Mitral valve surgery and coronary artery bypass grafting for moderate-to-severe ischemic mitral regurgitation: meta-analysis of clinical and echocardiographic outcomes

Objective: This meta-analysis was conducted to compare clinical and echocardiographic outcomes following isolated coronary artery bypass grafting (CABG) versus CABG and mitral valve (MV) surgery in patients with moderate-to-severe ischemic mitral regurgitation (IMR). Methods: Seven databases were systematically searched to identify relevant studies. For eligibility, studies were required to report on the primary endpoint of perioperative or late mortality. Data were analyzed according to predefined clinical endpoints. Results: Four randomized controlled trials (RCTs) (n = 505) and 15 observational studies (OS) (n = 3785) met the criteria for inclusion. Compared with isolated CABG, concomitant CABG and MV surgery was not associated with increased perioperative mortality (RCTs: relative risk [RR] 0.89, 95% confidence interval [CI], 0.26-3.02; OS: RR 1.40, 95% CI, 0.88-2.23). CABG and MV surgery was associated with significantly lower incidence of moderate-to-severe MR at follow-up (RCTs: RR 0.16, 95% CI, 0.04-0.75; OS: RR 0.20, 95% CI, 0.09-0.48). Late mortality was similar between the surgical approaches in RCTs (hazard ratio [HR] 1.20, 95% CI, 0.57-2.53) and OS (HR 0.99, 95% CI, 0.81-1.21). There were no significant differences in echocardiographic outcomes. These results remained consistent in subgroup analyses restricted to patients with strictly moderate IMR. Conclusions: In patients with moderate-to-severe IMR, the addition of MV surgery to CABG was not associated with increased perioperative mortality. Although concomitant MV surgery reduced recurrence of moderate-to-severe MR at follow-up, this was not associated with a reduction in late mortality. Larger trials with longer follow-up duration are required to further assess long-term survival and freedom from reintervention.