SPIROMETRIC CHANGES AFTER OPEN MITRAL SURGERY

New York Heart Association (NYHA) functional classification of cardiac patients is assessed by subjective impairment of respiratory reserve. We objectively studied pulmonary function by spirometry in 31 random patients (average age 27.2 years) with rheumatic mitral valve (MV) dis ease undergoing open surgery (7 reconstruction, 24 replacement) preope ratively, predischarge and at 3 month follow-up. fetter preoperative s pirometric parameters were observed in class II nonsmoker patients wit h smaller cardiothoracic ratio (CTR) and normal pulmonary artery press ure (PAP). After surgery mean PAP decreased to 19.0+/-6.7 mmHg, MV gra dient dropped to 3.4+/-2.9 mmHg, average CTR decreased to 52.3+/-5.5%. MV area increased significantly from 0.8+/-0.49 to 2.45+/-1.23 cm(2). Forced vital capacity (FVC), forced expiratory volume in one second F EV(1)), flow rates at 25%-75% of expired vital capacity (FEF (25-75%)) and maximum voluntary ventilation (MVV) decreased significantly in al l patients at discharge. Prolonged postoperative ventilatory support o ver 10 hours led to markedly reduced predischarge FVC, FEV(1), FEF(50) , MVV and maximum mid expiratory flow rate (MMEFR). Prolonged cardiopu lmonary bypass over 80 minutes caused further decrease in FVC. After 3 months all these parameters improved in all above the preoperative le vel but remained below the predicted values. Despite improvement in NY HA class, impaired spirometry was observed in 11 patients. Functional or hemodynamic improvement did not correlate with spirometric changes.