An Approach to Improve the Negative Predictive Value and Clinical Utility of Transthoracic Echocardiography in Suspected Native Valve Infective Endocarditis

Background In patients with suspected native valve infective endocarditis (IE), current guidelines recommend an initial transthoracic echocardiogram (TTE) followed by a transesophageal echocardiogram (TEE) if clinical suspicion remains. The guidelines do not account for quality of the initial TTE or other findings that may alter the study’s diagnostic characteristics. This may lead to unnecessary TEE procedures where the initial TTE was sufficient to rule out vegetation. Methods Patients with suspected native valve endocarditis that underwent a TTE followed by a TEE within 7 days between 1/1/2007 and 2/28/2014 were included. A negative TTE for vegetation was defined by either the standard approach (at least possible vegetation seen on TTE), or by applying a set of strict negative criteria incorporating other findings on TTE. Using TEE as the gold standard for presence of vegetation, the diagnostic performance of the two TTE approaches were compared. Results In total, 790 TTE/TEE pairs were identified. With the standard approach, 671 of the TTEs were negative, compared to 107 negative studies using the strict negative approach. The sensitivity and negative predictive value (NPV) of TTE for detecting vegetation were substantially improved using the strict negative approach (sensitivity: 98% [95% C.I. 95–99%] vs. 39% [95% C.I. 31%–47%], NPV: 97% [95% C.I. 92–99%] vs. 86% [95% C.I. 83–88%]). Conclusions The ability for TTE to exclude vegetation in patients is excellent when strict criteria for a negative study are applied. In low to intermediate risk patients with a strict negative TTE, follow up TEE may be unnecessary.