Bioprostheses and Mechanical Prostheses Predictors of Performance

Abstract

From 1975 to 1995, 4200 patients had bioprosthetic valve replacements (2240 aortic, 1607 mitral, 353 multiple) and 2038 had mechanical valve replacements (747 aortic, 928 mitral, 363 multiple). Freedom from major thromboembolism or both major thromboembolism and hemorrhage for aortic and mitral valve replacement at 15 years was significantly greater for bioprostheses than mechanical prostheses. Freedom from valve-related mortality and reoperation for both aortic and mitral valve replacements was the same for bioprostheses and mechanical prostheses. Advancing age increased overall mortality (all positions), valve-related mortality (aortic, mitral), major thromboembolism (aortic), thromboembolism and hemorrhage (aortic, mitral) but decreased reoperation (all positions). Coronary artery bypass grafting increased overall mortality (aortic, mitral) but not valve-related mortality, and it decreased reoperation rate (aortic, mitral). Overall mortality was not influenced by valve type in aortic or multiple valve replacement but it was decreased by bioprostheses in mitral valve replacement. Valve type did not influence valve-related mortality (all positions). Mechanical valves decreased reoperation only for aortic valve replacement but they increased major thromboembolism with and without hemorrhage for both aortic and mitral replacements. There is support for bioprostheses in aortic valve replacement and mechanical prostheses in mitral valve replacement but for neither in multiple valve replacements.