Efficacy of Mitral Valve Repair as an Adjunct Procedure to Coronary Artery Bypass Grafting in Moderate Ischemic Mitral Regurgitation: A Meta-Analysis of Randomized Trials

OBJECTIVE: Whether moderate ischemic mitral regurgitation (IMR) should be repaired during coronary artery bypass grafting (CABG) is still uncertain. This meta-analysis of randomized controlled trials (RCTs) evaluated the efficacy of adding mitral valve repair (MVR) to CABG in patients with moderate IMR. METHODS: We searched PubMed, the Cochrane Library, and the Web of Science for RCTs that compared the efficacy of CABG plus MVR with CABG alone. Four RCTs that included 505 patients met the eligibility criteria. RESULTS: CABG + MVR significantly reduced the risk of intermediate residual mitral regurgitation (MR) grade ≥2+ compared with CABG alone (risk ratio [RR] = 0.20, 95% confidence interval [CI] 0.04-0.92, p = 0.04), but did not have advantages on 30-day/in-hospital mortality (RR = 1.06, 95% CI 0.37-3.09, p = 0.91), intermediate mortality (RR = 0.90, 95% CI 0.48-1.67, p = 0.73), risk of intermediate NYHA class ≥II (RR = 0.62, 95% CI 0.24-1.62, p = 0.33), intermediate left ventricular ejection fraction (LVEF) (SMD = 0.04%, 95% CI -0.35 to 0.42, p = 0.84), and intermediate LV end-systolic volume index (LVESVI) (SMD = -0.20 mL/m(2) , 95% CI -0.92 to 0.51, p = 0.58). CONCLUSION: Compared with CABG alone, adding MVR to CABG in patients with moderate IMR reduces the residual MR grade, but has no significant effect on mortality, intermediate NYHA class, LVEF, and LVESVI. Further RCTs with larger sample size and longer follow-up are needed to more clearly elucidate the efficacy of MVR as an adjunct procedure to CABG in patients with moderate IMR.