Improvement in pulmonary function in mitral stenosis after percutaneous transvenous mitral commissurotomy.

Before and after percutaneous transvenous mitral commissurotomy (PTMC), pulmonary function studies were performed in 25 patients with mitral stenosis, in order to determine the effects of pulmonary hemodynamics on pulmonary function in patients with mitral stenosis. After PTMC, dramatic improvements in pulmonary hemodynamics were seen in all patients. With regard to pulmonary function data, the VC as percent predicted value increased from 87.6 +/- 16.1 percent to 94.7 +/- 14.4 percent (p less than 0.001). Although the ratio of FEV1/FVC was unchanged, the MVV as percent predicted value increased, and the ratio of RV/TLC, CV, and the difference in nitrogen concentration between 750 ml and 1,250 ml of expired volume decreased significantly. According to the maximum expiratory flow-volume curves, V ax 50% and Vmax 25% improved. Despite marked improvements in pulmonary ventilatory function soon after PTMC, the percent predicted diffusing capacity of the lung for carbon monoxide decreased significantly after PTMC. Arterial blood gas data, such as the partial pressure of oxygen and carbon dioxide in arterial blood and the alveolar-arterial differences in partial pressure of oxygen, did not improve within one or two weeks after PTMC. We conclude that in mitral stenosis, the majority of ventilatory function impairments are caused by hemodynamic alterations that are mainly reversible.