Does combined mitral valve surgery improve survival when compared to revascularization alone in patients with ischemic mitral regurgitation? A meta-analysis on 2479 patients

Objectives Optimal treatment of significant (>= 2+ grade) ischemic mitral regurgitation remains controversial, and the impact of mitral valve surgery (MVS) at the time of coronary artery bypass grafting (CABG) on early and late results has to be still clarified. Methods A systematic literature search for studies comparing CABG combined to MVS (repair or replacement) compared with CABG alone in patients with ischemic mitral regurgitation and meta-analysis for late mortality, postoperative New York Heart Association functional class and late residual mitral regurgitation grade was performed. Risk ratios and the standardized mean difference (SMD) under the fixed or random effects model were reported. Results A total of nine observational nonrandomized studies were identified including 2479 patients with ischemic mitral regurgitation who underwent CABG alone (n = 1515) and CABG combined to MVS (n = 964). Meta-analysis of the pooled study population showed that MVS did not have advantages on late mortality [risk ratio 1.02; 95% confidence interval (CI) 0.90 to 1.14, P = 0.731 compared with CABG alone. Combined MVS was significantly associated with a lower residual mitral regurgitation grade compared with CABG alone (SMD = -0.9; 95% Cl -1.250 to -0.559-, P<0.0001). However, postoperative New York Heart Association class was not significantly improved in the combined MVS group (SMD = -0.26; 95% Cl -0.766 to -0.24; P = 0.30). Conclusion Most surgeons commonly use additional mitral valve procedure to treat moderate or severe ischemic mitral regurgitation, because it seems logical to assume that the volume overload associated with mitral regurgitation will be detrimental particularly to the patient with compromised left ventricular function. However, until definitive evidence about the superiority of this approach will be available, a tailored surgical strategy should be considered especially in mild ischemic mitral regurgitation. J Cardiovasc Med 10:109-114 (C) 2009 Italian Federation of Cardiology.