Left Atrial Appendage Thrombus as a Marker of Disease Severity in 500 Patients with Atrial Fibrillation on Oral Anticoagulation: A 13-Year Follow-Up Study

<b>Background/Objective:</b> Whether left atrial appendage thrombus (LAAT) in patients with atrial fibrillation (AF) on chronic anticoagulation significantly increases cardiovascular risk is unknown. This study aimed to assess LAAT prevalence and its predictive role in cardiovascular events among consecutive anticoagulated patients with AF admitted for electrical cardioversion. <b>Methods:</b> This prospective study included 500 patients. The primary outcome was LAAT on transesophageal echocardiography. Patients were followed up for a median of 1927.5 (interquartile range 1004-2643) days to assess cardiovascular events. <b>Results:</b> LAAT was detected in 65 (13%) patients. No significant differences in stroke, transient ischemic attack, systemic thromboembolic events, or myocardial infarction prevalence were observed between patients with AF with and without LAAT. Hospitalization for heart failure (HF) was more frequent in patients with LAAT than in those without LAAT; however, the effect of LAAT on HF hospitalization was not statistically significant. Patients with LAAT had a significantly higher risk of cardiovascular death than those without LAAT. LAAT and greater left atrial (LA) diameter were associated with higher rates of cardiovascular death. The independent HF hospitalization predictors were greater LA diameter, lower left ventricular ejection fraction (LVEF), and estimated glomerular filtration rate (eGFR). <b>Conclusions:</b> Patients with AF who received anticoagulation therapy showed a high prevalence of LAAT. LAAT and greater LA diameter were associated with significantly higher rates of cardiovascular death. LAAT, greater LA diameter, lower LVEF, and lower eGFR were associated with poor prognosis in anticoagulated patients with AF and were predictors of disease severity.