Isolated replacement of a prosthesis or a bioprosthesis in the aortic valve position

The operative results of 203 aortic prosthetic valve reoperations performed in 175 patients from 1974 through 1986 were reviewed to identify groups at greater risk. Two to 4 reoperations were performed in 23 patients. The mean interval between the first and second valve procedures was 74 +/- 57 months. The most common indications for reoperation were thrombosis of mechanical prostheses (25%), degeneration of homografts (22%) and mechanical valve dysfunction (19%). Eighteen patients (9%) died. This mortality rate was significantly higher (p less than 0.05) than that of primary valve procedures performed during the same period. Mortality rates were higher among patients with prosthetic valve endocarditis (6 of 26 cases, 23%) and among those who underwent operation on an emergency basis (15 of 20, 25%). No significant correlation was found between mortality rates and the age or gender of the patients and the types of prostheses used originally.