Recovery of left ventricular function after surgical correction of mitral regurgitation caused by leaflet prolapse.

OBJECTIVE: Recovery of ventricular function after surgical correction of mitral regurgitation is often incomplete. We studied clinical and echocardiographic factors influencing return of normal left ventricular ejection fraction after mitral valve repair or replacement for mitral regurgitation caused by leaflet prolapse.
METHODS: We evaluated 1063 patients who had mitral valve repair or replacement between January 1, 1980, and December 31, 2000. A total of 2488 echocardiograms with follow-up ejection fractions were available for analysis.
RESULTS: Of the patients, 761 were men, 924 had valve repair, and 85% underwent surgery during the study's second decade. Compared with patients who had the operation in the 1980s, patients who had surgery in the 1990s had significantly smaller preoperative left heart dimensions and a 2.4-fold greater likelihood of an ejection fraction more than 60% during follow-up. Factors independently associated with higher ejection fraction at follow-up included valve repair (vs replacement), freedom from preoperative myocardial infarction, operation in the 1990s, greater preoperative ejection fraction, and smaller left ventricular dimensions. Patients with an ejection fraction of less than 50% at discharge were 3.5-fold less likely to recover normal ejection fraction during long-term follow-up (P < .001). Patients had a greater likelihood of a follow-up ejection fraction more than 60% if preoperative ejection fraction was more than 65% (hazard ratio, 1.7) or left ventricular end-systolic dimension was less than 36 mm (hazard ratio, 2.0).
CONCLUSION: Early repair of mitral regurgitation caused by leaflet prolapse, before deterioration in left heart size or function, increases the likelihood of subsequent normalization of left ventricular ejection fraction.