Left atrial appendage filling defect in exclusive early-phase scanning of dual-phase cardiac computed tomography: An indicator for elevated thromboembolic risk

Background: Dual-phase cardiac computed tomography (CCT) has been applied to detect left atrial appendage (LAA) thrombosis, which is characterized as the presence of LAA filling defects (LAADF) in both early- and delayed-phase scanning. However, the clinical implication of LAAFD in exclusive earlyphase scanning (LAAFD-EEpS) of CCT in patients with atrial fibrillation (AF) is unclear. Methods: The baseline clinical data and dual-phase CCT findings in 1183 AF patients (62.1 +/- 11.6 years, 59.9% male) was collected and analyzed. A further analysis of CCT and transesophageal echocardiography (TEE) data (within 5 days) in a subgroup of 687 patients was performed. LAAFD-EEpS was defined as LAAFD present in early-phase and absent in delayed-phase scanning of dual-phase CCT. Results: A total of 133 (11.2%) patients were detected with LAAFD-EEpS. Patients with LAAFD-EEpS had a higher prevalence of ischemic stroke or transient ischemic attack (TIA) (p < 0.001) and a higher predefined thromboembolic risk (p < 0.001). In multivariate analysis, a history of ischemic stroke or TIA was independently associated with LAAFD-EEpS (odds ratio [OR] 11.412, 95% confidence interval [CI] 6.561-19.851, p < 0.001). When spontaneous echo contrast in TEE was used as the reference standard, the sensitivity, specificity, positive predictive value, and negative predictive value of LAAFD-EEpS was 77.0% (95% CI 66.5-87.6%), 89.0% (95% CI 86.5-91.4%), 40.5% (95% CI 31.6-49.5%), 97.5% (96.3-98.8%), respectively. Conclusions: In AF patients, LAAFD-EEpS is not an uncommon finding in dual-phase CCT scanning, and is associated with elevated thromboembolic risk. (Cardiol J 2024; 31, 1: 95-102)