Effect of closed mitral valvotomy on spirometric pulmonary function tests in mitral stenosis.

The effect of closed mitral valvotomy on the spirometric pulmonary functions was studied in 25 patients with mitral stenosis. The tests were performed before and after operation, the latter at varying intervals (4 to 6 weeks and 8 to 12 months). The preoperative values were considerably low. After 4 to 6 weeks following surgery, further significant reduction in Forced Vital Capacity (FVC) and Forced Expiratory Volume in one second (FEV1) was observed. This was ascribed to the residual healing process and thoracotomy pain. However, Forced expiratory flow rate during mid segment of FVC (FEF25-75%), which reflects obstruction in small airways, did not show any variation. There was improvement in all the above parameters, 8-12 months after surgery. This suggests definite reversibility in the pulmonary functions following valvotomy.