Risk of left atrial appendage thrombus in older patients with atrial fibrillation.

Abstract

We aimed to compare the prevalence of left atrial appendage (LAA) thrombus and its predictors between old and young patients with atrial fibrillation (AF). The study included 1970 patients aged ≥ 65 (n = 822 (41.7%)) and < 65 (n = 1148 (58.3%)) referred for AF cardioversion or ablation preceded by transoesophageal echocardiography (TEE). Oral anticoagulation (OAC) was prescribed in 799 (97.2%) patients aged ≥ 65 years and in 1054 (91.8%) of those aged < 65 years (p < 0.001). In patients treated with OAC, those aged ≥ 65 years less often received vitamin K antagonist (VKA) (267 (33.4%) vs. 416 (39.5%)) and more often non-VKA-OAC (NOAC) (532 (66.6%) vs. 638 (60.5%), p = 0.008, p = 0.008) compared to patients < 65 years. On TEE, LAA thrombus was more often observed in patients aged ≥ 65 years than those aged < 65 years (63 (7.7%) vs. 46 (4.0%), p < 0.001), with an absolute but not statistically significant difference between patients aged 65-74 and ≥ 75 years (47 (7.3%) vs. 16 (8.8%), p = 0.528). In patients aged ≥ 65 years, there was no difference in the prevalence of LAA thrombus between patients treated with VKA and NOAC, in contrast to patients aged < 65 years, in whom such a difference was observed (27 (6.5%) vs. 16 (2.5%), p = 0.002). In multivariate logistic regression, predictors of LAA thrombus in both age groups were older age, non-paroxysmal AF, and heart failure, whereas only in patients aged < 65 years - VKA use, and in those aged ≥ 65 years - lower glomerular filtration rate and platelet count. Despite OAC use, older patients with AF remain at high risk of LAA thrombus formation. Older age, non-paroxysmal AF, and heart failure are predictors of LAA thrombus, irrespective of age.