Comparison of different oral anticoagulant regimens in patients with atrial fibrillation undergoing ablation or cardioversion

INTRODUCTION Non-vitamin K antagonist oral anticoagulants (NOACs) are an alternative to vitamin K antagonists (VKAs) for stroke prevention in atrial fibrillation (AF). OBJECTIVES The aim of the study was to assess the incidence of left atrial appendage (LAA) thrombus and dense spontaneous echo contrast (SEC), as well as to compare the clinical characteristics of patients with AF treated with different anticoagulant regimens. PATIENTS AND METHODS We studied 1033 consecutive patients with AF, who underwent transesophageal echocardiography (TEE) before AF ablation or cardioversion. We excluded 174 patients without any prior oral anticoagulation or who underwent bridging with heparin before TEE. RESULTS In the study group of 859 patients (median age, 61 years; men, 66%), 437 patients (50.9%) received VKAs; 191 (22.2%), dabigatran; 230 (26.8%), rivaroxaban; and 1 patient (0.1%), apixaban. There were no differences in baseline characteristics or the incidence of LAA thrombus (VKAs, 6.9%; NOACs, 5.5%; P = 0.40) and dense SEC (VKAs, 5.3%; NOACs, 3.3%; P = 0.18) between patients on VKAs and those on NOACs. Compared with patients treated with dabigatran, those on rivaroxaban more often had paroxysmal AF, higher ejection fraction, LAA emptying velocity, and platelet count, as well as lower left ventricular end-diastolic dimension and hematocrit. The frequency of LAA thrombus in patients receiving dabigatran and those receiving rivaroxaban was comparable (6.8% vs 4.4%; P = 0.29), while dense SEC occurred more often in patients treated with dabigatran (5.2% vs 1.7%; P = 0.06). In a logistic regression analysis, none of the oral anticoagulation regimens predicted LAA thrombus in TEE, whereas maximal LAA emptying velocity was the only parameter independently associated with the presence of thrombus. CONCLUSIONS In the studied group of patients with AF, the choice of anticoagulation did not depend on thromboembolic or bleeding risk.