Clinical performance of the Duromedics bileaflet pyrolite mechanical prosthesis

The Duromedics (Baxter Healthcare Corp., Edwards CVS Div., Irvine, Calif.) mechanical cardiac valvular prosthesis was implanted in 480 patients between 1984 and 1987 at the Montreal Heart Institute, the Hospital Clinic of Barcelona and the teaching hospitals of the University of British Columbia. The mean age of the patients was 52 years. The early mortality was 7.9% and the late mortality was 4.1% per patient-year. The overall survival at 4 years for aortic valve replacement (AVR) was 87.0% +/- 3.7% and for mitral valve replacement (MVR) was 81.9% +/- 2.9%. There were 16 valve-related reoperations in 14 patients--for prosthetic valve endocarditis in 9 patients, for thromboembolism in 1 patient and for nonstructural dysfunction in 4 patients. The freedom from thromboembolism at 3 and 4 years was 94.3% +/- 3.1% for AVR and 95.1% +/- 1.8% for MVR. The freedom from prosthetic valve endocarditis at 3 and 4 years was 95.3% +/- 2.2% for AVR and 96.2% +/- 1.6% for MVR. The freedom from structural valve deterioration for all positions was 100%. The freedom from reoperation at 4 years was 95.3% +/- 2.1% for AVR and 92.3% +/- 4.3% for MVR and from valve-related death was 98.7% +/- 1.3% for AVR and 96.2% +/- 1.6% for MVR. The freedom from all valve-related complications at 4 years was 87.7% +/- 3.8% for AVR and 85.7% +/- 2.9% for MVR. Long-term evaluation of the Duromedics prosthesis is required to determine the influence of documented structural valve deterioration.