RESUMO
We review the pathological specimens sent to the Pathology Department from January 1983 to June 1988 that belonged to 7567 patients. For this study we have selected specimens from 1139 patients (15.05% of the total), who were submitted to valvular replacement surgery. We analyzed 1037 "native" valves and 186 prosthesis. Rheumatic fever was confirmed in 68% of "native" valves. The remaining 32% includes a group in which this etiology was not confirmed by histology in spite of the clinical diagnosis. The leading cause of biological prosthesis replacement was dysfunction caused by calcification and fibrosis, and for mechanical prosthesis it was thrombosis. Included in this study are 747 patients who received 836 heterologous valves of bovine pericardium, fabricated at the "Instituto Nacional de Cardiología (INC)". The price of imported mechanical prosthesis is superior to the price of the prosthesis manufactured at INC. The difference varies between 1400% and 4000% depending on mechanical prosthesis type. The survival rate of the receiving patients of the INC implants was 82.2%, and the dysfunction rate of these prosthesis was 3.38% for the period studied, four and a half years.