Review: anticoagulants may be better than antiplatelet agents for nonfatal stroke but not other vascular or fatal events in nonrheumatic AF.

In patients with nonrheumatic atrial fibrilla-tion (AF), what are the benefits and risks of long-term anticoagulation with warfarin compared with those of antiplatelet treatment with aspirin or indoprofen? D a t a s o u r c e s Studies were identified by searching the Cochrane Controlled Trials Register, MEDLINE, EMBASE/Excerpta Medica, CINAHL, and SIGLE up to the end of 1999 with the terms atherosclerosis, atrial fibrillation, myocardial infarction, coronary disease, and anticoagulation and with a filter designed to retrieve randomized controlled trials. Authors were also contacted. Randomized controlled trials were selected if patients had nonrheumatic AF and received either anticoagulation or antiplatelet treatment for > 1 year. Trials that evaluated combined use of anticoagulation with antiplatelet drugs were excluded, as were studies that included patients with AF caused by thyro-toxicosis and mitral valve disease or those with heart-valve replacements. D a t a e x t r a c t i o n Data were extracted on study quality; patient characteristics; intervention, including drug, dose, withdrawals, and duration; international normalized ratio (INR); and outcomes of fatal and nonfatal cardiovascular events (stroke, myocardial infarction, and thromboembolism) and adverse effects, including major bleeding events. 5 RCTs (3298 patients) met the inclusion criteria. Follow-up ranged from 12 to 42 months. The anticoagulation and antiplatelet groups did not differ for any outcomes except for a reduction in nonfatal stroke (Table). Long-term anticoagulation may be more effective than antiplatelet treatment for preventing nonfatal stroke but not other vascu-lar events in patients with nonrheumatic AF. Systematic review of long term anticoagulation or antiplatelet treatment in patients with non-rheumatic atrial fibrillation. C o m m e n t a r y Taylor and colleagues state that " we would strongly favour antiplatelet drugs in preference to long term anticoagulation. " This recommendation is in marked contrast to other publications that strongly recommend oral anticoagulation for patients with AF, especially those at high risk for stroke (the risk for stroke varies markedly among patients with AF) (1, 2). Why the difference? Taylor and colleagues did not include a large randomized controlled trial of 455 high-risk patients that found a marked decrease in stroke when oral anticoagulation was compared with aspirin (hazard ratio 0.38, CI 0.23 to 0.64, P < 0.001) (3). Another randomized controlled trial not included compared adjusted-dose warfarin (INR 2.0 to 3.0) with aspirin plus fixed low-dose warfarin in high-risk patients and found a marked …