Comparison between transthoracic and transesophageal echocardiography in screening for infective endocarditis in patients with Staphylococcus aureus bacteremia

Echocardiography is an important diagnostic tool in evaluating a patient with Staphylococcus aureus bacteremia (SAB) for diagnosing infective endocarditis (IE). We sought to compare the utility of transthoracic echocardiography (TTE) with transesophageal echocardiography (TEE) in screening for IE in patients with SAB. We performed a retrospective chart review of 285 adult patients from two tertiary care hospitals with at least one positive blood culture for S. aureus between 2010 and 2012. Patients who underwent echocardiography were divided into two groups: TTE (screened with TTE only) and TEE (screened with both TTE and TEE). The demographic factors and clinical outcomes were compared between the groups. Of the 285 charts reviewed, 213 (74.7 %) patients were screened with echocardiography: 183 (85.9 %) were screened with TTE alone and 30 (14.1 %) were screened with both TTE and TEE. TEE disclosed more cases of definite IE than TTE (8 [26.7 %] vs. 22 [12.0 %], p = 0.046). The TEE group had higher mortality than the TTE group (15 [50.0 %] vs. 43 [23.5 %], p = 0.004). In patients with definite IE, mortality was higher in the TEE group than in the TTE group (6 [75.0 %] vs. 6 [27.3 %], p = 0.034). TEE discovered additional findings that were missed by TTE in 36.7 % of cases and refuted the findings of TTE in 13.3 % of cases. We do not support the routine use of TEE in patients with uncomplicated SAB. High-risk patients in which IE is a serious consideration should undergo investigation with TEE.