[Anticoagulant therapy in patients with atrial fibrillation: the experience of the Centers of Surveillance. Study group of the "Italian Study on Complications of Oral Anticoagulant Therapy" (ISCOAT)].

The present study evaluated the anticoagulant course of 580 patients (21% of the total number of patients, 317 males, half of them aged > 70 years) with atrial fibrillation (AF) enrolled in the ISCOAT study. During the 469 patient-years of follow-up 35 bleeding (7.6%; 2 fatal, 8 major) and 17 thrombotic events (3.6%) occurred. Bleeding was more frequent when AF was associated with other cardiovascular diseases (9.8%) and occurred even if the anticoagulation level was low (9% when INR was < 2), probably due to the presence of individual risk factors. As expected, thrombotic events were also more frequent when INR level was < 2. We conclude that in patients with AF the recommended therapeutic range seems to be INR 2-3, since this range proved to be safe and more effective than lower anticoagulation levels.