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Evevident
Original paper
2011NEJMCardiology

AVERROES

Apixaban in patients with atrial fibrillation

RCTAtrial fibrillation anticoagulation

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Overview

Apixaban beat aspirin for stroke prevention in AF patients unsuitable for warfarin.

Clinical takeaway

AVERROES is a clean teaching trial: aspirin is not an adequate substitute for anticoagulation when AF stroke risk warrants treatment.

Key result

Stroke or systemic embolism was reduced with apixaban versus aspirin without a large major-bleeding penalty.

Practice impact

DOACs displaced aspirin for AF stroke prevention in eligible patients.

Evidence

Study design

Randomized, double-blind trial stopped early for benefit.

Enrollment

5,599

Follow-up

Mean 1.1 years.

Geography

Multinational

Clinical question

Is apixaban superior to aspirin for preventing stroke or systemic embolism in AF patients unsuitable for warfarin?

Population

  • Patients with atrial fibrillation at increased stroke risk for whom vitamin K antagonist therapy was considered unsuitable.

Intervention

Apixaban 5 mg twice daily, dose-adjusted when indicated.

Comparator

Aspirin.

Primary outcome

Stroke or systemic embolism.

Apixaban was superior to aspirin for preventing stroke or systemic embolism in atrial fibrillation.

Hazard ratio / 0.45 / CI 95% CI 0.32-0.62 / p=<0.001

Key results

  • Stroke or systemic embolism was substantially reduced with apixaban.
  • Major bleeding was not significantly increased.
  • The trial was stopped early because of clear benefit.

Harms

  • Bleeding remains the major practical concern with any anticoagulant.
  • Dose adjustment and renal function assessment are needed.

Clinical Use

When to cite

  • When explaining why antiplatelet therapy is inadequate for AF stroke prevention.

Practice impact

  • Helped end aspirin's role as a default alternative for AF stroke prevention when anticoagulation is indicated.

Applicability

  • AF patients at elevated stroke risk who are candidates for apixaban but not warfarin.

Limitations

  • Warfarin-unsuitable population; ARISTOTLE answers apixaban versus warfarin.
  • Early stopping can magnify apparent benefit.

Common misinterpretations

  • Do not use aspirin for AF stroke prevention simply because it feels safer; it is much less effective.

Related evidence

ARISTOTLE - Later TrialROCKET AF - Similar Question

Citation

Connolly SJ, Eikelboom J, Joyner C, et al. Apixaban in patients with atrial fibrillation. N Engl J Med. 2011;364(9):806-817. doi:10.1056/NEJMoa1007432