Cardioembolic factors are responsible for 20–30% of ischemic strokes, especially atrial fibrillation (AF) through left atrial appendage (LAA) thrombus formation. The aim of the present study was to evaluate the prevalence and associated factors of LAA thrombus (LAAt) in patients with acute ischemic stroke by adding a cardiac CT during the initial imaging, and their early management and outcome accordingly.

From November 2018 to October 2019, 875 consecutive patients admitted with stroke like symptoms in the emergency department of our institution were included. All patients underwent a stroke CT protocol including a non-enhanced brain CT, a brain perfusion if necessary, a carotid CT angiography, a cardiac CT and a post-contrast brain CT. The cardiac CT was performed with a prospectively ECG gated volume acquisition.

Among 324 strokes confirmed, 35 LAAt patients (11%) and 289 no LAAt patients were analysed. Compared to no LAAt patients, LAAt patients were significantly older (82±12 vs. 74±14 years old, P=0.002), predominantly female (71% vs. 45%, P=0.004) and more often had previous AF history (63% vs. 15%, P<0.001) and previous stroke (32% vs. 14%, P=0.005). There was no significant difference between the 2 groups in brain localisation, severity scales at admission or hospital discharge. After ROC curve analysis, LA volume was strongly associated with LAAt (AUC=0.765; 95% CI: 0.691–0.840; P<0.001) with a best cut-off value of 86mL. Moreover, despite comparable stroke severity at admission, mortality rate was markedly higher in LAAt than in no LAAt group (37% vs. 13%, P<0.001).

This study highlights the contribution of cardiac CT, in addition to the usual brain CT in acute stroke imaging protocol in routine practice, for LAA thrombus evaluation. Such a strategy could be helpful for making decision with regard to early anticoagulation initiation. Further studies are needed to assess the impact on patients’ outcome.