Primary Prevention of Arterial Thromboembolism in Nonrheumatic Atrial Fibrillation: The PATAF trial study design

Patients with nonrheumatic atrial fibrillation (NRAF) have a higher risk of thromboembolism than patients in sinus rhythm. Several trials have been co nducted to establish the best preventive regimen in patients with NRAF, but not in the primary-care setting. The Primary Prevention of Arterial Thromb oembolism in Nonrheumatic Atrial Fibrillation (PATAF) study, a primary-care -based trial, was set up to compare the preventive efficacy of low-intensit y anticoagulation (AC), target range International Normalized Ratio (INR) 1 .1 < INR < 1.6 and regular-intensity AC (2.5 < INR < 3.5) therapies with th at of aspirin 150 mg/d for the occurrence of thromboembolism in NRAF patien ts. Patients eligible for regular-intensity AC were randomly assigned to aspiri n at 150 mg/d, low-intensity AC, or regular AC in group I. In cases of none ligibility for regular AC, the trial randomized patients between aspirin an d low-intensity AC (assigned to group II). Primary outcome events were stro ke (including intracranial hemorrhage), systemic embolism, major hemorrhage , or vascular death. Analysis of the data was based on Cox regression to co mpute the hazard ratio (HR) with a 95% confidence interval, using the Likel ihood ratio test. The trial randomized 729 patients. Patient enrollment and follow-up has bee n stopped, and the final analysis is now complete. We shall publish the mai n results as soon as possible. Control Clin Trials 1999;20:386-393 (C) Else vier Science Inc. 1999.