Abstract 11864: Incidence and Predictors of Left Atrial Thrombus in Patients With Atrial Fibrillation Under Standard Anticoagulation Therapy

Abstract

Background: The left atrial thrombus (LAT) formation is associated with thromboembolic events in atrial fibrillation (AF) patients. Objective: We investigated the incidence and associated factors of LAT in patients with AF who already on standard anticoagulation therapy. Methods: Medical records of 1,122 AF patients (mean 59.4 ± 11.0 years old, 58.3% male) who were on standard anticoagulation and underwent transesophageal echocardiography (TEE) from 2009 to 2019 were evaluated. Baseline clinical and echocardiographic data were analyzed. The main outcome of the study was the presence of LAT on TEE. The associated factors of the LAT were analyzed. Results: Warfarin and non-vitamin K oral anticoagulants (NOAC) were used in 74.4% and 25.6% of the patients. Among these patients, LAT was found in 60 patients (5.3%). The significant predictors of the LAT on TEE were elders (>75 years old, Odd ratio [OR] 1.99 [95% confidence interval 0.88-4.24]), persistent/permanent AF (OR 2.63 [1.45-4.95]), high CHA2DS2-VASc score (≥3 points, OR 2.06 [1.15-3.74]), low left ventricular ejection fraction (<40%, OR 2.12 [0.97-4.33]), and moderate-severe left atrial enlargement (LAE) (OR 3.92 [1.95-8.59]). Moderate-severe mitral regurgitation (MR) was associated with lower odds for LAT (OR 0.146 [0.04-0.37]). We gave each variable a score according to its weight (-3 points for MR, 2 points for LAE, and 1 point for the rest). If our risk score is 3 or more, the rate of LAT increases to 8.7% or more. Conclusions: Several clinical and echocardiographic predictors were useful for predicting presence of LAT in AF patients who are already on anticoagulation treatment. Screening for LA thrombus before left atrial interventions such as cardioversion, ablation procedure, or appendage occluder, should be warranted in patients with high risk score.