Abstract 15255: Clinical Risk Factors for Infective Endocarditis in Patients With Staphylococcus Aureus Bacteremia and the Diagnostic Utility of Transesophageal Echocardiogram

Abstract

Background: Approximately 25% of patients with staphylococcus aureus bacteremia (SAB) develop infective endocarditis (IE), which has a consequent mortality of 46%. Current guidelines recommend routine transthoracic echocardiography (TTE) for patients with SAB; transesophageal echocardiogram (TEE) is reserved for those patients in whom initial TTE is negative and clinical suspicion for IE remains high. We sought to elucidate high risk features of SAB associated with the development of IE that warrant a TEE after a negative TTE. Methods: This retrospective study included 213 patients who were diagnosed with SAB at the University of New Mexico Hospital between 2010-2020. A pre-determined list of clinical risk factors along with TTE and TEE status was extracted from the electronic medical record (Table 1). Our primary outcome was the development of IE in patients with SAB. Multivariate logistic regression analysis was used to identify clinical risk factors for IE. Sensitivity and specificity of TTE and TEE was also calculated (Table 1). Results: Out of 213 patients with SAB, 68 patients met diagnostic criteria for infectious endocarditis. Most patients (n=209) underwent TTE and 117 patients underwent subsequent TEE. Initial TTE was diagnostic in 42 patients with a sensitivity of 63% and specificity of 94%; 45 patients had a diagnostic TEE with a sensitivity of 83% and specificity of 98%. Multivariate analysis showed significantly increased risk of IE in patients who had a permanent pacemaker (aOR 32.3, CI 5.23 - 281, p<0.001) or a persistent fever (aOR 6.97, CI 2.42 - 21.0, P<0.001). Conclusions: The routine use of TEE in patients with SAB for the diagnosis of IE may not be necessary and introduces unnecessary procedural risk. Based on our analysis, we recommend that SAB patients with a permanent pacemaker (or other intracardiac prosthetic) or a persistent fever despite appropriate antibiotic therapy be screened with TEE when initial TTE is negative.