Biological valve prosthesis replacement--experiences and considerations.
Between 1976 and 1991. 1.017 tissue valve prostheses were implanted in 801 patients. During the same period 1876 mechanical valve prostheses were replaced. The hospital mortality was 8.1%. Till 1991 230 bioprostheses (22.6%) in the case of 166 patients (20.7%) had to be removed and replaced by other valve prostheses. There are no significant differences concerning the mortality between the first (8.1%) and the second operations (9.1%), and the durability of the various types of bioprostheses used, however, calcification, degeneration and other complications occurred more frequently and earlier in the case of mitral (24.5%) than in aortic (18.9%) bioprostheses, and in younger patients than in the older ones, as well. The mean age of patients was 46 years at the time of the first and 49 years at the time of the second operation. The incidence of reoperations was the highest in the seventh year after the first surgical intervention. In general, one size smaller prostheses were used in valve replacements after the removal of the first bioprostheses.