The effect of surgical therapy on covariate-survival relationships in patients with mitral valve disease.

The survival of 72 medically treated and 177 surgically treated mitral valve disease patients is compared for subgroups defined by 15 baseline variables. Overall, surgically treated patients had significantly better survival than medically treated patients, even though surgically treated patients were more symptomatic and had more exercise and hemodynamic impairment. The profile of a patient most likely to experience improved survival with surgical therapy would consist of one or more of the following: functional class III or IV, arterio-venous oxygen difference greater than or equal to 5.4 ml/100 ml, mean pulmonary artery pressure greater than or equal to 26 mm Hg, mean pulmonary capillary wedge pressure greater than or equal to 19 mm Hg, severity index = 3, left ventricular mass greater than or equal to 125 g/m2, ejection fraction = 31 to 50%, and end-diastolic volume greater than or equal to 103 ml/m2.