P382Prevalence of left atrial appendage thrombus in patients with atrial fibrillation/flutter: warfarin therapy versus direct oral anticoagulants

Abstract

Background: The left atrial appendage (LAA) is the predominant source of cardiac thrombi responsible for ischemic strokes in patients with atrial fibrillation/flutter. Transesophageal echocardiography (TEE) is a highly sensitive and specific imaging modality used to assess LAA anatomy before cardioversion or catheter ablation procedures. Purpose: The purpose of this study is to be determine the prevalence of LAA thrombus in patients with non-valvular atrial fibrillation/flutter who have been on therapeutic anticoagulation with warfarin versus DOACs for at least 3 weeks. Methods: This study was a retrospective chart review of patients with non-valvular atrial fibrillation/flutter who underwent TEE after receiving therapeutic anticoagulation with either warfarin or direct oral anticoagulants (DOACs) for at least 3 weeks. A Fisher exact t-test was used to determine whether the prevalence of TEE-documented LAA thrombus differed significantly between warfarin and DOAC recipients. Results: The 301 patients (mean age, 67610 y 65% male 92% Caucasian) received therapeutic outpatient anticoagulation with warfarin (n=55) or DOACs (n=246). The prevalence of LAA thrombus was substantially lower in patients receiving DOACs (1.2%) than in those receiving warfarin (9.1% p<0.006). Among the DOAC recipients, rates of LAA thrombus in patients taking apixaban, dabigatran, and rivaroxaban were 0.8%, 0%, and 1.9%, respectively. Other than the use of DOACs versus warfarin, there were no significant predictors of LAA thrombus in these patients. Conclusion: Among patients undergoing long-term anticoagulation for atrial fibrillation/flutter, the prevalence of LAA thrombus was significantly lower in patients taking DOACs than patients taking warfarin. Prospective clinical studies are warranted to determine whether routine TEE is necessary before ablation procedures in patients receiving DOACs.