The Mitroflow pericardial bioprosthesis. Comparison of early clinical performance in aortic and mitral positions.

Between 1983 and 1987 the Mitroflow pericardial prosthesis was implanted in 354 patients, ranging in age from 14 to 94 years (mean 60.1 years). The early mortality was 5.7% and the late mortality 2.9% per patient-year. The total cumulative follow-up was 853 years (mean 2.4 years). Patient survival at 4 years for aortic valve replacement (AVR) was 81.5% and for mitral valve replacement (MVR) 74.8%. The overall rate of valve-related complications was 4.8% per patient-year (41 complications): thromboembolism, 15; hemorrhage related to antithromboembolic therapy, 1; prosthetic valve endocarditis, 15; nonstructural dysfunction, 3; and structural valve deterioration, 7. At 4 years the freedom from thromboembolism was 91.5% +/- 2.7% for AVR and 91.1% +/- 4.0% for MVR, from prosthetic valve endocarditis 93.5% +/- 2.3% for AVR and 94.0% +/- 2.9% for MVR, from structural valve deterioration 97.3% +/- 2.1% for AVR and 92.6% +/- 3.2% for MVR, from valve-related mortality 96.9% +/- 1.4% for AVR and 97.5% +/- 1.8% for MVR, and from reoperation 93.5% +/- 2.8% for AVR and 83.1% +/- 5.1% for MVR. The freedom from the composite of all valve-related complications at 4 years was 81.1% +/- 4.2% for AVR and 75.3% +/- 2.8% for MVR. The Mitroflow valve has provided satisfactory clinical performance at the 4-year evaluation. Structural valve deterioration is greater in the mitral position than in the aortic position. Long-term evaluation of the Mitroflow valve is necessary to determine the impact of structural valve deterioration on its clinical performance.