Impact of a preoperative mitral regurgitation scoring system on outcome of surgical repair for mitral valve prolapse. 
The optimal timing of surgical correction of severe mitral regurgitation (MR) is important for improved morbidity and mortality.  We utilized a scoring system to decide the timing of procedures.  Based on clinical features and echocardiographic data, we hypothesized that preoperative semi-quantitation of MR using this scoring system may be useful for predicting prognosis after repair.  The MR score was composed of 6 parameters associated with disease severity (i.e., history of heart failure, atrial fibrillation, pulmonary hypertension, left ventricular end-systolic dimension, fractional shortening, and left atrial dimension).  The maximum score was 6.  Of 267 patients who underwent mitral valve repair in the last 10 years, 191 patients with mitral valve prolapse were studied.  Patients were categorized into 2 groups according to MR score (group low [L] : 0 to 2.5 and group high [H]: >/=3.0) irrespective of New York Heart Association functional class.  A significant difference in postoperative event-free survival was observed between both groups (p = 0.0014); the adjusted risk ratio was 3.4 (95% confidence interval 1.6 to 7.2).  Postoperative echocardiography showed larger left ventricular systolic dimensions (p <0.0001), lower fractional shortening (p = 0.0016), and larger left atrial dimensions (p <0.0001) in group H than group L. Thus, an MR score is a simple way to predict the prognosis of severe MR independently of subjective symptoms in patients undergoing mitral valve repair.