Incidence and Predictors of Left Atrial Appendage Thrombus in Patients Treated With Nonvitamin K Oral Anticoagulants Versus Warfarin Before Catheter Ablation for Atrial Fibrillation

The utility of routine transesophageal echocardiography (TEE) to exclude left atrial appendage (LAA) thrombus before atrial fibrillation (AF) ablation in patients treated with nonvitamin K oral anticoagulant (NOAC) therapy is unclear. This single-center retrospective study sought to investigate the incidence of LAA thrombus in patients undergoing routine TEE before AF ablation treated with warfarin or NOAC therapy. We included 937 routine pre-AF ablation TEE procedures performed in patients treated with warfarin (n = 517) or NOAC (n = 420). Patients were anticoagulated without interruption for at least 4 consecutive weeks before the TEE. Patients treated with warfarin had lower LAA velocity and underwent TEE earlier in the study period than those treated with NOAC (p <0.05). The incidence of LAA thrombus was higher in patients treated with warfarin (1.55%, 8 of 517) compared with patients treated with NOAC (0.24%, 1 of 420, p = 0.0473 for difference). No LAA thrombus was identified in NOAC-treated patients with a CHA₂DS₂-VASC score <5 and in warfarin-treated patients with a CHA₂DS₂-VASC score <2. TEE-related complications occurred in 3 of 937 procedures (0.3%). In conclusion, LAA thrombus is detected rarely during pre-AF ablation TEE. Treatment with an NOAC is associated with a lower incidence of pre-AF ablation LAA thrombus compared with warfarin.