NOACs and atrial fibrillation: Incidence and predictors of left atrial thrombus in the real world

Abstract

Aims: Despite optimal oral anticoagulation with vitamin K antagonist, left atrial (LA) thrombus could be detected in the left appendage (LAA) in >2% of patients with atrial fibrillation (AF) and CHA₂DS₂-VASc score≥1 but few data are available for patients treated with non-vitamin K antagonist oral anticoagulants (NOACs). We evaluated the occurrence and predictors of LA thrombi by means of transesophageal echocardiography (TOE) in consecutive patients with non-valvular AF who received for at least 3weeks Apixaban, Dabigatran, or Rivaroxaban.

Methods: This study included 414 consecutive patients (male 252, 60.6%, mean age 67.3years) referred to our Centers for catheter ablation of AF (n=220, 53.1%) or scheduled electrical cardioversion (n=194, 46.9%). Patients were on Dabigatran (n=160), Rivaroxaban (n=150) or Apixaban (n=104). TOE was performed in all cases within 12h prior to ablation or cardioversion.

Results: Preprocedural TOE revealed LA thrombus in 15/414 patients (3.6%), all located in the LAA (Apixaban 3/104 2.9%, Dabigatran 5/160 3.1%, and Rivaroxaban 7/150 4.7%, p=0.69). Of these, 14 patients had persistent AF. Patients with LAA thrombus had a mean CHA₂DS₂-VASc score of 3 (3-4). Higher CHA₂DS₂-VASc score (p=0.02), but not the type of NOAC, significantly predicted the presence of LA thrombus.

Conclusion: The incidence of LAA thrombus in a cohort of patients anticoagulated with NOACs is low but not negligible, in any case similar among the 3 drugs. Preprocedural TOE should be considered in patients with a CHA₂DS₂-VASc score>3.

Keywords: Atrial fibrillation; Left atrial thrombus; Non-vitamin K antagonist oral anticoagulants; Transesophageal echocardiography.