Abstract 3776: Apixaban Compared To Aspirin In Patients With Atrial Fibrillation And Prior Transient Ischemic Attack Or Stroke: Results Of A Predefined Subgroup Analysis From Averroes
Background In patients with atrial fibrillation (AF), vitamin K antagonists (VKA) effectively prevent stroke. However many patients are unsuitable for or unwilling to take VKAs despite a high risk of stroke. Apixaban, a novel factor Xa inhibitor, is effective and well tolerated in these patients.
Methods In AVERROES 5.599 patients with AF, at increased risk of stroke and unsuitable for VKA therapy were randomized to receive, double-blind, apixaban 5 mg twice daily or aspirin (81-324 mg/day). The mean duration of follow up was 1.1 years. The primary outcome was stroke or systemic embolism. A pre-specified subgroup analysis was performed to compare patients with and without prior TIA or ischemic stroke (NCT00496769).
Results In 764 patients with prior TIA or stroke there were 10 primary outcome events in those randomized to apixaban (2.46%/year) and 33 in those randomized to aspirin (8.27%/year), hazard ratio (HR) =0.29, 95% confidence interval (95% CI) 0.15-0.60; p<0.001)(p for interaction = 0.83) . There were 9 ischemic strokes in those randomized to apixaban (2.21%/year) and 27 in those randomized to aspirin (6.27%/year), hazard ratio (HR) =0.33, (95% CI) 0.15-0.69; p<0.002)(p for interaction = 0.64). Haemorrhagic stroke occurred in one patient on apixaban and 4 patients on aspirin. Mortality rates were 22 (5.30%/year) on apixaban and 27 (6.55%/year on aspirin, (HR=0.82, 95%CI 0.47-1.45; p= 0.50)(p value for interaction = 0.11). There were no statistically significant differences in major bleeds.
Conclusions In patients with AF who had a TIA or stroke and unsuitable for VKA therapy, apixaban reduced the risk of stroke or systemic embolism to larger extent than aspirin.
- © 2012 by American Heart Association, Inc.