Efficacy and Safety of Apixaban in Patients Following Cardioversion for Atrial Fibrillation: Insights From the ARISTOTLE Trial

Study Questions:

Does apixaban provide adequate protection from thromboembolic events in patients undergoing cardioversion of atrial fibrillation (AF)?

Methods:

This was a post-hoc of a randomized clinical trial in which 18,201 patients (mean age 69 years) with AF were randomly assigned to anticoagulation with apixaban or warfarin. In this trial, 743 cardioversions were performed in 540 patients. The primary endpoint of the study was stroke and systemic embolism within 30 days of cardioversion.

Results:

Cardioversion was performed at least once in 265 patients (mean CHADS2 score 1.8) in the apixaban group and 275 patients (mean CHADS2 score 1.9) in the warfarin group. Transesophageal echocardiographic confirmation of the absence of left atrial thrombus was available in 86 patients in the apixaban group and 85 patients in the warfarin group. There were no strokes or systemic emboli in the 30 days after cardioversion in either group. One patient in both groups had a myocardial infarction and one patient in both groups had a major bleeding event.

Conclusions:

The authors concluded that thromboembolic events following cardioversion of AF are rare in patients anticoagulated with apixaban or warfarin.

Perspective:

The need for monitoring the international normalized ratio (INR) in patients treated with warfarin is a major disadvantage compared to the new anticoagulants such as apixaban. However, in the setting of cardioversion, the INR provides objective verification of adequate anticoagulation. In the case of apixaban, adequate anticoagulation is assumed to be present, as long as the patient has been compliant. Because patient compliance sometimes is questionable, a pre-cardioversion transesophageal echocardiogram may be prudent more often in patients treated with one of the new anticoagulants than with warfarin.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Noninvasive Imaging, EP Basic Science, Echocardiography/Ultrasound

Keywords: Stroke, Myocardial Infarction, Warfarin, Electric Countershock, Pyrazoles, Blood Coagulation, Thrombosis, Cardiology, Embolism, Pyridones, Echocardiography


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