Outcomes of mitral valve repair compared with replacement in patients undergoing concomitant aortic valve surgery: a meta-analysis of observational studies

Long-term superiority of mitral valve (MV) repair compared with replacement is well established in degenerative MV disease. In rheumatic heart disease, its advantages are unclear and it is often performed in conjunction with aortic valve (AV) replacement. Herein, we performed a systematic review and meta-analysis comparing outcomes of MV repair vs replacement in patients undergoing concomitant AV replacement. PubMed, Cochrane and Web of Science databases were searched up to 25 January 2014 for English language studies comparing outcomes of MV repair vs replacement in patients undergoing simultaneous AV replacement. Data of selected studies were extracted. Study quality, publication bias and heterogeneity were assessed. Analysis was performed using a random effects model (meta-analysis of observational studies in epidemiology recommendation). A total of 1202 abstracts/titles were screened. Of these, 20 were selected for full text review and 8 studies (3924 patients) were included in the final analysis: 1255 underwent MV repair and 2669 underwent replacement. Late outcome data were available in seven studies (cumulative follow-up: 15 654 patient-years). The early (in hospital and up to 30 days post-surgery) mortality risk ratio (RR): 0.68, 95% confidence interval (CI): 0.53-0.87, P = 0.003 and late (>30 days post-surgery) mortality (RR: 0.76, 95% CI: 0.64-0.90 P = 0.001) were significantly lower in the MV repair group compared with the MV replacement group. The MV reoperation rate (RR: 1.89, 95% CI: 0.87-4.10, P = 0.108), thromboembolism (including valve thrombosis) (RR: 0.65, 95% CI: 0.38-1.13, P = 0.128) and major bleeding rates (RR: 0.88, 95% CI: 0.49-1.57, P = 0.659) were found to be comparable between the two groups. In a separate analysis of studies with exclusively rheumatic patients (n = 1106), the early as well as late mortality benefit of MV repair was lost (RR: 0.92, 95% CI: 0.44-1.90, P = 0.81 and RR: 0.69, 95% CI: 0.39-1.22, P = 0.199, respectively), whereas the MV reoperation rate became significantly higher (RR: 5.10, 95% CI: 1.62-16.05, P = 0.005) with MV repair. In patients undergoing concomitant mitral and AV surgery, MV repair is associated with improved early and late survival without any increased risk for mitral valve reoperation. However, in patients with rheumatic heart disease MV repair does not impart any survival advantage while the risk for MV reoperation remains significantly higher.