Partial Improvement in Pulmonary Function After Successful Percutaneous Balloon Mitral Valvotomy

This study was performed to assess the changes in pulmonary function after a successful percutaneous balloon mitral valvotomy (PBMV) in 23 consecutive patients with symptomatic mitral stenosis. Lung function preprocedure and postprocedure were evaluated by spirometric flow, static pulmonary volumes, and diffusion capacity of the lung for carbon monoxide (Dlco). At baseline, a reduction in small airways flow (maximal expiratory flow at 50% of vital capacity, 70 ± 29% of predicted value; maximal expiratory flow at 25% of vital capacity, 55 ± 26% of predicted value) and an increase in Dlco (118 ± 29%) and Krough Index (KCO; 123 ± 29% of predicted value) were observed. PBMV caused an improvement in hemodynamic parameters with an increase in mitral valve area (from 1.0 ± 0.3 to 1.9 ± 0.5 cm2; p < 0.001) and a decrease in left atrial pressure (from 17 ± 3 to 12 ± 5 mm Hg; p < 0.001). These changes were associated with a significant increase in FVC (from 2.8 ± 0.84 to 2.9 ± 0.80 L; p < 0.05) and in FEV1 (from 2.2 ± 0.72 to 2.3 ± 0.68 L; p < 0.05). A decrease in Dlco was observed after PBMV (from 26.7 ± 7 to 22.5 ± 5.4 mL/min/mm Hg; p < 0.001; and KCO, from 6.2 ± 1.4 to 5.2 ± 1.2 mL/min/mm Hg/L; p < 0.001). No significant changes in small airways flow were detected, suggesting only a partial improvement in pulmonary congestion. We conclude that the initial impairment of lung function in patients with symptomatic mitral stenosis is only partially ameliorated by PBMV.