External validation of CLOTS-AF score in patients with atrial fibrillation undergoing transesophageal echocardiography.

Predicting thromboembolic events caused by left atrial appendage thrombosis (LAAT) is crucial since it is the most concerning complication of nonvalvular atrial fibrillation (NVAF). The objective of this study was to establish the predictive effectiveness of a novel scoring system known as the CLOTS-AF score in identifying the existence of thrombus using transesophageal echocardiography (TEE) in patients with NVAF and to compare it with the CHA2DS2-VASc score. This study was conducted retrospectively with 668 NVAF patients who underwent TEE in a single centre. The patients were categorized into two categories based on the presence or absence of LAAT on TEE. The CLOTS-AF score was computed for all patients, which was then compared to the CHA2DS2-VASc score. Thrombus was detected in the left atrial appendage (LAA) of 114 (17%) individuals. The study revealed that the thrombus (+) group had substantially higher CHA2DS2-VASc scores and CLOTS-AF scores (3 (2-4); 4 (3-6), p < .001), respectively. Furthermore, the CLOTS-AF score was shown to be a better predictor of LAAT than the CHA2DS2-VASc score (AUC: 0.70 vs. AUC: 0.61, p < .001). This study could validate the CLOTS-AF score in an external cohort by demonstrating its significant predictive power and underscoring its vital role in clinical practice.