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

Introduction: We aimed to compare the prevalence of left atrial appendage (LAA) thrombus and its predictors between old and young patients with atrial fibrillation (AF).

Material And Methods: The study included 1970 patients aged ≥ 65 ( = 822 (41.7%)) and < 65 ( = 1148 (58.3%)) referred for AF cardioversion or ablation preceded by transoesophageal echocardiography (TEE).

Results: Oral anticoagulation (OAC) was prescribed in 799 (97.2%) patients aged ≥ 65 years and in 1054 (91.8%) of those aged < 65 years ( < 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%), = 0.008, = 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%), < 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%), = 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%), = 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.

Conclusions: 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.