MIDA Registry: Mitral Valve Repair vs. Replacement

Study Questions:

Using data from a multicenter, international registry, what are the long-term outcomes of mitral valve (MV) repair versus replacement among patients with degenerative mitral regurgitation (MR)?


MIDA is a multicenter registry enrolling patients with degenerative MR and flail leaflet in six tertiary European and US centers between 1980 and 2005. Outcomes after MV repair (n = 1,709) and replacement (n = 213) were analyzed overall, by propensity score matching, and by case weight estimation with a regression model to try to predict the inverse probability of undergoing treatment with MV repair. Statistical modeling was used to try to determine the impact of type of surgery on survival, stratifying for age group (<65 years, 65-74 years, >75 years).


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.


Among patients with degenerative MR and flail leaflet referred for mitral surgery, the authors concluded that MV repair was associated with lower operative mortality, better long-term survival, and fewer valve-related complications compared with MV replacement.


There are no large, prospective, randomized trials comparing MV repair and replacement among patients with degenerative MR. The MIDA registry is useful in that it is a large, multicenter registry; but data analysis and interpretation are limited by the nonrandomized nature of the registry and the substantial clinical differences between patients (including which patients underwent intervention, and which underwent MV repair vs. replacement). These data support that MV repair may be superior to MV replacement among patients with degenerative MR and flail mitral leaflet, but the amount of statistical modeling employed still allows questions.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Cardiac Surgery and VHD, Interventions and Structural Heart Disease, Mitral Regurgitation

Keywords: Cardiac Surgical Procedures, Comorbidity, Heart Valve Diseases, Mitral Valve Insufficiency, Prolapse, Survival, Transcatheter Aortic Valve Replacement

< Back to Listings