Carpentier-Edwards (C/E) high profile supra-annular porcine bioprostheses were implanted in 163 patients between September 1982-February 1987 in the mitral position due to rheumatic disease. The patients' ages ranged between 15 and 58 years (mean: 36.5 +/- 11.5). One hundred-two of the patients (62.5%) were female. The hospital mortality was 9.8% (16/163). The total cumulative follow-up period was 1093 patient-years (p-y) with a mean of 7.3 +/- 3.5 p-y (range 6 months-12 years). Linearised occurrence rates of the late complications were as follows: Thromboembolism 0.82%/p-v, anticoagulant-related bleeding 1.0%/p-y, prosthetic valve endocarditis 0.09%/p-y. Actuarial survival rates for 5 and 12 years were 87% +/- 6% and 76% +/- 9%, respectively, with 95% confidence limits. Freedom from structural deterioration was 92% +/- 5% for 5 years and 44% +/- 11% for 12 years. Freedom from all valve-related complications was 81% +/- 7 for 5 years and 26% +/- 9 for 12 years. In conclusion, this prosthesis provides satisfactory clinical performance in young population despite the high risk of degeneration with good prognosis and better tolerability of reoperation.