Bioprosthetic valve longevity in the elderly : an 18-year longitudinal study. Discussion

The issue of bioprosthetic valve durability has become of critical importance as the number of elderly patients requiring valve operation has continued to increase. Our previous study showed bioprosthetic valve durability to be in excess of 83% at 13 years for patients 70 years of age and older at the time of implantation. There is limited follow-up data in the literature beyond this time point, however. Accordingly a retrospective analysis was conducted of all patients with bioprosthetic valves who were 70 years of age and over at the time of implantation. From September 1974 to April 1994, 1007 patients 70 years of age and over underwent valve replacement using a porcine bioprosthesis. The patients ranged in age from 70 to 104 years (mean, 75 ± 4.3 years). There were 549 men (54.5%) and 458 women (45.5%). Preoperatively 98.8% of the patients were in New York Heart Association functional class III or IV. Operation was performed as an emergency in 66 patients (6.6%). The hospital mortality was 10.9% (110 patients), with 897 hospital survivors. There were 961 valves at risk. Follow-up extended from 1 month to 18.8 years (mean, 56.6 months). The cumulative follow-up is 4232.3 patient-years. A total of 31 valves failed, 12 in the aortic position and 19 in the mitral position (p < 0.0024). The causes of valve failure have included structural deterioration (16 valves), prosthetic endocarditis (7 valves), nonstructural dysfunction (5 valves), prosthetic thrombosis (1 valve), and other (2 valves). The actuarial freedom from valve failure at 9 years was 94.3% ± 1.4% (standard error of the mean; 150 valves at risk) and 84.4% ± 4.4% at 18 years (5 valves at risk). Patient sex was not found to influence the incidence of structural deterioration, but valve site did (p = 0.0024). This experience further documents the favorable long-term results associated with the use of the porcine bioprosthesis in patients 70 years of age and over. It furnishes increasing evidence that the bioprothesis frequently outlives the patient.