Role of negative trans-thoracic echocardiography in the diagnosis of infective endocarditis

Background: The search for the presence of vegetations in patients with suspected infective endocarditis is a major indication for trans-esophageal echocardiographic (TEE) examinations. Advances in harmonic imaging and ongoing improvement in modern echocardiographic systems allow adequate quality of diagnostic images in most patients. Objectives: To investigate whether TEE examinations are always necessary for the assessment of patients with suspected infective endocarditis. Methods: During 2012–2014, 230 trans-thoracic echo (TTE) exams in patients with suspected infective endocarditis were performed at our center. Demographic, epidemiological, clinical and echocardiographic data were collected and analyzed, and the final clinical diagnosis and outcome were determined. Results: Of 230 patients, 24 had definite infective endocarditis by clinical assessment. TEE examination was undertaken in 76 of the 230 patients based on the clinical decision of the attending physician. All TTE exams were classified as: (i) positive, i.e., vegetations present; (ii) clearly negative; or (iii) non-conclusive. Of the 92 with clearly negative TTE exams, 20 underwent TEE and all were negative. All clearly negative patients had native valves, adequate quality images, and in all 92 the final diagnosis was not infective endocarditis. Thus, the negative predictive value of a clearly negative TTE examination was 100%. Conclusions: In patients with native cardiac valves referred for evaluation for infective endocarditis, an adequate quality TTE with clearly negative examination may be sufficient for the diagnosis.