Outcomes of patients subjected to aortic valve replacement surgery using mechanical or biological prostheses

Objective: This paper evaluates outcomes in patients subjected to surgery for replacement of the aortic valve using biological or mechanical substitutes, where selection of the type of prosthesis is relevant. Methods: Three hundred and one patients, randomly selected, who had been subjected to aortic valve replacement surgery between 1990 and 2005, with a maximum follow-up period of 20 years. Results: Survival at 5, 10 and 15 years after surgery using mechanical substitute was 83.9%, 75.4% and 60.2% and, for biological substitute, was 89.3%, 70.4% and 58.4%, respectively (P=0.939). Factors associated with death were: age, obesity, pulmonary disease, arrhythmia, bleeding and aortic valve failure. Probability free of reoperation for these patients at 5, 10 and 15 years after surgery using mechanical substitute was 97.9%, 95.8% and 95.8% and, for those using bioprostheses, was 94.6%, 91.0% and 83.3%, respectively (P=0.057). Factors associated with reoperation were: renal failure, prosthesis endocarditis and age. Probability free of bleeding events at 5, 10 and 15 years after surgery using mechanical substitute was 94.5%, 91.7% and 91.7% and, for bioprostheses, was 98.6%, 97.8% and 97.8%, respectively (P=0.047). Factors associated with bleeding events were: renal failure and mechanical prostheses. Conclusions: The authors have concluded that: 1) mortality was statistically similar in the groups; 2) patient characteristics at baseline were a major determinant of late mortality after surgery; 3) there was a tendency toward reoperation in the bioprostheses group; 4) patients using mechanical prosthesis had more bleeding events as time passed; 5) data presented in this paper is in accordance with current literature.