Abstract Number: Esoc2026a2164 Venous-Phase Non-Ecg-Gated Cardiac Ct to Detect Intracardíac Thrombosis in the Acute Phase of Stroke

Abstract Background and aims Breakthrough stroke (BT) in patients with atrial fibrillation (AF) receiving anticoagulation (ACO) are at risk of left atrial appendage thrombosis (LAAT). We evaluated the usefulness of delayed venous-phase cardiac CT to detect cardiac thrombus. Methods We conducted a retrospective analysis of consecutive BT patients who underwent a modified CT protocol for hyperacute stroke, including venous-phase non–ECG-gated cardiac CT (CCT) without additional contrast injection. Detection of LAAT, quality of left atrial appendage (LAA) contrast filling in hounsfield units (HU), thrombus location, and factors associated with thrombus detection. Results 127 patients were included (mean age 81 years; 55.9% women; baseline NIHSS 6 IQR 3–15). LAAT was detected in 15% (n=19), predominantly in the LAA (84.2%), and was associated with lower attenuation values (HU) compared with patients without LAAT (63 HU IQR 58–79 vs 151 HU IQR 133–178; p0.001). Median injection-to-scan delay was 186 seconds (IQR 172–226). LAA contrast filling was optimal, with no difference between aortic and LAA attenuation (165±46 HU vs 170±38 HU; p=0.098). Patients with LAAT had a larger left atrial (LA) area on cardiac CT (37.6 cm2 IQR 31–46 vs 32 cm2 IQR 28–37; p=0.007) adjusted by age. A ROC showed LA area on cardiac CT 30cm2 to rule out LAAT (sensitivity 89%, specificity 33%) and LA area 38cm2 to suspect LAAT (sensitivity 47%, specificity 80%). Conclusions Venous-phase cardiac CT facilitates thrombus detection with minimal delay and without additional contrast administration. LA enlargement appears to be a risk marker for LAAT. Conflict of interest Jorge Pagola: nothing to disclose, Fabian Andres: nothing to disclose, Claudia Meza: nothing to disclose, Giulio Giulio: nothing to disclose, Jesus Juega: nothing to disclose, Federica Rizzo: nothing to disclose, Georgina Figueras: nothing to disclose, Carlos A. Molina: nothing to disclose, Hug Cuellarhug: nothing to disclose