Extended CTA scan range for early detection of left atrial and left atrial appendage thrombus and other filling defects in acute ischemic stroke

BACKGROUND: The left atrium (LA) and left atrial appendage (LAA) are common sites of thrombus formation leading to cardioembolic stroke. We aimed to include LA/LAA in acute-phase stroke CT angiography (CTA) to detect potential embolic sources early. METHODS: The CTA scan range was extended to include the LA/LAA. We retrospectively reviewed CTAs from patients treated at Donostia University Hospital between December 2020 and November 2021. LA/LAA images were classified as normal filling, non-well-defined filling defect, and thrombus-suggestive filling defect. Clinical, demographic, and stroke severity data were compared across groups. RESULTS: Among 299 patients included, 6 (2%) had thrombus-suggestive filling defects, and 32 (11%) had non-well-defined defects. Both groups had more severe strokes (median NIHSS 16 vs. 13, p < 0.01), higher mortality (29% vs. 6%, p < 0.01), and more pre-existing heart disease (74% vs. 27%, p < 0.01) and known atrial fibrillation (AF) (63% vs. 8%, p < 0.01). AF was more frequently diagnosed during follow-up in the non-well-defined filling defect group than in the normal group (50% vs. 19%, p = 0.02). Prior AF was the only independent predictor of thrombus-suggestive filling defect, which was observed despite high rates of anticoagulation (50%). CONCLUSIONS: Including LA/LAA in acute CTA allows early identification of thrombus-suggestive and non-well-defined filling defects, both linked to worse outcomes and potential therapeutic consequences.