Failure of clinical features of low probability endocarditis. The early echo remains essential.

OBJECTIVE:To investigate if earlier reported retrospectively derived criteria for predicting absence of infective endocarditis (IE) on transthoracic echocardiography could be prospectively confirmed or improved with transoesophageal echocardiography (TOE). DESIGN:Prospective analysis of the relationship between predefined clinical IE features and findings on TOE in 708 IE suspected patients. RESULTS:The previously reported criteria were rejected as 1/10 of our confirmed IE patients fulfilled criteria for predicting absence of IE. However, our study generated another model of low probability of IE: This disease was absent in 99.4% of patients with negative blood cultures and absence of vascular phenomena and predisposing cardiac conditions. Such patients accounted for 25% of our population of patients suspected of IE. CONCLUSIONS:The utility of earlier reported clinical criteria for predicting absence of IE proved insufficient. Instead the study generated new simpler criteria of low probability of IE. However, these included negative blood cultures, but echocardiography must not be postponed while awaiting the results of blood cultures. Therefore the proposed new criteria only apply to patients with documented negative blood cultures when the suspicion of IE arises, in our study only 10% of the population. Accordingly, the study documented the essential role of early echocardiography in suspected IE.