Factors determining normalization of pulmonary vascular resistance following successful balloon mitral valvotomy

Balloon mitral valvotomy (BMV) provides improvement in pulmonary vascular resistance (PVR) in patients with severe mitral stenosis. Its normalization, however, remains questionable. We evaluated PVR before, after BMV, and at follow-up in 37 patients who had a previous successful BMV. Patients were divided into 2 groups: group 1 had 21 patients with normalized PVR (<125 dynes/s/cm5) either after BMV or at follow-up, and group 2 had 16 patients with persistently abnormal PVR. Patients in group 2 were older than patients in group 1 (55+/-13 vs 43+/-14 years, p = 0.01) and had atrial fibrillation more frequently (10 [63%] vs 6 [29%], p = 0.04). Age, cardiac rhythm, mitral valve area, pulmonary bed gradient, pulmonary artery pressure, and PVR before the procedure were significant univariate predictors for normalization of PVR. Age, echocardiographic score, systolic pulmonary artery pressure, and mitral regurgitation were all independent determinants of normalization of PVR in a multivariate logistic regression model. We conclude that PVR failed to return to normal in 16 patients (43%) after successful BMV; this can be predicted by baseline clinical and hemodynamic parameters.