Impact of additive mitral valve surgery to coronary artery bypass grafting on mortality in patients with coronary artery disease and ischaemic mitral regurgitation: A systematic review and meta-analysis of randomized trials and observational studies

Aims Treatment of ischaemic mitral regurgitation (IMR) remains controversial. While IMR is associated with worse outcomes, randomized controlled trials (RCTs) and observational studies provided conflicting evidence regarding the benefit of mitral valve replacement (MVR) or repair (MVr) in addition to coronary artery bypass grafting (CABG). We conducted a meta-analysis incorporating data from published RCTs and observational studies comparing CABG vs. CABG + MVR/MVr. Methods and results WesearchedPubMed,MEDLINE, Embase,Ovid, andCochrane for RCTs and observational studies comparingCABG (Group 1) vs. CABG + MVR/MVr (Group 2). Outcome was 30-day and 1-year mortality after surgical intervention.Mantel-Haenszel odds ratio (OR) was calculated using random-effects meta-analysis for the outcome. Heterogeneity was assessed by I2 statistics. Four RCTs and 11 observational studies met the inclusion criteria (5781 patients, 507 in RCTs, 5274 in observational studies). Group 1 vs. 2 weighted mean left ventricular ejection fraction in RCTs and combined RCTs/observational studies was 41.5+12.3 vs. 40.3+10.4% (P-value = 0.24) and 45.5+7.2 vs. 38+10% (P-value , 0.001), respectively. In RCTs, there was no difference in 30-day [OR: 0.95, 95% confidence interval (95% CI): 0.30-3.08, P = 0.94] or 1-year (OR: 0.90, 95% CI: 0.43-1.87, P = 0.78) mortality, respectively. For combined RCTs/observational studies, therewas no difference in mortality at 30 days (OR: 0.67, 95% CI: 0.43-1.04, P = 0.08) or at 1 year (OR: 0.90, 95% CI: 0.7-1.15, P = 0.39). Conclusion In a meta-analysis of RCTs and observational studies of IMR patients, the addition of MVR/MVr to CABG did not improve survival.