Circulation on the Run – Details, episodes & analysis

This week, please join author Gregory Wyant and Associate Editor Gabriele Schiattarella as they discuss the article "Induction of DEPP1 by HIF Mediates Multiple Hallmarks of Ischemic Cardiomyopathy."

For the episode transcript, visit: https://www.ahajournals.org/do/10.1161/podcast.20240830.316198

This week, please join author Gary Owens and Associate Editor Iris Jaffe as they discuss the article "A Novel Mouse Model of Myocardial Infarction, Plaque Rupture, and Stroke Shows Improved Survival With Myeloperoxidase Inhibition."

For the episode transcript, visit: 

https://www.ahajournals.org/do/10.1161/podcast.20240825.966308

This week, please join Social Media Editors Shirin Doroudgar and Susmita Sahoo as they speak with the 2024 Loscalzo Award recipient, Mark C. Blaser, regarding his article "Multiomics of Tissue Extracellular Vesicles Identifies Unique Modulators of Atherosclerosis and Calcific Aortic Valve Stenosis." The Loscalzo Award recognizes the best Basic/Translational article published in Circulation in the preceding 12 months.

For the episode transcript, visit: https://www.ahajournals.org/do/10.1161/podcast.20240621.715149

This week, please join authors Jonas Oldgren and Signild Åsberg as they discuss the article "Early Versus Delayed Non–Vitamin K Antagonist Oral Anticoagulant Therapy After Acute Ischemic Stroke in Atrial Fibrillation (TIMING): A Registry-Based Randomized Controlled Noninferiority Study."

Dr. Carolyn Lam:

Welcome to Circulation on The Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.

Dr. Greg Hundley:

And I'm Dr. Greg Hundley, Associate Editor, Director of the Poly Heart Center at VCU Health in Richmond, Virginia.

Dr. Carolyn Lam:

Today's featured paper is a very important discussion, and in fact, the first study to compare early versus delayed NOACs after acute ischemic stroke in patients with atrial fibrillation. The timing study. You're not going to want to miss this, but you're going to have to wait for it, because we're going to discuss all the papers in today's issue. Can I start, Greg? Because I want to start, or is it too early to start with a Greg quiz? With the quiz question being, what is cell-free DNA?

Dr. Greg Hundley:

Oh, thank you Dr. Lam. I really appreciate your wonderment into the world of preclinical science. So something maybe short DNA fragments, but I'm not sure.

Dr. Carolyn Lam:

Aw, you're absolutely right. It's circulating DNA fragments predominantly from mononuclear zones that represent cell injury and/or turnover. So what we know is elevated total cell-free DNA concentration has been associated with worse prognosis in a variety of conditions such as sepsis, trauma, malignancy. In addition, and this may be where a lot of us have heard of cell-free DNA, it's become clinically relevant as a noninvasive marker of solid organ transplant rejection as well as a tool for genotyping and surveillance in oncology.

However, in today's paper, given the parallels in the pathogenesis of pulmonary artery hypertension, two of the diseases I've talked about before that are characterized by increased cell proliferation and turnover, like the cancers and inflammatory mediated tissue injury. Now this particular study sought to determine if plasma cell-free DNA concentrations were elevated in pulmonary artery hypertension, and if those levels would correlate with disease severity or predict outcomes.

Dr. Greg Hundley:

Oh wow, Carolyn, this sounds really informative. So what did they find?

Dr. Carolyn Lam:

Well, this study from corresponding authors, Dr. Solomon from NIH Clinical Center and Dr. Agbor-Enoh from NHLBI in Bethesda and their team found that circulating cell-free DNA is elevated in patients with pulmonary arterial hypertension compared to healthy controls. In two independent PAH patient cohorts, cell-free DNA concentrations increased with severity of disease and predicted transplant free survival in the larger of the two cohorts.

Interestingly, methylation patterns revealed increased cell-free DNA originating from biologically plausible sites including erythrocyte progenator and myeloid lineage inflammatory cells, vascular endothelium, and cardiac myocytes. So the implications are that in pulmonary arterial hypertension, cell-free DNA concentrations could serve as a non-invasive biomarker of underlying disease activity, may add prognostic value to currently use risk scores, and may provide a unique noninvasive window into its pathogenesis.

Dr. Greg Hundley:

Wow, Carolyn. So another interesting technique and pathophysiologic study highlighting the utility of circulating cell-free DNA. Wow. Well, Carolyn, how about I start in with my first study and it comes to us from the world of clinical science and refers to the paradise MI echocardiographic substudy. So Carolyn, the prospective RNE versus ACE inhibitor trial to determine superiority in reducing heart failure events after myocardial infarction.

So the Paradise MI echo study tested the effect of Sacubitril/Valsartan compared to Ramipril on LV function and adverse remodeling following high risk acute myocardial infarction. So this substudy included 544 Paradise MI participants that underwent echocardiography at randomization, and then again later at eight months. Patients were randomized within a half to seven days of their presentation with their index, myocardial infarction, to receive a target dose of Sacubitril/Valsartan of 200 milligrams or Ramipril five milligrams twice daily.

Dr. Carolyn Lam:

All right. So the Paradise MI echo substudy, what did they find?

Dr. Greg Hundley:

Right Carolyn, so treatment with Sacubitril/Valsartan compared to Ramipril following acute myocardial infarction did not result in changes in left ventricular ejection fraction or left atrial volume at eight months. Patients randomized to Sacubitril/Valsartan had less LV enlargement and greater improvement in filling pressure, and thus there are new insights here in that treatment with Sacubitril/Valsartan compared to Ramipril early following acute myocardial infarction may beneficially impact LV size and diastolic properties possibly due to reductions in LV filling pressure.

Dr. Carolyn Lam:

Oh, very nice, Greg. Thank you. Another clinical study here, and this time a paper aimed to evaluate the influence of sex on the effects of empagliflozin in patients with HFpEF enrolled in the Emperor Preserved trial.

Dr. Greg Hundley:

Ah, Carolyn, two of your favorite things, sex differences and SGLT2 inhibitors. So Carolyn, remind us, what did Emperor Preserved show us?

Dr. Carolyn Lam:

Ah, so Emperor Preserved studied the sodium glucose cotransporter 2 or SGLT2 inhibitor empagliflozin in patients with HFpEF, which is an ejection fraction above 40%, and showed a significant reduction in the risk of cardiovascular death or heart failure hospitalization. In the current paper, corresponding author Dr. Javed Butler from University of Mississippi Medical Center and colleagues found that empagliflozin reduced the risk of the primary outcome of cardiovascular death or hospitalization for heart failure to a similar degree in both women and men with HFpEF irrespective of baseline left ventricular ejection fraction.

Empagliflozin produced comparable benefits for the pre-specified secondary outcomes of total heart failure hospitalizations, cardiovascular death, and all-cause mortality, as well as physiologic measures and health status. The pattern of the effects of empagliflozin and HFpEF in both sexes in EMPEROR- Preserved stands in contrast to the influence of sex on the response to neprilysin inhibition. So very interesting paper. I encourage everyone to pick it up, of course, because it's two of my favorite topics.

Dr. Greg Hundley:

Very nice, Carolyn. Well, my next paper comes to us from the world of pre-clinical science, and it's from Dr. Chunyu Zeng from Diping Hospital, the third military medical university. Carolyn, adverse environmental exposure during the prenatal period can lead to diseases in offspring, including hypertension. Now whether or not the hypertensive phenotype can be trans-generationally transmitted is really not new.

Dr. Carolyn Lam:

Wow, that's interesting. So what did this paper find?

Dr. Greg Hundley:

Carolyn, this was really interesting. So these authors in a rat model, they found that prenatal lipopolysaccharide exposure can impair the ability to excrete a salt load and induce hypertension from the first to the third generations, with the fourth and fifth generations inducing salt-sensitive hypertension. And Carolyn, really interestingly, and based on these findings, they treated lipopolysaccharide exposed pregnant rats with the reactive oxygen species scavenger temple, which successfully prevented hypertension in the first-generation offspring and the transgenerational inheritance of hypertension.

So Carolyn, these findings show that adverse prenatal exposure induces transgenerational hypertension through an epigenetic regulated mechanism. And these findings identify potentially preventive and therapeutic strategies for this form of generationally transmitted hypertension. Really interesting.

Dr. Carolyn Lam:

Wow, that sounds wild. Very, very interesting. Well, let's go through the other things that are in today's issue. There's a research letter by Dr. Moayedi on anteroposterior pacer pad position is more likely to capture than anterolateral for transcutaneous cardiac pacing.

Dr. Greg Hundley:

Great, Carolyn. And I've got a research letter from Professor Porrello entitled, “Defining the Fetal Gene Program at Single Cell Resolution in Pediatric Dilated Cardiomyopathy.” And then lastly, there's an ECG Challenge from Dr. Chen entitled, “A Shark Thin Electric Cardiogram in the Intensive Care Unit.” Well Carolyn, how about we get onto that featured discussion and learn more about non-vitamin K antagonists after acute ischemic stroke?

Dr. Carolyn Lam:

Yep. In patients with EF, here we go.

Today's feature discussion is all about atrial fibrillation, how it's a risk factor for stroke, but also about how we've never known really how soon after an acute stroke can we start oral anticoagulation to prevent recurrent strokes? Today we're going to talk about the timing study. It's the first randomized controlled study to evaluate the efficacy and safety of initiation of treatment with NOACs within 10 days of acute ischemic stroke in patients with atrial fibrillation.

Wow. What an exciting study, and also how exciting that we have two co-first authors. We have Dr. Jonas Oldgren and Dr. Signild Åsberg from Uppsala University in Sweden, and this represents a partnership between neurology and cardiology. I mean really unique in many aspects as well as the way this study was performed, which is truly, truly a feat in itself. May I ask you both please to tell me the story of how this study came to be in the first place?

Dr. Signild Åsberg:

Well, we like to mention the late Professor Gesteruen student who actually was the first to bring this question to the table. Together we talked with the cardiology department and Jonas Oldgren to see if we can collaborate to solve this important question for us that works with stroke patient, because it's on a weekly or even a daily basis, troublesome question.

Dr. Jonas Oldgren:

My background is as a cardiologist and professor of coagulation research. I've been very interested in anticoagulants, antithrombotic treatments, and had the pleasure and privilege to be part of the development of the novel oral anticoagulants. And in all those pivotal trials, we excluded patients with a recent stroke at least seven days from the stroke, sometimes even 30 days from the acute stroke we excluded them from the studies.

So when we found the exciting results with at least as good efficacy as warfarin and at least as good safety as warfarin and the tremendous reduction in intracerebral or intracranial bleeds, that was a finding which was not evaluated in acute stroke patients with atrial fibrillation. And when Signild approached me with this idea, I said, "Well this is absolutely a very important question and why hasn't it been resolved earlier?"

And the problem is, of course, that these are patients who are in a sensible setting earlier after the acute ischemic stroke, and when are we able to safely start an effective treatment?

Dr. Carolyn Lam:

Oh, I couldn't agree more with you about how important that is. I mean, when we have an acute stroke patient, we just don't know whether we should start the NOAC early or delay it and we definitely need that evidence gap filled. But I'm also so intrigued with the way you did it with the Swedish Stroke Register. I mean, what a powerful way to look at important questions like this. Could you tell us a bit more about the method used?

Dr. Jonas Oldgren:

Yeah, so in cardiology we started rather early by using our national health registries for doing randomized controlled trials. We did a lot of observational studies in our registries, both in stroke and in cardiovascular medicine, otherwise in every other area of medicine. But in the end we realized that we could at best be hypothesis generating, but we still needed to add randomized controlled studies to have the last piece of the puzzle to provide good evidence.

And then we ran a lot of studies in cardiologists, especially in myocardial infarction patients, by just adding to simplify, by adding a randomization module, and then follow the patients in the registries because we know that we have high quality data in the registry. For instance, in the stroke registry. So we anyway collect every important data on each and every patient in the register. So by adding a randomization module, we can facilitate the conduct of a clinical study.

Dr. Carolyn Lam:

Wow. The way you say it, you make it sound so simple, but I can tell you what you have there in Sweden is like the envy of the whole world, and everybody's thinking about how to do a registry based trial like that. So maybe after you tell us the results, you could also share a little bit of how difficult and challenging it can be as well. But would either of you like to share the results?

Dr. Signild Åsberg:

Well, the major result from our trial is that initiating NOAC within four days is non-inferior to starting in a delayed phase of up to 10 days. So that's our key finding. But equally important is that we didn't have any patients explaining as symptomatic and terrible hemorrhage, and that is extremely good news for us who worked with these patients.

Dr. Carolyn Lam:

That is such an important message. The early initiation was non-inferior. Could you expand on non-inferior in terms of what primary outcome?

Dr. Jonas Oldgren:

Yeah, so the primary outcome was really a clinically important outcome we think, both from the cardiac perspective but also from stroke specialists. So we had a combination composite of symptomatic intracerebral hemorrhages, ischemic strokes and death. And this is what matters to patients and to doctors. We would like to avoid strokes, and it doesn't matter if it's an ischemic stroke or if it's a hemorrhagic stroke. We would like to avoid them. And of course we would not like to have an increased mortality as well.

So it's a relevant endpoint. And when we designed the study, the main drug used was warfarin, and there we knew that there was a lot of hemorrhagic transformations and a lot of intracerebral hemorrhages. So we designed the trial to look at these three endpoints to prevent ischemic strokes, but to avoid hemorrhagic strokes. And that is why we choose to have a non-inferiority design, because we also have the advantage of starting early if we can make the decision to start with the stroke specialists sometimes in collaboration with the cardiologist, and then we can have the patient step down unit earlier if the treatment is already started.

So that was the choice of a non-inferiority design. We of course also tested for superiority, but unfortunately we didn't meet that superiority testing endpoint. But as Signal mentioned, I think thrilling results is to have no symptomatic intracerebral hemorrhage in any of the groups. That really speaks in favor of the safety of this drug or these drugs that we used, but also the concept to start early. We can also note that we had some ... I mean there were numerically lower rates of both ischemic strokes and deaths in the early group, albeit not meeting the significance for superiority, but it's important. And as we see also the events tend to occur very early. So we really gain with treating our patients earlier with this intervention.

Dr. Carolyn Lam:

Oh indeed. And to all the listeners, do pick up the paper because if you look at the Kaplan-Meier curves, they're really impressive, exactly like you said, numerical differences, although the trial did demonstrate non-inferiority and could not demonstrate the superiority. But have a look at those figures. And if I could just clarify the comparator arm, notice that we've been saying NOACs, not a particular NOACs. So could you expand on that a bit?

Dr. Signild Åsberg:

We used all the four NOACs that we have in Sweden, so that was to the physician's discretion to choose between them. So that was not a part of the randomization. So we only randomized the timing to the early phase or the delayed phase.

Dr. Carolyn Lam:

I love that. And then if you could please educate the cardiologist in me, please. There are symptomatic intracerebral hemorrhages, and then there are all kinds of little things that you can pick up if you image the brain and hemorrhagic transformation and microbleeds and all these things. So I think one of the things here was their systematic imaging and does it matter? Could you teach us a little bit more about these different types of bleeds?

Dr. Signild Åsberg:

We did not have a systematic imaging, but in Sweden that is performed mostly by CT on admission. So that was for all patients. And then on events, the imaging was performed and reported through the registry. And yes, there were hemorrhagic transformation actually in three patients, two in the early phase, and one in the delayed phase, but only one before day 10. So all blood that was seen on imaging was reported, but we used symptomatic criteria from the stroke severity scale.

Dr. Carolyn Lam:

Thank you. That's a good clarification. And then the study aimed for a larger number, and here perhaps if either of you could tell us the story, the struggles, and how you ended up with these beautiful results.

Dr. Signild Åsberg:

Yeah, struggle is the word. It was troublesome and we had long talks. So why was this happening? Why didn't science recruit more? But I think one issue might have been that NOACs had been on the market for a while once we started, and even the stroke physicians were getting used to it and had trouble not to start. Before the timing study started, we did a observational pre-timing study just to see how we were doing in Sweden at this stage. Because we didn't really know that.

We know that a lot of patients were discharged with oral anticoagulation, but we didn't really know when they started. And so by that study we could see that in median time to initiation was five days, already before the timing study. So one thought was that this was for some physicians then had to delay their start. They were getting used to start early. So that could have been one explanation.

Dr. Jonas Oldgren:

And of course there has been a lot of observational studies looking at the safety of NOACs or other oral anticoagulants in the early setting after acute ischemic stroke in patients with atrial fibrillation. And of course with the evidence from such studies, albeit observational doctors felt perhaps more confident starting very early despite the lack of evidence from randomized control trials.

So we had the opportunity to follow those patients as well in the stroke registry. Every patient with an acute stroke in Sweden attending a stroke unit is registered. So we have in the supplement of the paper in circulation, we have observational data from the centers participating in stroke, but patients not randomized in the timing study. And we also have observational data from all stroke centers in Sweden. So we can see that many start very earlier with NOACs based on observational data, based on experiences.

And perhaps we're more and more reluctant to randomize the patient in the study because as Signal says, that means there is a 50% chance of delayed treatment by randomization. And when we started this study, there were no evidence from randomized controlled trials within the first 14 days. But while running the study for a couple of years, you start to believe that there seemed to be safety because no one saw any symptomatic intracerebral hemorrhage. And we discussed that, of course, at investigative meetings that this seemed to be a very good treatment, which is bad for running a clinical study, but it's of course good for the patients.

Dr. Carolyn Lam:

Interesting. So echo points kind of may have shifted a little bit even during the course of the trial. So just thank you so much all the more. Thank you for seeing this to completion in the sense of a beautiful manuscript with very meaningful results. If I could ask you both to each summarize just very quickly what the take home message is for clinical practice from neurologist's point of view and cardiologist's point of view?

Dr. Signild Åsberg:

Yeah, what I would say, it seems both safe and reasonable to initiate NOAC earlier after an acute ischemic stroke. So I think that's the key take home message that really to consider the acute secondary prevention.

Dr. Jonas Oldgren:

I may bring that from another perspective. I think when there's lack of data in collaboration, we can do a lot. So in this case, we had a great collaboration in the student committee, cardiologist and stroke specialists collaborating to run such a study. And we are extremely grateful for all the sites and all the investigators at the sites participating in the study. And then of course grateful to circulation for publishing it because we are very proud of this study.

Dr. Carolyn Lam:

And we are proud to be publishing this. So ladies and gentlemen, you heard it right here in Circulation On The Run. Remember this is about early versus delayed initiation of NOACs in patients after an acute stroke who also have atrial fibrillation. And this is a very, very, I think, important study that fills an important evidence gap. We're so grateful to both of you for being here to discuss it, and to the audience for listening today. You've been listening to Circulation On The Run. And don't forget to tune in again next week.

Dr. Greg Hundley:

This program is Copyright of the American Heart Association 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit AHAjournals.org.

This week, please join authors Hanna-Kaisa Nordenswan and Jukka Lehtonen, as well as Associate Editor Mark Link as they discuss the article "Incidence of Sudden Cardiac Death and Life-Threatening Arrhythmias in Clinically Manifest Cardiac Sarcoidosis With and Without Current Indications for an Implantable Cardioverter Defibrillator."

Dr. Carolyn Lam:

Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.

Dr. Greg Hundley:

And I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center, VCU Health in Richmond, Virginia.

Dr. Peder Myhre:

And I'm Dr. Peder Myhre, Social Media Editor in Circulation from Akershus University Hospital, and University of Oslo, Norway.

Dr. Carolyn Lam:

Oh, I am so excited about our feature paper today. It is about a condition that may not be as commonly encountered, but this paper can change clinical practice. It's about cardiac sarcoidosis and the indications for an ICD. Listen up. Very important stuff and discussion coming right up. But first, let's grab coffees and discuss the other papers in today's issues. Shall we?

Dr. Greg Hundley:

Right. So Carolyn, Peder, how about I go first? And so, both of you... we start with a really interesting, very practical study. It's somewhat unclear whether replacing an oral glucose tolerance test with just a hemoglobin A1C measurement for diagnosing diabetes is justified. And so these authors led by Adam Tabák, from University College of London in the United Kingdom, aimed to assess proportion of oral glucose tolerance tests, diagnosed diabetes cases that can be confirmed with hemoglobin A1C measures. And to examine whether individuals with oral glucose tolerance test diagnoses, but non-diagnostic hemoglobin and A1C are at higher risk of macro and microvascular disease. So the study included 5,773 men and women from the population based Whitehall II prospective of cohort study in the United Kingdom.

New oral glucose tolerance tests, diabetes cases diagnosed in clinical examinations between the years of 2002 and 2004. And again, in 2007 and 2009 were assessed for hemoglobin A1C confirmation of a value greater than 6.5% in these. And then again, so in those years, and then again, in subsequent clinical examinations in the periods of 2012 to 2013 and 2015 to 2016, now all participants were followed for major cardiovascular events via linkage to electronic health records until the year of 2017. And for incident chronic kidney disease by an estimated glomerular filtration blade of less than 60 mLs per minute per meter squared, until the last clinical examination.

Dr. Peder Myhre:

Thank you, Greg. That is such an important study with direct clinical implications. And I'm so curious to know what did they find?

Dr. Greg Hundley:

Right, Peder. Right, Carolyn. Carolyn's in the background, it's like a mind meld with Peder. She's going to keep pounding me with these same questions. Okay. So in this population based cohort study, with five yearly repeated oral glucose tolerance tests and hemoglobin A1C measurements, only 59.3% of the oral glucose tolerance tests diagnosed diabetes cases were confirmed by hemoglobin A1C at the same or a subsequent examination during 4.1 years of follow up. Incident oral glucose tolerance test diagnosed diabetes cases with hemoglobin A1C confirmation, and preexisting diabetes cases had similarly increased risks of cardiovascular disease and chronic kidney disease. While notably unconfirmed oral glucose tolerance test cases had a similar risk as the diabetes free population.

Dr. Peder Myhre:

Wow. That is really remarkable, Greg. Thank you for that summary. But can you please just give us, from this complicated paper, can you just give us some take-home points for the listeners.

Dr. Greg Hundley:

Right, Peder. So first, in this study, people with oral glucose tolerance tests diagnosed diabetes without diagnostic hemoglobin A1C have a risk of cardiovascular disease and chronic kidney disease, similar to the diabetes free population. And therefore, replacement of oral glucose tolerance tests with hemoglobin A1C based diagnoses appears justified. Second, there seems to be no need to consider oral glucose tolerance testing when hemoglobin A1C and fasting glucose levels are apparently inconclusive. Fasting glucose tests are needed only in exceptional circumstances where hemoglobin A1C results are felt to be unreliable. And then, finally, these findings lend confidence to widespread use of hemoglobin A1C for diagnosing diabetes in the vast majority of clinical settings.

Dr. Peder Myhre:

Wow. Greg, thank you so much. This was so helpful. Well, I'm going to move on to the second original research article. And that is from the DAPA-HF trial, that I know Carolyn has been quizzing you throughout the years about. So I'm not going to quiz you, but I'm just going to ask you. Did you know that SGLT-2 inhibitors increase hematocrit and that it has been identified as one of the key mediators of the clinical benefits on this class of drugs.

Dr. Greg Hundley:

So Peder, they're really interesting. And the second week of this you're popping out with these quizzes. I didn't do this to Carolyn. It was like a couple months. So anyway, but-

Dr. Carolyn Lam:

Way to go, Peder. Way to go.

Dr. Greg Hundley:

Yeah. Well, the good news is, I can just say yes. I did know that.

Dr. Peder Myhre:

That's nice. And in this paper, we're going to learn even more. Because the authors are taking this further by looking into the iron metabolism and assessing iron deficiency in the DAPA-HF trial. So just to remind you, although, you are familiar with it at this point, Greg, and of course, Carolyn, the DAPA-HF trial was large RCT testing efficacy and safety of the SGLT-2 inhibitor compared to placebo in patients with heart failure and a reduced ejection fraction. And in this post talk analysis, the authors examine the prevalence and consequences of iron deficiency and the effect of dapagliflozin on markers of iron metabolism. They also analyze the effect dapagliflozin on outcomes according to iron status at baseline.

Dr. Greg Hundley:

Oh, wow, Peder. So what did they find?

Dr. Peder Myhre:

So in total, 44% of patients in DAPA-HF were defined as iron deficient. And that was defined as having less than 100 nanogram per milliliter of ferritin or a key set of less than 20% and a ferritin level between 100 and 299 nanogram per milliliter. So the rate of the primary outcome was higher in patients with iron deficiency compared to those without. That was 16 versus 10 per 100% years. And the effect of dapagliflozin on the primary outcome was consistent in iron deficient compared to iron replace patients with a fever interaction of 4.59.

And similar findings were observed for cardiovascular death, heart failure hospitalizations and all-cause mortality. And finally, and very importantly, ferritin, T cell, and hepcidin were reduced with dapagliflozin versus placebo. So the authors conclude that iron deficiency was common in DAPA-HF. And associated with worse outcomes. Dapagliflozin, appeared to increase iron utilization, but improved outcomes, irrespective of iron status at baseline.

Dr. Greg Hundley:

Very nice, Peder. Wow. Just another important piece of information that we're learning about SGLT-2 inhibition. Well, Peder, my next paper comes from the world of preclinical science and it's from a group of authors led by Dr. Osamu Takeuchi from Kyoto University. Primary pulmonary arterial hypertension, Peder, is often characterized by obliterative pulmonary vascular remodeling, resulting in right heart failure. And although, the pathogenesis of pulmonary arterial hypertension is not fully understood. Inflammatory responses and cytokines have been shown to be associated with pulmonary arterial hypertension, particularly with connective tissue disease. So in this sense, Regnase-1 and RNAs, which regulates mRNAs in coding genes related to immune reactions was investigated in relationship to the pathogenesis of pulmonary hypertension.

Dr. Peder Myhre:

Wow, Greg. Pulmonary arterial, a hypertension and mRNA degradation of IL-6. So what did they find, Greg?

Dr. Greg Hundley:

Right, Peder. So these investigators examined the expression levels of Z3H12A in coding Regnase-1, in peripheral blood mononuclear cells from pulmonary hypertension patients classified under various types of pulmonary hypertension, searching for an association between the ZC3H12A expression and the clinical features associated with pulmonary hypertension. They then generated mice lacking Regnase-1 and myeloid cells, including alveolar macrophages and examined right ventricular systolic pressures, and histologic changes in the lung.

They found that Regnase-1 maintains lung innate immune homeostasis via the control of IL-6 and PDGF in alveolar macrophages, thereby, suppressing the development of pulmonary arterial hypertension in mice. And furthermore, the decreased expression of Regnase-1 in various types of pulmonary hypertension implied its involvement in pulmonary hypertension pathogenesis. And then, therefore, may serve as a disease biomarker as well as a therapeutic target for pulmonary hypertension. Very, very interesting work from the world of preclinical science. So how about we jump and see what else is in the mail bag?

Dr. Peder Myhre:

So we have From the Literature by Dr. Tracy Hampton, and this time we get three summaries from preclinical science papers published on their journals. First, there is a summary of a paper suggesting that circadian and pluripotency networks control longevity related genes, and that was published in cell metabolism. There is also a summary from a paper on the varied responses to a high fat diet using mouse models published in high science. And finally, there is a summary related to Brugada syndrome and how gene therapy is a potential future therapy. And that was published in scientific translational medicine. So Greg, what did you have in the mail bag?

Dr. Greg Hundley:

Sure. Well, Peder, I've got a research letter from Professor Fang entitled “Mitochondrial Stress Induces HRIEIF2A Pathway that's Protective for Cardiomyopathy.”

Dr. Peder Myhre:

And finally, we have clinical implications of basic research from Dr. Garry and colleagues entitled “Cardiac Xenotransplantation, the Clinical Impact of Science and Discovery.” So let's move on the future discussion, Carolyn.

Dr. Carolyn Lam:

Absolutely. Thank you for excellent summary, Greg and Peder. Now, let's go the feature discussion on cardiac sarcoidosis.

Dr. Greg Hundley:

You bet.

Dr. Carolyn Lam:

Wow. Today's feature discussion is on a rare, but very important topic. And it's that of cardiac sarcoidosis. And you have to listen up because today's paper could actually change practice. So I'm very pleased and grateful to have the authors of this paper. The corresponding author, Dr. Hanna-Kaisa Nordenswan and coauthor, Dr. Jukka Lehtonen both from Helsinki University Hospital. As well as our associate editor, Dr. Mark Link, from UT Southwestern to discuss this very important paper. Hannah-Kaisa if you don't mind, could you start by just telling us about your paper and what you found?

Dr. Hanna-Kaisa Nordenswan:

Thank you so much for inviting us to the podcast. So cardiac sarcoidosis predisposes to sudden cardiac death. But how well the current guidelines for implantable cardioverter-defibrillators in CS issued by the Heart Rhythm Society in 2014 and the American College of Cardiology, American Heart Association and Heart Rhythm Society, consortium guidelines from 2017, discriminate high from low risk of sudden cardiac death is unknown. And this is what we wanted to examine. So our study is a nationwide study, including 398 patients with cardiac sarcoidosis. All patients had clinical cardiac manifestations and a histological diagnosis of sarcoidosis.

The histological diagnosis was myocardial in nearly one half of the population. So patients with and without class 1 to 2A indications for an implantable cardioverting-defibrillator at presentation were identified from this population. The occurrence of fatal or aborted sudden cardiac death and sustained ventricular tachycardias in follow-up were recorded. We also noted ICD indications emerging first on, follow up.

Dr. Carolyn Lam:

Great. What did you find?

Dr. Hanna-Kaisa Nordenswan:

So, first of all, we found that by the current ICD guidelines, 85 to 100% of our patients had at least one strong to modest class 1 to 2a indication for an early ICD implementation. And we also found a 10%, five-year cumulative incidence of sudden cardiac death in our population of cardiac sarcoidosis patients. Further, we found that patients without an early indication for an ICD by the Heart Rhythm Society guidelines had nearly 5% cumulative risk of sudden cardiac death at five years. These patients further had a 53% cumulative risk of either developing an indication or suffering from a life-threatening ventricular arrhythmia at five years follow up. Finally, we also found that a diagnosis of cardiac sarcoidosis based on myocardial histology, IE definite CS. So definite cardiac sarcoidosis predicted twice higher combined five-year risk of sudden cardiac death and life-threatening ventricular arrhythmia than diagnosis based on extra cardiac histology, IE probable cardiac sarcoidosis.

Dr. Carolyn Lam:

Wow. Thank you so much, Hannah-Kaisa and congratulations on such impactful findings. 398 patients and if I read correctly, a cohort spanning 30 years. Jukka, could you tell us a little bit more on how these patients were identified? And I think this is important too, because it speaks to the generalizability of your findings.

Dr. Jukka Lehtonen:

Exactly. Yeah. So we have a very proactive approach to cardiac sarcoidosis. So basically, if I give you an example, so we screen all patients less than 60 years of age with MRI. And if the MRI shows that there's any signs of myocardial damage, we do endomyocardial biopsy. And then, if we do biopsy, once take 10 samples from the right ventricular septum. If that comes out negative, as it very often comes, then we do a PET study. And if there's an extra cardiac signal, then we do biopsy that side. So usually, it's lymph nodes very often. And that gives us a probable cardiac sarcoidosis.

So probable cardiac sarcoidosis is the terminology that's used in Heart Rhythm Society, 2014 guidelines. It has the same prognosis, basically, the definite cardiac sarcoidosis that's based on endomyocardial biopsy. So if the PET shows no signal outside the heart, we usually repeat the biopsy either right or left side, depending where there's most signal. And we can do that up to three times. So we have a very proactive approach. And that explains why we have so many patients.

So because you may end up taking 30 biopsy samples and you have one sample that's positive. So that explains why 5.3 million people can have such a huge number of sarcoid patients. We don't think that we are special. We just think that we are very active in biopsy area. And I know that this is something that differs in different places, and the different centers in the US have very different policies, and in Europe as well. So why I think this explains why we have such a large population and why they're all biopsy verified cases.

Dr. Carolyn Lam:

Thank you so much, Mark. I know that as editors we spotted immediately what a precious, valuable cohort in data we were looking at. Could you frame that for us? Take us behind the scenes a little bit on what you thought when this paper first crossed your desk.

Dr. Mark Link:

Yeah. This was a paper that caught our interest right away for a number of reasons. One, is the large number of sarcoid patients, nearly 400, that's one of the largest series that's ever been published. And two, is the systematic way in which sarcoid was approached. And what we found fascinating is that once you had a diagnosis of cardiac sarcoid, be it either probable or actual, there was a high risk of having ventricular arrhythmias. And this is something that in the guidelines, it's not so clear, because it's clear if the EF's less than 35%, you should get an ICD. But if your EF's greater than 35% by current guidelines, that's not a class 1 indication. So we thought this paper had the possibility to move guidelines and that perhaps we should think about an ICD and any patient that has diagnosis of cardiac sarcoid.

Dr. Carolyn Lam:

Wow. That's a brave postulation though. Exactly, as I said at the beginning, I think it may be practice changing. What do you think about that? Jukka and Hannah?

Dr. Jukka Lehtonen:

I think that's exactly what we have noticed that we have, most of the cardiac sarcoid patients are less than 50 years of age. So I think, the average age is 49 or something. And they're mostly females, so 70% are females. So it's pretty unique cardiac disease, that's more common in females than in males. And I think this population is benefiting tremendously from the ICD therapy, so that's something that we can see. It's not based on randomized data, it's follow up data, but these patients have lots of ICD events, events treated by an ICD. So we think that this is a major problem. Our previous papers have shown that the mortality in sarcoidosis is 90% is ventricle arrhythmia. So this conclusion fits with that previous findings as well.

Dr. Carolyn Lam:

Wow. Hannah has this impacted your personal clinical practice? I mean, do you now therefore think any patient, especially, if they've got confirmed cardiac sarcoidosis biopsy proven. Are you going to just, no matter what, regardless, anything else be more likely to put an ICD?

Dr. Hanna-Kaisa Nordenswan:

Yeah. Based on this study, we think that all cardiac sarcoidosis patients presenting with clinical cardiac manifestations and with histologically proven cardiac sarcoidosis should be considered for an ICD implantation. But with patients, with having non-definite cardiac sarcoidosis and without class 1 to 2A indications for an ICD in these patients, probably, the pros and cons of an ICD should be carefully discussed. Well, if an ICD is not implanted, at least repeated risk appraisal is needed regularly during follow up.

Dr. Carolyn Lam:

That's great comments. Mark, what do you think is going to be needed as future steps to get it to change practice? Or do you think this is it? Because, I mean, this is... the issue is, it's not easy to say let's just do a trial in cardiac sarcoidosis, right? Where are we going to find those patients and so on. What do you think, Mark?

Dr. Mark Link:

Yeah. That's a very good question. Because this isn't randomized trial data, and the strength of evidence is best with randomized trial data. And will we get a randomized trial in sarcoid? I doubt it. I really doubt it. So we're going to be left with registry data. And so where I would see this going is other registries coming out, showing their data. I think we do need confirmatory data from another large registry or two, and that's going to change practice, but are we there yet? I don't know. I don't know. Based on the lack of randomized trial data.

Dr. Carolyn Lam:

Thanks. If I could then for the last questions, if I could give it to the authors, what are your plans for next steps, if any. Maybe, Jukka, do you want to start first?

Dr. Jukka Lehtonen:

Well, I think cardiac sarcoidosis has lots of open questions. It has only open questions. I think the direction we are going is to go to the drug trial. So whether treatment of the inflammation by different agents would provide benefit in terms of arrhythmias and heart failure. So there's an idea that take patients with, for example, that's something that we haven't finalized yet, but take patients with normal ejection fraction, randomized them to cortisone and no cortisone and see how they do. Because we don't really know whether even corticosteroids actually make a huge difference.

I think we have more than 200 cardiac sarcoid patients under follow up in our hospital. And I can see that there are patients that have very good prognosis and no events whatsoever over many years or even decade. And then we have other patients that have lots of events, arrhythmias and develop heart failure. So I think we need trials that help us to distinguish those patients and also trials that help us select right medications for each group.

Dr. Carolyn Lam:

Thank you, Hannah?

Dr. Hanna-Kaisa Nordenswan:

Based on this particular study, we think that also the next study should preferably be a larger multicenter study that would focus on the prognostic factors in cardiac sarcoidosis. Perhaps, a risk score could be developed by using more detailed information of the presenting manifestations and ventricular function and imaging findings, cardiac magnetic resonance and positron emission tomography.

Dr. Mark Link:

Yeah. And we at the editorial staff thought this was important enough paper to have an editorial, to comment on its usefulness and way forward in dealing with cardiac sarcoid patients. And this editorial is written by Rick Patton and will accompany the printed issue.

Dr. Carolyn Lam:

Thanks. And so, you heard it, everyone pick up that editorial, pick up that paper. This is an important topic, and so grateful that it was published with us. Thank you once again to the authors. Thank you once again, Mark, for managing this paper. So lovely. And thank you, audience for joining us today from Greg and I, you've been listening to Circulation on the Run. Don't forget to tune in again next week.

Dr. Greg Hundley:

This program is copyright of the American Heart Association, 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.

This week, please join author Jonathan Sterne and Associate Editor Shinya Goto as they discuss the article "Association of COVID-19 With Major Arterial and Venous Thrombotic Diseases: A Population-Wide Cohort Study of 48 Million Adults in England and Wales."

Dr. Carolyn Lam:

Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the Journal and its editors. We're your co-hosts. I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.

Dr. Greg Hundley:

And I'm Dr. Greg Hundley, associate editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia.

Dr. Carolyn Lam:

Oh, Greg, we've got a special treat for everyone today. We have a third co-host and he is none other than Peder Myhre from Norway! Really adding to the diversity of our podcast: me from Asia, you from the US, and Peder from Europe. Welcome, Peder.

Dr. Peder Myhre:

Thank you so much, Carolyn. It's truly an honor to be here and I'm looking forward to being part of this podcast today.

Dr. Carolyn Lam:

Awesome. Well, here we go. Looks like we have a feature paper, Greg?

Dr. Greg Hundley:

Absolutely, Carolyn. Peder, welcome. So, listeners, our feature today will involve COVID-19 and its association with arterial and venous thrombotic diseases. But before we get to that, we're going to all grab a cup of coffee from all over the world and get into some of the other articles in the issue. Peder, Carolyn, how about I go first?

My first study involves a prospective cohort of 94,000 individuals from the UK Biobank, who had device-measured physical activity from 2013 to 2015 and were free from myocardial infarction and heart failure. Now, Peder and Carolyn, the study was performed because although objectively measured physical activity has been found associated with acute cardiovascular outcomes, it has not been found associated with heart failure and, of course, a syndrome that's been expanding worldwide. As such this study led by Carlos Celis-Morales from the University of Glasgow aimed to investigate the dose response relationship between device-measured physical activity and heart failure by intensity of the physical activity. Now physical activity was measured with a wrist-worn accelerometer and time spent on light, moderate, and vigorous intensity physical activity was extracted. Incidental heart failure was ascertained from linked hospital and death records.

Dr. Peder Myhre:

Wow, Greg. That sounds amazing. Tell us, what did they find?

Dr. Greg Hundley:

You bet, Peder! These investigators found that, compared with participants who undertook no moderate to vigorous intensity physical activity, those who performed 150 to 300 minutes per week of moderate intensity physical activity or 75 to 150 minutes per week of vigorous intensity physical activity were at lower risk of heart failure. Now, interestingly, the association between vigorous intensity physical activity and heart failure was a reverse J-shaped curve with a potentially lower risk reduction above 150 minutes per week.

And so, the take-home message for this first paper is that device-measured physical activity, especially moderate intensity physical activity, was associated with a lower risk of heart failure. Probably current vigorous intensity physical activity recommendations should be encouraged, but not necessarily increased. In contrast, increasing moderate intensity physical activity may be beneficial, even among those meeting current recommendations.

Dr. Peder Myhre:

Wow, Greg. That was a great summary. And the second original research article today is about high density lipoproteins. As you know, raising HDL cholesterol levels to prevent cardiovascular disease remains a hot topic. HDL plays a key role in reverse cholesterol transport and may be cardioprotective and reduce infarct size in the setting of myocardial injury. Lecithin cholesterol acyl transferase, LCAT, is the rate limiting enzyme in the reverse cholesterol transport and a recombinant human LCAT called MEDI6012 has previously been shown to increase HDL cholesterol. So in this study from the corresponding author, Marc Bonaca from University of Colorado School of Medicine, the investigators in the real team is 63B multicenter placebo control trial investigated whether randomized patients to, MEDI6012 or placebo would reduce the infarct size as measured by cardiac MRI, 10 to 12 weeks after the STEMI.

Dr. Greg Hundley:

Very interesting, Peder. So, MRI assessments of LV mass after PCI. So, what did they find?

Dr. Peder Myhre:

So, Greg, the authors successfully enrolled 593 patients with a median age of 62 years and 78% males. And the median time from symptom onset to randomization was 146 minutes and only 13 minutes from hospitalization to randomization. And the index MI was anterior in 70% and 65% had TIMI Flow grade 0-1. And then to the main results at 12 weeks, the infarct size did not defer between the treatment group. So that was a 9.7% infarct size for MEDI6012 versus 10.5% for placebo with a P value of 0.79. And there was also no difference in noncalcified black volume. So the authors conclude that enhanced reverse cholesterol transport with recombinant human LCAT did not reduce infarct size or late regression of noncalcified coronary REPL at 12 weeks. Okay, Greg. So tell me about the 3rd paper you have today?

Dr. Greg Hundley:

Peder, what a great description on that previous paper, beautiful job there. So Peder, this next article pertains to cardio toxicity related to the administration of anthracycline-based chemotherapy. And an example would be Doxorubicin. And this occurs in patients often with certain types of cancer. As you know, Doxorubicin is still utilized for the treatment of leukemia, lymphoma, soft tissue sarcoma and in the setting of adjuvant breast cancer treatment. And so to this end, the authors, led by Lorrie Kirshenbaum from St. Boniface Hospital abstract research, wanted to assess cytokine mediated inflammation in myocellular injury, as a result of some of the inflammation that's induced by the administration of Doxorubicin. So as a little bit of background, cytokines, such as TNF alpha, have been implicated in cardiac dysfunction and toxicity associated with Doxorubicin. Now, while TNF alpha can elicit different cellular responses, including survival or death, the mechanisms underlying these divergent outcomes in the heart really somewhat remain cryptic.

The E3 ubiquitin ligase, TRAF2, provides a critical signaling platform for K63 length poly ubiquitin nation of rip K1, crucial for NF-kB activation by TNF alpha and survival. Whether alterations in TNF alpha, TRAF2, NF-kB activation signaling underlie the cardiotoxic effects of Doxorubicin, remains poorly understood. So herein, these authors investigated TRAF2 signaling in the pathogenesis of Doxorubicin cardio toxicity.

Dr. Peder Myhre:

Oh wow, Greg. So we're talking mitochondrial dysfunction in Doxorubicin cardiomyopathy. So please tell me, what did they find and what were the clinical implications?

Dr. Greg Hundley:

Very nice. Peder, you remind me of Carolyn, asking me the clinical implications. Okay, so first, in mouse models and in vitro measures in rats, mouse and human pluripotent stem cell derived cardiomyocytes, these investigators monitored TNF alpha levels, LDH, cardiac ultra structure and function, mitochondrial biogenics, as you just suggested, and cardiac cell viability. They found that a novel signaling axis exists that functionally connects the cardiotoxic effects of Doxorubicin to proteasomal degradation of TRAF2. Disruption of the critical TRAF2 survival pathway by Doxorubicin, sensitizes cardiomyocytes to TNF alpha and BNIP3 mediated necrotic cell death. Perhaps, interventions that stabilize TRAF2, so here's the clinical implication, may prove beneficial in mitigating the cardiotoxic effects in cancer patients undergoing anthracycline-based chemotherapy.

Dr. Carolyn Lam:

So Greg, he may sound like me, but this is me going what an amazing summary and especially in something that is your specialty cardio-oncology, that's amazing. Thank you. Peder, I assume you've got one more paper?

Dr. Peder Myhre:

So Greg, now I'm going to sound like you and say that we are going to stay within the world of preclinical science. So genome-wide association studies have identified many genetic loci that are robustly associated with coronary artery disease. However, the underlying biological mechanisms are still unknown for most of these loci, hindering the progress to medical translation. And there is evidence to suggest that the genetic influence of coronary artery disease sociability may partly act through vascular smooth muscle cells. So corresponding author, Shu Ye from University of Leicester, performed genotyping, RNA sequencing and cell behavior assays on the large bank of vascular smooth muscle cells with an N of almost 1500. And through these extensive analysis, they saw to identify genes whose expression was influenced by coronary artery disease associated variants.

Dr. Greg Hundley:

Very nice, Peder. So, more about cardiac gene expression. So, what did they find?

Dr. Peder Myhre:

Approximately 60% of the known coronary artery disease associated variants show statistically significant effects in vascular smooth muscle cells and the study identified 84 candidate causal genes whose expression quantitative trait, loci signals in vascular smooth muscle cells, significantly co-localized with reported coronary artery disease association signals, of which 38 of them are potentially druggable, so, that was the clinical implications. The authors conclude that a large percentage of coronary artery disease loci can modulate genes, gene expression in vascular smooth muscle cells and influence these cell behavior. Several candidate causal genes identified are likely to be druggable and thus represent potential therapeutic targets. And Greg, accompanying this paper is a beautiful editorial by doctors O'Donnell and Bradner entitled "Bridging the Gap to Translating Genome-Wide Discoveries into Therapies to Prevent and Treat Atherosclerotic Cardiovascular Disease."

Dr. Greg Hundley:

Very nicely done Peder, very nicely done. Well, as usual, we have some other items, we call it in the mail bag because we receive these wonderful research letters and also research correspondence. So I'll go first. First, Dr. Al-Khatib has a research letter entitled, "Duration of Anticoagulation Interruption before Invasive Procedures and Outcomes in Patients with Atrial Fibrillation Insights from the Aristotle Trial." And also there's a nice ECG analysis by Dr. Tsai entitled, "A Peculiar Wide-Complex Tachycardia During Flecainide Treatment."

Dr. Peder Myhre:

Nice, Greg, and there's also an exchange on letters to the editors and the response from Professors Zhao and Ding, and again, a response from Professor Zhang regarding the prior letter by Jin et al. pertaining to the previously published article "Micro RNA, 210 Controls, Mitochondrial Metabolism and Protects Heart Function in Myocardial Infarction."

Dr. Greg Hundley:

Beautifully done, Peder. Oh, wow. Welcome to this team. We're so excited to have you. And now Carolyn, I think we're going to jump over to that feature discussion and learn a little bit more about COVID-19 and arterial and venous thrombotic disease.

Dr. Carolyn Lam:

You bet! Let's go, Greg and Peder.

Now we all know that infection with COVID 19 induces a pro-thrombotic state, but the long term effects of COVID-19 on the incidence of vascular disease, both arterial and venous, remain unclear. That is until today's feature paper. We're so grateful to have corresponding author Dr. Jonathan Stern, from the University of Bristol, as well as our associate editor, Dr. Shinya Goto from Tokai University School of Medicine to join us and discuss this very important paper today. Jonathan, could you start us off on telling us why it's so important to look at this? Haven't we always known that infections, COVID or not, are associated with pro-thrombotic state? So what's so different about what you did and what you found this time?

Dr. Jonathan Stern:

So, yes, I think we already knew that serious infections, in particular infections leading to hospitalization, can result in thrombotic events, either arterial or venous. And it was also clear from January, February, March 2020, that COVID led to very serious infection and therefore was likely to lead to vascular events. The questions that we set out to address, beyond simply establishing that COVID does indeed do this, was to quantify by how much COVID multiplies the rate at which these thrombotic events occurred, to do that separately for different events, such as myocardial infarction, stroke, venous thromboembolism, pulmonary embolism. And then to importantly, because we analyzed a very large dataset, which we might want to talk about, to try to separate out the amount by which the rating events was multiplied over time and in important subgroups, for example, in hospital people who were hospitalized for their COVID, compared with people who weren't hospitalized for their COVID, by age and sex, and by other demographic characteristics.

Dr. Carolyn Lam:

I love that, you see, that really set out the novel information this added with, may I add, very important clinical implications, which we'll get to them. You've already teed me up to talk about this 48 million adults that you managed to look at. Oh my goodness! Tell us, how in the world did you do that?

Dr. Jonathan Stern:

Well, I think the first thing to say is that it's my absolute privilege to talk about this paper on behalf of a really incredible team that put the work together. And a lot of that work, or that work started with really unlocking the power of NHS data because of the COVID pandemic. So in the UK, we have a national health service, free at the point of delivery to everybody. The NHS assembled electronic health records, and there's been a long and proud history of research based on electronic health records in the UK. But for the first time, because of the pandemic, a combined data resource for the whole of England, so that's a population of about 58 million people, was established and that linked primary care data - data from family doctors, data on secondary care hospital admissions, data on COVID testing and subsequently, although it's not the subject of this paper, data on vaccination.

So those data were all linked and put into one place within what's called a trusted research environment with very strict controls on what can be output from the environment in order to protect patient privacy. And that was really done during 2020. And then the analyses for this paper took place during 2021, and it was an enormous amount of work by a large and absolutely fantastic team of people across multiple UK universities and national health service institutions.

Dr. Carolyn Lam:

Wow. Bravo! We talk about big data, we talk about using it. I trained in the NHS system. Who knew that this could come out to reveal such important results? So thank you for that as a background, but now, tell us what you found please?

Dr. Jonathan Stern:

So we found that rates of these conditions, they were primarily acute lymph infarction and ischemic stroke, which we grouped together with other conditions as arterial thrombotic events, and then deep vein thrombosis and pulmonary embolism, which we grouped together with other conditions as venous events. And we found that rates were substantially multiplied immediately after a diagnosis of COVID by up to 748 times, that the amount by which rates were multiplied diminished with time since COVID, but importantly that even six months to a year after that first diagnosis of COVID, rates of venous events were still about double in people who'd had COVID, compared to people who had COVID. And we found, it seemed quite clear that the persistence of the elevated risk was longer for venous events than for arterial events.

Dr. Carolyn Lam:

Just really fascinating results and Shinya, could I ask, what are your thoughts on this? And as you were managing this paper, the implications?

Dr. Shinya Goto:

First of all, thank you very much, Jonathan, for choosing saturation for your great paper. I'm handling quite a lot of papers, but your paper was very attractive. As Carolyn mentioned, it's huge data! 48 million, it's surprising, and also you also pick up booster rate of arterial embolism event for years, and you have also shown adjusted rate is initially increased quite a lot and then decreased gradually. And even after two months, three months still, there is a persisted higher risk. And as you mentioned, for the venous thrombo embolism, it's persisted for more than year to year. It's surprising. COVID-19's a different disease. Perhaps COVID-19 infection cuts to the vascular endarterial cell, perhaps, your research raised a lot of research questions, like endarterial damage induced by COVID-19 in the past 6 months; I would say more than half a year to one year. So that mechanistical insight is very important. And you raise a lot of any clinical questions.

Dr. Jonathan Stern:

Well, thank you very much for your kind words and you are right, I think we are left with questions about maybe in three areas. Firstly, for how long is there an elevation in risk? I should probably say, for those who haven't read the paper, that these results relate to events that occurred in England and Wales during 2020. And so that is in an era before vaccination and when we were dealing with the original variant, and to some extent, the alpha variant. So we are still waiting to see what the implications were over longer periods, and we will be doing that, we will be extending follow up. In fact, we are at the moment extending those results. I think, secondly, we are left with questions about the mechanisms, which you articulated, and thirdly, there's the question about, well, what are the implications for clinical management of patients with COVID-19? And in particular, for patients who've had severe COVID-19, for example, severe enough to be hospitalized for it?

Dr. Shinya Goto:

Yeah, you have also showed a very important point that even known hospitalization for COVID-19, the risk of thrombosis becomes high. So it's very surprising. And even non-hospitalized patients have a higher risk of thrombosis. That is probably the huge difference between other virus infections and COVID-19.

Dr. Jonathan Stern:

Yes. The good news, if you weren't hospitalized for your COVID, is that the elevation in risk declines more rapidly for people with less severe COVID who weren't hospitalized than for people with more severe COVID who were hospitalized. But nonetheless, as you say, particularly in the first week, two weeks, three weeks after COVID, there is a clear elevation in the risk of both arterial and venous events, even if you were not hospitalized for your COVID. We should probably also bear in mind that these results for 2020, when there were severe constraints for some of the time on health service resources. So you probably had to be pretty sick to get hospitalized at that time.

Dr. Carolyn Lam:

That was a very important caveat that you just highlighted. So thank you for contextualizing those findings for us, Jonathan, but then I kind of wish all podcast guests were like you, and you already asked a question, I was going to ask you. Which is, okay, so what's the clinical implication? Should we all be taking some low dose NOAC or aspirin? Whether you're hospitalized or not? Or if you were in 2020? Because, jokes aside, I know that you found some very important risk factors? Or these events which had clinical implications? Could you expand on it?

Dr. Jonathan Stern:

So maybe I'd start by saying that we didn't find that these patterns varied dramatically either by sex or by age. And in fact, when we were planning the analyses, I was convinced that we would see dramatic differences in these hazard ratios by age. And, broadly speaking, the facts on a multiplicative scale, the amount by which your rate is multiplied, looked similar across age groups and by sex. On the other hand, we did see the amount by rates of arterial and venous events were multiplied, appeared greater in people of Asian ethnicity or Black ethnicity than in people of White ethnicity. A counterintuitive finding was that the amount by which your rate was multiplied is lower, if you've had a prior event than if you hadn't. Those are the sorts of extents to which we can say something about how your own characteristics predict the consequences once you've had COVID.

In terms of management, obviously the pandemic has been tumultuous for medicine and for medical research and things have moved on greatly since the pre-vaccination era, 2020 and early 2021, to which these analyses relate. So the first thing to say is, don't get hospitalized with COVID, and the best way to not be hospitalized with COVID, is to be fully vaccinated for COVID. And that's a message that I think the whole of the medical profession has communicated loudly and clearly for a long time now.

So the second thing is, well, okay, what about if, nonetheless, you got COVID, particularly severe COVID, and we discussed this in the team extensively, and I particularly want to mention the senior clinical author, Dr. Will Whiteley from the University of Edinburgh in this regard, and I think the main message here is that risk factor management, cardiovascular risk factor management is always important, but it's probably particularly important in people who've had severe COVID to review risk factor management and make sure that existing guidelines in terms of cholesterol lowering, blood pressure lowering and so on, are being adhered to. We don't... So the most important thing is adherence to existing cardiovascular risk management guidelines. I think we don't have evidence that specific additional interventions are indicated in people who've had COVID, and COVID now in the era of Omicron and widespread vaccination is not the same as COVID during 2020.

Dr. Shinya Goto:

Jonathan, you have raised a very important issue. I strongly recommend all audiences to read this paper. We have to know persistent or higher risk of myocardial infarction, ischemic stroke, may be controlled more regularly controlled. Don't fear the COVID-19 infection to visiting the healthcare professional. In my country, some of the population stopped coming to the healthcare professional because they fear so much about infection from the hospital or clinic. But it's very important to keep that regular control like static and blood pressure control. Maybe we don't have that data about aspiring or not, but strong message your paper gave is that risk factor control after COVID-19 is very important.

Dr. Jonathan Stern:

I completely agree.

Dr. Carolyn Lam:

And I would add to that, remember the days when people were stopping their ACE inhibitors and so on for those fear? So what a great message and thank you for giving us a little bit of a peek into the future of what you're planning next with more follow up, in a population that is vaccinated from a different strain perhaps. And I think this still encourages hopefully more trials and research into this whole area of how we should be managing these patients. Well, thank you so much both of you for discussing this very, very current relevant, important paper. Thank you for publishing it in circulation with us. And to the audience, thank you for joining us today. From Greg and I, you've been listening to Circulation on the Run, and don't forget to tune in again next week.

Speaker 6:

This program is copyright of the American Heart Association, 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.

This week, please join authors Svati Shah and Senthil Selvaraj as well as Guest Editor and Editorialist Manuel Mayr as they discuss the article "Metabolomic Profiling of the Effects of Dapagliflozin in Heart Failure With Reduced Ejection Fraction: DEFINE-HF" and the editorial "SGLT2 Inhibitors in Heart Failure: Targeted Metabolomics and Energetic Metabolism."

Dr. Carolyn Lam:

Welcome to Circulation On Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts, I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.

Dr. Greg Hundley:

And I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center at VCU Health Richmond, Virginia.

Dr. Carolyn Lam:

In today's feature paper, we will be talking about the metabolomic profiling of the effects of dapagliflozin in heart failure, and this is from the DEFINE-HF trial. It's just such a cool paper with a lot of insights you have to hear from the authors. But, before we get there, let's talk about some of the other papers in today's issue. Shall we, Greg?

Dr. Greg Hundley:

You bet, Carolyn. Well, how about if I go first?

Dr. Carolyn Lam:

Please.

Dr. Greg Hundley:

Thank you, Carolyn. My first paper comes to us from Professor Paulus Kirchhof from the Universitäres Herzzentrum in Hamburg. Carolyn, in the randomized EAST-AFNET 4 study, so the early treatment of atrial fibrillation for stroke prevention, these trial investigators demonstrated that systematic initiation of early rhythm control reduced adverse cardiovascular outcomes in patients with recently diagnosed atrial fibrillation and stroke risk factors. However, the effectiveness and safety of early rhythm control in patients with multiple cardiovascular comorbidities is not known. Carolyn, in this study, it was a prespecified sub-analysis of the EAST-AFNET 4 trial and it compared the effectiveness and safety of early rhythm control with usual care stratified into patients with high CHA2DS2-VASc scores of greater than or equal to 4.

Dr. Carolyn Lam:

Nice. Okay. Important question, what did they find?

Dr. Greg Hundley:

Right, Carolyn. Quite a bit of data in this study, so let's walk through it carefully. First, in regards to the study population, the EAST-AFNET 4 randomized 1093 patients with CHA2DS2-VASc scores of greater than or equal to 4, these were predominantly women, 61% female, and then also 1,696 patients with CHA2DS2-VASc of less than four, and these were predominantly men, so only 37% women.

Now let's get to the date. Early rhythm control reduced the composite primary efficacy outcome of cardiovascular death, stroke, or hospitalization for worsening heart failure or for acute coronary syndrome in patients with high CHA2DS2-VASc scores of greater than 4, but not in patients with CHA2DS2-VASc scores of less than 4. Second, now Carolyn, the primary safety outcome, so death, stroke, or serious adverse events of rhythm control therapy, was not different between study groups in patients with high CHA2DS2-VASc scores of greater than 4, but occurred more often in patients with low CHA2DS2-VASc scores randomized to early rhythm control. Now Carolyn, life threatening events or death were not different between the groups. When female sex was ignored for the creation of high and lower groups, the interaction P was not significant for the primary efficacy outcome, but remained significant for the primary safety outcome.

Dr. Carolyn Lam:

Oh, you are right. A lot of interesting data here. What's a take home message?

Dr. Greg Hundley:

Right, Carolyn. So the take home message is the following. Patients with recently diagnosed atrial fibrillation and multiple cardiovascular comorbidities should be considered to have priority access to early rhythm control to reduce cardiovascular outcomes, and a specific trial of early rhythm control in these patients is really needed as a next step.

Dr. Carolyn Lam:

Oh, thank you, Greg. The next paper focuses on arrhythmogenic right ventricular cardiomyopathy, which we know is characterized by a high propensity to life threatening arrhythmias and progressive loss of heart muscle. More than 40% of reported genetic variants linked to arrhythmogenic right ventricular cardiomyopathy, or ARVC, reside in a gene called plakophilin-2, or PKP2. In today's paper, Dr. Delmar and Lundby from NYU Grossman School of Medicine and University of Copenhagen, respectively, and their colleagues, described a comprehensive characterization of the ARVC molecular landscape using a multidisciplinary approach including human samples from ARVC patients with PKP2 mutations and left ventricular ejection fraction above 45%, as well as PKP2-deficient murine and human induced pluripotent stem cell-derived cardiomyocytes. They studied all of these with comprehensive proteomics and functional analysis.

Dr. Greg Hundley:

Wow, Carolyn, another great study in circulation combining both preclinical murine models as well as data from human subjects. So, what did they find?

Dr. Carolyn Lam:

Precisely, Greg. Here's what they found. Loss of nuclear envelope integrity and subsequent DNA damage is a key substrate in the molecular pathology of AR VC. The authors further showed transcriptional down regulation of proteins of the electron transcript chain as an early event in the molecular pathophysiology of the disease prior to an ejection fraction falling below 45%. This associates with increased oxidant production, with the clinical message being, therefore, that the authors propose therapies that limit oxidant formation may be a possible intervention to restrict DNA damage in ARVC.

Dr. Greg Hundley:

Very nice, Carolyn. Okay, our next paper comes from Dr. Donald Lloyd-Jones from Northwestern University, the Feinberg School of Medicine. Carolyn, you can tell the change in inflection of my voice because it's time for another Carolyn's quiz. Carolyn, open-ended question. Can you remind us of life's essential eight?

Dr. Carolyn Lam:

Oh boy, Greg. It's like asking me to name the dwarfs. I know I'm going to forget one, but here you go. Diet, exercise, cholesterol, weight, smoking, sugar must be there, diabetes, blood pressure. You see, I got seven. What's the eighth?

Dr. Greg Hundley:

Yeah. Remember seven dwarfs, Sleepy.

Dr. Carolyn Lam:

Sleep.

Dr. Greg Hundley:

Very good. Great job, Carolyn.

Dr. Carolyn Lam:

Thank you.

Dr. Greg Hundley:

Recently, the American Heart Association recently published an updated algorithm for quantifying cardiovascular health, the Life's Essential 8 score. In this study, the investigative team quantified US levels of cardiovascular health using the new score. They included non-pregnant, non-institutionalized individuals aged 2 through 79 years who were free of cardiovascular disease from the National Health and Nutrition Examination Surveys that were conducted between 2013 and 2018.

Now, for all participants, they calculated the overall cardiovascular health score, and it ranged from 0, which is really low, to 100, which is the highest, as well as the score for each component. And Carolyn, yes, you are very close. Remember the eight? Diet, physical activity, nicotine exposure, sleep duration, body mass index, blood lipids, blood glucose, and blood pressure, and they used published American Heart Association definitions of these. The cardiovascular health scores were assessed across strata of age, sex, race, ethnicity, family income, and depression.

Dr. Carolyn Lam:

Okay, Greg. What did they find?

Dr. Greg Hundley:

Right, Carolyn. There were 23,400 plus participants, representing 201,728,000 adults and 74 million children. The overall mean cardiovascular health score was 64.7 among adults using all eight metrics, and it was 65.5 for the three metrics available of diet, physical activity, and BMI among the children and adolescents that were aged 2 through 19 years.

Now, for the adults there were significant differences in mean cardiovascular health scores by sex, age, and racial ethnic group. Mean scores were lowest for diet, physical activity, and the BMI metrics. There were large differences in mean scores across demographic groups for diet, nicotine exposure, blood glucose, and blood pressure. In children, diet scores were low, 40.6, and were progressively lower in higher age groups. Large differences were also noted in mean physical activity and BMI by sociodemographic group.

Carolyn, this study basically identifies wide ranges of scores across multiple domains of the essential eight, and thus, this new Life's Essential 8 score helps identify large group and individual differences in cardiovascular health. Additionally, overall, cardiovascular health in the US population remains well below optimal levels, and there are both broad and targeted opportunities to monitor, preserve, and improve cardiovascular health across the life course in both individuals, as well as the population at large.

Dr. Carolyn Lam:

Wow. Thanks, Greg. Truly really interesting. Everyone's going to have to pick up that paper and all the other papers in this issue, because there's also an In Depth paper by Dr. Whelton on “Harmonization of the ACC/AHA and ESC/ESH Blood Pressure Hypertension Guidelines, Comparisons, Reflections, and Recommendations. There's a Research Letter by Dr. Munshi on the accurate classification of cardiomyopathy etiology by chromatin accessibility.

Dr. Greg Hundley:

Carolyn, I have got to report an exchange of letters from Professor Sun and Weng regarding the article, “Legumain Is an Endogenous Modulator of Integrin αvβ3 Triggering Vascular Degeneration, Dissection, and Rupture.” And then Carolyn, lastly, there's a Perspective piece from Professor Vidal-Petiot entitled, “Thresholds for Hypertension Definition, Treatment Initiation, and Treatment Targets: Recent Guidelines at a Glance.” Well, Carolyn, how about we get on to that feature discussion?

Dr. Carolyn Lam:

Yes, let's go Greg.

Wow, we have a star stud cast for today's feature discussion, and on a star studied topic, if I may. It's on the SGLT2 inhibitors, this time in the DEFINE-HF study and really going into the mechanism of action of SGLT2 inhibitors. Now, that's one question I personally get all the time. How do these things work? Today's paper brings us one step closer, for sure, in the understanding. I'm so grateful to have the first author, Dr. Senthil Selvaraj from University of Pennsylvania, as well as the corresponding author of the paper, Dr. Svati Shah, associate editor, as well as the corresponding author from Duke Molecular Physiology Institute. We also have Dr. Manuel Mayr who was both the guest editor and editorialist for this paper, and Dr. Mayr is from Kings College London, British Heart Foundation Center. Welcome, everyone. Senthil, get us started here. The DEFINE-HF study, just a quick summary, what that was about and then what you did, what you found.

Dr. Senthil Selvaraj:

Absolutely. Good morning, everyone, or maybe good evening for your time, Carolyn, but we were very excited about this study and the ability to do targeted metabolomic profiling in DEFINE. This audience is well familiar with the fact that SGLT2 inhibitors are foundational therapy in heart failure reduced ejection fraction, and the interesting thing is, despite a lot of literature, we still don't know why. Whether it relates to change in inflammation or endothelial function, but given the mechanism of action, metabolism is sort of at its core. So in this study we sought to identify metabolic pathways that were associated with dapagliflozin treatment using this targeted metabolomics platform in which we assayed 63 metabolites, acylcarnitine, which are markers of fatty acid oxidation, several amino acids, and ketone-related metabolites.

To do this, we studied 234 participants from DEFINE, which is a 12-week placebo-controlled trial of dapagliflozin in this population, and we perform principal components analysis for dimensionality reduction techniques. In this study, briefly we found that, first, our principal components analysis yielded 13 different factors that accounted for the substantial proportion in the variation of the data, and that two in particular, ketone-related metabolites and short acylcarnitines in factor 6, as well as medium-chain acylcarnitines in factor 7 were differentially associated with dapagliflozin treatment. Specifically, there were increases in several ketone-related metabolites and short acylcarnitines, as well as several medium-chain acylcarnitines, really speaking to, potentially, changes in fatty acid as well as ketone biology with dapagliflozin treatment.

The second aim of our study was to look at changes in metabolites and changes in endpoint studying DEFINE, which included NT-proBNP as well as KCCQ scores. We found that dicarboxylate long-chain acylcarnitines and aromatic amino acids really related to worsening heart failure endpoints there. So, a lot to impact, a lot that we found, and appreciative about the opportunity.

Dr. Carolyn Lam:

Oh, wow. Thank you so much for that amazing summary. Svati, I've heard you speak so many times on metabolomics on our calls, but this is really so important. First, I think the question is, congratulations for thinking ahead of time to collect the samples and to do all of this. Congratulations on that. Could I ask if you went in with any specific hypothesis or were you surprised by these findings, Svati?

Dr. Svati Shah:

Yeah, Carolyn, thank you so much. It was such a pleasure to work with Senthil on this and I really want to highlight what an incredible early career investigator he is. He's really going to set the metabolism world on fire. I also wanted to say thank you to the PI of the clinical trial, the parent clinical trial DEFINE-HF Mikhail Kosiborod, who did the really hard work of collecting the samples along with the clinical trial itself.

To me, what's really cool is to be able to take a clinical trial like this with really important clinical outcomes well adjudicated and to be able to dig into the mechanism at a metabolic level of what might be going on with SGLT2 inhibitors. Going into this, Carolyn, we suspected that ketone-related biology was at play. There have been studies in other populations, non-HFrEF populations, that have shown that SGLT2 inhibitors have what appears to be beneficial impacts on ketone biology and induced ketosis. So, going into this, we suspected that this ketone pathway was going to come up. I think what's exciting is, not only did we find that the ketone pathway was differential modified by dapagliflozin, but that it wasn't at the level of severe ketosis that we would be concerned about. And then secondly, we found pathways of fatty acid oxidation. Some related to the effects of the medication and some related to changes in functional outcome. So it really enhanced beyond what we already knew about ketone biology, expanded our understanding of potential mechanisms of SGLT2 inhibitors, and expanded this into the HFrEF space, Carolyn.

Dr. Carolyn Lam:

Oh, that's so nice. I'm bursting with questions, but I really, really have to ask Dr. Manuel Mayr, first, could you put these findings into context for us and tell us what they mean clinically?

Dr. Manuel Mayr:

Yeah, Carolyn. First of all, I want to join you in congratulating the authors to this important study. As Svati mentioned, previous studies have reported effects of SGLT2 inhibitors on ketone bodies, but the present study really adds to the literature because it uses the state of the art metabolomic techniques. It uses a technique called mass spectrometry, but they also have a rating of, I think, in total, 63 metabolites in over 200 patients. Mass spectrometry is becoming increasingly important for cardiovascular precision medicine because we can use it in clinical trials to provide an unbiased assessment of metabolites and proteins. So it's a very versatile technology. I think this study really adds to the rapidly growing literature that SGLT2 inhibition is a principle of unloading the failing heart from metabolic stress.

Dr. Carolyn Lam:

Wow, I really like that and your editorial is just beautiful. I love that you say, "After the serendipitous findings of improved heart failure outcomes with SGLT2 inhibitors, mechanisms were postulated, but studies, such as the one we're discussing, are needed to really uncover what's the real thing." Now, I know this may sound really oversimplified and so on, but I'd really love for Senthil or Svati to just bear with me as I ask, what are you going to say to people who go, "Okay, then we should just be downing ketones," Or, "We should be Working on the fatty acid parts of it," Or taking conclusions like that. What would you say to something like that?

Dr. Senthil Selvaraj:

I'm happy to go first. It's a really wonderful question and I do think that this study raises the question of whether we should be exogenously increasing ketone levels to provide some sort of benefit. I would say the jury's still out there. I think it's a hot topic right now. But there are also differences between how we raise key tone levels, whether you do that endogenously in the body, or whether you give something like a ketone supplement, so exogenous ketone supplementation. And I think that there are completely different physiologies there. So more to come. I think there are a lot of studies in this space.

The ketogenic diet is something that I'm often asked as well, whether that might provide benefit to heart failure. There are a lot of ways that I can, but one thing that we need to be mindful of is the fact that it will reduce glycogen stores as well, which may impact exercise capacity. So, we need more data. I would say the other thing that we found in our studies, while they were increased in ketone levels and markers of fatty acid oxidation with dapagliflozin treatment, we aren't necessarily sure that those mediate the benefits of SGLT2 inhibitors. DEFINE has important clinically relevant endpoints, but it is not an event-based trial. And so we don't know and we can't link the changes in metabolites with changes in outcomes quite yet.

Dr. Svati Shah:

Carolyn, just to add to the wonderful response that Senthil just gave, I think we do have to be careful. We don't know whether these are direct effects of SGLT2 inhibitors or whether these are related to the caloric loss that we know happens with these medications. I think it's important to point out that we're looking in the blood, we don't actually know what's happening at the tissue level, so we do have to be a little bit careful. We have made inferences that this is reporting on substrate fuel selection in the heart, but we also suspect that skeletal muscle and other organs are heavily involved in some of the pathways we're seeing. So I just wanted to make those important caveat to the epidemiologic work that we do.

Dr. Carolyn Lam:

And those are so important, so thank you Senthil and Svati. Manuel, I'd love to invite your thoughts because you did sort of point out some of these points in your editorial. Could you maybe discuss a bit of those and raise any questions, perhaps?

Dr. Manuel Mayr:

Yes. I think Svati and Senthil have nicely mentioned already that these measurements are performed in plasma. So the changes in plasma could be due to, for example, increased production in the liver due to decreased consumption in other tissues. So I guess the next step would be, and I would be really interested on what the authors want to pursue, is to provide direct evidence for the energetic hypothesis, that really the heart is consuming these keto bodies and what type of measurements could be performed to provide direct evidence in humans for these metabolic hypothesis.

Dr. Senthil Selvaraj:

That's a really great question, Manuel. There was a really nice study that was published about a year or two ago in Science in which the authors did coronary sinus sampling. So really to get arterial venous gradients, measure substances in the arterial system as well as the coronary sinus venous system and get extraction. I think that that study would be very interesting to understand. You take patients on SGLT2 inhibitors, those who are not, and to understand what is the heart chewing on. Obviously more invasive than some other approaches, but other studies that I think would be really interesting in those space would be flux studies and stable isotope studies. Again, as Svati really nicely mentioned, these are systemic physiology snapshots whenever we do less localized techniques like that, but they're still very important because heart failure is a systemic process.

Dr. Carolyn Lam:

Anything to add, Svati?

Dr. Svati Shah:

No, I think you said it beautifully. I'll just say on the sort of epidemiologic side, to be able to link this to harder outcomes, DEFINE-HF wasn't really designed to be able to do that. So as we expand our understanding of SGLT2 inhibitors, understand different populations, and to link these pathways to more objective outcomes, I think, will be really useful, also.

Dr. Carolyn Lam:

Indeed. Manual, in your editorial, you actually discuss some of your own work, which may be the ones that Senthil is actually talking about. What is your view?

Dr. Manuel Mayr:

Well, I think I'm very excited that beyond fatty acid metabolism and glucose metabolism, ketones have extracted increasing attention. Ketone body metabolism, I think, has long been underappreciated. We still need to understand to what extent it really acts as a fuel and that it can help to overcome the energy deficit that creates heart failure. I think, as mentioned by Svati and Senthil, we need more studies in this area, and of course other trials are ongoing where they're going to measure, for example, the phosphocreatine to ATP ratio by using phosphor-NMR spectroscopy. So we get direct evidence whether there really is an energetic improvement upon SGLT2 inhibition. I think this will be studies to look forward to and to add to the growing literature that metabolism is important as a therapeutic target for heart failure.

Dr. Carolyn Lam:

Oh, such exciting times. You mentioned the EMPA-VISION trial in your editorial. I think I'm trying to tell everybody, you have to pick up the paper and the editorial. You're going to learn so much. This is so cool. Thank you so, so much all of you for being on this podcast, for sharing your thoughts. I'm sure everyone has learned a lot and enjoyed it just as I have. On behalf of Greg and I, thank you for being here, thank you for joining us today, and don't forget to tune in again next week. Thank you.

Dr. Greg Hundley:

This program is copyright of the American Heart Association 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.

This week, please join author Keith Channon as he discusses the article "Risk of Myocarditis After Sequential Doses of COVID-19 Vaccine and SARS-CoV-2 Infection by Age and Sex."

Dr. Carolyn Lam:

Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts, I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke-National University of Singapore.

Dr. Greg Hundley:

And I'm Dr. Greg Hundley, associate editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia.

Dr. Carolyn Lam:

Oh, Greg, today's feature paper, something that's really been discussed a lot in the press and in lay public as well, the risk of myocarditis following sequential doses of the COVID-19 vaccine and SARS-CoV-2 infection by age and sex. Everyone's going to want to tune into that one. But before we get there, shall we go through some of the key papers in today's issue?

Dr. Greg Hundley:

You bet, Carolyn. How about if I go first?

Dr. Carolyn Lam:

Please.

Dr. Greg Hundley:

So Carolyn, this first manuscript involves the world of machine learning and ECG interpretation. And as you know, novel targeted treatments increase the need for prompt hypertrophic cardiomyopathy detection; however, it's low prevalence, 0.5%, and resemblance to common diseases really present challenges. So Carolyn, these authors, led by Dr. Rahul Deo from Brigham and Women's Hospital, sought to develop machine learning models to detect hypertrophic cardiomyopathy and differentiate it from other cardiac conditions using EKGs and echocardiograms with a robust generalizability across multiple cohorts.

So Carolyn, what did they do? They used single-institution hypertrophic cardiomyopathy EKG models that were then trained and validated on data from three academic medical centers in the United States and Japan using a federated learning approach, which enables training on distributed data without data sharing. Models were validated on held out test sets for each institution and from a fourth academic medical center and were further evaluated for discrimination of hypertrophic cardiomyopathy from aortic stenosis, long-standing hypertension, and cardiac amyloidosis. And then finally, automated detection was compared to manual interpretation by three cardiologists on a data set with a realistic hypertrophic cardiomyopathy prevalence.

Dr. Carolyn Lam:

Wow, incredible. So what were the results?

Dr. Greg Hundley:

Right, Carolyn. So the authors identified 74,476 EKGs for 56,129 patients and 8,392 echocardiograms for 6,825 patients across the four academic medical centers. Now, while ECG models trained on data from each institution displayed excellent discrimination of hypertrophic cardiomyopathy on internal test data, the generalizability was limited, most notably for a model trained in Japan and then subsequently tested in the United States. Now, however, when trained in a federated manner, discrimination of hypertrophic cardiomyopathy was excellent across all institutions, including for phenotypic subgroups. The models further discriminated hypertrophic cardiomyopathy from hypertension, aortic stenosis, and cardiac amyloid. Analysis of ECG and echocardiography paired data from 11,823 patients from an external institution indicated a higher sensitivity of automated HCM detection at a given positive predictive value compared with cardiologists.

So Carolyn, in conclusion, federated learning improved the generalizability of models that use EKGs and echocardiograms to detect and differentiate hypertrophic cardiomyopathy from other causes of left ventricular hypertrophy compared to training within a single institution. It will be really interesting to see the future applicability of these methods.

Dr. Carolyn Lam:

Oh, I'm such a fan of this work. Awesome. Thank you, Greg. My paper, it's a preclinical paper that uncovers a novel mechanism through which GATA4 mutations can lead to heart disease.

Dr. Greg Hundley:

All right, Carolyn, no quiz this time, I'm just coming right out. I'm reversing the question on the teacher. Tell me, what is GATA4?

Dr. Carolyn Lam:

I'm glad you asked, Greg. GATA4 is a zinc finger-containing DNA binding transcription factor essential for normal cardiac development and homeostasis in mice and humans, and mutations in this gene have been reported in human heart defects. Now, in today's paper, authors led by Dr. Srivastava from Gladstone Institutes in San Francisco, California, showed that GATA4 regulated cell-type-specific splicing through direct interaction with RNA and the spliceosome in human-induced pluripotent stem cell-derived cardiac progenitors.

An unbiased search for GATA4 interacting proteins in these human iPS cells revealed interaction with many members of the spliceosome complex. GATA4 also bound to pre-messenger RNAs in a sequence-specific manner that resulted in generation of alternatively spliced isoforms in human iPS cells. Many of these GATA4-dependent isoforms had distinct functional properties illustrating the importance of the splicing regulation to cardiac function.

Dr. Greg Hundley:

Wow, Carolyn, another really interesting study from the world of preclinical science. So what's the take home message here?

Dr. Carolyn Lam:

So these results essentially uncover a previously unrecognized function for GATA4 in regulating alternative splicing through direct RNA interaction. Several genes that have splicing regulated by GATA4 have functional consequences and many are associated with dilated cardiomyopathy, thus suggesting a novel role for GATA4 in achieving the necessary cardiac proteome in normal and stress-responsive conditions.

Dr. Greg Hundley:

Very nice, Carolyn, wow. Well, my next paper comes to us from back in the world of clinical science and it's from Professor Bertrand Cariou from L'institut du Thorax in Inserm UMR1087. So Carolyn, only a few genes causally related to plasma LDL-C levels have been identified so far, and only one, ANGPTL3, has been causally related to combined hypocholesterolemia. In this study, the authors aim to elucidate the genetic origin of an unexplained combined hypocholesterolemia inherited in four generations of a French family and used next generation sequencing and identified a novel dominant rare variant in the LIPC gene encoding for hepatic lipase, which co-segregates with the phenotype. They characterize the impact of this LIPC-E97G variant on circulating lipid and lipoprotein levels in family members using nuclear magnetic resonance based lipoprotein profiling and lipids.

Dr. Carolyn Lam:

Wow, what an interesting approach to study patients and families with hypocholesterolemia for once instead of hyper. Interesting. So what did they find?

Dr. Greg Hundley:

Right, Carolyn. So the investigative team found that this unique LIPC-E97G variant specifically increases the phospholipase activity of hepatic lipase without affecting triglyceride lipase activity. And second, the hypocholesterolemic phenotype related to LIPC-E97G variant is due to an increased clearance of cholesterol within triglyceride-rich lipoprotein remnants predominantly by extrahepatic tissues.

Dr. Carolyn Lam:

Wow, so what are the implications?

Dr. Greg Hundley:

Right, Carolyn. So the novel gain of function variant in LIPC potentially represents the second cause of familial combined hypocholesterolemia after loss of function variants in ANGPTL3. And second, this study highlights an unexpected and critical role of the phospholipase activity of hepatic lipase encoded by LIPC in LDL-C metabolism and identifies it as a potential novel drug target. And then finally, Carolyn, additional data, I think, are warranted to clarify the impact of LIPC-E97G-related combined hypocholesterolemia on atherosclerosis and atherosclerotic cardiovascular disease due to the occurrence of documented coronary stenosis and evolutive carotid atherosclerosis in index cases.

Dr. Carolyn Lam:

Oh, very, very interesting. Thanks, Greg. Well, let's wrap up with the discussion of what else is in today's issue. There's an In Depth paper by Dr. Hadley on protecting cardiovascular health from wildfire smoke. There's also a Research Letter by Dr. Mevorach on myocarditis after BNT162b2 COVID-19 third booster vaccine in Israel.

Dr. Greg Hundley:

Right, Carolyn. And then I've got an exchange of letters from Professors Condello and Doenst regarding the article Cytokine Hemoadsorption During Cardiac Surgery Versus Standard Surgical Care for Infective Endocarditis from the REMOVE study: Results From a Multicenter Randomized Controlled Trial. Well, how about we get on to that feature discussion and learn a little bit more about COVID-19 vaccine and SARS-CoV-2 infection.

Dr. Carolyn Lam:

Let's go, Greg, thanks.

Dr. Greg Hundley:

Listeners, welcome to this September 6th feature discussion. And with us today, very interesting topic pertaining to vaccination for SARS-CoV-2 virus prevention. And we have with us Dr. Keith Channon from Oxford, England, to discuss this very interesting paper.

Well, Keith, welcome. I wanted to start by asking you, can you describe for us a little the background information that went into the preparation of your study, and what was the hypothesis that you wanted to address?

Dr. Keith Channon:

Thanks, Greg, for the opportunity to join you in this interesting conversation today. A group of cardiologists in the UK based at the University of Oxford, and principally at the University of Edinburgh, have been interested in the question as to whether COVID infection and/or COVID vaccination might lead to a higher incidence of myocarditis. And this is a topic that has been the subject of previous publications in the field.

And the provocation for us undertaking this study is that those previous studies have tended to be relatively small, and they've also not been able to necessarily test the details, time association, between myocarditis occurring in relation to sequential doses of vaccination. And that's important because, of course, we're now all receiving sequential doses of booster vaccines, and also those vaccines are often delivered, different vaccine types to different people in different countries. So we wanted to test whether there does appear to be a significant association between the occurrence of myocarditis and both COVID infection and the sequential different COVID vaccinations.

Dr. Greg Hundley:

Very nice. So Keith, can you describe for us, what study population did you enroll for this initiative? And then also, what was your study design?

Dr. Keith Channon:

Thank you. So, one of the really exciting things about this type of study and probably what makes it unique is that in countries with healthcare system, like that in the UK, which is the National Health Service, and universities, such as the University of Oxford and the University of Edinburgh, where there are very strong academic links between researchers and the National Health Service, we've been able to leverage an enormous data set, which is almost 43 million people in the UK who underwent vaccination against COVID-19. And rather than having to follow up 43 million people as part of a research study, we were able to take advantage of National Health Service centralized coded hospital records, number one. Number two, we took advantage of the UK's national database on COVID vaccination. And number three, we were able to look at hospital outcomes and also COVID testing.

So we were able to put together those three data sets for us to understand who developed COVID infection, who received COVID vaccination, and if so, which vaccine and when, and who then was admitted to hospital with a coded diagnosis of myocarditis. And in 43 million people, even though myocarditis is a very uncommon outcome, there were sufficient cases in that very large population to draw statistically meaningful conclusions.

I think that the UK is probably one of the few countries where this type of research can be done. And academic organizations, like our universities, the National Health Service, and also cardiovascular research funders, such as the British Heart Foundation, have put in a lot of resource and effort into giving us those capabilities to answer questions like this, and it's turned out to be a very powerful capability.

Dr. Greg Hundley:

Very nice. And so Keith, can you describe for us your study results?

Dr. Keith Channon:

So the study looked at a large 43 million people approximately over a period of time during the early to mid-phase of the COVID pandemic and looked at the likelihood that people would be diagnosed with myocarditis following either vaccination or COVID test positive. And we compared that likelihood with the likelihood of myocarditis occurring outside of those periods; because, of course, myocarditis occurs reasonably commonly in the general population. So this is another powerful aspect of the study design. It has a curated approach to look at the incidence of myocarditis in the 28 days after either vaccination or COVID infection, and it corrects, or it controls for that relative to the incidence of myocarditis outside of those sampling periods.

And what we found simply is that there is indeed, as previous studies have shown, a small but significant association between receiving a COVID-19 vaccine and being diagnosed with myocarditis in the following 28 days. However, in the population as a whole, the risk of myocarditis after vaccination is substantially lower than the risk of developing myocarditis after COVID infection, and I think that's an important finding. When we looked at subgroups, which is interesting, we found that the highest risk of developing myocarditis was in men less than age 40, so younger men, and that was one finding. And also, there did seem to be some differences in the risk of myocarditis occurring after different sequential vaccine doses.

Dr. Greg Hundley:

Keith, just a quick clarification point, what vaccines did you examine?

Dr. Keith Channon:

So in the UK, the three vaccines that have been largely used of the AstraZeneca Oxford viral vaccine, ChAdOx1, which was of course introduced very early in the UK, along with the Pfizer mRNA vaccine, and then laterally, Moderna vaccine, which of course in the UK was brought in rather later. And I think that's interesting because, as we can go on and discuss, there do appear to be some possible differences between those vaccines in terms of the likelihood of being diagnosed with myocarditis afterwards. But of course, even our experiment in 43 million people is not a perfect design because it's an observational study, and the periods in the pandemic when people were receiving principally the first two vaccines, which were by far the most numerous, was a different period in the natural history of the pandemic than when we started administering Moderna.

So it is important to recognize that it was not a prospectively controlled randomized trial of different vaccines; it was an observational study of pretty much a whole country and how it responded to the implementation of those different vaccines, which were all given to different people at different times of the pandemic. And of course, different times of the pandemic means that many different people will have already had a COVID infection and then gone on to have a booster or third vaccination. So, if you like, the immunological landscape in which these different vaccines were given in this very large population will have been different.

Dr. Greg Hundley:

Right. So I understand there are differences in timing, great point, but did you see any differences in the occurrence of myocarditis relative to either of the mRNA vaccines versus the adenovirus vaccine?

Dr. Keith Channon:

Yeah, we did. What we found is that, interestingly, there did appear to be a higher likelihood of being diagnosed with myocarditis in the 28 days after the mRNA-1273 vaccine, Moderna vaccine, and that was particularly, as I've already said, in men younger than the age of 40 years. I should say again, of course, that vaccine was given to the smallest number of people in the UK and it also tended to be rolled out later, so it was the second or third dose of the vaccine where that signal was most seen. But again, the second and third dose was by definition typically the booster vaccine later on in the pandemic. But that's what we found.

We did find these interesting differences. The incidence of myocarditis was increased after all of the vaccine doses compared with the period when people had not received a vaccine, but this was a very modest increase for most of the vaccines; but for the mRNA vaccines, particularly Moderna, it seemed to be more strikingly increased in the 28 days after the second or third dose of the vaccine. So I guess the message from that result is that there do seem to be these intriguing differences, both in the response to different COVID vaccines, either viral or mRNA or indeed even different types of mRNA vaccine, and possibly after the different dose of vaccines. In other words, after second or third sequential doses.

Dr. Greg Hundley:

And Keith, you mentioned a few minutes ago that you also had an opportunity to examine situations where maybe a patient had a vaccine and then subsequently contracted COVID, or vice versa, maybe they had had COVID and then later on had a vaccine, did you find any differences in the incidence of myocarditis in those situations as opposed to, perhaps, patients that really never had a documented episode of a COVID infection and then always had received the two vaccines and the booster dose?

Dr. Keith Channon:

Yeah, that's a harder question and is less powerfully addressed by our study, even though we were able to temporally control for that. Previous COVID infection did not preclude the risk of myocarditis after subsequent vaccine doses, but it wasn't a big enough signal to be able to give much detail over the relative risk between... Because if you think of the permutations of COVID infection plus or minus three vaccines, there's a lot of different sequential steps there, but having had COVID first doesn't prevent this small but significant signal; having a vaccine before you then get COVID infection does reduce your risk of myocarditis along with pretty much all other COVID complications.

So I think that's a really important public health message here and indeed the overarching finding of our study, which you could argue is the least exciting one but perhaps the most important, which is that you have a higher likelihood of suffering with myocarditis after COVID infection compared with after a COVID vaccination. And if you have COVID vaccination, in general, your risk of myocarditis is lower, obviously your risk of COVID infection is lower, and your risk of getting myocarditis after that COVID infection, should you still get one is also lower. So I think these are very intriguing, interesting findings that might make us think about mechanism and vaccine policy, but ultimately there are very strong endorsement of getting vaccinated to prevent the consequences of COVID-19.

Dr. Greg Hundley:

Excellent point. And then, Keith, just quickly, next study that maybe your group is considering in this space with this large database?

Dr. Keith Channon:

Yes. Well, I think there are two aspects to the study. Our group, which, as I've said, focuses mainly on large epidemiological data sets, having established this infrastructure in the UK led by universities like Oxford and Edinburgh and funded by the British Heart Foundation and others, means that we now have this infrastructure. So the surveillance and the data collection and the analysis is ongoing and we'll be able to add more cases and more power and more data, and there will be other studies that we can look at.

Second, I think there are some really quite interesting mechanistic studies that could be done based on these provocative findings to try to understand which different types of vaccines and, indeed, the immune responses which those vaccines generate. How are they linked to myocarditis and, indeed, to other cardiac and even other organ complications from COVID-19? And there are ongoing studies in the UK and elsewhere in the world that are very much focused on looking at the organ-specific consequences of COVID infection in patients who've been vaccinated or not. For example, using detailed cardiac MRI to look at the heart and look for subclinical myocarditis and to correlate any evidence of subclinical myocarditis with the immune signature, both the antibody and the cellular immune response, in the blood from those patients.

So I think what we're going to see here are enormous epidemiological studies with n=43 million, and we're also going to see more mechanistic experimental medicine immunology studies to try and tease out mechanism, and I think to understand two things. One is how to protect ourselves best against COVID-19, and what are the best vaccines and how best to use them. And second, if we can learn something about the mechanisms of myocarditis along the way, that's a really useful bonus that's come out of this pandemic.

Dr. Greg Hundley:

Very nice. Well, listeners, we want to thank Dr. Keith Channon for bringing us this very interesting article from Great Britain highlighting that, overall, the risk of myocarditis is greater following SARS-CoV-2 infection as opposed to a COVID-19 vaccination, and even really remains modest following sequential doses, including the booster dose of some of the mRNA vaccines.

Well, on behalf of Carolyn and myself, we want to wish you a great week and we will catch you next week on the run. This program is a copyright of the American Heart Association 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit AHAjournals.org.

This week, please join author Rod Stables and Associate Editor Nick Mills as they discuss the article "Routine Pressure Wire Assessment Versus Conventional Angiography in the Management of Patients With Coronary Artery Disease: The RIPCORD 2 Trial."

Dr. Carolyn Lam:

Welcome to Circulation on the Run, your weekly podcast, summary and backstage pass through the journal and its editors. We're your co-hosts! I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.

Dr. Greg Hundley:

And I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center at VCU Health in Richmond, Virginia.

Well, Carolyn, this week's feature... Very interesting. There is a lot of information about using fractional flow reserve during contrast coronary angiography. But how does that compare to just reviewing the angiograms when managing patients with coronary artery disease?

Well, we are going to hear some results from the RIPCORD 2 trial, and they may surprise you a little bit. But, before we get to that interesting feature discussion with authors and editors, how about we grab a cup of coffee and dive into some of the other articles in the issue?

Dr. Carolyn Lam:

Yeah, let's do that, Greg. Do you have a paper to share first?

Dr. Greg Hundley:

Oh, thanks Carolyn. Sure.

So Carolyn, as we know, Apolipoprotein B or apoB, provides an integrated measure of atherogenic risk. But whether apoB levels and apoB lowering hold incremental predictive information on residual risk after acute coronary syndromes, beyond that provided by low density, lipoprotein cholesterol, or LDLC, that's uncertain. So Carolyn this study emanates from the Odyssey Outcomes trial, which compared the Proprotein Convertase Subtilisin/Kexin Type 9 inhibitor, Evolocumab with placebo in 18,924 patients with recent ACS and elevated atherogenic lipoproteins despite optimized statin therapy. Now the primary outcome was major adverse cardiovascular events. So MACE was coronary heart disease, death, nonfatal myocardial infarction, fatal non-fatal ischemic stroke, and hospitalization for unstable angina. And associations between baseline ApoB or ApoB at four months and MACE were assessed in adjusted Cox proportional hazards and propensity score matched models over median of 2.8 years.

Dr. Carolyn Lam:

Oh, right. So what were the results, Greg?

Dr. Greg Hundley:

Right, Carolyn so impatience with recent ACS and elevated atherogenic lipoproteins, MACE increased across baseline ApoB strata, and now evolocumab reduced MACE across all strata of baseline ApoB, with larger absolute reductions in patients with higher baseline levels. Lower achieved ApoB was associated with lower risk of MACE, even after accounting for achieved LDLC or Non-HDLC indicating that ApoB provides incremental information. And therefore, Carolyn, if it is modified achievement of an ApoB level less than or equal to 35 milligrams per deciliter may reduce lipoprotein attributable residual risk after ACS. Isn't that interesting?

Dr. Carolyn Lam:

Yes. Very nice, Greg. Thank you. This next paper is a pre-specified analysis of the EMPEROR-Preserved trial, looking at patients with and without diabetes.

Dr. Greg Hundley:

So remind us, Carolyn, what was the EMPEROR-Preserved trial and what did it show?

Dr. Carolyn Lam:

Well, in EMPEROR-Preserved Empagliflozin, the SGLT2 inhibitor reduced risk of the composite of cardiovascular death or heart failure hospitalization, as well as first and recurrent heart failure hospitalizations and slowed renal function decline in patients with heart failure and an ejection fraction greater than 40%. So the current paper sought to determine if effects were consistent in patients with, and without diabetes, of the almost 6,000 patients enrolled, 49% had diabetes. The risk of adverse outcomes, first of all, was higher in patients with diabetes. Now the treatment effect of Empagliflozin was however, similar in that Empagliflozin reduced the rate of the primary outcome and total heart failure hospitalization, irrespective of diabetes status. The effect of Empagliflozen falls into attenuate GFR decline, however, was also present in patients with, and without diabetes, although more pronounced in patients with diabetes. Now across all these three endpoints, the effect of Empagliflozen did not differ in patients with prediabetes or normal glycemia. And importantly, there was no increased risk of hypoglycemic events in either subgroup compared with placebo. So a very nice paper there. And that was from Dr. Gerasimos Filippatos from Athens University Hospital Attikon and colleagues.

Dr. Greg Hundley:

Wow, Carolyn, just really interesting information coming out of the world of SGLT2 innovation. Well, Carolyn, my next paper comes to us from the world of preclinical science and it's from Dr. Kunhua Song from the University of Colorado Anschutz Medical campus. So Carolyn, abnormalities of calcium homeostasis are closely associated with cardiac arrhythmias and heart failure and conditions that cause death of millions of people every year. Now, Carolyn Triadin physically interacts with the Ryanodine receptor 2 and plays an important role in releasing calcium from the sarcoplasmic reticulum to increase the free intracellular calcium concentration in cardiomyocytes.

Now alternative splicing of a single Triadin gene produces multiple Triadin isoforms, the predominant cardiac Triadin isoform mouse Mt1 or human Trisk 32 is encoded by Triadin exons from one to eight. In humans, mutations in the Triadin gene that lead to a reduction in Trisk 32 levels in the heart cause cardiac dysfunction, cardiac arrhythmias and sudden death. Decreased levels of Trisk 32, in the heart, are also common in patients with heart failure. However, mechanisms that regulate alternative splicing of the Triadin gene to maintain levels of cardiac Triadin protein in the heart, remains somewhat elusive.

Dr. Carolyn Lam:

Wow. I am always learning from these cool papers. Thanks Greg. So what were the results?

Dr. Greg Hundley:

So Carolyn, the investigators found several things. First, the cardio MyoSite specific long non-encoding RNA or link RNA Triadin AS is essential for maintenance of cardiac function, exercise capacity and normal lifespan and Triadin AS knockout mice were found predisposed to cardiac arrhythmias in response to catecholamine challenge. And finally Carolyn, Triadin AS controls, levels, of cardiac Triadin isoforms, by regulating the splicing of the Triadin gene.

Dr. Carolyn Lam:

Oh, wow. All right. So could you bring it home for us, Greg? What are the clinical take home messages?

Dr. Greg Hundley:

Right, Carolyn. So cardiac explants from human heart failure patients as well as patients with cardiac arrhythmias, demonstrate reduced expression of Triadin AS and Triadin. And then next the mechanism of the Triadin AS and Triandin AS mediated alternative splicing of the Triadin gene to specifically control levels of cardiac isoforms of Triadin in the heart, provides a potential strategy for the treatment of cardiac arrhythmias and heart failure.

Dr. Carolyn Lam:

Wow. Thank you, Greg. Well, let's talk about what else is in today's issue. There's a Research Letter by Dr. Agarwal on Chlorthalidone for resistant hypertension and advanced chronic kidney disease.

Dr. Greg Hundley:

And Carolyn, I've got a perspective piece by Professor Cowie pertaining to atrial fibrillation entitled, “I'm Sorry, Mrs. Jones, but We Cannot Make You Feel Better Today.” Well, Carolyn, how about we get onto that feature discussion and review the utility of fractional flow reserve measurements, in patients undergoing contrast coronary angiography.

Dr. Carolyn Lam:

Great, let's go.

Dr. Greg Hundley:

Welcome listeners to this August 30th feature discussion. And we have with us this afternoon, Dr. Rod Staples from Liverpool and our own associate editor, Dr. Nick Mills from Edinburgh, Scotland. And gentlemen, welcome, Rod we'll start with you. Can you describe for us the background information that went into the preparation of your study and what was the hypothesis that you wanted to address?

Dr. Rod Staples:

Okay, well thanks very much for hosting today. I'm very grateful to be working circulation on this. I'm working with my co-lead investigator Professor Nick Harrison from Southampton, who's been doing an enormous amount of work on coronary physiology. He actually did the original RIPCORD study, what I suppose we'd now call RIPCORD 1, but it was called RIPCORD in the early days, an observational study that showed that systematic use of fractional flow reserve at the time of diagnostic angiography. Assessing the functional significance measured in each of the major coronary vessels, appeared in an observational study to have a dramatic effect on the subsequent management plans allocated to patients. And we decided to test this in a prospective randomized trial.

Dr. Greg Hundley:

Very nice. And so the exact hypothesis that you were going to test was what?

Dr. Rod Staples:

At the time of coronary angiography, a strategy of systematic measurement of fractional flow reserve in each and every coronary vessel, large enough to be considered for revascularization, would improve outcomes compared to a strategy based on angiographic assessments alone.

Dr. Greg Hundley:

Very nice. And so you mentioned a randomized trial. Can you describe further your study design and then which study population did you include?

Dr. Rod Staples:

Well, this is a classic multicenter randomized trial performed in the UK. We actually recruited in 17 different UK centers. We asked them to assess patients who were scheduled for invasive, currently angiography for participation against some very minimal inclusion and exclusion criteria, trying to keep the trial generalizable with good external validity. I think one important point to note is that we did allow the inclusion of both patients being assessed with elective angiography for stable symptoms, but in the end half of the population were recruited in the context of a stabilized acute coronary syndrome, a Non-ST-elevation event a day or so down the line.

Dr. Greg Hundley:

And just a quick breakdown, how many men, how many women?

Dr. Rod Staples:

Well, it's in that respect, the population is very, very typical for this type of cardiovascular trial. A 70, 30 split an age in the midsixties, a diabetic population in the high teens. So a very typical population we've seen in all this kind of trial environment.

Dr. Greg Hundley:

Very nice. And so about 1100 patients. And then what were your study results?

Dr. Rod Staples:

Well, I think there was a very good adherence to the study protocol, very, very few crossovers. And also we were pleased to see that our investigators stayed true to the protocol in that the median number of epicardial vessels assessed by FFR in that randomized arm was four. So there was a good assessment by FFR. The trial was interesting in another respect, in that we assessed an economic outcome based on all NHS hospital costs over the following year and a patient reported outcome based on quality of life using the WHOQOL, and interestingly we found no significant differences either in total subsequent hospital costs from randomization for a year, or indeed in patient reported quality of life by WHOQOL or Angina symptoms by the Canadian Cardiovascular Society classification.

Dr. Greg Hundley:

Very nice. And then, what about clinical events? Did you examine those as well?

Dr. Rod Staples:

We did. And again, just a little caveat here, the trial is again interesting in that, what is often in the UK these days called a lean efficient methodology. Whereby, rather than individually contacting individual trial participants or scouring medical records, we interrogated the central national NHS digital repository of all hospital admissions. And we examined electronically a download of every hospitalization event for every patient using algorithms based on diagnostic and procedural codes to define events. And again, we found a very credible representative rate exactly at incidents and events we would've predicted, but again, no difference between the randomized groups.

Dr. Greg Hundley:

Very nice, well listeners, now we're going to turn to our own Associate Editor, Dr. Nick Mills. And Nick, again, you see many papers come across your desk. What attracted you to this particular manuscript? And it's very interesting study results.

Dr. Nick Mills:

Thanks, Greg. Firstly, it addresses an important clinical question. Going beyond that, what appealed to me was it was investigator initiated. It was managed by independent trials unit. It recruited a target, it reported the registered outcomes and it was thoughtfully interpreted. And the fact that it didn't prove the hypothesis was irrelevant because it addresses a really important clinical question. And I think it requires some context, and that is that from the previous randomized trials The FAME series, we have been chastised as interventional cardiologists for not using FFR for relatively low use of FFR clinical practice. It's always around one in 20 patients in most series, given the evidence that FFR guided intervention improves outcomes. But actually what FFR is good at is discouraging you from stenting patients with stable Coronary Disease.

And so, I think a pragmatic trial that addresses that, the fundamental question, should we be doing more FFR more broadly in both acute and stable disease to guide revascularization with a definitive message that we shouldn't, it doesn't improve quality of life. It doesn't alter costs. Clinical outcomes are similar, but there are more complications associated with routine pressure wire use, gives us a very clear steer for the future. So this is a really important trial addressing a fairly fundamental clinical question.

Dr. Greg Hundley:

Very interesting. Well, Rod, we're going to turn back to you with Nick's comments and how we're really seeing an evolution in thought processes regarding both diagnostic angiography, and then also the use of functional testing. What do you see is the next study, really in this sphere of research that would be performed?

Dr. Rod Staples:

Well, I agree with Nick in a way that this raises important philosophical points about the use of intelligence, selective employment of tests or interventions, and that perhaps we need to reflect this in the way we conduct our future studies. I think we're all aware that fractional flow reserve and other measures of functional significance are tremendously valuable in certain clinical settings. And that value's been proven in randomized trials, but in PRECORD 2, for example, if a patient randomized to angiography only was an acute coronary syndrome patient, who had inverted their T waves in their anterior leads, had an associated troponin rise, an echocardiogram had shown some Hypokinesia in the anterior territory. Then I think the potential value of PCI in the LAD does not necessarily require FFR confirmation, and hence that patient will have an equivalent outcome in the angiography group. Similarly, high quality pre-angiography preparation in the elective population with functional testing, stress testing, other forms of imaging mean that we can reserve the use of invasive fractional flow reserve, tight indices to more selective use.

Dr. Greg Hundley:

And Nick, turning to you, what do you think is the next research study that could be informative in this space?

Dr. Nick Mills:

I think our whole philosophy by how to manage stable coronary disease is changing. In part because of some other landmark trials that the Ischemia trial and some of the key secondary analyses of the Ischemia trial that tells the Pathoma burden, low attenuation plaque, other aspects of chronic disease are vitally important in predicting major events in the future. And that leaves us with the role for FFR or CT FFR, primarily to manage symptoms. And I think we're getting increasingly good evaluating patients before they get to the Cathflow, optimizing their medical treatment. And so for me, the trial that we really need to help us, is a CT FFR trial to understand the role of Ischemia testing plus anatomical testing and how they dovetail in guiding treatment decisions before they get to the cath lab. I think we need to move this before the lab, always going to be a role for intelligent FFR testing in selected patients once we get to it. But I think that the question probably needs to be addressed before they get to the cath lab.

Dr. Greg Hundley:

Very nice. Well listeners, we want to thank, Dr. Rod Staples from Liverpool and Dr. Nick Mills from Edinburgh, Scotland for bringing us this very interesting study, highlighting that a strategy of systematic FFR assessment, when compared to angiography alone, did not result in a significant reduction in cost or improvement in quality of life.

Well, on behalf of Carolyn and myself, we want to wish you a great week and we will catch you next week On the Run.

This program is copyright of the American Heart Association, 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.

This week, please join author Kory Lavine and Associate Editor Thomas Eschenhagen as they discuss the article "Donor Macrophages Modulate Rejection After Heart Transplantation."

Dr. Carolyn Lam:            

Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.

Dr. Greg Hundley:          

I'm Dr. Greg Hundley, associate editor and director of the Pauley Heart Center at VCU Health in Richmond, Virginia.

Well, Carolyn, this week's feature, we are going to the world of preclinical science and we are going to learn about a very important new finding pertaining to heart transplant rejection, and macrophages may modulate this, but before we get to that feature, how about we grab a cup of coffee and go through some of the other articles in the issue?

Dr. Carolyn Lam:            

I got mine. Would you like to go first, Greg?

Dr. Greg Hundley:          

You bet, Carolyn. Well, my first study comes to us from Dr. Michael Pencino from Duke University. Carolyn, this study was performed to understand the predictive utility of a previously derived polygenic risk score for long-term risk of coronary heart disease and its additive value beyond traditional risk factors and how that might be able to inform prevention strategies. To accomplish this, data from adults aged 20 to 59 free of cardiovascular health disease from the Framingham Offspring Study and the Atherosclerosis Risk in Communities, or ARIC Study, were analyzed. Now, since the polygenic risk score was derived from people of predominantly European ancestry, individuals who self-reported white race were those that were included.

Dr. Carolyn Lam:            

Oh, interesting, so what did they find, Greg?

Dr. Greg Hundley:          

Right, Carolyn. Somewhat surprisingly, they found that, among 9,757 participants, both the traditional risk factor score and the polygenic risk score where significantly associated with incident cardiovascular heart disease in young, early midlife, and late midlife. Now, the delta C index, when the polygenic risk score was added to the traditional risk factor, score was 0.03, 0.02, and 0.002 in the young, the early midlife, and the late-midlife participants, respectively.

Carolyn, despite a statistically significant association between the polygenic risk score and the 30-year risk of cardiovascular heart disease, the C index improved only marginally with the addition of the polygenic risk score to the traditional risk factor model among young adults and did not improve among midlife adults and, thus, Carolyn, the polygenic risk score, an immutable factor, has limited clinical utility for long-term cardiovascular heart disease prediction when added to a traditional risk factor model.

Dr. Carolyn Lam:            

I really like that, Greg, because I think it also tells us that the traditional risk factors, which we can do something about, are still very important. Isn't that great? Well, the next paper is about POTS. Remember what that is? Should I give you a quiz? All right. It's okay. POTS, or Postural Orthostatic Tachycardia Syndrome, is a disorder of orthostatic intolerance that primarily affects females of childbearing age. While the underlying pathophysiology of POTS is not fully understood, it has been suggested that autoimmunity may play a role. Now, the aim of this study was to compare concentrations of autoantibodies to cardiovascular G protein-coupled receptors between 116 POTS patients and 81 healthy controls, and they were from Calgary, Canada, and Malmo, Sweden.

Dr. Greg Hundley:          

Carolyn, really interesting, so what did they find here?

Dr. Carolyn Lam:            

The investigators, led by Dr. Raj from University of Calgary in Canada, found that commercially available autoantibody concentrations to G protein-coupled receptors were not increased or altered in POTS patients relative to healthy controls as assessed using ELISA. Now, while this study suggests that these G protein-coupled receptor autoantibody concentrations alone cannot explain the pathophysiology of POTS, autoantibody activity and signals not picked up by ELISA should still be explored as these results may provide more insights into the pathophysiology of POTS.

Dr. Greg Hundley:          

Very nice, Carolyn. Well, my next study comes to us from the world of pulmonary arterial hypertension. Carolyn, clinical worsening is commonly used as an endpoint in pulmonary arterial hypertension trials. These authors, led by Dr. Steeve Provencher from the Institut Universitaire de Cardiologie Pneumologie de Quebec, aimed to assess the trial-level surrogacy of clinical worsening for mortality in pulmonary artery hypertension trials and whether the various clinical worsening components were similar in terms of frequency of occurrence, treatment-related relative risk reduction and importance to patients.

Dr. Carolyn Lam:            

Okay, so what did they find?

Dr. Greg Hundley:          

Right, Carolyn, so they searched MEDLINE, Embase and the Cochrane Library for trials evaluating the effects of pulmonary arterial hypertension on clinical worsening and, among 35 independent cohorts, so 9,450 patients, the effects of pulmonary arterial hypertension-specific therapies on clinical worsening modestly correlated with mortality. Additionally, study-level clinical worsening was not found to be a surrogate for mortality in pulmonary arterial-hypertension trials. Moreover, components of clinical worsening largely vary in frequency, response to therapy and importance to patients and, thus, are not necessarily interchangeable.

Dr. Carolyn Lam:            

Thank you, Greg. Can I tell you about some other papers in today's issue? There's a Research Letter from Dr. Cosentino on cardiorenal outcomes with ertugliflozin by baseline metformin use, and this is a post hoc analysis of the VERTIS CV trial.

Dr. Greg Hundley:          

Oh, very good, Carolyn. Well, I've got an exchange of letters from Professors Boriani and Steinberg regarding the article “Driving Restrictions and Early Arrhythmias in Patients Receiving a Secondary Prevention Implantable Cardioverter-Defibrillator, the DREAM-ICD-II Study.” There's also an ECG Challenge from Professor Gao entitled “Syncope in a 3-Year-Old Child During the Perioperative Period. What is the diagnosis? What Signs Point Toward Impending Life-threatening Event?”

Then, finally, there's a nice, On My Mind piece from Professor Greenland entitled “Insurance Payers Should Cover Selective Coronary Artery Calcium Testing in Intermediate Risk Primary Prevention Patients.” Well, Carolyn, how about we get on to that feature discussion and dive into the world of rejection after heart transplantation?

Dr. Carolyn Lam:            

Yay. Here we go.

Dr. Greg Hundley:          

Welcome, listeners, to this feature discussion on August 23rd. We have a very interesting article today to discuss with our author and associate editor pertaining to preclinical science and cardiac transplant rejection. Our author today is Dr. Kory Lavine from Washington University in St. Louis and our associate editor today is Dr. Thomas Eschenhagen from Hamburg, Germany. Welcome gentlemen.

Kory, we'll start with you. Can you describe for us some of the background information pertaining to the construct of your study and what was the hypothesis that you wanted to address?

Dr. Kory Lavine:              

Well, thank you for having me. Our study focused on heart transplant rejection, which remains a major clinical challenge that limits both the survival of heart transplant recipients as well as availability of donor hearts. Current clinical practice really focuses on suppressing the immune system in a global way, and that is somewhat effective, but carries important risks that include infection and life-threatening malignancies.

Many studies have appropriately focused on immune cells that infiltrate the transplanted heart that come from the recipient to search for new ways to suppress the immune system safely. What we've understood and learned over the past several years is that the donor heart has its own immune system and its own immune cells, and the majority of those immune cells that come with the donor heart are macrophages that can be broadly divided into two distinct lineages with different functions, tissue-resident macrophages, which lack the cell surface receptors CCR2, and monocyte-derived macrophages with expressed cell surface receptors CCR2. We tested the hypothesis in this study that these macrophages that come with the donor heart remain active for a period of time after transplantation and play important roles in either suppressing or accelerating heart transplant rejection.

Dr. Greg Hundley:          

What was the hypothesis that you wanted to address with your study?

Dr. Kory Lavine:              

Yeah, so our prior work and others' work within this field had suggested that tissue-resident macrophages, CCR2-negative macrophages, are inflammatory, and CCR2-positive macrophages have the opposite functions being inflammatory and play roles in potentiating and initiating inflammation in the heart. In this study, we hypothesized that CCR2-negative macrophages would protect from rejection, while CCR2-positive macrophages may promote heart transplant rejection and could serve as a new therapeutic target to prevent rejection in transplant recipients.

Dr. Greg Hundley:          

Excellent. Kory, can you describe for us the study design that you used to test your hypothesis?

Dr. Kory Lavine:              

Yeah. The study design and approach we used involved a mouse model of heart transplantation where we transplant a donor heart into a recipient mouse that's fully mismatched at all the MHC loci, and this serves as a nice model for both cellular and antibody-mediated rejection. To facilitate tracking these donor macrophages, we used various genetic lineage tracing systems and, to study their phenotypes, we used single-cell RNA sequencing and, to understand their function, we used mouse models that allow us to specifically deplete each of the donor macrophage populations as well as genetic models to manipulate their activation and signaling.

Dr. Greg Hundley:          

The outcome measures were going to be what?

Dr. Kory Lavine:              

Yeah. The outcome measures for transplant rejection in this mouse model are allograph survival, so the survival of the transplanted heart. We're able to directly look at how much rejection is present by histopathology, and then we're able to observe various mechanistic features using detailed phenotyping such as single-cell RNA sequencing and T-cell activation assays.

Dr. Greg Hundley:          

Very nice, Kory. Well, all, our listeners, we're very excited to hear what were your study results?

Dr. Kory Lavine:              

We learned that donor macrophages are dynamic and they survive for a period of time after transplantation or eventually lost due to transplant rejection. When we phenotyped the macrophages that came from the donor heart, we learned that they remained transcriptionally distinct from immune cells that enter the heart that were derived from the recipients, and they had important and distinct functions. If we depleted the tissue-resident macrophages that were CCR2-negative, we observed reduced allograph survival and increased rejection. If we depleted CCR2-positive macrophages that came from the donor heart, we observed improved allograph survival and reduced rejection.

Mechanistically, we learned that CCR2-positive macrophages are activated through a MyD88-dependent pathway and, if we inhibited MyD88 cytokines which controls the expression of pro-inflammatory cytokines and chemokines, we could prolong the survival of the donor heart for a very significant period of time, reduce rejection and prevent the development of T-cells that would attack the donor heart. From a mechanistic aspect, what we uncovered is that this signaling pathway in CCR2-positive macrophages regulated the recruitment of an activation of antigen-presenting cells which played important roles in generating T-cells that would target the transplanted heart.

Dr. Greg Hundley:          

It sounds like a really informative and leap forward in the whole sphere of transplant rejection. Well, listeners, now we're going to turn to our associate editor, Dr. Thomas Eschenhagen.

Thomas, you have many papers come across your desk. What attracted you to this particular paper and then, secondly, how do you put the results of this study really in the context of other research examining heart transplant rejection?

Dr. Thomas Eschenhagen:          

Yeah, thanks for having me. I mean, first, we got attracted by this paper because it's somewhat an out-of-the-box approach. It's not the standard approach to improve the systemic immunosuppression as many studies did and with actually a lot of success over the last 30 years, survivor got much better. There had been a lot of progress in the field of transplantation medicine as we all know, but as Kory said already, we still have 30% rejection, and these immunosuppressions come at a price. Having this study which turns around somehow the argumentation and looks at the donor organ was something which really attracted us. It uses advanced methods and it applies somewhat in a practical way a concept which emerged over the last, I don't know, maybe decade this concept that macrophages are really very different kind of cells. They're all called macrophages, but they're quite different and even maybe in certain respects having opposing effect.

I think many people know about this M1/M2 concept. It's CCR2 receptor positive and negative. It's criticized by some people, but here we see that it really seems to be really important and, of course, then the third argument why we really like the story is that it has a specific, clear translation impact. I mean, looking at the heart, the donor heart, and potentially even treating the donor heart before transplanting it is something which comes immediately out of the story, and that's something which we found super attractive.

Dr. Greg Hundley:          

Really interesting, so really understanding the mechanism and focusing on donor hearts. Well, listeners, let's circle back with Kory.

Kory, given that, what do you think is the next study that really needs to be performed in this sphere of research?

Dr. Kory Lavine:              

I think Thomas said it exactly as we're thinking about it, so the next area that we're really excited to attack and we're hopeful that the field will focus on is ways to build methods and technologies to treat the donor heart between the time of procurement and the time of transplant, when it's being transported and potentially even being perfused for a period of time. We're really interested in finding approaches to identify small molecules and other potential biologic therapies that could be used to prevent the activation of donor CCR2-positive macrophages.

It's a really attractive approach because treating the donor heart ex vivo decreases the risk of adversely affecting other organs that may be transplanted if you're treating the donor, for instance, and it may decrease the risk of immunosuppression and infection by not having to treat the recipient and we're catching the heart in this window where the risks are much lower.

The other area that we're really excited to focus on is trying to identify the exact mediators that are generated from donor CCR2-positive macrophages that mediate the recruitment and activation of antigen-presenting cells because that would represent another potential therapeutic target.

Dr. Greg Hundley:          

Very nice. Thomas, what are your thoughts about what might be the next study to be performed really in this sphere of research?

Dr. Thomas Eschenhagen:

It's obviously something rather a question to Kory than to me, but I agree to what he said. I think it is pretty obvious what are the next steps mechanistically on the one hand, but practically on the other hand. I mean, at this point, we are at the mouse level, so the question is to which extent can this concept be translated into larger animals and then finally in humans? I was wondering, given these newer methods to keep donor hearts alive for long, extended periods, I was wondering which extent you are already collaborating with the respective groups who develop this approach because that obviously would increase the window of opportunity here for drugs. I think it's really an exciting and pretty visible next steps which we see here, and I can just hope that you're going this path and that it will be successful.

Dr. Greg Hundley:          

Kory, any thoughts on those collaborations that Thomas just spoke of?

Dr. Kory Lavine:              

We're definitely establishing collaborations to focus on ex vivo profusion of donor hearts because that's, as Thomas mentioned, is a perfect window to manipulate the immune populations that are within the donor heart. Those studies have to be team science, they have to be collaborative and they have to have a focus on large animals and then moving into clinic. We're definitely forming those collaborations and excited to work as a group.

Dr. Greg Hundley:          

Very nice. Well, listeners, what an exciting paper to discuss here as part of this feature discussion from the world of preclinical science. We want to thank Dr. Kory Lavine from Washington University in St. Louis, Missouri, and also our own associate editor, Dr. Thomas Eschenhagen from Hamburg Germany, for really bringing us this research study highlighting that distinct populations of donor and recipient macrophages coexist within the transplanted heart, and donor CCR2-positive macrophages are key mediators of allograph rejection and deletion of MyD88 signaling in donor macrophages is sufficient to suppress rejection and extend allograph survival.

Well, on behalf of Carolyn and myself, we want to wish you a great week, and we will catch you next week on the run.

Dr. Greg Hundley:          

This program is copyright of the American Heart association, 2022. The opinions expressed by the speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.