# Apixaban Reduces Stroke Risk without Increasing Bleeding Compared to Aspirin in Patients with Atrial Fibrillation Unsuited for Vitamin K Antagonists

 

 

      DynaMed Weekly Update - Volume 6, Issue 6 

Thromboembolic prophylaxis is recommended to reduce the risk of stroke in patients with atrial fibrillation. Vitamin K antagonists (VKAs) such as warfarin are usually preferred, but aspirin is a commonly used alternative for patients unable or unwilling to take VKAs. The AVERROES trial compared apixaban, a factor Xa inhibitor, vs. aspirin for thromboembolic prophylaxis in 5,599 patients with atrial fibrillation unsuited to vitamin K antagonists. Patients were randomized to apixaban 5 mg twice daily vs. aspirin 81-324 mg/day. In the month prior to the trial, 76% had been taking aspirin and 15% had taken a VKA. At mean follow-up of 1.1 years, the overall risk of stroke was significantly reduced in the apixaban group (1.7% vs. 3.8%, p < 0.001, NNT 48) ([level 1 \[likely reliable\] evidence](http://www.epnet.com/dynamed/levels.php)). Apixaban was also associated with reduced rates of ischemic stroke (1.3% vs. 3.3%, p < 0.001, NNT 50), disabling or fatal stroke (1.1% vs. 2.6%, p < 0.001, NNT 67), and systemic embolism (0.007% vs. 0.5%, p = 0.01, NNT 203). There were no significant differences in all-cause mortality (4% vs. 5%, p = 0.07) or major bleeding (1.6% vs. 1.4%). The trial was stopped early at a preplanned interim analysis due to the reduced incidence of stroke in the apixaban group. Apixaban is not yet approved by the FDA ([N Engl J Med 2011 Feb 10 early online](http://www.nejm.org/doi/full/10.1056/NEJMoa1007432)).

For more information, see the [Thromboembolic prophylaxis in atrial fibrillation](http://search.ebscohost.com/login.aspx?direct=true&site=dynamed&id=AN+114787) topic in DynaMed.