European Society of Cardiology-Proposed Diagnostic Echocardiographic Algorithm in Elective Patients with Clinical Suspicion of Infective Endocarditis: Diagnostic Yield and Prognostic Implications in Clinical Practice

Background: Echocardiography plays a central role in diagnosing infective endocarditis (IE). Accordingly, the European Society of Cardiology (ESC) has proposed a diagnostic echocardiographic algorithm. However, new studies are still needed to evaluate the degree of implementation of these guidelines in clinical practice and their consequences on incidence and prognosis of IE. Aim: This study aims to investigate the diagnostic yield of the ESC proposed echocardiographic algorithm in patients with suspected IE. We also examined the association among IE diagnosis and clinical outcomes. Methods: Retrospective analysis of a series of patients undergoing the ESC algorithm for clinical suspicion of IE at our institution. Results: Between 2009 and 2013, 323 cases were managed by a multidisciplinary team for clinical suspicion of IE. Following ESC algorithm, 26 (8%) patients were diagnosed with IE and 297 (92%) had IE excluded. In 92% of patients with a good-quality negative transthoracic echocardiography (TTE) and low level of clinical suspicion, the first TTE was considered sufficient to rule out IE. During a mean follow-up of 2.3 +/- 1.4 years, patients who had a final diagnosis of IE showed similar mortality (P = 0.2) and rates of combined endpoint (all-cause death, stroke/transient ischemic attack, advanced atrioventricular block, and heart failure) compared to patients without echocardiographic diagnosis of IE (P = 0.5). Only 1% of the patients who had IE excluded experienced IE in the following 3 months, none of them in the subgroup of patients, in which a first negative TTE was considered sufficient to rule out IE. Conclusions: In spite of the current ESC recommendation TTE is used as part of a routine fever screen. Consequently, only a minority of patients had a final echocardiographic diagnosis of IE. Although in patients with low clinical suspicion a first negative TTE is sufficient to rule out IE, the incidence of clinical events is similar regardless the final diagnosis of IE.