Diagnostic Yield of Transthoracic Echocardiography Among US Emergency Department Observation Unit Patients Evaluated...

Patients with potential transient ischemic attacks (TIA) are often evaluated with transthoracic echocardiography (TTE) to identify cardioembolic sources. The diagnostic yield of TTE among patients in an emergency department observation unit (EDOU) with suspected TIA is unknown. We aimed to determine the diagnostic yield of TTE in a US EDOU TIA cohort.

We conducted an observational cohort study using the Wake Forest Emergency Medicine TIA Registry. We included patients ≥18 years old evaluated in the EDOU TIA protocol at a large academic tertiary care center between July 1, 2021 and December 1, 2023. TTE results were reviewed for high-risk cardioembolic features, which we included as patent foramen ovale (PFO), left ventricular ejection fraction (LVEF) ≤40%, focal wall motion abnormalities, and ventricular thrombus. The diagnostic yield, defined as the proportion of patients who were found to have a high-risk cardioembolic feature on TTE, was calculated and reported with an exact 95% confidence interval (95% CI) and used to determine the number needed to test.

Among the 686 patients included in our cohort, 67.1% (460/686) underwent TTE. The diagnostic yield of TTE was 19.4% (95% CI, 15.7-23.0%), which corresponds to a number needed to test of 6 (95% CI, 5-7). In our cohort, TTE identified 63 PFOs, 26 instances of LVEF ≤ 40%, 6 focal wall motion abnormalities, and 0 ventricular thrombi.

Among patients with suspected TIA in the EDOU, TTE was useful in the detection of high-risk cardioembolic features, especially PFOs and reduced LVEF. These findings support the continued use of TTE for those evaluated for TIA in the EDOU.