Archief Roodbont

Atrial fibrillation (AF) is present in about 12% of patients older than 75, and it increases stroke risk fivefold. Although anticoagulants clearly are more effective than antiplatelet agents for lowering stroke risk, their relative risks and benefits in elders, who might be at higher risk for intracranial hemorrhage than are younger people, are not clear. Because of concerns about hemorrhage, fewer than half of older patients with AF receive warfarin.

In a prospective study, investigators compared the efficacy of warfarin with that of aspirin for preventing stroke in 973 patients (age, 75; mean age, 81.5) with AF who were recruited from 260 general practices in England and Wales. Patients were randomized to receive either warfarin (target international normalized ratio, 2–3) or aspirin (75 mg daily). Exclusion criteria included terminal illness, bleeding history, blood pressure higher than 180/110 mm Hg, and a primary care physician’s judgment that a patient’s risk for stroke and hemorrhage was too high for the patient to take warfarin.

During a mean follow-up of 2.7 years, 24 primary events occurred in the warfarin group (21 strokes, 2 other intracranial hemorrhages, and 1 systemic embolus), and 48 occurred in the aspirin group (44 strokes, 1 other intracranial hemorrhage, and 3 systemic emboli), which yielded an annual relative risk of 0.48 in the warfarin group. The annual risk for intracranial hemorrhage did not differ between groups. The annual risk for extracranial hemorrhage was 1.4% in the warfarin group and 1.6% in the aspirin group (RR in the warfarin group, 0.87). The number needed to treat per year to prevent a primary event was 50.

Comment: This study provides strong evidence that warfarin is superior to aspirin for preventing strokes in appropriately selected older patients with AF and that it confers no additional risk for intracranial bleeding. Emergency physicians should remain alert for older patients with AF (both previously diagnosed and newly discovered [Journal Watch Emergency Medicine Aug 30 2007]) and ensure that such patients receive appropriate anticoagulation, unless they have contraindications (e.g., frequent falling).

— Kristi L. Koenig, MD, FACEP

Published in Journal Watch Emergency Medicine September 7, 2007