Andrew Dunn, MD, FACP, FHM
In older adults with atrial fibrillation (AF) for whom vitamin K antagonist (VKA) therapy is unsuitable, what are the efficacy and safety of apixaban for stroke prevention?
Randomized controlled trial (Apixaban Versus Acetylsalicylic Acid [ASA] to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment [AVERROES]). ClinicalTrials.gov NCT00496769.
Blinded (patients, clinicians, and outcome adjudicators).*
Mean 1.1 years (trial was stopped early for apparent benefit when prespecified stopping rules were met).
522 centers in 36 countries.
5599 adults ≥ 50 years of age (mean age 70 y, 59% men) who had AF; for whom VKA therapy was shown or expected to be unsuitable; and who had ≥ 1 of prior stroke or transient ischemic attack, age ≥ 75 years, arterial hypertension, diabetes mellitus, heart failure, left ventricular ejection fraction ≤ 35%, or documented peripheral arterial disease. Exclusion criteria included current VKA therapy, conditions other than AF that required long-term anticoagulation, valvular disease requiring surgery, serious bleeding event in the past 6 months or high risk for bleeding, severe renal insufficiency, alanine aminotransferase or aspartate aminotransferase > 2 times the upper limit of normal, total bilirubin > 1.5 times the upper limit of normal, and aspirin allergy.
Apixaban, 5 mg twice daily (n = 2808), or aspirin, 81 to 324 mg/d (n = 2791). Matching placebos were used.
Primary efficacy outcome was a composite of stroke or systemic embolism. Primary safety outcome was major bleeding. Other outcomes included hemorrhagic stroke, ischemic stroke, death, and hospitalization for cardiovascular cause.
100% (intention-to-treat analysis).
The apixaban group had fewer strokes or systemic emboli, ischemic strokes, and cardiovascular hospitalizations than did the aspirin group (Table). Groups did not differ for major bleeding, hemorrhagic stroke, or death (Table).
In older adults with atrial fibrillation for whom vitamin K antagonist therapy was unsuitable, apixaban reduced stroke and systemic embolism and did not increase major bleeding compared with aspirin.
Apixaban vs aspirin in adults with atrial fibrillation for whom vitamin K antagonist therapy was unsuitable†
†Abbreviations defined in Glossary. RRR, RRI, NNT, NNH, and CI calculated from hazard ratios and control event rates in article.
Dunn A. Apixaban reduced stroke and systemic embolism compared with aspirin in adults with AF for whom VKA therapy was unsuitable. Ann Intern Med. ;154:JC4–3. doi: 10.7326/0003-4819-154-8-201104190-02003
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Published: Ann Intern Med. 2011;154(8):JC4-3.
Neurology, Prevention/Screening, Stroke.
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