Echocardiography Versus no Echocardiography in S. Aureus Bacteraemia and VIRSTA Score < 3

Overview

Staphylococcus aureus is the most frequent cause of both healthcare-associated and community-acquired bloodstream infections worldwide. Infective endocarditis (IE) has been detected in 5-17% of cases and is a determinant of poor prognosis. The investigators developed a score (the VIRSTA score) based on patients' characteristics to rule out IE with high confidence (negative predictive value (NPV) above 99%) in patients with SAB. This score, with a cut-off of 3 has been externally validated by two international studies which have also established its high NPV. The 2023 European society of cardiology (ESC) guidelines state that echocardiography should be considered in all patients with Staphylococcus aureus bacteremia (SAB) using risk scores (including VIRSTA score) to guide the use or not of echocardiography. While recommended, the investigators think that VIRSTA score must be evaluated in terms of patients' outcome.

In the interventional arm (no-echocardiography strategy) without echocardiography, at the individual level, not performing an echocardiography will avoid a useless examination, the mobilization of the patient and the discomfort related to its performance. In this arm, the theoretical risk is to diagnose Infective endocarditis (IE ) only at a later phase stage, i.e., at a phase of symptomatic manifestation of valve regurgitation or at the occurrence of relapse of bacteremia due to insufficient duration of antibiotic treatment. It should be noted that patients with prosthetic valve, who have "de facto" a VIRSTA score \> 3, will therefore not be included in the protocol. Given the expected rarity of IE in patients with a VIRSTA score \<3 and the theoretical consequences of not performing echocardiography, the primary endpoint chosen will be mortality and Staphylococcus aureus bacteraemia (SAB) relapse. The endpoint will be assessed at 90 days and not at discharge to capture relapses of inadequately treated bacteremia and the mid-term consequences of a possible delay in IE diagnosis. On a collective scale, not performing echocardiography in many patients in whom it is not useful will allow resources to be allocated to the individuals who need it most.