From September 1984 to December 1992, 145 selected patients underwent mitral valve replacement using cadaver aortic valves obtained during rotine autopsy, processed in glutaraldehyde and mounted into flexible stents made of Celcon and covered with Dacron fabric. Mean age was 22.5 years, ranging from 5 to 77 years and 54.5% (79 patients) were 15 years old or younger. Twenty patients (13.8%) had undergone previous mitral valve replacement using porcine, bovine pericardial and dura mater valves, which were calcified. Six patients had undergone a previous mitral valvuloplasty. Hospital mortality (30 days) was 2.1% (3 patients). It was collected 709 patient-years of total follow-up, corresponding to a mean follow-up of 5 years per patient. The longest follow-up was 9 years and 5 months. Late complications related to the allograft were present in 48 patients, including fibrocalcification, thromboembolism, endocarditis and peri-valvular leak, corresponding to an incidence of 6.8% ± 0.9% per patient-year. Fibrocalcification was the most important late complication, and it was observed in 37 patients, representing an incidence of 5.2% ± 0.8% per patient-year. All patients who developed calcification in the implanted valves were 15 years old or younger. Calcification developed from 14 to 100 months after implantation and the mean interval between valve insertion and calcification was 46 months. Reoperations were performed on 44 patients, and the allobioprosthesis was replaced in 30 of them. The incidence of reoperation was 6.3% ± 0.9% per patient-year. There were 15 late deaths with a mortality rate of 2.1 % ± 0.5% per patient-year. Only 3 deaths were valve related. The 10-year acturial survival was 82.9% ± 4.8%. The overall 10-year freedom from valve dysfuntion due to calcification was replaced in 30 of them. The incidence of reoperation was 6.3% ± 0.9% per patient-year. There were 15 late deaths with a mortality rate of 2.1 % ± 0.5% per patient-year. Only 3 deaths were valve related. The 10-year 62.1 % ± 11.2%; for patients 15 years old or younger was 24.2% ± 11.2%, and it was 100% for patients older than 15 years. Although fibrocalcification has remained the most important late complication observed in the pediatric age group and the main cause for reoperation, its incidence was much lower than the calcification rate reported in the literature for xenobioprostheses in young patients.
heart valves prostheses; valvar substitutes