Immediate results of percutaneous mitral commissurotomy. A predictive model on a series of 1514 patients

Abstract

Background: The wide use of percutaneous mitral commissurotomy (PMC) underlines the need to identify the predictive factors of the results. Using a large series allowed us to develop a multivariate model that can be applied to improve patient selection.

Methods and results: Between 1986 and 1995. PMC was undertaken in 1514 patients. Mean age was 45 +/- 15 years. Echocardiography showed that 245 patients (16%) had pliable valves and mild chordal thickening (group 1), 886 (59%) had extensive subvalvular disease (group 2), and 383 (25%) had calcified valves (group 3). PMC failed in 22 patients; it was performed with a single balloon in 30 patients, a double balloon in 586, and the Inoue balloon in 876. Good immediate results were defined as a valve area > or = 1.5 cm2 with mitral regurgitation Sellers' grade < or = 2 and were obtained in 1348 patients (89%). A logistic model developed from the first 1088 cases identified the following predictors of immediate results: age (P = .004), echocardiographic group (P < .0001), valve area (P < .0001), and effective balloon dilating area (EBDA) (P = .03). Two interactions were significant: age at previous commissurotomy (P = .013) and EBDA by initial mitral regurgitation (P = .034). The type of balloon was of borderline significance (P = .09). The model was validated on an independent sample comprising the subsequent 426 procedures. For a threshold of probability of good results of .75, sensitivity was 92%, specificity 25%, and predictive accuracy 87%.

Conclusions: Prediction of the immediate results of PMC is multifactorial. The predictive model developed and validated can be contributive in decision making for individual patients.