Effects of valvular surgery on overall and regional lung function in patients with mitral stenosis.

Changes in overall and regional pulmonary function after open heart surgery were studied in 23 patients with mitral stenosis, grouped according to hemodynamic abnormality at cardiac catheterization. In group 1 (pulmonary arterial pressure less than 25 mm Hg), no pulmonary function disorders were detected before or after surgery. In group 2 (pulmonary hypertension with no or slight tricuspid regurgitation) lung volumes increased significantly within normal ranges after surgery. However, group 3 patients (pulmonary hypertension and moderate or severe tricuspid regurgitation, restrictive and obstructive impairment, uneven alveolar ventilation, disturbed diffusing capacity) did not recover after surgery. The regional perfusion distribution by 133Xe, expressed as the upper over lower lung field ratio, showed significant changes after surgery in groups 1 and 2, but no change in group 3. In groups 1 and 2 it seems that lung parenchyma and pulmonary vessels were not greatly damaged, while in group 3 organic changes in the lung occurred.