ROLE OF ANTICOAGULANT-THERAPY IN ATRIAL-FIBRILLATION

Role of Anticoagulant Therapy in Atrial Fibrillation. Atrial fibrillat ion belongs to the group of cardiovascular diseases that most frequent ly predispose to arterial thromboembolic events. Within the last years , the AFASAK, BAATAF, SPAF I, SPINAF, and CAFA trials have consistentl y demonstrated a significant, approximately 70%, risk reduction for st roke on oral anticoagulation in patients with nonrheumatic atrial fibr illation. This benefit by far outweighed the slight increase in annual major hemorrhage. Recently, additional trials (SPAF II, EAFT, SPAF II I, and others) have shed further light on important questions concerni ng risk factors, secondary prophylaxis, the optimal intensity of antic oagulation, and the role of aspirin and other antiplatelet drugs. The main results of these studies are discussed in this review. The majori ty of patients with atrial fibrillation are >65 years of age and have other clinical or echocardiographic risk factors. In these patients, a djusted-dose warfarin with target international normalized ratios (INR s) 2.0 to 3.0 is effective and safe. The risk of stroke rises with INR values <2.0, whereas INR values >3.0 result in an increase in intrace rebral hemorrhages, especially in the very elderly. In contrast, no an ticoagulation seems warranted in younger atrial fibrillation patients <60 years of age without any clinical or echocardiographic risk factor . An overview of all randomized trials that compared aspirin with plac ebo and/or adjusted-dose warfarin indicates that adjusted dose warfari n is approximately 50% more effective than aspirin for primary and sec ondary prevention of stroke, at least in patients with atrial fibrilla tion who have clinical risk factors. Therefore, oral anticoagulation c learly is the therapy of choice for prevention of thromboembolism in p atients with atrial fibrillation.