Comparative assessment of bioprosthesis durability in the aortic position.

Published durability results of porcine and pericardial bioprostheses in the aortic position have been reviewed for the purpose of a qualitative comparison between these valve types, and also with previously reviewed series of homograft valves. Porcine bioprostheses exhibit a wide range of failure curves, with a characteristic Weibull-shaped pattern. Patient characteristics must account for the majority of differences seen among the series. Newer series generally contain older patients and have better results. A second generation pericardial valve has distinctly better durability than a previously discontinued pericardial model, and appears to be as durable as that of the best porcine valve series. Homograft valves using cold antibiotic storage have durability results approximately equal to porcine valves, but with younger patients on the average. The results with cryopreserved valves may be comparable, but insufficient long term information is available. To make these qualitative comparisons quantitative would require a formal analysis which takes age and other patient-related characteristics into account.