Results:

At baseline, patients undergoing MV repair were younger, had more comorbidities, and were more likely to present with a posterior leaflet prolapse than those undergoing MV replacement. After propensity score matching as well as after inverse probability-of-treatment weighting, the two treatment groups were balanced and absolute standardized differences were usually below 10%, suggesting adequate matching. Operative mortality (defined as a death within 30 days of surgery or during the same hospitalization) was lower after MV repair than after replacement, both in the entire cohort (1.3 vs. 4.7%; p < 0.001) and in the propensity-matched population (0.2% vs. 4.4%; p < 0.001). During a mean follow-up of 9.2 years (range 4.4–18.1 years), 552 deaths were observed, of which 207 were cardiovascular. Twenty-year survival was better after MV repair than after MV replacement, both in the entire cohort (46% vs. 23%, p < 0.001) and in the propensity-matched group (41% vs. 24%, p < 0.001). Similar superior results of MV repair versus replacement were noted in patient subsets based on age, sex, and other stratification criteria (all p < 0.001). MV repair also was associated with a reduced incidence of reoperations and valve-related complications.