Should the mitral valve be repaired for moderate ischemic mitral regurgitation at the time of revascularization surgery?

Background Ischemic mitral regurgitation (IMR) is associated with increased mortality and recurrent congestive heart failure following coronary artery bypass graft (CABG) surgery. While mitral surgery should be undertaken for severe MR during CABG, the treatment of moderate IMR remains controversial. We conducted a meta-analysis to determine the outcomes of CABG alone and combine with mitral valve repair (MVr) in moderate IMR. Methods A literature search was conducted by Pubmed, Ovid, and Embase, which included 643 articles. Eleven studies (seven observational studies and four randomized controlled trials) with a total of 1406 patients were included (CABG alone = 864 and CABG plus MVr = 542). Results There was no difference in operative mortality (odds ratio 1.56, 95% confidence interval [CI] 0.92-2.71) or long-term survival at 1 or 5 years (hazard ratio 0.98, 95%CI 0.71-1.35, P = 0.49) between the two groups, and little evidence of heterogeneity was found in the studies (I2 = 0.0, P = 0.562). There was significantly greater improvement in MR grade (weighted mean difference [WMD] −1.15, 95%CI −1.67 to −0.064, P = < 0.001) and left ventricular systolic diameter (WMD −3.02, 95%CI −4.85 to −1.18, P = 0.001) following CABG and MVr compared to CABG alone. No difference in postoperative functional class or ejection fraction was found. Conclusions Our results show that in the presence of moderate IMR, adding MVr to revascularization reduces MR grade on follow-up echocardiography and promotes ventricular remodeling, with no improvement in long-term survival or functional class.