Infective endocarditis -: A prospective study at the end of the twentieth century -: New predisposing conditions, new etiologic agents, and still a high mortality

From March 1994 to October 1996 we prospectively collected 109 episodes of infective endocarditis (IE) with an incidence of 6.4 cases/100,000 inhabitants per year. Mean age was 50 years, and 58 (35%) cases were in patients older than 60 years. Fifty-two (48%) episodes occurred on native valves, 39 (36%) were in intravenous drug users, and 18 (16.5%) were cases of prosthetic valve endocarditis. Eighteen cases (16.5%) were nosocomially acquired, and 36 cases were in human immunodeficiency virus (HIV)-positive patients. Durack classification did not reject any definitely proven cases, while the von Reyn and Steckelberg classifications rejected 26.6% and 40%, respectively. The tricuspid valve was the most common (37.6%) site of infection. Mitral valve was affected in 28 cases, aortic in 21, and both in 9. Staphylococci were the main etiologic agent in every group of patients. Staphylococcus aureus caused 49 (45%) cases. Only 9% of all episodes of IE are now caused by group viridans Streptococci. Transthoracic echocardiography diagnosed only 54 (49.5%) cases. Transesophageal echocardiography confirmed the diagnosis in another 38 cases. Related mortality was 26%. Bad prognosis factors in multivariate analysis were early prosthetic valve endocarditis, congestive heart failure during the episode, and acute renal dysfunction. With this study we have observed many changes in IE: new predisposing conditions, new populations at risk, new etiologic agents, and new diagnostic criteria and procedures, but in our experience IE is still a serious infection with a fearsome mortality, especially in seriously compromised populations like those patients with early prosthetic valve endocarditis.