Contribution of echocardiography in the diagnosis of definitive infective endocarditis: the infectious disease specialist's point of view.

In 1994, the original Duke criteria introduced the usefulness of echocardiography for the diagnosis of definitive infective endocarditis (IE). Recently, the European Society of Cardiology (ESC) highlighted the need of complementary imaging to support the diagnosis of embolic events and cardiac involvement when echocardiography findings are negative or doubtful. We decided to study the usefulness of transthoracic and transesophageal echocardiography (TTE/TEE) for the diagnosis of definitive IE in patients who already benefited from complementary investigations. A retrospective bicentric study was conducted among patients hospitalized for an IE (2006-2017). Modified Duke criteria were calculated for each patient before and after findings of TTE/TEE. Thereafter, patients were classified by the local task force into three groups: excluded, possible, and definitive IE. Overall, 86 episodes were studied. The median patient age was 72 years (18-95). Microorganisms involved were mostly Staphylococcus aureus (32.5%) and Streptococcus spp. (40.7%). The mortality rate was 17.4%. Before echocardiography, there were 3 excluded IE (3.5%), 51 possible IE (59.3%), and 32 definitive IE (37.2%). After echocardiography findings, we observed 62 definitive (72.1%) and 24 possible IE (27.9%) (p < 0.0001). Our cohort revealed that 19.8% of the definitive and possible IE had a normal echocardiography. The rate of septic emboli did not statistically differ between patients who had a contributive or a normal echocardiography (76.5% vs. 76.8%). TTE and TEE play a major role in the diagnosis of definitive IE, even if we consider findings of complementary imaging. Physicians should be wary that definitive IE may present with a non-contributive echocardiography, mentioned as normal.