Long-term clinical outcome of mitral valve repair in asymptomatic severe mitral regurgitation.

OBJECTIVE: To assess the long-term survival, the incidence of cardiac complications and the factors that predict outcome in asymptomatic patients with severe degenerative mitral regurgitation (MR) undergoing mitral valve repair.
METHODS: Up to 143 asymptomatic patients (mean age 63+/-12 years) with severe degenerative MR who underwent mitral valve repair between 1990 and 2001 were subsequently followed up for a median of 8 years. The study population was subdivided into three subgroups: patients with left ventricular (LV) dysfunction and/or dilatation (n=18), patients with atrial fibrillation and/or pulmonary hypertension (n=44) and patients without MR-related complications (n=81).
RESULTS: For the patients, 10-year overall and cardiovascular survival was 82+/-4% and 90+/-3%. At 10 years, patients without preoperative MR-related complications had significantly better overall survival than patients with preoperative LV dysfunction and/or dilatation (89+/-4% vs 57+/-13%, log rank p=0.001). Patients without preoperative MR-related complications also tended to have a better 10-year overall and cardiovascular survival than patients with atrial fibrillation and/or pulmonary hypertension (overall survival of 79+/-8%), although this did not reach statistical significance (log rank p=0.17). Cox regression analysis identified the baseline left ventricular ejection fraction and age as the sole independent predictors of outcome.
CONCLUSION: Our data indicate that in asymptomatic patients with severe degenerative MR, mitral valve repair is associated with an excellent long-term prognosis. Nonetheless, the presence of preoperative MR-related complications, in particular LV dysfunction and/or dilatation, greatly attenuates the benefits of surgery. This suggests that mitral valve repair should be performed early, before any MR-related complications ensue.