Clinical criteria and the appropriate use of transthoracic echocardiography for the exclusion of infective endocarditis.

BACKGROUND Clinical guidelines currently suggest that transthoracic echocardiography (TTE) be carried out in all patients with suspected endocarditis, but the use of TTE where there is a low probability of infective endocarditis has a poor diagnostic yield. This screening approach may no longer be appropriate. OBJECTIVE To examine whether clinical criteria might aid decision making with respect to the use of TTE in possible endocarditis. DESIGN A retrospective review of patient records. SETTING Cardiology department of a tertiary referral centre. PATIENTS 500 consecutive hospital inpatients referred for TTE to exclude endocarditis. MAIN OUTCOME MEASURES Evidence of endocardial vegetations on TTE and the presence of predetermined clinical criteria that may predispose to, or be suggestive of, endocarditis. RESULTS Evidence of infective endocarditis was detected on echocardiography in 43 of the 500 patients (8.6%). In 239 patients (48%), vegetations and certain prespecified clinical criteria were both absent. These criteria were: vasculitic/embolic phenomena; the presence of central venous access; a recent history of injected drug use; presence of a prosthetic valve; and positive blood cultures. The collective absence of these five criteria indicated a zero probability of TTE showing evidence of endocarditis. CONCLUSIONS The use of simple clinical criteria during the decision making process may avoid many unnecessary TTE examinations in hospital inpatients with a low probability of endocarditis.