Bicuspid aortic valve--A silent danger: analysis of 50 cases of infective endocarditis.

We analyzed 50 cases of bicuspid aortic valve endocarditis in patients who presented to St. Thomas' Hospital from 1970 through 1998. These represented 12.3% of the 408 cases of native valve endocarditis (NVE). All patients were male, and their mean age was 39 years. Forty-five of the 50 cases were pathologically proven; 47 were clinically definite according to the Duke criteria and 49 according to our modifications of the Duke criteria. Viridans streptococci and staphylococci accounted for 72% of cases. The prevalences of clinical features were similar to those seen in NVE: fever (temperature >/=38 degrees C, 74%) and malaise (70%), although dyspnea was more frequent (36%). There was a high incidence of serious complications (72% heart failure; 30% periannular abscesses). Surgery was required during the initial admission in 82% of cases. Overall mortality was 14%, and surgical mortality was 9%. Few patients knew they had a "heart condition," and a bicuspid aortic valve was detected in only 35% of echocardiograms performed before surgery.