Andrew Evans

Background and Purpose — Long-term anticoagulation is routinely used for secondary stroke prevention in atrial fibrillation, often regardless of stroke subtype. Although the role of warfarin in cardioembolic stroke is established, it may not prevent recurrence in other stroke subtypes, even in the presence of atrial fibrillation. Methods — This was a 2-year, prospective, intervention study conducted in a district general hospital. Participants included 386 acute stroke patients with atrial fibrillation. Subjects were characterized for stroke subtype on clinical, neuroimaging, carotid ultrasonographic, and echocardiographic criteria. Eligible patients were treated with adjusted-dose warfarin (international normalized ratio, 2.0 to 3.0). Aspirin (75 to 300 mg/d) was used in patients with contraindications or those who refused anticoagulation. The main outcome measures were rate of recurrent stroke by subtype and major and minor bleeding complications. Results — The aspirin group (n=172) was comparable to the warfarin group (n=214) in terms of age, sex, risk factors, and initial stroke subtype. The rate of recurrent stroke was higher (9.5% versus 4.9%, P P P Conclusions — In this cohort of stroke patients with atrial fibrillation, anticoagulation was superior to aspirin in preventing cardioembolic but not lacunar recurrence. Determination of stroke subtype may be important in anticoagulation decisions for secondary prevention, and further studies are required.

Research from JAMA Internal Medicine — Are the Results of Randomized Controlled Trials on Anticoagulation in Patients With Atrial Fibrillation Generalizable to Clinical Practice?

Background and Purpose —Secondary prevention trials do not distinguish outcomes according to stroke cause. The purpose of the study was to determine whether trial efficacy of anticoagulation for secondary prevention could be replicated in clinical practice in strokes of different etiology. Methods —A 2-year observation study was undertaken in 288 stroke patients with atrial fibrillation (mean age 76 years; 55% women) who were receiving anticoagulation therapy to maintain an international normalized ratio of 2.0 to 3.0. Comparisons were made of (1) patient characteristics, anticoagulation control, and annual stroke/hemorrhage rates with those of the European Atrial Fibrillation Trial and (2) cause of recurrent stroke by initial stroke subtype. Results —Subjects were 5 years older (95% CI 3 to 7 years), and more patients had small-vessel stroke (26% versus 14%; 95% CI 3% to 17%) compared with corresponding trial data. The duration spent in the target anticoagulation range (55% versus 59%), recurrent stroke rate (5.1% versus 3.6% per year), and major (2.3% versus 2.2% per year) or minor (9.5% versus 11.8% per year) hemorrhage rates were comparable with those in patients receiving warfarin in the randomized study. Ten of 14 (71%) of embolic recurrences occurred in patients with a previous cardioembolic episode, and 8 of 11 (73%) lacunar recurrences occurred in patients with previous lacunar stroke as the qualifying event for anticoagulation ( P =0.025). Only 3 of 14 cardioembolic compared with 8 of 11 lacunar recurrences occurred during adequate anticoagulation. Conclusions —Anticoagulation for secondary stroke prevention in clinical practice achieves outcomes comparable with those of randomized trials. Nearly 26% of qualifying strokes and 40% of recurrences were nonembolic; stroke subtype should be considered when making treatment decisions.