Impact of Negative Trans-thoracic Echocardiography in the Diagnosis of Infective Endocarditis

Background: Search for vegetations is one of main indication for trans-esophageal echo examinations. Improvement in harmonic imaging and development of modern echo machines allow high diagnostic image quality in most patients.

Objective: We sought to investigate whether trans-esophageal echo examinations are always necessary for the evaluation of patients, that referred for echocardiography for the purpose of vegetations.

Methods: During 2012-2014 230 trans-thoracic echo exams were performed in search for infective endocarditis. Clinical, demographic, epidemiologic and echocardiographic data were collected, revised and analyzed. Outcome of the patients was determined in relation to the demographic and clinical data.

Results: All 230 trans-thoracic echo examinations were divided into 3 groups: 1) positive exams, in which vegetations were present, 2) clearly negative examinations, 3) non-conclusive exams. 20 of the 92 patients with clearly negative trans-thoracic echo exams underwent trans-esophageal echocardiography, all were negative. All patients with clearly negative trans-thoracic echo examination had native valve, high image quality and in all final diagnosis was not infective endocarditis. The negative predictive value of a clearly negative trans-thoracic echo examination was 100%. Advanced age, and chronic renal failure were strongest independent predictors of mortality in our study population.

Conclusions: In patients with native cardiac valves, referred for the evaluation for infective endocarditis, an adequate quality TTE with clearly negative examination may be sufficient for the diagnosis.