Outcome of watchful waiting in asymptomatic severe mitral regurgitation

The management of asymptomatic severe mitral regurgitation remains controversial. The aim of this study was to evaluate the outcome of a watchful waiting strategy in which patients are referred to surgery when symptoms occur or when asymptomatic patients develop left ventricular (LV) enlargement, LV dysfunction, pulmonary hypertension, or recurrent atrial fibrillation.

A total of 132 consecutive asymptomatic patients (age 55+/-15 years, 49 female) with severe degenerative mitral regurgitation (flail leaflet or valve prolapse) were prospectively followed up for 62+/-26 months. Patients underwent serial clinical and echocardiographic examinations and were referred for surgery when the criteria mentioned above were fulfilled. Overall survival was not statistically different from expected survival either in the total group or in the subgroup of patients with flail leaflet. Eight deaths were observed. Thirty-eight patients developed criteria for surgery (symptoms, 24; LV criteria, 9; pulmonary hypertension or atrial fibrillation, 5). Survival free of any indication for surgery was 92+/-2% at 2 years, 78+/-4% at 4 years, 65+/-5% at 6 years, and 55+/-6% at 8 years. Patients with flail leaflet tended to develop criteria for surgery slightly but not significantly earlier. There was no operative mortality. Postoperative outcome was good with regard to survival, symptomatic status, and postoperative LV function.

Asymptomatic patients with severe degenerative mitral regurgitation can be safely followed up until either symptoms occur or currently recommended cutoff values for LV size, LV function, or pulmonary hypertension are reached. This management strategy is associated with good perioperative and postoperative outcome but requires careful follow-up.