Porcine Cardiac Bioprostheses: Evaluation of Long-term Results in 990 Patients

Abstract

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.