Effect of mitral valve surgery on severely impaired pulmonary function

To evaluate the effect of surgery on severely impaired pulmonary function associated with mitral valve disease, we examined the relationship between postoperative improvements in pulmonary function and pulmonary circulation in 238 patients who underwent mitral valve surgery. Of these patients 17 met the preoperative criteria for severely impaired pulmonary function: forced expiratory volume in 1 second = FEV1 < or = 1000 ml. They showed average values for vital capacity (VC) of 1343 +/- 203 ml, for % of vital capacity for predicted values (%VC) of 52.0 +/- 6.5%, and for FEV1 of 851 +/- 104 ml. Moderate elevations of mean pulmonary arterial pressure (PAP: 36.2 +/- 10.2 mmHg), mean pulmonary arterial wedge pressure (PAWP: 23.0 +/- 9.6 mmHg), and pulmonary vascular resistance (PVR: 329 +/- 147 dyne.sec.cm-5) were also observed. Postoperatively, 4 of the 17 patients required long-term respiratory support for more than one week, and 3 patients died in hospital; this mortality rate, however, was not significantly different to that of patients with preoperative FEV1 > 1000 ml. In long-surviving patients, pulmonary function improved in the late postoperative period. Significant relationships were recognized between delta FEV1 (delta: postoperative value--preoperative value) and delta PAP, delta PAWP, and delta PVR. The delta VC and delta %VC also correlated significantly with delta PAP, delta PAWP and delta PVR. In conclusion, in patients with mitral valve disease impaired pulmonary function cannot be used to exclude patients from operation. Furthermore, severely impaired pulmonary function should improve with the improvement of pulmonary circulation after surgery.