Abstract 18949: Bariatric Surgery is Associated With Improved Coronary Microvascular Function and Cardiorespiratory Fitness in Patients With Ischemia and Non-Obstructive Coronary Arteries (INOCA)

Abstract

Introduction - Severe obesity is associated with cardiometabolic disease and coronary microvascular dysfunction, as reflected by impaired coronary flow reserve (CFR). Bariatric surgery promotes sustained weight loss and lower incidence of diabetic microvascular complications, but its effect on the coronary microcirculation is unclear. In this ongoing pilot study, we aimed to investigate the impact of bariatric surgery on CFR, endothelial function, and cardiorespiratory fitness in patients with severe obesity and INOCA. Methods - Consecutive patients (N=19) with severe obesity (BMI≥35 kg/m 2 ), exertional dyspnea and planned bariatric surgery were enrolled. Patients underwent cardiac stress positron emission tomography (PET), peripheral arterial tonometry (PAT), echocardiogram and cardiopulmonary exercise testing (CPET) at baseline and after a median of 6.2 months post-surgery (N=9 completed to date). CFR was quantified as stress/rest myocardial blood flow (MBF) from PET. Reactive hyperemia index (RHI), a marker of endothelial function, was calculated as the ratio between PAT signal post and pre-occlusion in the corresponding arm. Results - Median age was 50 (Q1-Q3 42-54) years and 63% were female. At baseline, median BMI was 43 (40-54), LVEF was 0.62, and %LV visual ischemia was 0. Higher BMI inversely correlated with CFR (r= -0.53, p=0.02). As compared to baseline, patients post-surgery (78% sleeve gastrectomy, 22% gastric bypass) had significantly decreased BMI (45.2 vs. 34.3, p=0.008) and improved stress MBF [1.8 (1.3-2.2) vs. 2.4 (1.8-2.8), p<0.02], CFR [2.3 (1.9-2.6) vs. 3.1 (2.4-3.6), p<0.02] and peripheral endothelial function [RHI 1.5 (1.4-1.8) vs. 2.4 (1.8-2.8) vs. p=0.04]. These changes were accompanied on CPET by significantly higher exercise workload [112 (84.2-146) vs. 124.5 (90.5-149) W, p=0.046] and relative peak VO 2 [12.5 (11.9-14) vs. 15.2 (12.6-17) mL/kg/min, p=0.028]. Higher stress MBF directly correlated with relative peak VO 2 (r=0.53, p=0.04). Conclusion - In this pilot clinical study, bariatric surgery was associated with significant improvements in coronary microvascular function, peripheral endothelial function, and cardiorespiratory fitness in symptomatic patients with severe obesity after six months.