Survival After Coronary Artery Bypass Grafting With or Without Mitral Valve Repair for Moderate Ischemic Mitral Regurgitation

BACKGROUND: The surgical management of moderate ischemic mitral regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) remains controversial, with limited real-world evidence, particularly from Asian populations. METHODS: We retrospectively analyzed 650 patients with moderate IMR who underwent isolated CABG (n = 493) or CABG with mitral valve repair (n = 157) between August 2009 and April 2024. Inverse probability of treatment weighting was applied to adjust for baseline differences. The primary end point was all-cause mortality; the secondary end point was major adverse cardiovascular and cerebrovascular events. RESULTS: During a median follow-up of 36.6 months, CABG with mitral valve repair was associated with lower all-cause mortality (multivariable hazard ratio, 0.41; 95% CI, 0.22-0.79; weighted log-rank P = .006) and fewer composite events (weighted log-rank P = .001), mainly driven by fewer deaths and rehospitalizations for heart failure. Findings were consistent across sensitivity and subgroup analyses. Echocardiographic follow-up (median, 11.6 months) showed greater improvement in mitral regurgitation (75.4% vs 50.4%; P < .001) and a larger reduction in left ventricular end-diastolic diameter (4.0 [0-7.8] mm vs 3.0 [-1.0 to 6.0] mm; P = .026). CABG with repair was associated with longer postoperative intubation, intensive care unit stay, and increased risk of acute kidney injury, without increased early mortality. CONCLUSIONS: In one of the largest Asian real-world cohorts, concomitant mitral valve repair during CABG for moderate IMR was associated with lower mortality and fewer major adverse cardiovascular and cerebrovascular events and greater echocardiographic improvement but at the expense of increased perioperative morbidity.