Abstract Body: Introduction:
Echocardiography, the current gold standard for evaluating cardioembolic sources of acute ischemic stroke (AIS), is relatively low yield, not readily available at all hospitals, and may delay treatment and disposition. Cardiac CT angiography (CCTA) can also be used to identify cardioembolic sources of stroke. Many prior studies of CCTA in AIS have been enriched with a patient population most likely to have embolic stroke and/or large vessel occlusion. We report the preliminary results of a pilot study assessing the utility of CCTA in the routine evaluation of all AIS and TIA stroke patients.

Methods:
In 2024, we integrated CCTA into the standard of care diagnostic evaluation of patients with AIS and TIA in addition to routine echocardiography (TTE or TEE). CCTA was obtained for all AIS patients when possible, but limitations included scanner availability, cardiology availability, and CT tech training. CCTA could be integrated directly into the stroke code imaging (i.e. combined with CT Angiograms of the Head/Neck utilizing a single contrast bolus) or obtained as a standalone study. The patient’s demographics, stroke characteristics, and type of CCTA obtained (integrated vs standalone) were reported using descriptive statistics. To assess the diagnostic yield of CCTA we analyzed: 1) the number of times echocardiography changed the stroke etiology and 2) the number of times CCTA changed the stroke etiology (by TOAST criteria). In addition, we studied how often echocardiography or CCTA findings changed management. We tested statistical significance using McNemar's mid P-test.

Results:
Our study population consisted of 88 patients with the final diagnosis of AIS or TIA. The median age was 70 IQR: 65-80, female 48.9%, median NIHSS: 2.5, IQR: 0-9, AIS 70 (79.5%). (Table 1). Echocardiography changed the diagnosed stroke etiology in 1 (1.1%) of patients, CCTA changed the diagnosed stroke etiology in 6 (6.8%) of patients (p=0.07). Echocardiography changed management in 1 (1.1%) of patients, whereas CCTA changed management in 10 (11.4%) of patients (p<0.01) (see Table 2 for detailed CCTA findings).

Conclusions:
In our real-world pilot study, CCTA more commonly changed clinical management than echocardiography (11.4% vs 1.1%). Further studies of the diagnostic yield of routine CCTA in patients with AIS and TIA are warranted.