PREDICTION OF OUTCOME AFTER VALVE-REPLACEMENT FOR RHEUMATIC MITRAL REGURGITATION IN THE ERA OF CHORDAL PRESERVATION

Background Noninvasive predictors of important outcomes after valve re placement for mitral regurgitation have not been examined in a rheumat ic population (in whom the results of valve repair are suboptimal) in the era of chordal preservation. Timing of valve replacement thus rema ins a difficult question in rheumatic mitral regurgitation. Methods an d Results Of 278 patients followed after valve replacement, 66 had pur e or predominant mitral regurgitation, and in 61 of these the etiology was rheumatic. The mean age was 24 years. After a mean follow-up of 2 4+/-10 months, the ability of preoperative clinical and echocardiograp hic data to predict outcome was assessed prospectively, and the possib le impact of chordal preservation (n=35) on survival and postoperative left ventricular function was examined retrospectively. There were no perioperative deaths. There were six postoperative deaths, all the re sult of heart failure and all related to left ventricular dysfunction. The mean probability of survival was .90 at 16 months. In a stepwise Cox proportional hazards regression analysis, the only independent pre dictor of postoperative death was preoperative end-systolic diameter. According to a logistic model, the probabilities of death (n=6) and de ath or severe heart failure (n=7) increased abruptly at a preoperative end-systolic diameter of 51 mm (probabilities, .23 and .31, respectiv ely), and the accuracy of this cut point for predicting outcomes was 9 7% and 98%, respectively. Multiple linear regression analysis identifi ed a large preoperative end-systolic diameter and the need to use tric uspid annuloplasty as significant independent predictors of postoperat ive fractional shortening; the use of chordal preservation (n=35) was not a predictor of postoperative fractional shortening. A good outcome was predicted at a preoperative end-systolic diameter of 40 mm: proba bility of death or heart failure was .0001, and predicted mean postope rative fractional shortening was 0.27 after mitral valve replacement w ithout tricuspid annuloplasty. Conclusions When preoperative end-systo lic diameter is more than 50 mm, a poor postoperative outcome is predi cted despite chordal preservation in relatively young patients with rh eumatic mitral regurgitation, and alternative strategies should theref ore be considered. When preoperative end-systolic diameter is 40 mm or less, an excellent outcome is predicted, and close observation withou t surgery would appear to be reasonable in the absence of symptoms.