Apixaban Outperforms Warfarin in Stroke Risk Reduction Among Cardioversion Patients

Apixaban (Eliquis) was found to lower the risk of stroke more significantly than warfarin among anticoagulation-naïve patients with atrial fibrillation undergoing cardioversion, according to a late-breaking study presented at the European Society of Cardiology Congress.

However, the authors noted that bleeding rates—a potentially serious adverse event associated with anticoagulants—were similar among both treatment groups.

Atrial fibrillation is a heart rhythm disorder that increases the risk of stroke and death. Treatment includes pharmacotherapy with anticoagulants and cardioversion to prevent adverse health events. During cardioversion, the heart’s normal rhythm is restored and maintained.

Apixaban works by inhibiting factor Xa, a substance required for clotting. This anticoagulant is fast-acting and easy to use, according to the authors. They added that other standard anticoagulants, such as heparin and warfarin, are more difficult to use. Heparin is an injectable drug and warfarin has a delayed effect.

Typically, patients scheduled for cardioversion receive heparin and/or warfarin to reduce the risk of stroke. The authors report that apixaban has not been tested in this patient population.

The aim of the EMANATE2 trial was to determine the rate of stroke and bleeding for apixaban versus warfarin with heparin. Included in the study were 1500 patients who have received less than 48 hours of anticoagulant therapy and were undergoing cardioversion due to new onset non-valvular atrial fibrillation.

Patients were randomized to receive apixaban 5-mg twice per day or treatment with heparin and warfarin. At the discretion of the researchers, patients could also receive an initial 10-mg or 5-mg dose of apixaban if the procedure was fast approaching, according to the study.

The authors compared rates of stroke, systemic embolism, death, major bleeding, and non-major bleeding in both groups.

No patients treated with apixaban experienced a stroke compared with 6 among patients receiving standard care. The authors noted that there were no systemic embolic events in either cohort.

Major bleeding events were similar among the groups, with 3 occurring in the apixaban group and 6 in the standard care group. Clinically significant non-major bleeds occurred in 11 apixaban-treated patients and 13 standard care patients, according to the study.

The authors also found that there were 2 deaths in the apixaban cohort, while there was only 1 in the standard care cohort.

Among patients who received the initial dose of apixaban, there were no strokes or systemic embolic events, 1 death, 1 major bleed, and 4 non-major bleeds, according to the session.

"In patients with atrial fibrillation undergoing cardioversion, apixaban with or without a loading dose was safe, resulting in few bleeding events and less strokes than conventional anticoagulant therapy,” said principal investigator Michael Ezekowitz, MD. “We expect these findings will be translated into clinical practice."