Percutaneous balloon mitral valvuloplasty using the Inoue balloon: analysis of echocardiographic and other variables related to immediate outcome

To determine whether the mitral valve morphology influences the results of percutaneous balloon mitral valvuloplasty for mitral stenosis, two-dimensional echocardiography was performed before valvuloplasty in 126 patients (mean age 25.5±9.4 years) and in 30 normal controls. The 2D echocardiographic features of mitral valve leaflets: thickness, length and motion; diastolic mitral valvular excursion; chordal length; mitral annular diameter; subvalvular distance ratio; distance between mid mitral annulus to left ventricular apex, base and tip of papillary muscle and effective balloon dilating area, effective balloon dilating area/body surface area and effective balloon dilating diameter/mitral annular diameter were then correlated to the immediate post-valvuloplasty mitral valve area. For the total patients population, post-valvuloplasty valve area increased from 0.67±0.17 to 2.1±0.86 cm2 (P<0.0001), mean transmitral diastolic gradient decreased from 24.5±9.0 to 6.0±3.0 mmHg (P<0.0001), mean left atrial pressure decreased from 29.7±6.2 to 12.7±4.8 mmHg (P<0.0001), mean pulmonary artery pressure decreased from 44.8±14.2 to 25.4±9.5 mmHg (P<0.0001) and cardiac index increased from 2.7±0.38 to 3.1±0.55 l/min/m2 (P<0.0001). The patients were divided into three groups on the basis of post-valvuloplasty mitral valve area. Group I had valve area <1.5 cm2, group II had valve area from 1.5 to 1.9 cm2 and group III had valve area ≥2.0 cm2. On comparison, no statistically significant difference was found in any of the echocardiographic variables in the three groups. On univariate, multivariate, multiple regression and discriminate function analysis, none of the variables were found to have significant influence on immediate result of valvuloplasty. There was no significant difference in the incidence of mitral regurgitation in any of the three groups. We conclude that the extent of mitral valvular and subvalvular deformity do not have a significant effect on the immediate outcome of mitral valvuloplasty using the Inoue balloon and it can be successfully performed in patients with severe subvalvular fibrosis. Unique balloon geometry and stepwise balloon sizing may explain these acceptable immediate results in severely deformed valves.