Predictive Value of Viable Myocardium of Papillary Muscle-Ventricular Wall Complex for Improvement in Moderate Ischemic Mitral Regurgitation

Background Performing a mitral valve procedure during coronary artery bypass grafting (CABG) in patients with coronary artery disease complicated by moderate ischemic mitral regurgitation (IMR) remains controversial. This study aimed to assess the benefit of isolated CABG and to develop a new index of viable myocardium within the papillary muscle-ventricular wall complex (VM-PM-VWC) to predict the improvement of IMR by CABG alone. Methods In total, 122 patients (age, 62.34 ± 8.53 years; 78.70% male) with moderate IMR who underwent CABG alone at Beijing Anzhen Hospital were retrospectively analyzed. All patients underwent 99m Tc-sestamibi single-photon emission computed tomography (SPECT) and 18 -fluorine fluorodeoxyglucose positron emission tomography ( 18 F-FDG PET) to evaluate the VM-PM-VWC. Based on the postoperative echocardiography results at 1-year follow-up, patients were divided into IMR-unimproved (moderate or severe IMR, n = 38) and IMR-improved (no or mild IMR, n = 84) groups. Factors associated with improvement were analyzed by multivariate logistic regression. Results The VM-PM-VWC was an independent factor for moderate IMR improvement (odds ratio, 1.16; 95% confidence interval [CI], 1.09-1.24; P < 0.001). The cutoff value for moderate IMR improvement was 12.50%, with a sensitivity and specificity of 76.32% and 80.95%, respectively (area under the curve [AUC] 0.830; 95% CI, 0.741-0.919; P < 0.001). During a median follow-up of 3.71 (interquartile range: 2.17-5.10) years, major cardiovascular and cerebrovascular event-free survival was higher in the improved group than in the unimproved group ( P < 0.001). Conclusions Most patients with moderate IMR improved from isolated CABG. The VM-PM-VWC was an independent predictor of IMR improvement, which could help surgical decision making. Clinical Trial Registration ChiCTR2100042454.