Long-term outcomes comparison of mitral valve repair or replacement for secondary mitral valve regurgitation. An updated systematic review and reconstructed time-to-event study-level meta-analysis.

Background and aim. The ideal surgical intervention for secondary mitral regurgitation (SMR), a disease of the left ventricle not the mitral valve itself, is still debated. We performed an updated systematic review and study-level meta-analysis investigating mitral valve repair (MVr) versus mitral valve replacement (MVR) for adult patients with SMR, with or without coronary artery disease (CAD).Methods. PubMed, CENTRAL and EMBASE were searched for studies comparing MVr versus MVR. Randomized trial or observational studies were considered eligible. Primary endpoint was long-term mortality for any cause. Kaplan-Meier survival curves were reconstructed and compared with Cox linear regression. Landmark analysis and time-varying hazard ratio (HR) were analyzed. Sensitivity analyses included meta-regression and separate sub-analysis. A random effects model was used.Results. Twenty-three studies (MVr=3,727 and MVR=2,839) were included. One study was a randomized trial, and 19 studies were adjusted. The mean weighted follow-up was 3.7±2.8 years. MVR was associated with significative greater late mortality (HR=1.26; 95% CI, 1.14-1.39; P<0.0001) at 10-year follow-up. There was a time-varying trend showing an increased risk of mortality in the first 2 years after MVR (HR=1.38; 95% CI, 1.21-1.56; P<0.0001), after which this difference dissipated (HR=0.94; 95% CI, 0.81-1.09; P=0.41). Separate sub-analyses showed comparable long-term mortality in patients with concomitant coronary surgery ≥90%, left ventricle ejection fraction ≤40%, and sub-valvular apparatus preservation rate of 100%.Conclusions. Compared to repair, MVR is associated with higher probability of mortality in the first 2 years following surgery, after which the two procedures showed comparable late mortality rate.