The number of myocardial infarction segments connected to papillary muscle is associated with the improvement in moderate ischemic mitral regurgitation

BACKGROUND: We evaluated whether the number of myocardial infarction (MI) segments connected to the papillary muscle (PM), as assessed using cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE), predicts whether moderate ischemic mitral regurgitation (IMR) improves after isolated coronary artery bypass grafting (CABG) to guide the choice of surgical strategy. METHODS: A total of 54 patients diagnosed with coronary heart disease (CHD) complicated with moderate IMR who underwent isolated CABG were selected continuously in this retrospective study at Beijing Anzhen Hospital. All patients underwent preoperative LGE. The patients were divided into the IMR improved group (37 patients) and the unimproved group (17 patients) according to 1-year postoperative echocardiography. The factors associated with no IMR improvement after isolated CABG were analyzed. There was no trial registration and no publication of the study protocol. RESULTS: The number of MI segments connected to PM was an independent risk factor for no IMR improvement after isolated CABG [odds ratio 4.39; 95% confidence interval (CI): 1.93–9.98; P<0.001]. The optimal receiver operating characteristic (ROC) curve cut-off value for no IMR improvement was ≥2 (sensitivity: 82.4%; specificity: 83.8%). Follow-up at 1–5 years (median, 2.8 years) showed that the incidences of major adverse cardiovascular and cerebrovascular events (5.4% vs. 23.5%; P=0.041) and New York Heart Association (NYHA) grade (P=0.026) were higher in the unimproved group. CONCLUSIONS: In patients with CHD complicated with moderate IMR, the number of MI segments connected to PM is an independent risk factor for no IMR improvement after isolated CABG. Mitral valve surgery should be performed simultaneously with CABG in patients with ≥2 MI segments connected to the PM.