Determinants of survival after aortic valve replacement.

The aim of this study to was evaluate the surgical results of Aortic Valve Replacement (AVR) and to identify the predictive variables associated to risk. A total of 650 consecutive patients underwent isolated AVR at the Thoracic Surgery Centre, S. Jo?o Hospital, Oporto, between January 1976 and December 1996. There were 29 (4.5%) early operative deaths and 108 follow-up deaths (64 cardiac and 44 non cardiac), which represents a linearized rate of 2.3% patients per year. The 5, 10 and 15 year cumulative survival rates for the 650 patients were 85 +/- 3%; 76 +/- 4.1% and 64 +/- 6.6, respectively. According to data in the literature, six preoperative variable and four operative variables were selected to be tested for association to risk. Multivariate analysis identified advanced age and the year of operation as the most important predictors of mortality followed by the type of the prosthesis (the mechanical valves performing better than the biological ones) and the prosthetic valve size (the small prosthesis performing worse than the others). We concluded that AVR is currently a low risk procedure at our Centre. The patient's age emerges as the main risk factor for overall mortality; a mechanical prosthesis should be preferred, at least before the age of 60, and prostheses with a ring size below 21-mm should be avoided.