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

Abstract

Approximately 25% of patients with staphylococcus aureus bacteremia (SAB) develop infective endocarditis (IE), which has a consequent mortality of 25-46%. Current guidelines recommend routine transthoracic echocardiography (TTE) for patients with SAB; transesophageal echocardiogram (TEE) is reserved for those 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. 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. The primary outcome was development of IE in patients with SAB. Multivariate logistic regression analysis was used to identify clinical risk factors for IE. Moreover, sensitivity and specificity of TTE and TEE was calculated. Out of 213 patients with SAB, 68 patients met diagnostic criteria for IE. Most patients (n = 209) underwent TTE and 171 patients underwent subsequent TEE. The overall sensitivity of TTE was 63% and overall sensitivity of TEE was 88%. Multivariate analysis showed significantly increased risk of IE in patients who had implanted permanent pacemaker (aOR 32.3, CI 5.23 - 281, p < 0.001) and persistent fever (aOR 6.97, CI 2.42 - 21.0 P < 0.001). Based on our analysis, we recommend that TEE should be strongly considered after negative TTE in SAB patients with intracardiac prosthetics or persistent fever despite appropriate antibiotic therapy.