Value and limitations of the duke criteria for the diagnosis of infective endocarditis

OBJECTIVES The purpose of this study was to assess the value and limitation s of Duke criteria for the of infective endocarditis (IE). BACKGROUND Duke criteria have been shown to be more sensitive in diagnosing IE than the von Reyn criteria, bur the diagnosis of IE remains difficult i n some patients. METHODS Both classifications were applied in 93 consecutive patients with p athologically proven IE Blood cultures, and transthoracic and transesophage al echocardiography were performed in all patients. RESULTS Sensitivities for the diagnosis of IE were 56% and 76% for von Reyn and Duke criteria, respectively Fifty-two patients were correctly classifi ed as "probabbe IE" by von Reyn and "definite IE" by Duke criteria (group 1 ) However, discrepancies were observed in 41 patients. Eleven patients (gro up 2) were misclassified as "rejected" by von Reyn, but were "definite IE" by Duke criteria; this difference could be explained by negative blood cult ures and positive echocardiogram in all patients. In eight patients (group 3), the diagnosis of IE was "possible" by von Reyn but "definite" by Duke c riteria. This difference was essentially explained by the failure of the vo n Reyn classification to consider echocardiographic abnormalities as major criteria. Twenty-two patients (group 4) were misclassified as possible IE u sing Duke criteria were present in 19 criteria were present in 19 being fal se negative of this classification. Echocardiographic major patients, but b lood cultures were negative in 21 patients. The cause of negative blood cul tures was prior antibiotic therapy in 11 patients and Q-fever endocarditis diagnosed by positive serology in three cases. CONCLUSIONS Twenty-four percent of patients with proved IE remain misclassi fied as "possible IE" despite the use of Duke criteria, especially in cases of culture-negative and Q-fever IE. Increasing the diagnostic value of ech ographic criteria in patients with prior antibiotic therapy and typical ech ocardiographic findings and considering the serologic diagnosis of Q-fever as a major criterion would further improve the clinical diagnosis of IE. (C ) 1999 by the American College of Cardiology.