For years, warfarin and other vitamin K inhibitors have been used effectively to prevent stroke in patients with atrial fibrillation (AF). However, a recent study published in the New England Journal of Medicine
suggests that Xa inhibitor Apixaban prevents stroke more effectively than warfarin, and does so with fewer side effects and a lower mortality rate.
Though warfarin and other vitamin K inhibitors are typically effective at preventing blood clots and stroke in patients with AF, many patients cannot be prescribed the medications due to multiple food and drug interactions. The ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Event in Atrial Fibrillation) trial was designed as a double-blind study to evaluate the efficacy of apixaban in preventing stroke as compared with warfarin. The study followed 18,201 patients with both AF and one or more of the following five risk factors for stroke:
- Age of at least 75 years
- Previous stroke, transient ischemic attack, or systemic embolism
- Symptomatic heart failure within the previous three months or left ventricular ejection fraction of no more than 40%
- Diabetes mellitus
- Hypertension requiring pharmacologic treatment
Patients were randomly assigned to the warfarin or apixaban group, each of which included just over 9,000 patients. The median duration for follow-up was 1.8 years.
The trial found that apixaban outperformed warfarin on the primary metric, with a rate of stroke or systematic embolism 21% lower for those patients receiving apixaban (1.27% per year vs 1.60% per year respectively). In addition to proving more effective in preventing stroke, apixaban also limited adverse outcomes, with lower rates of major bleeding (2.13% per year for apixaban patients vs. 3.09% per year for warfarin patients) and death from any cause (3.52% per year for apixaban patients vs. 3.94% per year for warfarin patients).
Apixaban is the third warfarin alternative to prove equally or more effective than warfarin in preventing stroke in a randomized clinical trial.