Porcine cardiac bioprostheses: Evaluation of long-term results in 990 patients

Clinical results with porcine bioprostheses were reviewed for 990 patients who underwent heart valve replacement from January, 1974, to December, 1980. Eight hundred and seventy-four Hancock, 283 Carpentier-Edwards, and 10 Liotta bioprostheses were used. In 23 patients, 26 mechanical prostheses were implanted as well. Overall operative mortality was 60 out of 990 (6.06%): 30 out of 506 (5.9%) for mitral valve replacement (MVR), 13 out of 287 (4.5%) for aortic valve replacement (AVR), 1 out of 4 (25%) for tricuspid valve replacement, 0 out of 2 for pulmonary valve replacement, and 16 out of 191 (8.4%) for multiple valve replacement. Cumulative follow-up covered 1,793 patient-years. (Actuarial survival at 7 years was 76.6 ± 3% for MVR. At 6 years, it was 83.2 ± 2.8% for AVR and 55 ± 13.5% for multiple valve replacement.) Prosthesis-related survival at 7 years was 91.7 ± 1.9% for MVR, and at 6 years, it was 96.6 ± 1.5% for AVR and 95.1 ± 2.2% for multiple valve replacement. Bioprosthesis survival, considering deaths or complications that led to reoperation as final events, was 84.2 ± 3.7% at 7 years for mitral valves and 87.7 ± 3.8% at 6 years for aortic valves. Emboli per 100 patient-years numbered 3.2 for MVR, 0.5 for AVR, and 1.6 for multiple valve replacement. Twenty-seven patients underwent reoperation, 12 for perivalvular leak, 5 for endocarditis, 6 for valve thrombosis, and 4 for primary tissue failure (linearized rates of 0.7, 0.3, 0.3, and 0.2% per patient-year, respectively). The probability of remaining free from any complications was 59.6 ± 4.9% at 7 years after MVR, 72.9 ± 4.6% at 6 years after AVR, and 34.9 ± 11.2% at 6 years after multiple valve replacement. No operative deaths occurred at reoperation for perivalvular leak or primary tissue failure. Late improvement was recorded in 90.2% of survivors, whereas 8.9% did not change and 0.9% worsened according to New York Heart Association functional classification. The intrinsic durability of bioprostheses appears to be very satisfactory over the long term (6 to 7 years), and the risk of failure appears well balanced by the advantages of a low incidence of thromboembolism and no mandatory anticoagulant therapy.