Abstract 15744: Simplified Criteria to Risk Stratify for the Mode of Echocardiography in Patients with Mrsa Bacteremia at Low Risk of Infectious Endocarditis

Abstract

Background: AHA 2005 guidelines suggested the use of transesophageal echocardiography (TEE) in patients with staphylococcal bacteremia (SAB) suspected for infectious endocarditis (IE). However a subset of these patients may be at low risk for IE and not require TEE as the first test. The aim of our study is to identify these low risk patients based on a clinical criterion and see if TEE changed any plan in these patients.

Methods: Consecutive patients (n=398) presenting with SAB were evaluated retrospectively from 2005 to 2009 at our institution. IE was diagnosed based on modified Duke's criteria. Data was collected for various risk factors for IE by chart review. Predictors of IE were calculated by multivariate analysis.

Results: Overall 398 (mean age 58.6 +/− 17.1 years, women 40.2%), with SAB were included. The diagnosis of IE was classified as definite in 44 (11%), possible in 119 (29.9%) and rejected in 235 (59%) based on Duke's criteria. The significant clinical predictors are given in table. A criteria was formed based on these variables, with less than one positive variable predicting low risk patients. In total 44 of 44 patients with documented IE fulfilled at least 1 criterion (sensitivity 100%, negative predictive value 100%). 34 of 44 patients with documented IE fulfilled at least 2 criteria (sensitivity 77.2%, negative predictive value 95.1%). Among the 68 low risk patients without these risk factors, 23 (33.8%) had transthoracic echocardiogram (TTE) as the first imaging study, 5 (7.4%) had TEE, 1 (1.5%) got TEE followed by TTE and 39 (57.5%) did not get any imaging done. TEE results did not change or add to the management in any of the low risk patients.

Conclusion: Our simplified criteria to risk stratify the patients with SAB on presentation that are suspected for IE may provide better resource utilization of modes of echocardiography.