Jan 13, 2020
Dr Greg Hundley: Welcome listeners. This is Dr Greg Hundley from the VCU Pauley Heart Center in Richmond, who is in the second of his two-week stint without his dear friend, Dr Carolyn Lam who will be returning in a week or two. Our feature article this week is from Dr Mikhail Kosiborod from Saint Luke's Mid America Heart Institute and the Georgia Institute for Global Health, and University of New South Wales. And we'll review the effects of dapagliflozin on quality of life and other metrics in patients with heart failure and reduced ejection fraction. But first, let's have a look at the other articles in this issue and just like last week we've got four other original manuscripts. The first two are sort of clinically related and that very first article comes from Dr Ben Levine from University of Texas Southwestern and he serves as the corresponding author and he's examining future predictors of the development of heart failure and preserved ejection fraction or HFpEF.
His team tested the hypothesis as to whether patients with LVH and elevated cardiac biomarkers would demonstrate elevated LV myocardial stiffness when compared to healthy controls as a key marker for future HFpEF. The team recruited 46 patients with LVH. The LV septum was greater than 11 millimeters and elevated cardiac biomarkers, so the NTproBNP was greater than 40 or the cardiac troponin T was greater than 0.6. And they were recruited along with 61 age and sex-matched cohort of healthy controls. To define LV pressure volume relationships, right heart catheterization and 3D echocardiography were performed while preload was manipulated using lower body negative pressure and rapid saline infusion. They found that the left ventricle was less distensible in the LVH patients relative to the controls, that is they had a smaller volume for the same filling pressure. When preload was expressed as transmural filling pressure or wedge pressure minus right atrial pressure left ventricular myocardial stiffness was nearly 30% greater in the LVH group compared to the controls.
The author's note that although LV myocardial stiffness of LVH patients was greater than that of the healthy controls at this relatively early stage, further studies are required to clarify whether interventions such as exercise training to improve LV compliance may prevent the full manifestation of the HFpEF syndrome in these high-risk individuals.
Well, the second paper comes from Professor John McMurry of the British Heart Foundation Cardiovascular Research Center at the University of Glasgow in the United Kingdom. And the paper is somewhat similar to our feature article because it emanates from the DAPA Heart Failure dataset that we will hear about later. So in this paper, the authors examined the effects of Dapagliflozin according to age, given potential concerns about the efficacy and safety of therapies in the elderly in the prior trial. A clinical trial that as we know, demonstrated that a reduced risk of mortality and heart failure hospitalizations occurred in patients with HFrEF.
So in this current study, a total of 4,744 patients that were 22 to 94 years of age were randomized. 636 were less than 55 years of age, 1,242 we're 55 to 64 years of age 1,717 were 65 to 74, and finally 1,149 were greater than 75 years of age. Consistent benefits were observed for the components of the primary outcome of all-cause mortality and symptoms across all the age groups. Although the adverse events and the study drug discontinuation increased with age, neither was significantly more common with Dapagliflozin across any of the age groups. There was no significant imbalance and tolerability or safety events between Dapagliflozin and placebo, even in the very old population group. So we'll have more to discuss later in the feature discussion with a second paper that really looks also at the DAPA-HF study.
The next original article comes from our world of Basic Science and it reports that the deficiency of circulating monocytes ameliorates the progression of myxomatous valve degeneration in the Marfan syndrome. And this paper comes from Dr Katherine Yutzey from Cincinnati Children's Medical Center. Well, first is some background, leukocytes comprised primarily of macrophages have recently been detected in myxomatous valves, but the timing of the presence and the contributions of these cells in myxomatous mitral valve degeneration is not known. So the authors found in this study that Marfan syndrome mice recapitulated the histopathologic features of myxomatous valve disease by two months of age, including mitral valve thickening, increased leaflet cellularity and extracellular matrix abnormalities characterized by proteoglycan accumulation and collagen fragmentation.
Concurrently, disease mitral valves of the Marfan syndrome mice exhibited a marked increase of infiltrating and resident macrophages along with increased chemokine activity and inflammatory extracellular matrix modification. Likewise, mitral valve specimens obtained from gene-edited Marfan syndrome pigs as well as human subjects exhibited increased monocytes and macrophages detected by immunofluorescence. So remarkably deficiency of monocytes was protected against mitral valve disease progression resulting in a significant reduction of macrophages, had minimal leaflet thickening and preserved mitral valve integrity. So the authors identify for the first time in this interesting study from the world of basic science that monocytes are a viable candidate for targeted therapy in myxomatous valve degeneration.
The second basic science original article in this issue is entitled "Genetic IL-6 Signaling Deficiency Attenuates Cardiovascular Risk in Clonal Hematopoiesis" and the corresponding there is Pradeep Natarajan from the Mass. General is background clonal hematopoiesis of indeterminate potential or CHIP is a term that refers to clonal expansion of hematopoietic STEM cells due to acquired leukemic mutations in genes such as DNMT3A or TET2. In humans, CHIP associates with prevalent myocardial infarction. In mice CHIP accelerates atherosclerosis and increases IL-6 and IL-1 beta expression raising the hypothesis that IL-6 pathway antagonism in CHIP carriers would decrease cardiovascular disease risk.
So in this study, the authors observed some really exciting results. They analyzed over 34,000 samples from the UK Biobank and identified 1,079 individuals with CHIP, including 432 with large clones an LV fraction greater than 10%. During a 6.9-year median follow-up CHIP presence was associated with increased incidents, cardiovascular disease event risk with greater risk from large CHIP clones. IL6R attenuated cardiovascular event risk among participants with large CHIP clones but not in individuals without CHIP. This really exciting research results suggest that CHIP is associated with increased risk of incident cardiovascular disease. And among carriers of large CHIP clones, genetically reduced IL-6 signaling abdicated this risk. Really exciting results in an emerging area of science.
So what else is in the issue? Well, in our in depth review feature, Professor Stephan Rosencrantz from the University of Cologne Heart Center reviews the systemic consequences of pulmonary hypertension with right side heart failure. And then an On My Mind piece, our own associate editor, Dr Vlad Zaha coupled with doctors Walter Myers and Javid Moslehi from Vanderbilt discuss the impact of evolving immunotherapies for cancer and their impact on the cardiovascular system. In our mailbag, Dr Xiayan Shen from the Medical Classification Center of the Singapore Armed Forces discusses in a research letter the prevalence of Brugada Syndrome in a large Singaporean young male population. In letters to the editor, Dr Muddassir Mehmood from University of Tennessee Medical Center in one letter and Dr Goodarz Danaei from Boston in a response letter discuss the importance of diet relative to the development of HFpEF and how heart failure may be coded in by the World Health Organization when assessing global cardiovascular outcomes.
Bridget Kuhn in our cardiology news feature reports on preliminary results from the International Childhood Cardiovascular Cohort or i3C Consortium that was presented at the 2019 European Society of cardiology Congress. The i3C Consortium used data on 40,000 patients who participated in seven major longitudinal cohort studies that evaluated childhood cardiovascular risk factors from repeated measures during childhood and adolescence. And finally, our own Molly Klemarczyk at Circulation gathered and combined a very nice serial update that highlights important articles from our circulation family of journals, including electrophysiology, imaging, heart failure, and others.
Well, listeners, that's a summary of what's in the journal. But let's now proceed to our feature discussion to learn more about the rapidly emerging field of SGLT2 inhibition.
Well listeners, we are very excited for this feature discussion we have today, Dr Mikhail Kosiborod from Saint Luke's Mid America heart Institute and our own associate editor, Dr Justin Ezekowitz from Alberta, Canada. And we're going to be discussing the paper related to the effects of Dapagliflozin on symptoms, function and quality of life in patients with heart failure and reduced ejection fraction. They're going to be presenting results from the DAPA Heart Failure trial. Well Mikhail, I was wondering could you orient us a little bit to the DAPA heart failure trial. And then what was the hypothesis that you were trying to address in the current study?
Dr Mikhail Kosiborod: DAPA-HF was the first heart failure outcome trial trying to answer two critical questions about the effects of SGLT2 inhibitors in patients with heart failure and reduced ejection fraction. We knew from prior trials, outcome trials in patients with diabetes SGLT2 agents can effectively prevent heart failure inpatients, overwhelming majority of which did not have heart failure and baseline. But what we didn't know was whether these agents can also be used as therapies for patients with established heart failure, and specifically heart failure with reduced ejection fraction. And they reduce death or worsening heart failure in the patient population. And the second question was whether that effect, if in fact this medications can significantly improve outcomes in patients with heart failure reduced ejection fraction. Can they do that even in patients who do not have type 2 diabetes? Because, in a diabetes trial it appears that that heart failure protective effect may be completely independent on the hemoglobin AONC.
And so DAPA-HF was specifically designed to test those two hypotheses. It enrolled about 4,800 patients with heart failure and reduced ejection fraction about 45% of which had types 2 diabetes. And there's a majority of us, 55% did not. And the main trial results that were published prior to risk analysis showed that in fact dapagliflozin significantly reduced the risk of the composite endpoint of cardiovascular death and worsening heart failure. It was a 26% relative risk reduction and the effects were identical in patients with or without type two diabetes. So both of those hypothesis were proven to be correct. It was effective therapies for established heart failure and reduced ejection fraction, and it was equally effective regardless of diabetes status. Now what we did in this study is really trying to understand the effects not just on cardiovascular deaths and hospitalization for heart failure, but on health status, which is symptoms, physical limitations, and quality of life.
He knows that heart failure is a debilitating disease, causes high burden of symptoms, and physical limitations, has adverse impact on quality of lives. We know that two key goals of managing heart failure are to; one, reduce deaths and hospitalizations for heart failure and two to reduce the burden of symptoms and physical limitations and improve the quality of life. So, that was really the focus of this specific analysis that we're talking about today.
Dr Greg Hundley: Excellent. So I understand you use the KCCQ-12, maybe help us understand what that test is and then tell us a little bit about your methods and your study population. Did you use the whole study population?
Dr Mikhail Kosiborod: KCCQ stands for Kansas City Cardiomyopathy Questionnaire and we actually in the study we use KCCQ-23 which is the full Kansas City Cardiomyopathy Questionnaire, consists of 23 items. And it a disease-specific tools for evaluating health status and heart failure.
So it essentially assesses four key domains, which are the symptom burden, physical implementations, quality of life, and social limitations. In this particular study is a primary endpoint as a primary part of the KCCQ as KCCQ total symptom score, which is a domain that focuses on symptoms. And the idea behind KCCQ is that you have a debilitating disease, which is heart failure. That disease has impact on the patient by causing symptoms, the symptoms then translate to physical limitations. And the combination of the symptom burden physical limitations has an impact on quality of life and social limitation. So that's why are this four different domains assessing these four components of the adverse effects of the heart failure compared to health status. And just very briefly, to mention that KCCQ has been proven to be responsive to clinical change. It's highly for data predictive of death and hospitalizations from heart failure. It has been extensively validated both of them hearts failure was reduced enters and the ejection fraction.
And so we essentially focused, or the primary focus of the paper was really to evaluate the effect of dapagliflozin versus placebo on a Kansas City Cardiomyopathy Questionnaire or KCCQ level symptom score. But we also looked at other domains as well. We looked at the clinical summary score, which includes both symptoms and physical limitations and we looked at the overall summary score, which includes all of the four domains that I mentioned before.
Dr Greg Hundley: What did you find?
Dr Mikhail Kosiborod: The patients treated with dapagliflozin had a greater improvement in health status as assessed by a KCCQ total symptom score or for that matter KCCQ clinical summary overall summary score as compared to patients treated with placebo. So if you look at the mean effect, there is some improvement in the patients taking placebo. That's what we call a placebo effect. And it's very commonly seen in clinical trials. We assessed health status, but there was a greater improvement with dapagliflozin as compared with the placebo, it was statistically significant even in four months. But as the effects were further amplified to eight months and this differences were, I would say favorable when you kind of compare the effect of Dapagliflozin versus other established heart failure therapies when you look at the effects on health status.
What I think was even more important than analysis from a clinician standpoint, and then they think it's actually much more meaningful clinically is what we call a responder analysis. And that's where we look as the proportion of patients that have a clinically meaningful improvement with one type of therapy versus other in this case Dapagliflozin versus placebo.
So it's been previously established that at five-point difference or a five-point change rising KCCQ is what's considered to be clinically meaningful or minimal clinically meaningful difference. So a 5.2 grade deterioration KCCQ means it's a clinically important deterioration. And a five-point or greater improvement is a clinically important improvement. And then we also looked at the proportion of patients with moderate and large improvements in health status as well defined as STEM point of grade of two, or two point a great improvement. And essentially what we found was that significantly fewer patients treated with dapagliflozin and as compared with placebo had a clinical importance deterioration. And significantly greater proportion of patients treated with dapagliflozin has small, moderate, large improvements in health status. And the numbers needed to treat to see those differences, as the small moderate large improvements was very favorable ranging typically between 12 and 18 and over eight-months-treatment period.
Dr Greg Hundley: Outstanding. So both clinically relevant as well as statistically significant findings. Now we're going to bring in Justin, our associate editor. Justin, help us put these results into the just our perspective in looking at SGLT2 inhibitors, particularly for treatment for heart failure.
Dr Justin Ezekowitz: This is an exciting class of medications and we're eagerly awaiting these results because we saw the DAPA-HF Overall results. The majority of us treat patients with a pretty symptomatic disease and as such this quality of life is quite an important change. There's ongoing trials we're eagerly awaiting which are also going to be using other medications in the same class, but I think one question that remained was, are these simply improving symptoms by one meaning, so the total symptom score? Or the overall quality of life? And I think you nicely, elegantly portrayed that in the figures and you have. The one other part maybe Mikhail, you could expand upon, which is when you think about DAPA-HF, and the quality of life gains and across all the three different ways of looking at quality of life, where do you see this in terms of its relationship to other things that we know improve quality of life? Where we send patients, for example, CRT or put them on an RNE. Where does this fit on top of those types of changes?
Dr Mikhail Kosiborod: Thanks Justin. I think it's a really important question because it says think critical from a clinical standpoint to put it in the context of other therapies that had been previously shown to improve health status, which means again, reduced symptoms, improve physical and patient quality of life. And there are a number of perhaps the types of therapies on heart failure and LVCF that have been evaluated particularly on side this one there also have been studies with exercise training in heart failure or and the ones that you brought up, which is cardiac resynchronization therapy in patients with heart failure reduced ejection fraction and left bundle branch block. And as that perhaps, if you kind of think about it. What are some of the most effective treatments to improve the health status? That is ones that we typically would consider as such, which is CRT in patients with half RAF and a left bundle branch block.
And in fact, if you look at the mean effects dapagliflozin compares very favorably even with highly effective therapies such as TRT. Relatively few studies have previously reported to this responder in analysis. But if you look at Digoxin comparing those to dapagliflozin, one of the recent ones that I can think of is [inaudible 00:20:23], again dapagliflozin compares very favorably when you look at this types of responder analysis where again you look at proportion of patients, it was a clinically meaningful change.
So I think the beautiful thing about putting the study in the context of further studies looking at health status and also in the original main results that were published from a DAPA-HF early this year is that it's really kind of a full house if you will. So as the agent reduced deaths, reduced hospitalizations and made patients feel better and all of that, with very favorable safety profile. So, if you kind of think about risk benefit analysis and you look at numbers need to treat both for clinical outcomes such as CVS and hospitalizations for heart failure for example, where health status, it looks really impactful from a clinical standpoint.
Dr Greg Hundley: So relevance to other therapeutic interventions for heart failure is what this whole class of agents seems to be showing? So briefly, what do you see is the next important study in the field?
Dr Mikhail Kosiborod: I will waffle on this question a little bit and say there was more than one, but my views are there kind of two key components to this. One is that there are additional trials going on and heart failure with reduced ejection fraction with other agents. And so seeing what happens with those other agents in the class in a similar patient population and whether is this a class effect or not? Now the diabetes trials would suggest that these may well be class effects but I think it's nice to have validation of that. I would say that is one real important questions that hopefully we will have additional answers to in the coming year or so.
And the second and perhaps I would argue even more important question is whether these agents can also be effective in improving outcomes in patients with heart failure and preserved ejection fraction. That's a patient population that has also very high debilitating burden of symptoms that has poor prognosis and for which unlike them, half rubs, there are very few, if any medications that have been proven to be disease-modifying and actually have shown outcomes and benefit. So I would say those in my mind, are the two critical developments that we'll be seeing. And the good news is, there are the trials going on with more than one agent in a class and half to half as well. Great.
Dr Greg Hundley: And Justin?
Dr Justin Ezekowitz: Yeah, I think that there's been an explosion of therapies and Mikhail is bang on with this is the one class where we're excited about. I think the other groups of medications include Omecamtiv Mecarbil we'll know in a year or two. We'll hear more details in the spring and then there's a few other medications that Mikhail mentioned. I think this is a real good message though, that both HFrEF and HFpEF, it's the rise of medications again. Because we were on a device track for a while, but I think the medications have such more potent effect on the underlying structure and function that it's great to see that there's been such a development and explosion of medications that may obviate the need for implanted devices or advanced therapies, so we're very excited about that.
Dr Greg Hundley: Outstanding. Well, listeners, we've had the opportunity to hear from Mikhail Kosiborod from Saint Luke's Mid America Heart Institute and our own associate editor, Dr Justin Ezekowitz from Alberta, Canada, and learn more about SGLT2 inhibition and its importance in improving clinically symptomatology both in those with diabetes and heart failure, but also those with heart failure alone.
On behalf of Carolyn and myself, we wish you a great week and we look forward to running and having a coffee chat next week. Take care of. This program is copyright the American Heart Association, 2020