cycle transferase. DLST protein levels were reduced in pressure overload mice, while they were partially maintained in micro RNA 146A knockout mice. Furthermore, overexpression of DLST in wild type mice, protected against cardiac hypertrophy and dysfunction in Vivo. Thus, micro RNA 146A and its target DLST are important metabolic players in LV dysfunction. These results also opened the door to novel therapies to treat metabolic disturbances and improve energy efficiency of a failing heart.
Program cell death is critically involved in ischemic cardiac injury, pathologic cardiac remodeling, and heart failure progression. Our next paper sheds light on the regulatory mechanisms of necroptosis and its significance in the pathogenesis of heart failure. Using genetic mouse models, first authors Dr. Guo and Yin, corresponding author Dr. Liu, and colleagues from University of Washington in Seattle, identified a critical role for a tumor necrosis factor receptor associated factor 2 or TRAF2 in myocardial survival and homeostasis by suppressing necroptosis.
The authors delineated an important TRAF2 mediated NF-KB independent pro-survival pathway in the heart by suppressing necroptotic signaling. They identified novel molecular mechanisms whereby TRAF2 suppressed TNF receptor 1 mediated, receptor interacting protein 3 dependent necroptosis, which is critical for myocardial survival and homeostasis. Thus, this finding suggests that the necroptosis suppressing TRAF2 signaling pathway and its effectors may serve as novel therapeutic targets for pathologic cardiac remodeling and heart failure.
Our next paper tells us that cerebral hyperperfusion may be associated with accelerated cognitive decline and an increased risk of dementia in the general population. First author Dr. Walters, corresponding authors Dr. Ikram, and colleagues from Erasmus University Medical Center in Rotterdam, The Netherlands, measured cerebral blood flow by 2D phase contrast MRI in non-demented participants of the population based Rotterdam study. A 4,759 participants with a median age of 61 years, and a median follow up of 6.9 years, 123 participants developed dementia.
Lower cerebral perfusion was associated with higher risk of dementia and this risk was even higher with increasing severity of white matter hyperintensities on MRI. At cognitive reexamination after an average of 5.7 years, lower baseline perfusion was associated with accelerated decline in cognition, which was similar after excluding those with incident dementia, and again, most pronounced in individuals with higher volumes of white matter hyperintensities.
Thus, lower cerebral perfusion was associated with accelerated cognitive decline and increased risk of dementia in the general population. This association was modified by hypertension and cerebral small vessel disease, possibly reflecting impaired arteriola and capillary function. This paper calls for further long term study and evaluation of optimizing cerebral perfusion as a means to prevent cognitive deterioration, for example, in patients with heart failure or carotid artery stenosis.
Well, that wraps it up for our summaries. Now for our feature discussion. For today's feature discussion, we will be looking at data from the Society of Thoracic Surgeons Database. This time looking at the effect of body mass index on perioperative outcomes of congenital heart operations in children, adolescents, and young adults. To discuss this, we have none other than the first and corresponding author, Dr. Michael O’Byrne from Children's National Medical Center in Washington D.C., as well as Dr. Naveed Sattar, Associate Editor from University of Oxford. Welcome gentlemen.
Dr Michael O’Byrne: Good morning.
Dr Naveed Sattar: Good morning.
Dr Carolyn Lam: Michael, we know that extreme body mass indices, very high or very low, has been associated with increased risk of at first, perioperative outcomes in mainly older adults undergoing cardiac surgery. We also know about the obesity paradox in conditions like heart failure, so why was it important to look at this specific group of patients? Congenital heart patients and children, adolescents, and young adults?
Dr Michael O’Byrne: Yeah, I think that as a pediatric cardiologist, a lot of the data that we use to guide our management is extrapolated from adult studies. However, in this particular case, it wasn't clear necessarily that adult data would necessarily be applicable to children and adolescents and young adults. We are aware that there are epidemiologic trends that congenital heart disease population ages and there are also in increasing problems of obesity among children in the United States.
The convention wisdom among surgeons in the United States is that obesity would increase perioperative risk and the thought is that some combination of exposure to hypertension and diabetes and peripheral vascular disease might impede wound healing and that body habit as itself might be a risk for the technical approach in wound healing. Acknowledging that there's a lot of evidence both for extreme BMI being a risk in surgical patients and adults, but also the idea that obesity paradox might be important in children because the biological mechanisms might be different.
Children themselves are exposed, their sort of dose response or dose exposure is less, they're younger, and so haven't been obese for a prolonged period of time, so that the integrated effect of having diabetes, hypertension, and obesity might be less. At the same time, we also acknowledge that in children with heart disease, we have congenital cardiac disease, the same issues with cachexia and frailty are present. i.e. that children with very low body mass index might be assigned to their own medical frailty, or a part of a heart failure cachexia syndrome.
One of the challenges in dealing with children with congenital heart disease, however, as you know is that its rarer than cardiac disease of the aging and additionally, that the population is very heterogenous in terms of the actual defects that are present and the surgeries that are performed. It was relevant to look and see over a wide range of sort of technical complexity surgeries with a wide range of sort of intrinsic preoperative risk of perioperative outcome, whether or not BMI would be associated with an adverse outcome. Either operative mortality in this case, or a composite outcome of mortality, major adverse events, and wound infection.
Dr Carolyn Lam: Wow, that makes a lot of sense and congratulations. This is not just the first, it's huge and really comprehensive. Could you just tell us a little bit more about what you did and what you found?
Dr Michael O’Byrne: I think as this point, I'd have to acknowledge that the challenges that we described in terms of both a sample size and in terms of getting a representative sample, is a constant challenge in our field and we have to give credit to my co-authors Marshall and Jeff Jacobs for their work in developing the collaboration that allowed for the STS Congenital Heart Surgery Database to exist. Also, on top of shepherding the database, their research, along with the people at Duke Clinical Research Institute, they've developed a robust risk stratification model for mortality that we utilize as part of this study. Without that, this would be really be very challenging.
What we did is performed an observational cohort study using the STS Congenital Heart Surgery Database to look at the risk of perioperative mortality and composite outcome in patients undergoing surgery in the United States between 2010 and 2015. We looked at both the actual events, the sort of observed events, in terms of mortality and adverse events, and then created multivariate models to adjust for the known covariance.
We hypothesized that extreme BMI, either very high or very low, would be associated with increased risk of mortality and increased risk of that composite outcome. What we found that operative mortality and that perioperative adverse events occurred more frequently in obese and severely underweight subjects. However, because they have an unequal distribution of potentially important covariance, we used multivariate modeling to adjust for those covariance.
Our multivariate models for death, however, the severely underweight subjects had an odds ratio of 1.4 and obese subjects had an odds ratio of 1.3, but neither was specifically significant in that context. We sort of anticipated that with a possibility given the very low event rate. That's the reason we've used a composite outcome, a higher event rate.
For that composite outcome, in both different versions of the multivariate model that we used, the severely underweight subjects had an odds ratio of 1.5, underweight subjects had an odds ratio of 1.3, and obese subjects had an odds ratio of 1.2. An increased risk in all three of those populations of interest relative to normal weight or just overweight subjects.
Dr Carolyn Lam: We're always saying that at circulation we do want to publish papers that have direct and important clinical implications, so Naveed, could you share some thoughts on what this means clinically?
Dr Naveed Sattar: Yeah, I think they went through the review process and I think the paper was very well written. I think Michael and his colleagues clearly understood the strength and the limitations of the data so that you can only ever itself prove associations here and therefore, clinically when we push them on trying to make clinical inferences, I think clearly they recognize that once they find associations between obesity and adverse outcomes and underweight.
What they need to do next, now this is a paper that then leads you to think, "Well actually, I need to do some clinical trials to prove that module ..." You're preventing these outcomes or in very under knowledge where they're actually increasing the BMI but improving their nutrition, cannot also improve outcomes following surgery. Now those are tough things to do. Michael, what do you think from some of the clinical inference? My inferences were the associations were there, particularly for the normal [inaudible 00:12:35] outcomes, but actually to prove that, to make a difference, you probably might need to do some intervention trials or is that how you take it as well?
Dr Michael O’Byrne: I agree with you 100%. I think that as an epidemiologist, I think that what we see in an observational study like this is an association. The two next levels of research that are necessary at this point are to see whether or not in this population BMI is a modifiable factor in the short run before surgery, or even in the long run. And the second question to answer is whether those adjustments in BMI, if they are achievable, affect outcome with surgery. Absolutely.
It's a tremendous challenge, both logistically in organizing a study, and honestly, in terms of capturing a cohort that would be large enough, given that this is almost 100% of the surgeries that occurred over a six year period in the United States.
Dr Naveed Sattar: I looked at it and thought, "Well, the mortality association once you adjusted were not quite significant but are there any individuals you would not do surgery on based on their BMI based on these results?
Dr Michael O’Byrne: The motivation for the study is exactly to try to begin to shed light on that kind of question. I think that it might be what I would call a tiebreaker potentially, if you have a situation where a patient is near meeting criteria but isn't quite at a place where you need to do surgery at that point. It might dissuade you from proceeding immediately potentially pursuing a course that might adjust their BMI in the correct direction.
At the same time also, in a patient who's underweight particularly to evaluate whether their medical regimen has been optimized and if there are other residual lesions that can be addressed in a non-surgical or medical fashion.
Dr Naveed Sattar: I suppose the other trick with this type of research research is always trying to make sure that people understand these are the associations and not trying to attribute causality because it's always physical, isn't it? But I think you and your team did that very well and I'm sure we had a back and forth with review but I think your discussion section, your limitation section, is beautifully written and covers those kinds of caveats, which I think is important as well.
Dr Michael O’Byrne: I thank you for that. That's very complimentary and we certainly strived for that, but I think that you as an editor, and also in terms of the reviewers also, were very helpful in that sort of collaborative process to try to make sure that we're communicating it. It's not always clear in a project that takes months and years to finish when you're writing it necessarily, you may be constantly aware of trying to be clear in your communication but it's also helpful to have a reviewer from the outside carefully read the study.
Dr Carolyn Lam: That's wonderful and Michael, may I just join Naveed in congratulating you on beautiful paper? And maybe just one other little question, did you have any insights into the mechanisms of increased risk for composite events in the extremes of BMI?
Dr Michael O’Byrne: I think it's an important question. There's been a tremendous amount of research in adult cardiac disease about whether it is the BMI as a steady state or BMI changes immediately before and after surgery that are relevant in this case. From this kind of observational study, it's very hard and very challenging to try to make any sort of inferences about the causes. It would be an important part of any study moving forward to include ways to investigate that, and honestly, as an interventional cardiologist and epidemiologist, I probably would defer to Naveed, he might have more cogent and logical ideas about that than I do.
Dr Naveed Sattar: We've had lots of research from a whole variety of researchers. We all understand it's finally serious but recognize it's difficult, so one of the ways moving forward and I think Michael and his colleagues have this is if you have serial BMI data prior to surgery, that could try and inform on reverse causality because of the low BMI, but in terms of the mechanisms, remember these are associations, but I think mechanisms are well covered if you are obese and clearly you have risk factors for death, across the vasculature, across the cardiac functions, across the whole variety of things.
We know those mechanisms, question is, to what extent are they actually operating and causing increased risk in the surgical arena and that's a really tough ask. I think people can come up with a multitude of mechanisms. I think the key things, like this particular paper, is that there are potential mechanisms but these are associations ... Look, this is what we found, and clinically now we need to try and address this within the following types of interventions or at least provide some guidance to colleagues and clinicians.
Exactly as Michael says, if there is somebody who is approaching surgery whose quite obese, perhaps they should try and intervene to try and lessen their weight for a short period of time prior to [inaudible 00:17:07], you know what happens. It would be nice to do some big trials but I think doing trials in this area is going to be really tough, but with imagination, with good collaboration across centers, trials are not impossible. I think they can be done.
Dr Michael O’Byrne: Naveed, I think, actually articulated what I think is both the difficulty of doing that trial but also the importance of it. I think that looking at ... In these databases, we don't have a serial BMI and I think that's an important missing piece of information that we tried to address in our discussion and I think it's something that would be really valuable moving forward. And certainly testing interventions, whether they're medical, interventional, or surgical, to help these patients who are obese either lose or maintain an appropriate weight is the next step.
On the converse side, this research highlighted to me the prevalence of chachectic or underweight patients in our population and it's something that outside of the infant period, we don't necessarily think about tremendously and we don't think about it as a modifiable factor. I think that's another group of patients who also deserve some attention.
Dr Carolyn Lam: Listeners, you've been listening to Circulation on the Run. I'm sure you learned a lot as I did. 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. Our podcast today highlights an important perspective piece on charting a future together and turning discovery science into cardiovascular health. You don't want to miss this, coming up right after these summaries. The first original paper tells us about the importance of changes in exercise capacity following transcatheter aortic valve replacement or TAVR.
First author, Dr. Altisent, corresponding author, Dr. Rodés-Cabau, and colleagues from Quebec Heart and Lung Institute in Canada studied a total of 305 patients undergoing TAVR with baseline and six month followup exercise capacity assessments by six minute walk tests. They found that close to one-third of patients undergoing TAVR failed to improve their exercise capacity despite an optimal hemodynamic result post-procedure.
Factors associated with a lesser exercise capacity improvement included patient characteristics such as older age, female sex, non-cardiac comorbidities, such as chronic obstructive lung disease, peripheral artery disease and bleeding episodes resulting in reduced hemoglobin levels. Importantly, the absence of an improvement in physical performance at six months post-TAVR was an independent predictor of mortality and adverse cardiovascular outcomes during the ensuing four years and particularly among patients with a greater impairment of exercise capacity pre-TAVR.
Thus, implementing exercise capacity assessment pre and post-TAVR may help to improve patient risk stratification and augment the accuracy of the prognostic information given to patients, helping to identify those requiring more intensive followup assessment. The next study provides mechanistic insights into the adverse health outcomes associated with particulate matter exposure in the air. First author, Dr. Lee, corresponding author, Dr. Kahn, from Fudan University in Shanghai, China and colleagues conducted a randomized double-blind crossover trial in 55 healthy college students in Shanghai. Real and sham air purifiers were placed in participant's dormitories in random orders for nine days with a 12 day washout period.
Serum metabolites were quantified using gas chromatography mass spec and ultra-high performance liquid chromatography mass spec. They found that higher particulate matter exposure led to a significant increase in cortisol, cortisone, epinephrine and norepinephrine. Between treatment, differences were also observed for glucose, amino acids, fatty acids and lipids. They also found that higher blood pressure, hormones, insulin resistance and biomarkers of oxidative stress and inflammation were present among individuals with higher exposure to particulate matter.
Thus, this study showed that activation of the hypothalamus-pituitary-adrenal and sympathetic-adrenal medullary axis may contribute to the adverse cardiovascular and metabolic effects of particulate matter exposure in the air. In China, indoor air purification may be a practical way to reduce personal exposure to particulate matter. The next study shows that N-acetylcysteine may be new effective thrombolytic treatment. First author, Dr. Lizarrondo, corresponding author, Dr. Gauberti and colleagues from Inserm, France hypothesized that N-acetylcysteine might cleave the von Willebrand factor multimers inside occlusive thrombi, thereby leading to their disillusion and arterial recanalization.
To test this hypothesis, the authors used experimental models of thrombotic stroke induced by either intra-arterial thrombin injection or ferric chloride application followed by measurement of cerebral blood flow using a combination of Laser Doppler Flowmetry and magnetic resonance imaging. They showed that intravenous and acetylcysteine administration promoted lysis of arterial thrombi that were resistant to conventional approaches such as recombinant TPA, direct thrombin inhibitors and anti-platelet treatments. Furthermore, through in vitro and in vivo experiments, they provided evidence that the molecular target underlying the thrombolytic effects of N-acetylcysteine were principally the von Willebrand factor that crosslinked platelets in arterial thrombi.
Co-administration of N-acetylcysteine and a non-peptidic GP2B3A inhibitor further improved its thrombolytic efficacy essentially by accelerating thrombus disillusion and preventing rethrombosis. In a new large vessel thromboembolic stroke model in mice, this co-treatment significantly improved ischemic lesion size and neurological outcomes. Importantly, N-acetylcysteine did not worsen hemorrhagic stroke outcome suggesting that exerted thrombolytic effects without significantly impairing normal hemostasis. Thus, in summary, N-acetylcysteine was shown to be an effective and safe alternative to currently available anti-thrombotic agents to restore vessel patency after arterial occlusion.
The clinical implications of the study are wide reaching considering the very wide availability, low cost and apparent safety of N-acetylcysteine. This is discussed in an accompanying editorial by Dr. Lillicrap from Queens University, Kingston, Canada. The final study identifies a novel mechanism for regulation of cardiac fibrosis that revolves around plasminogen activator inhibitor type 1 or PAI-1. First, author, Dr. Flevaris, corresponding author, Dr. Vaughan and colleagues of Northwestern University, Feinberg School of Medicine in Chicago, Illinois showed that cardiac fibrosis was detected by late gadolinium enhancement cardiac MRI in two otherwise healthy humans with complete PAI-1 deficiency due to a homozygous frameshift mutation in serpene 1.
They further performed a series of mouse experiments to show that treatment of young PAI-1 deficient mice with angiotensin 2 induced extensive hypertrophy and fibrotic cardiomyopathy. Ventricular myocytes were found to be the important source of cardiac transforming growth factor beta or TGF beta and PAI-1 regulated TGF beta synthesis by cardiomyocytes in vitro as well as in vivo during cardiac injury. PAI-1 deficiency significantly enhanced multiple TGF beta signaling elements and transcriptional targets. Thus, in summary, this study show that PAI-1 is an essential repressor or cardiac fibrosis and access a molecular switch that controls the cardiac TGF beta access and its early transcriptional effects that lead to myocardial fibrosis.
Modulation of the cardiomyocytes TGF beta access represents a unique therapeutic strategy that may abrogate fibrotic signaling and cardiac fibrosis. Well, that wraps it up for your summaries. Now for our featured discussion. We are incredibly privileged today to have the director of the National Heart, Lung and Blood Institute, Dr. Gary Gibbonss with us on the podcast, as he talks about his perspective piece entitled "Charting Our Future Together: Turning Discovery Science into Cardiovascular Health." Also, joining me today is our editor in chief, Dr. Joseph Hill from UT Southwestern. Joe, I know you share my incredible excitement and enthusiasm at having Dr. Gibbonss on this podcast with us.
Maybe could I invite you to say a few words to frame just how important this perspective piece is for Circulation?
Dr. Joseph Hill: We all know that cardiovascular medicine and science are evolving at an unprecedented pace. The challenges we face are evolving and yet the opportunities and the tools and the resources at our disposal are unprecedented in their scope and vision. We're very pleased that Gary has provided strong leadership at NHLBI now for several years and has laid out in this perspective piece here where he thinks the next steps are specifically around this strategic vision that focuses on precision medicine and data science. I would love to hear Gary provide additional perspective on that vision.
Dr. Gary Gibbons: Well, thank you, Joe. As the director of NHLBI, clearly we're public servants and we're accountable stewards of the nation's investment in heart, lung and blood and sleep disorders. This piece gave us an opportunity to outline some of the opportunities that lay ahead in a strategic visioning process. First, I should note that a key part of the legacy of the NHLBI is to make strategic investment with enduring principles in mind to really support investigator initiated discovery science as really the core foundational element of our research portfolio, as well as to maintain a balance portfolio to really expands to spectrum of basic translation clinical population and implementation science.
In this piece, we particularly want to highlight our strategic visioning process in which we encourage the broad input of the NHLBI community that actually included over 4,000 participants in this process from every state in the country. Indeed, 42 countries around the world to provide the most compelling questions and critical challenges that the field faces around strategic goals of understanding normal human biology, reducing disease, accelerating translation and preparing a biomedical workforce and resources for the discovery science of the 21st century.
Out of that strategic vision, we focus in on two elements that emerged that relate it to precision medicine and data science for this piece and really that was the central core of what we wanted to share with the Circulation readership about how these two areas we think are going to be transformative in the years ahead.
Dr. Carolyn Lam: Dr. Gibbons, you know, when the term precision medicine is used, sometimes it's a bit fuzzy I think in the minds of a lot of people. Could you maybe give a few examples or perhaps a specific idea that comes to mind?
Dr. Gary Gibbons: You're right. There's often a lot said about it than probably a bit of hype about it. In some ways you could see this as a legacy of cardiovascular medicine and science. It could be argued that the definition of cardiovascular risk factors that came out of the Framingham Heart Study many years ago was the first sort of forerunner of precision medicine. It helped us indeed define those individuals who are at the greatest risk of having a heart attack and that to this day has played a role in directing targeted preventive treatments of the highest risk individuals in order to prevent heart attacks. That has continued to evolve.
I think what's new now is that we have, as Dr. Hill mentioned, new modalities of both imaging and analytics of computational science, as well as novel biomarkers and genetic markers that can help us be even more precise in that risk assessment. That's really I think the greater opportunity to further subcategorize patient populations to get the right drug to the right patient at the right time with a more strategic treatment approach.
Dr. Joseph Hill: Gary, that's very exciting. I think your vision is absolutely compelling. I like how you categorize the NHLBI as a catalyst for the future. I'd like to think that the Biomedical Journals, the AHA Portfolio of Journals and Circulation are also catalysts that will partner with NHLBI and other entities to chart the course for the future. That again the challenges that we face now are different than they were back in the era when Framingham first got started after World War II. The tools that we have are also evolving rapidly and certainly our perspective from Circulation is that we are stewards of helping chart that course, helping identify and bring forth the best science around the world. In many ways we look to you as a partner.
Dr. Gary Gibbons: Oh, absolutely. The NHLBI really can't fulfill our mission of turning discovery science into the health of the nation and indeed around the world without a circle of partners and that certainly includes the platforms of disseminating new knowledge like Circulation, as well as partner organizations such as American Heart Association. We definitely appreciate the value that your organ brings to really enhancing our efforts to not only take discovery science, but make that knowledge available to practitioners and researchers and patients.
I think a key part of the 21st century is how we not only can discover and generate new knowledge, but how we can facilitate that movement of data to knowledge and from knowledge to action that actually enhances the lives of patients in the real world context. Again I believe your journal plays an important role in helping to do that.
Dr. Carolyn Lam: You both mentioned critical challenges that we're facing and will face. The Chinese for these challenges or crisis, the word is actually wéijī. Okay? Wéi is actually meaning danger, whereas jī is for jīhuey which is opportunity. In every challenge, there's always this new opportunity and I just really would like to ask what are the greatest challenge and perhaps the greatest opportunity?
Dr. Gary Gibbons: I think the challenge that we probably face is the emerging epidemic of non-communicable diseases typically cardiovascular disease throughout the world. Not only in the most industrialized nations, but indeed mainly the developing nations. This will quickly surpass communicable infectious diseases as the major burden and causes of mortality worldwide. We're dealing with a global challenge. Increasingly, we recognize that scientific discovery and analysis is often siloed in various packets. Our vision for the future is really to promote the creation of a global reach of what we're calling a Data Commons. That is that a disease has no borders. Science should not be limited to national states.
It is part of the commonwealth if you will of information and knowledge that really should transcend national borders. We say this is a global community of data and information and knowledge exchange and collaboration. As part of this global community, it's that we think this diverse and inclusive approach will be critical to the best minds and best practitioners of the world learning from each other and contributing to this commonwealth of knowledge. We're excited because the opportunity on the other side of that challenge is that it's an unprecedented capability of power to communicate now. We I think are communicating with you from Singapore and we're in a digital age in which this notion of communication and knowledge exchange should be more fast than it's ever been before.
Indeed, we can create computer platforms that are similar to what exist for a Facebook or a Google that are global in scope. The vision is really to say what would happen if we could turn that toward biomedicine and make biomedicine part of this data science such that we have global contributions to our understanding, knowledge exchange and really create that sort of global sandbox if you will of knowledge exchange and discovery. That's part of this notion of creating a Data Commons and really advancing data science as an element of a strategic vision.
As we move forward with precision medicine and data science, our most sacrosanct stewardship is for the next generations. A critical element is to ensure that we're providing them with the tools and training to really lead the charge of advancing these exciting areas of science and that indeed will be a global enterprise.
Dr. Joseph Hill: That's very exciting, Gary. I take my hat off to you for the leadership that you have maintained at the NHLBI during these times that are once very challenging and at the same time exhilarating. I look forward to working with you through our journal and partnering with you to bring to fruition much of what you had laid out in your vision.
Dr. Gary Gibbons: Thank you, Joe. We look forward to our ongoing partnership.
Dr. Carolyn Lam: Thank you, listeners, for joining us today. Do join us again next week.
Carolyn: 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.
Later on in this podcast, we will be meeting Dr. Nancy Schweitzer, Editor-in-Chief of the new Circulation Heart Failure. We will be discussing today's feature paper on acute myocarditis as well as hearing about her visions for the journal. All that coming right up after these summaries.
The first original paper this week suggests that day-to-day blood pressure variability may be a significant risk factor for dementia. First author Dr. Oishi, corresponding author Dr. Ohara, and colleagues of Kyushu University from Fukuoka, Japan, studied a total of 1,674 community-dwelling Japanese elderly without dementia, who were followed up for five years, and had home blood pressure measured three times every morning for a median of 28 days.
They found that the age and sex adjusted incidences of all-cause dementia, vascular dementia, and Alzheimer's disease increased significantly with increasing day-to-day variability of home systolic blood pressure. These associations remained unchanged after adjusting for potential confounding factors, including average home systolic blood pressure. The study, therefore, suggests that the measurement of day-to-day blood pressure variability, using home blood pressure monitoring, may be a useful way to assess future risk of dementia, irrespective of dementia subtype.
The next paper is one of the first studies to directly target a gene within the fibroblast of a mammalian heart and show a direct role in regulating cardiac fibrosis. Co-corresponding authors Dr. Molkentin from Howard Hughes Medical Center and Cincinnati Children's Hospital Medical Center and Dr. Davis from University of Washington and colleagues performed an elegant series of mouse experiments to show that the gene-encoding p38 alpha mitogen-activated protein kinase was required to mediate fibroblast activation in the mouse heart following injury.
They also showed that forced activation of p38 within fibroblasts, using a transgenic approach, was sufficient to drive fibrosis in multiple tissues of the mouse, including the heart.
In totality, their findings indicated that p38 mitogen-activated protein kinase was a nodal signaling effector within the cardiac fibroblast that drove both wound healing and long term fibrosis in heart failure. In other words, it appears to play a crucial role in the control of both physiological and pathological processes. The clinical implications are that pharmacologic inhibition of p38 mitogen-activated protein kinase in heart failure could reduce progressive fibrosis. However, the same inhibition during acute myocardial infarction injury may inhibit wound healing and be detrimental. These issues are discussed in an accompanying editorial by doctors, Stratton, Koch and McKinsey.
Receptors, well known for their roles in angiogenesis and cancer, may play a role in atherosclerosis, as shown in the next paper, which looked at the Eph-family of receptor tyrosine kinases. These are the largest family in the mammalian genome, which interact with ephrin ligands on adjacent cells to mediate cell adhesion repulsion signaling.
First author, Dr. Finney, corresponding author, Dr. Orr, from LSU Health Sciences Center, Shreveport, and colleagues assessed the role of EPHA2 in atherosclerosis by deleting the EPHA2 in a mouse model of atherosclerosis and by assessing EPHA2 function in multiple vascular cell culture models.
The authors identified a novel role for EPHA2 in atherosclerosis by regulating both plaque inflammation and progression to advance atherosclerotic lesions. Cell culture studies suggested that endothelial EPHA2 contributed to atherosclerotic inflammation by promoting monocyte firm adhesion, whereas, smooth muscle EPHA2 expression regulated the progression to advanced atherosclerosis by regulating smooth muscle proliferation and extracellular matrix deposition.
The clinical implications are that blunting EPHA2 ligation may selectively reduce plaque-associated inflammation. Since the effect of EPHA2 on smooth muscle proliferation appears to be largely ligand independent, unlike its effect on inflammation, the blunting of EPHA2 ligation may limit inflammation while leaving smooth muscle fibroproliferative remodeling intact.
Well, that wraps it up for our summaries. Now, let's go to our feature discussion.
Our feature paper today may cause us to think a little bit differently about fulminant versus non-fulminant acute myocarditis because the findings are actually in contrast with previous studies and are extremely insightful.
And, to discuss this, I am so pleased to have the corresponding author, Dr. Enrico Ammirati from Niguarda Hospital in Milan, Italy, as well as Dr. Nancy Sweitzer, Associate Editor of Circulation from University of Arizona, who managed this paper. But importantly, also, the Editor In Chief of Circulation Heart Failure. Welcome, Enrico and Nancy.
Nancy: Thank you, Carolyn.
Carolyn: Enrico, could I ask you to start by clarifying the conditions that we're talking about here? When we say acute myocarditis or fulminant myocarditis, and non-fulminant myocarditis, what exactly are we referring to?
Enrico: We refer to an acute condition and fulminant myocarditis is a myocarditis inflammation of the myocardium that's a media anatomic or mechanical support due to an anatomic instability, while non-fulminant myocarditis it's a condition where the patient remains hemodynamically stable. Previous records have suggested that despite their dramatic presentation of patient with a fulminant myocarditis might have better outcome than those with acute fulminant myocarditis.
Now in this study we have over 55 patients with fulminant myocarditis and in particular, 34 patients with fulminant myocarditis with viral genomes within two weeks from the onset of symptoms, whereas in the previous record, in particular from [inaudible 00:07:38] we have shown in 15 occasions of fulminant myocarditis, that fulminant myocarditis as quite a good prognosis.
But what we believe it is that gives disparity between our results that connected all acute patients admitted to the emergency department with [inaudible 00:08:01] and symptoms onset within one month to two weeks before. Is the main difference comparing [inaudible 00:08:11] this study [inaudible 00:08:13] patient with onset of symptoms since one year before the onset of symptoms. And we believe that we enroll acute patients.
Whereas in the other study, there was sort of selection by us. It was true that in those previous studies, they have all just patients who we were endomyocardia biopsied performed whereas in our study we did not perform endomyocardia biopsies in that case. But we feel that we have a snapshot of the acute stage of a fulminant myocarditis, so we connected all the patients, whereas in previous study, maybe some of the patients they had acute symptoms died before evaluation from the other researchers.
Carolyn: Indeed, it makes a lot of sense that there may be some survival bias involved. For example, if the sickest patient didn't get a biopsy, for example.
Nancy, when you were managing this paper, what were the kind of the discussions that occurred at the editorial discussions?
Nancy: I think that Dr. Ammirati pointed it out really well. The editors felt that this was a very important paper because it really looked inclusively at myocarditis in the modern era, and showed us where perhaps bias in prior studies had led us astray in terms of our beliefs about, particularly the outcomes in this syndrome. Not only the outcomes in the fulminant patients, who have a very profound and important early mortality risk, but also the outcomes in the non-fulminant patients, who in this study, really do extremely well and do not progress to LV dysfunction, which has been a long-held belief, I think. So understanding much better the full spectrum of myocarditis was made much easier because of the comprehensive look Dr. Ammirati and his colleagues took.
Carolyn: Enrico, I do congratulate you on a beautiful paper. As I said, as a heart failure cardiologist myself, it has changed my thinking. Could you maybe share just a bit more details of what your study found and how this is important clinically?
Enrico: What we have found it is that hospital deaths or heart transplantation was about 25 percent in fulminant myocarditis compared to ten percent in non-fulminant myocarditis and despite greater improvement in the left ventricle injection fraction [inaudible 00:10:56] in fulminant myocarditis compared to non-fulminant forms. The proportion of patients with the left ventricle injection fraction below 55% [inaudible 00:11:09] was higher in fulminant myocarditis comparing it to non-fulminant myocarditis. So we have to pay great attention to do this form of myocarditis not thinking that this is a condition that can simply recover with time but we have to aggressively manage this condition, and we have to see about trials designed [inaudible 00:11:39] in this specific setting to improve the [inaudible 00:11:50] outcome and to reduce myocardial injury during the acute phase.
Carolyn: True. And Nancy, I mean you see tons of these patients too. How has this impacted you?
Nancy: It's interesting, it definitely has impacted me. I like everyone, taught and taught on my teaching rounds for many years that the fulminant patients we were seeing, despite how ill they were, would have better outcomes than those who were non-fulminant. And also, many patients who present with dilated cardiomyopathy who are non-ischemic are told after searching for some viral illness in the year prior to their presentation that probably they had a virus attack the heart or an inflammation of the heart. I've stopped saying those things, and I continue to see review of papers that I'm handling about myocarditis refer to these misconceptions. So I think this is going to be a really important paper, and clarifying our understanding of how this disease evolves over time.
Enrico: I fully agree, I fully agree with this message, and [inaudible 00:12:54] but I believe that the traditions that are involved in [inaudible 00:13:00] maybe can be misleading for other cardiologists.
Carolyn: Nancy, I'm gonna switch tracks a little bit, I mean your explanation of that already gets me so excited about the kinds of papers that are gonna get to be seen at the new Circulation Heart Failure under your leadership. So could you just tell us a little bit more about your vision as editor-in-chief.
Nancy: Well Carolyn, Circulation Heart Failure is an excellent journal Dr. [inaudible 00:13:33] has stewarded it beautifully in its first decade of life. In many ways I don't want to change the journal, I want the very best science that's helping us have a deeper understanding of the disease processes and therapies that affect our patients. That said, I would say we have a couple new initiatives, or sort of slight differences in how we're going to manage the journal going forward. I must say, the content we get is spectacular, and we're so fortunate to be able to look through the papers we get, and try to choose the very best science. It's an amazing privilege for me and the new team.
We're really interested in young investigators and those people who are starting out in their career. The emerging scientists who are producing the best heart failure science. Early in your career you might not have the weight of data behind you to merit publication and circulation proper, but we hope that with good science well thought out excellent hypotheses, Circulation Heart Failure will be an appropriate target for those emerging investigators.
We found some great pleasure in approaching young scientists at meetings, and discussing their work, and asking them to send it to our journal. And that's been great fun and we've seen wonderful yield from that. We've been getting submissions from people we've spoken to whose work we admire, and we really hope to build that part of the journal up. Hand in hand with that is an effort at building our social media presence. We're an entirely online journal. We're very interested in visually appealing content. We do have an images in case report section. And we're going to work to try to build an online community for our young investigators who may not have the money to travel internationally, but who really needed global community of heart failure research colleagues, and we hope to be a place to build that.
And finally, we're interested in some areas that maybe, are emerging or underrepresented in other journals. Areas like ... the way technology is transforming heart failure mechanical circulatory support devices, wearable devices, the other technologies we're using increasingly in our patients. And the world of pulmonary hypertension, and right ventricular dysfunction, which is sort of searching for a journal home, and we hope that we can be that journal home. And of course representing the full spectrum of therapies for heart failures including transplantation. I already mentioned mechanical circulatory support, you know, all the richness that is the evolving field of heart failure, and how we ... I think as professionals in that field think about and treat our patients a little differently than other people caring for heart failure.
Carolyn: Listeners, you just heard it right here, on Circulation on the Run.
Thank you so much for joining us this week. Tune in again next week for even more exciting news.