Prediction of successful outcome in 130 patients undergoing percutaneous balloon mitral valvotomy

We studied 130 patients undergoing percutaneous balloon mitral valvotomy. The relation between valvular morphology according to a previously described echocardiographic scoring system and hemodynamic outcome expressed as qualitative ("good" and suboptimal) and as absolute change in valve area was analyzed. The relative importance of the individual components of this echocardiographic score (valvular thickening, mobility, calcification, and subvalvular disease) to the change in valve area after valvotomy was also examined. Mean transmitral pressure gradient decreased from 16±6 to 6±3 mm Hg (p<0.0001), and mitral valve area increased from 0.9±0.3 to 1.8±0.7 cm² (p<0.0001). Results in individual patients were variable. Eighty-four percent (61 of 73) of patients with an echocardiographic score of 8 or less had a "good" outcome (final valve area ≥1.5 cm² and an increase in valve area of ≥25%), whereas 58% (33 of 57) of patients with an echocardiographic score of 8 or more had a suboptimal result (p<0.001). The sensitivity of an echocardiographic score of 8 or less for predicting a "good" outcome was 72%, and the specificity was 73%. The echocardiographic score correlated negatively (r=-0.40, p<0.0001) with the absolute increase in mitral valve area after valvotomy, but there was substantial scatter in the data. Of the four components of the total echocardiographic score, valvular thickening correlated best with the absolute change in valve area (r=-0.47, p<0.0001). Multiple regression analysis selected valvular thickening as the only morphological predictor of the change in valve area, followed by a larger effective balloon dilating area and sinus rhythm. The equation derived from this multivariate analysis was used to predict the absolute change in valve area after valvotomy. Although the predicted and the observed change in valve area correlated significantly (r=0.56, p<0.0001), there was substantial scatter in the data.