Persistent Left Atrial Appendage Thrombus in Atrial Fibrillation Despite Anticoagulation

Area of Science:

• Cardiology
• Internal Medicine
• Thrombosis Research

Background:

• Current atrial fibrillation guidelines suggest 4 weeks of uninterrupted oral anticoagulation (OAC) is sufficient to rule out left atrial appendage thrombus before procedures.
• However, persistent thrombus can be observed in some patients even with documented OAC compliance.

Purpose of the Study:

• To assess the characteristics and management strategies for patients presenting with left atrial appendage (LAA) thrombus despite adherence to OAC.
• To evaluate outcomes and treatment efficacy in this patient cohort.

Main Methods:

• A review of clinical history, management, and outcomes was conducted for patients with LAA thrombus identified on preprocedural transesophageal echocardiography (TEE).
• The study included patients undergoing AF-related procedures between 2021 and 2024.

Main Results:

• Out of 3653 preprocedural TEEs, 65 (1.8%) showed LAA thrombus. Of these, 39 patients (60%) had documented OAC compliance of at least 4 weeks.
• Apixaban was the most common OAC (64%). Two patients (3%) experienced embolic events, and 8 (12%) died during follow-up.
• Thrombus resolution occurred in 12/32 patients (31%) after switching OAC agents or continuing therapy. Left atrial appendage occlusion (LAA-O) was successful in seven patients with persistent thrombus.

Conclusions:

• A significant proportion of patients (60%) with LAA thrombus undergoing procedures had adhered to OAC for over 4 weeks.
• Switching OAC agents or prolonging treatment duration led to thrombus resolution in 31% of cases, while LAA-O provided an alternative for persistent thrombi.
• Factors associated with a lower probability of having thrombus on TEE included non-valvular AF, OAC compliance >4 weeks, CHADS-VASc score ≤2, and normal ejection fraction.