Influence of mitral valve morphology on mitral balloon commissurotomy: immediate and six-month results from the NHLBI Balloon Valvuloplasty Registry.

Echocardiographic data were analyzed in 555 patients undergoing mitral balloon commissurotomy (MBC). Patients were enrolled in the National Heart, Lung, and Blood Institute Balloon Valvuloplasty Registry from 24 centers. There were 456 women and 99 men with a mean age of 54 years. Before MBC the two-dimensional echocardiographic variables of mitral valve thickness, mobility, calcification, and subvalvular disease were evaluated and assigned scores of 1 to 4. The mitral valve morphology score was related to mitral valve area (MVA) measured after MBC by cardiac catheterization. The leaflet mobility score was related to the immediate post-MBC MVA: 2.2 +/- 0.8 cm2 for grade 1, 1.9 +/- 0.7 cm2 for grade 2, 1.7 +/- 0.7 cm2 for grade 3, and 1.9 +/- 0.9 cm2 for grade 4 (p less than 0.001). Results of the MVA after MBC showed a similar relationship for each echocardiographic variable. The total morphology score (sum of the four variables) showed a weak relationship to MVA immediately after MBC (r = 0.24), which was persistent at 6 months after MBC (r = -0.25). Multiple regression analysis showed that the MVA after MBC is predicted by pre-MBC MVA (p less than 0.001), left atrial size (p = 0.01), balloon diameter (p = 0.02), cardiac output (p = 0.004), and leaflet mobility (p = 0.01). The R2 of the model was 0.31 (p less than 0.001). Total morphology score, leaflet thickness, calcification, and subvalvular disease were not important univariate or multivariate predictors of the results of MBC.(ABSTRACT TRUNCATED AT 250 WORDS)