Surgical Repair of Moderate Ischemic Mitral Regurgitation--A Systematic Review and Meta-analysis

Introduction Moderate mitral regurgitation (MR) of ischemic etiology has been associated with worse outcomes after coronary artery bypass grafting (CABG). Studies comparing concomitant mitral valve replacement/repair (MVR/Re) with CABG and standalone CABG have reported conflicting results. We performed a systematic review and meta-analysis of the published literature. Patients and Methods We searched using PubMed, Cochrane, EMBASE, CINAHL, and Google scholar databases from January 1960 to June 2016 for clinical trials comparing CABG to CABG + MVR/Re for moderate MR. Pooled risk ratio or mean difference (MD) with 95% confidence intervals (CI) for individual outcomes were calculated using random effects model and heterogeneity was assessed using Cochrane's Q-statistic. Results A total of 11 studies were included. Mean follow-up was 35.3 months. All-cause mortality (Mantel-Haenszel [MH] risk ratio [RR]: 0.96, 95% CI: 0.75-1.24, p = 0.775), early mortality (MH RR: 0.65, 95% CI: 0.39-1.07, p = 0.092), and stroke rates (MH RR 0.65, 95% CI: 0.21-2.03, p = 0.464) were similar between CABG and CABG + MVR/Re groups. Adverse event at follow-up was lower with CABG (MH RR: 0.90, 95% CI: 0.61-1.32, p = 0.584). MD of change from baseline in left ventricular (LV) end-systolic dimension (MD: - 2.50, 95% CI: - 5.21 to - 0.21, p = 0.071) and LV ejection fraction (MD: 0.48, 95% CI: - 2.48 to 3.44, p = 0.750) were not significantly different between the groups. Incidence of moderate MR (MH RR: 3.24, 95% CI: 1.79-5.89, p < 0.001) was higher in the CABG only group. Conclusion Addition of MVR/Re to CABG in patients with moderate ischemic MR did not result in improvement in early or overall mortality, stroke risk, or intermediate markers of LV function when compared with CABG alone.