Lack of durability of the mitroflow valve does not affect survival

Background and aim of the study: The aim of the study was to compare the du rability and risk of reoperation in patients undergoing isolated aortic val ve replacement with either a porcine standard Carpentier Edwards or a Mitro flow pericardial valve. Methods: Follow up evaluation was performed in 118 patients receiving a Mit roflow valve (M) and 94 patients receiving a standard Carpentier Edwards po rcine valve (CE) between 1980 and 1987. The two groups were identical in te rms of clinical characteristics; only prosthesis size differed, with small- sized valves used more frequently among the Mitroflow group. Results: The risk of structural valve deterioration (SVD) was 2.3% per pati ent-year (pt-yr) in CE valves, and 5.4 per pt-yr in M valves. Freedom from SVD was 100%, 87 +/- 4% and 63 +/- 8% at 5, 10 and 15 years for CE valves, and 96 +/- 2%, 56 +/- 7% and 5 +/- 4% for M valves. Freedom of reoperation was 98 +/- 1%, 83 +/- 5% and 76 +/- 7% at 5, 10 and 15 years respectively f or CE valves, and 94 +/- 2%, 55 +/- 7% and 11 +/- 9% for M valves. Despite the high number of valve-related reoperations, survival at 5, 10 and 15 yea rs was not affected in M valve patients. Multivariate analysis (Cox model) showed that age and valve type were the two main risk factors for SVD and r eoperation; though the latter factor had no impact on survival, Conclusions: In younger patients (aged <75 years), the CE valves offer supe rior results to the M counterpart in valve replacement. However, in patient s aged > 75 years, pericardial and porcine bioprostheses demonstrate equiva lent durability despite post-implantation tissue changes in the former mate rial.