A study of lung function and oxygen uptake during exercises in cases undergoing mitral valve surgery

In 1986-7, 80 cases with isolated mitral valve disease undergoing open heart surgery were studied, for spirometry, resting and exercise, oxygen uptake (VO2) preoperatively and 3 months postoperatively. Pulmonary artery pressures (PAP) were recorded prior to surgical correction and soon afterward. Pulmonary hypertension was mild (I) in 56.2%, moderate (II) in 25% and severe (III) in 18.8% cases. Though spirometric functions were lower with severe PH, these did not improve significantly 3 months later. But direct MBC improved significantly in grs. I and II, along with exercise VO2 and mean PAP. (DMBC:75.7 lit. to 91.8 lit: P less than 0.001; Exercise VO2 798 ml to 983 ml: P less than 0.001). Mean PAP 56.8 to 39.5 mm: P less than 0.001). Thus these functions may be used to objectively evaluate physiologic changes in cardiac surgical cases.