Patients with heart failure with preserved ejection fraction (HFpEF) without obesity have a higher prevalence of coronary microvascular dysfunction (CMD) compared with obese patients, a report shows. These results were reported by Kai Nogami, MD, from Mayo Clinic in Rochester, Minnesota, and colleagues, in a manuscript published online in JACC: Heart Failure. HFpEF has become increasingly common, along with obesity, and these two combined have been categorized as an individual clinical presentation. Weight loss is typically associated with better clinical outcomes. The association between HFpEF and non-obese patients has been studied less frequently, and data are lacking. HFpEF is also commonly known to be associated with CMD, and CMD and obesity do not have a direct association. The investigators in this single-center study examined the pathophysiology of HFpEF in non-obese patients by looking at these patients’ coronary microvasculature. This was a retrospective cohort study that took place between 2005 and 2025. Patients were evaluated for endothelium-dependent CMD (CMDE− ), defined as an endothelium-dependent coronary flow reserve (CFR) <1.5, and endothelium-independent CMD (CMDE+), defined as endothelium-independent CFR (CFRE-) <2.5. Patients included in the study had exertional cardiac symptoms and angina with nonobstructive coronary arteries (ANOCA) and underwent coronary function testing (CFT) as well as exercise right heart catheterization (RHC). A total of 314 patients were included in the Mayo Clinic study, and 172 of them had data available from endothelium-dependent and endothelium-independent testing. Of these patients, 45.9% had obesity and 33.1% had HFpEF. Patients without obesity but with HFpEF had significantly higher rates of CMDE- (with obesity=47.1%, without obesity=78.3%; p=0.028) and CMDE+ (with obesity=55.9%, without obesity=82.6%; p=0.047), compared with obese patients. Patients with HFpEF and no obesity had higher rates of both CMDE- and CMDE+ combined (65.2%) compared with those who were obese (26.5%). Non-obese patients were more likely to have both CMD phenotypes if they had HFpEF compared with non-obese patients who did not have HFpEF. Patients with lower CFRE- were significantly more likely to have HFpEF if they were not obese (p<0.001). This association was not seen in patients who had obesity. “These data suggest the important role of CMD in the pathophysiology of HFpEF, highlighting a relatively greater role in patients without obesity,” the authors wrote, noting that they are currently conducting a trial to evaluate a coronary sinus reducer in patients with concomitant HFpEF and CMD (Efficacy of the COronary SInus Reducer in Patients With Refractor Angina II [COSIRA-II]). Overall, patients with ANOCA and HFpEF who were not obese had higher rates of CMD compared with obese patients. HFpEF and CMD were also significantly associated with one another, indicating potential CMD mechanisms underlying HFpEF development in non-obese patients. Source: Nogami K, Borlaug BA, Harada T, et al. Higher prevalence of coronary microvascular dysfunction in patients with HFpEF without obesity. JACC Heart Fail. 2026 January 27 (Article in Press). Image Credit: PeakPoints/peopleimages.com – stock.adobe.com