PERIOPERATIVE EVENTS IN PATIENTS WITH FAILED MECHANICAL AND BIOPROSTHETIC VALVES

From 1963 through 1991, 1037 patients underwent reoperative valvular p rocedures. The 478 patients having reoperations for either failed biop rosthetic (n = 212) or mechanical (n = 265) valves were evaluated. The re were 210 male (44%) and 268 female (56%) patients. The mean age at reoperation of the patients in the bioprosthesis group was 59.7 years and and that in the mechanical valve group was 56.1 years (p = 0.0006) . The mean interval to the time of reoperation was 84.7 months in the mechanical valve group and 74 months in the bioprosthesis group. There was no difference between the two groups in he functional class at re operation. More severe mitral valve stenosis and incompetence, more se vere aortic valve stenosis, and higher right ventricular and pulmonary arterial pressures were noted in the bioprosthesis group than in the mechanical valve group. Hemolysis (p = 0.05) was more prevalent in the patients with mechanical valves than in the ones with bioprostheses. A longer aortic occlusion time (p = 0.0001) and longer cardiopulmonary bypass time (p = 0.0001) were required for the reoperations in the bi oprosthesis group. The operative mortality was 13.2% for the bioprosth esis patients and 12.4% for the mechanical valve patients. The risk fa ctors for hospital death included the cross-clamp time (p = 0.0001), t he functional class (p = 0.00001), the presence of ascites (p = 0.02), hepatomegaly (p = 0.002), and decreasing ejection fraction (p = 0.05) . We conclude that mechanical valve failures do not produce catastroph ic events resulting in poor reoperative results.