Oct 21, 2019
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Dr Greg Hundley, associate editor for Circulation, from the Pauley Heart Center at VCU Health in Richmond, Virginia. Well, Carolyn, our feature article, this issue reminds us of the importance of the physical exam in patients with heart failure and reduced ejection fraction involving those that were enrolled in the PARADIGM-HF. Remember a trial of sacubitril/valsartan versus ACE inhibition in those with a reduced ejection fraction? Can't wait to hear more of the discussion of the importance of that physical exam. Carolyn, how about you talk about your first article?
Dr Carolyn Lam: I will because this first paper reports a novel ventricular tachycardia or VT ablation strategy guided by a voltage independent mapping display during sinus rhythm.
Dr Greg Hundley: Well, Carolyn, since many of us don't do VT ablations every day, how about a little background on this one first?
Dr Carolyn Lam: Substrate modification during sinus rhythm is actually the mainstay ablation strategy for scar related VT. With the recent trend being more extensive ablation, aimed to homogenize the entire scar region. These authors are led by Dr Tung from the University of Chicago Medicine Center for Arrhythmia Care, and colleagues. They had hypothesized that a greater understanding of the nature and characteristics of the scar would be most prone to reentry, may actually improve the precision and yield of ablation. Now, they had previously demonstrated that sites critical for reentrant VT localized to regions of activation slowing during sinus rhythm or so-called deceleration zones rather than regions with latest activation. In the current study, they aim to prospectively assess the outcomes of VT ablation guided primarily by targeting these deceleration zones identified by propagational analysis of ventricular activation during sinus rhythm.
Dr Greg Hundley: Interesting. What did they find, Carolyn?
Dr Carolyn Lam: They studied 120 patients with scar related VT who are prospectively enrolled in the U Chicago VT ablation registry between 2016 and 2018, who underwent 144 ablation procedures for scar related VT. They performed high density mapping during baseline rhythm and identified the deceleration zones which all localized to successful termination sites in 95% of cases. The median total radio frequency application duration was 29 minutes to target the deceleration zone, representing ablation of 18% of the low voltage area. At a mean of 12 months, 70% freedom from VT recurrence was achieved with an overall survival rate of 87%. A novel voltage independent high-density mapping display may further identify the functional substrate for VT during sinus rhythm and guide targeted ablation thus obviating the need for extensive radio frequency delivery.
Dr Greg Hundley: Fantastic, Carolyn.
Well, my first paper is from Professor Mark Nicolls from Stanford University. It's entitled Phenotypically Silent Bone Morphogenic Protein Receptor 2 or Bmpr2 mutations, that predispose rats to inflammation induced pulmonary arterial hypertension by enhancing the risk for neointimal transformation. While being the most common inherited risk factor for pulmonary arterial hypertension, Bmpr2 germ line mutations only result in disease in 20% of mutation carriers. A finding that suggest a second hit is required to elicit vascular pathology. Transgenic mouse models of Bmpr2 mutations were developed in this study to better understand the relationship between these phenotypically silent gene mutations and the predisposition to pulmonary arterial hypertension.
Dr Carolyn Lam: Huh. What did they find Greg?
Dr Greg Hundley: In this new two hit model of disease, Bmpr2 mutant rats subjected to pulmonary inflammation, developed severe pulmonary arterial hypertension with vascular remodeling and the pulmonary arterial endothelial cell transformation that occurred did so in three phases. An initial apoptosis phase induced by exogenous LTB4. Second, a proliferative phase relying on P38 mediated noncanonical TGF-beta signaling. And then finally a terminal inflammatory phase in which pulmonary arterial endothelial cells utilized the canonical TGF-beta pathway, expressed mesenchymal markers and produced LTB4, IL6 and NF-kappa beta signaling molecules. The clinical implications include that in phenotypically silent Bmpr2, haploinsufficient individuals, a second hit of pulmonary inflammation may put them at risk for subsequently developing pulmonary arterial hypertension. And this lung inflammation while usually self-limited may cause durable and inflammatory vascular lesions in these genetically susceptible patients.
Dr Carolyn Lam: Wow, that is super interesting. Thanks Greg for that great summary.
Well, my next paper really looks at the temporal trends in survival after pediatric in hospital cardiac arrest in the United States. This is from Dr Holmberg from Beth Israel Deaconess Medical Center and colleagues who performed an observational study of hospitalized pediatric patients who received CPR from January 2000 to December 2018 and were included in the Get With the Guidelines resuscitation registry.
Dr Greg Hundley: Carolyn, what did they find?
Dr Carolyn Lam: They found that survival has improved for pediatric events requiring CPR in the US with a 19% absolute increase in survival for in hospital pulseless cardiac arrests and a 9% absolute increase in survival for non-pulseless events between 2000 and 2018. However, survival from pulseless cardiac arrest appeared to have reached a plateau following 2010. The increase in survival over time is reassuring and perhaps provides some evidence for the progress of quality improvement efforts. However, given the plateau and survival following 2010, there is a continued need for clinical focus and new interventions to improve outcomes of pediatric in hospital cardiac arrests. And Greg, are you now going to tell us what's in the mailbag?
Dr Greg Hundley: Absolutely Carolyn. Professor Wei, from Harvard, provides a new perspective on using the restricted mean survival time difference as an alternative to the proportional hazards model and hazard ratios for analyzing risk in clinical cardiovascular studies. In another article, Eric Peterson from Duke provides a white paper discussing randomized clinical trials versus EMR extracted data to inform new therapies in cardiovascular disease. And he really reviews what are the issues we need to overcome using these EMR strategies? And on my mind piece from Dr Glenn Levine from Baylor, discusses the role of psychological wellbeing as it relates to cardiovascular disease. And then we have a large series of letters in this issue.
First, Otmar Pfister and Kari Nytrøen, each have letters regarding high intensity interval training. Dong-Vu Nguyen, asked for several points of clarification regarding the utility of BNP assessments in syncope and whether other metrics incorporating clinical information could be useful. There's a corresponding response from Christian Müller from the PRICIPLE study with great discourse. And then finally an important research letter from Dr Rodés-Cabau in Quebec, evaluates the left atrial occlude or thrombus occurrence among eight centers in Canada and in this letter provides data that suggests thrombi can occur in those that have implanted left atrial occluders and raises considerations for anticoagulation of these patients. Great set of letters in this issue of the journal.
Dr Carolyn Lam: Absolutely Greg and thanks for sharing that. Let's go onto our feature discussion.
Dr Greg Hundley: You bet.
Welcome everyone to discussion of our featured article and today we have Senthil Selvaraj from University of Pennsylvania and our own Mark Drazner, associate editor at Circulation from the University of Texas Southwestern and we're going to be discussing some very interesting results regarding the physical exam as they've been generated from the PARADIGM heart failure trial. And remember that's a prospective comparison of an Angiotensin Receptor-Neprilysin inhibitor with an angiotensin converting enzyme inhibitor to determine the impact of those two therapies on all-cause mortality and also morbidity in heart failure. Senthil, welcome to this discussion. We're very excited to have the opportunity to discuss your article and I wonder before we get started, could you tell us a little bit about the background and the hypothesis for why you wanted to perform the study and then afterwards tell us a little bit about the study population and the methods.
Dr Senthil Selvaraj: I think the impetus for this study torn out of the fact that we do the clinical exam so often, and I think like many cardiology clinicians in the community, we perform this so often, but we don't know what the actual impact is of performing the clinical exam. What I wanted to understand and the primary motivation was to really understand what the change in the physical exam meant in terms of subsequent prognosis. Does decreasing congestion actually relate to improved cardiovascular outcomes? I think this is an area that is hard to study by randomized controlled trials. In my opinion I think there is not so much equipoise in performing a trial of decongestion versus no decongestion. I think this is sort of one way that we can understand epidemiologic methods, whether lowering congestion improve outcomes.
I had a number of other interesting analysis. I think the first is we've had a number of studies that have evaluated the physical exam, but I think that an updated analysis in a population receiving contemporary management was particularly important, particularly given the fact that the risk rad versus insignificantly in the past couple of decades essentially related to improvements in therapy. The second is we formed the physical exam in conjunction with a number of other additional forensic markers in the use of validated risk scores that to understand those and have utility above and beyond this. For instance, can I just check a natural aside and will that be doing a physical exam. And I think while that's easier, I don't know that that necessarily is the right thing to do. And that was another motivation.
Dr Greg Hundley: What was your overall study design and your study population?
Dr Senthil Selvaraj: The overall study design was to use the PARADIGM-HF cohort. And in our analysis, we did a time updated analysis, which is different than many other analyses previously done. That means that every single point that a patient goes into a clinical trial visit, we updated their physical exam, possible because the study investigators did perform an exam at each of these visits. And so what we did was we used the physical exam and number of signs of congestion as the time bearing covariate and looked at its relationship to outcomes, but also just as importantly why might think decreasing congestion or changing congestion has really stuck out as very important about to want to feel better. And I anything quantifying that relationship while it's intuitive I think is also very important.
Dr Greg Hundley: And just remind us who's in PARADIGM heart failure? Well what was the study population? And just very quickly the randomization arms?
Dr Senthil Selvaraj: PARADIGM-HF was a randomized controlled international multicenter trial of patients with heart failure ejection fraction which has been defined in this study as less than or equal to 40%, near two, three or four symptoms, elevated natriuretic peptides, depending on the trial compared an angiotensin converting enzyme inhibitor and Angiotensin Neprilysin inhibitor to control valsartan.
Dr Greg Hundley: Tell us what were your study results? And how did they pertain to the outcomes that were gathered in PARADIGM-HF?
Dr Senthil Selvaraj: We first divided our cohort based upon the total number of signs and as might imagine increasing congestion was associated with a number of adverse clinical features. We then looked at the association between the number of signs and the efficacy outcomes, which included a primary composite outcome of time to heart failure, hospitalization as well as cardiovascular mortality and then we individually looked at those as well as all-cause mortality. And as we show in our paper, there was really a striking relationship between time updated times of congestion as well as all of the efficacy adjusted for baseline natriuretic peptides which are available in all of our participants in PARADIGM-HF as well as MAGGIC risk score and New York Heart Association class to get at the question of whether improving congestion, where the relationship congestion above and beyond symptoms is still valid.
The other thing that we did is because we only looked at natriuretic peptides at baseline is that we've formed a sub study where we evaluated, since you had natriuretic peptides during follow-up as well at the one month visit and eight month visit and compare the utility of signs of congestion and outcomes and you can still see that there was a significant relationship in this sub analysis. The participants would complete NP data. We further looked at relationship and congestion and quality of life and there is a significant relationship such that for every sign of congestion that you decrease, there is a five-point increase in KCCQ, the quality of life score which some have considered to be a clinically significant increase in times of congestion.
We also looked at the relationship between the treatment arm and reduction of congestion as sacubitril/valsartan was associated with significant reduction in clinical congestion, which has mirrored its impact on natriuretic peptides as well. And finally to understand whether reducing congestion was actually associated with improved outcomes, we entered both the baseline congestion and change of congestion into models that looked at the relationship with outcomes and found that change of congestion was a very strong predictor of outcomes even after baseline congestion, which we interpreted to mean that reduction in congestion was a mutable factor, and that reducing congestion is actually associated with improved outcomes.
Dr Greg Hundley: Signs of congestion on the physical exam, you had JVD, peripheral edema, rales, and then an S3 and so you're adding those up and making a score. And so when one of those particular findings dropped off in terms of score, that's what you're indicating by change in congestion, is that correct?
Dr Senthil Selvaraj: That's really correct. We analyzed this in two methods. The first is a dichotomous presence of a physical exam science. As you said, the presence or absence of JVD, the presence or absence of a DMO rales and an aspirate. The investigators also graded two of those signs of congestion, which included a DMN rale that we formed a complimentary analysis where we created a sign score where we gave partial credits to gradations of the physical exam and we saw very similar outcomes as well.
Dr Greg Hundley: Mark Drazner at UT Southwestern has done a lot looking at the importance of our physical exam and assessing patients with heart failure. Mark, how do you feel the results of this study compare with previously published works?
Dr Mark Drazner: Thanks Greg. First, always a pleasure to join you on this and I do want to congratulate Dr Selvaraj and his team on this outstanding paper to generate considerable enthusiasm among the editorial team and reviewers I'd say. It's a really interesting study for several fold and you've heard a lot of the important methods by Dr Selvaraj already. I would just highlight there've been a number of previous studies that have looked at markers of congestion from physical exam and showed that they had prognostic utility, but a major question that has been addressed to me personally and I think in the field, does that add any independent information beyond just sending BMPR natriuretic peptide level measurement?
And this analysis here as you've heard, one of the big advances was that they were able to adjust for natriuretic peptide levels and showed that the exam or the markers of congestion did add independent prognostic information. I think that's an important step forward, as is bringing the relevance again about the markers of congestion and prognostic utility to patients being receiving the most modern-day therapy including ARNI therapy, which is unparalleled opportunity because of the PARADIGM trial to look at that question. I think those two are really set this paper. I think this is going to be a standard, this is the standard for assessing prognostic utility congestion in heart failure by far in the literature in my opinion.
Dr Greg Hundley: What we're saying is that our following the patients and identifying these physical exam changes during an initiation of ARNI therapy can be really helpful in determining that particular patient's long-term prognosis. Coming back to both of you, maybe first Mark and then we'll come back to Senthil, what do you see is the next study in this field? Both in terms of new therapies in heart failure and the relationship of physical exam and then also perhaps just briefly some thoughts on ARNI therapy.
Dr Mark Drazner: I think this paper highlights the incredible importance of congestion in modern day therapy. And there are a number of other studies that looked at this recently, including there's an analysis of TOPCAT preserved heart failure showing again congestion being linked to adverse outcomes. I think that question is resolved that even in modern day therapy. The next step in my opinion is to understand why clinical congestion, the pathway from clinical congestion to adverse outcomes. What are the links? Can we target those links to try to interrupt that cycle? And what is the most effective way to achieve decongestion? We heard that now ARNI appears to be a mediator of decongestion and we need more work on that I think. I would say looking at the pathway from congestion to adverse outcomes and then what is the optimal way to decongest our patients.
Dr Greg Hundley: Very good. Senthil, do you have anything to add to that?
Dr Senthil Selvaraj: I think that's great. I completely agree with Dr Drazner on this. I think one question would be to understand truly as Dr Drazner said, the optimal way to decongest patients and so for instance, the way that we have traditionally done this is by increasing diuretic. There are a number of experimental and novel ways that we can decongest patients. I think one unanswered question actually is does increasing a diuretic potentially at the expense of activating the renin angiotensin aldosterone access, actually afford benefit if you decongest patients. It's an analysis that I think is ripe and timely and not been adequately addressed. I think that that would be one potential way to go. And the second is, I think as you mentioned in clinical trials, I think clinical congestion may not be an outcome, a pre-specified outcome of course. But I do think that it is an important outcome aside from just looking at decreases in other surrogate markers such as natriuretic peptides. It's easy to perform. It's collected on many investigator visits during these trials and therefore these are ripe analyses.
Dr Greg Hundley: Listeners, we look forward to speaking with you next week and have a great week.
Dr Carolyn Lam: This program is copyright American Heart Association 2019.