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

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. 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. 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%). 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.