WHAT IS THE OPTIMAL WARFARIN DOSE FOR SECONDARY PREVENTION OF STROKE?
Low-intensity warfarin appears to be a safer preventive therapy than conventional-intensity warfarin for the secondary prevention of stroke in patients with nonvalvular atrial fibrillation, according to a report in the April Stroke. The only previously conducted study on the efficacy of warfarin for secondary prevention of stroke in patients with nonvalvular atrial fibrillation was the European Atrial Fibrillation Trial (EAFT). Results from that trial indicated that warfarin at an international normalized ratio (INR) of 2.5 to 4.0 reduced the annual risk of stroke from 12% to 4% and was associated with a low incidence of major hemorrhagic events (2.8% per year). Hemorrhagic complications were, however, more common in the anticoagulation group than in the control group (risk ratio, 3.4). The investigators noted that no treatment effect was apparent with anticoagulation below an INR of 2.0. They did not evaluate the efficacy of various doses of warfarin within the INR 1.0 to 1.9 group. H
