For this week's Feature Discussion, please join authors Erik Näslund, Mehran Anvari, Editorialist Philip Schauer, and Associate Editor Ian Neeland as they discuss, in a panel forum, the articles: "Association of Metabolic Surgery With Major Adverse Cardiovascular Outcomes in Patients With Previous Myocardial Infarction and Severe Obesity: A Nationwide Cohort Study," "Bariatric Surgery and Cardiovascular Outcomes in Patients With Obesity and Cardiovascular Disease: A Population-Based Retrospective Cohort Study," and accompanying editorial "After 70 Years, Metabolic Surgery has Earned a Cardiovascular Outcome Trial." 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, Director of the Pauley Heart Center in Richmond, Virginia with VCU Health. Well, Carolyn, another double feature this week and investigating the world of metabolic, or as we also know, bariatric surgery and the impact of bariatric surgery on cardiovascular outcomes. Dr. Greg Hundley: But before we get to that double feature discussion today, how about we grab a cup of coffee and we jump into some of the other articles in the issue. I'll go first this week, Carolyn. The first article comes from Professor Andreas Schuster from University Medical Center in Göttingen. Carolyn, as you know, right heart catheterization using exercise stress represents a key method for the diagnosis of heart failure with preserved ejection fraction but carries the risk of that invasive procedure. These authors hypothesized that real time cardiovascular magnetic resonance exercise imaging with pathophysiologic data at excellent temporal and spatial resolution may represent a contemporary non-invasive alternative for diagnosing HFpEF. Dr. Carolyn Lam: Wow, Greg, you know how I love talking about HFpEF? I actually managed this paper. Could you just describe what they found? It's so exciting. Dr. Greg Hundley: Yeah, Carolyn. Even the methods are interesting here, where these authors created a situation where you're riding a bicycle and obtaining an MRI scan at the same time. Let's get to the results. The HFpEF stress trial, prospectively recruited 75 patients with echocardiographic signs of diastolic dysfunction and dyspnea on exertion with E to E primes greater than eight, New York Heart Association class greater than or equal to two. To then, undergo echocardiography, right heart catheterization and then this real time pedaling a bicycle CMR exam at rest and during exercise stress. And so what they found Carolyn, the real time CMR allowed a highly accurate identification of HFpEF during physiological exercise and qualifies, perhaps, as a suitable non-invasive diagnostic alternative to the invasive procedures. So Carolyn, I think these results will need to be confirmed in a multicenter prospective approach, but really interesting innovation here, in this particular study. Dr. Carolyn Lam: So Greg, the paper I want to talk about, actually, is the first indicative critical role of cardiac macrophages in pressure overload-induced cardiac fibrosis and dysfunction and reveal macrophage micro RNA-21 as a key molecule for the pro-fibrotic role of cardiac macrophages. Now, this comes from Dr. Engelhardt from Munich, Germany, and colleagues who show that within the myocardium, micro RNA-21 has the strongest expression in cardiac macrophages. Where it is also the single strongest express micro RNA among all micro RNAs. Targeted genetic deletion of micro RNA-21 in macrophages of mice prevented their pro-inflammatory polarization and subsequent pressure overload-induced cardiac fibrosis and dysfunction. Analysis of intercellular communication using cell sequencing identified the cardiac fibroblasts as the primary recipient cell of intercellular signal