[Development of severe mitral regurgitation following percutaneous transvenous mitral valve commissurotomy]

The purpose of this study was to analyze the risk factors of unexpected occurrence of mitral regurgitation (MR) following percutaneous transvenous mitral valve commissurotomy (PTMC) in patients with mitral stenosis. The analyzed factors were clinical pictures, hemodynamic findings, echocardiographic findings and balloon inflation techniques during PTMC. Among 24 patients undergoing successful PTMC using an Inoue's balloon, severe MR developed in five patients (21%). No significant correlation in the occurrence of MR was observed in clinical findings, hemodynamic data and balloon inflation techniques including the times and size of ballooning. Echocardiographic findings of the mitral valve including the pliability of the mitral leaflet and localized calcification of the mitral orifice were the most contributory factors to the occurrence of severe MR. The localized alternation of valve stiffness produced localized tear or excessive dilatation of the mitral leaflet during PTMC, resulting in severe MR. Hemodynamic results and calculated mitral valve areas after PTMC showed significant improvement in both groups with and without MR. However, symptomatic improvement in patients with severe MR was less prominent when compared to the patients without MR. Thus, the complete echocardiographic evaluation of the mitral valve apparatus before PTMC is important to prevent severe MR.