Anticoagulants in atrial fibrillation: A guide to best use

Anticoagulation dramatically reduces the risk of ischemic stroke in patients with atrial fibrillation; however, the use of warfarin in older persons increases the danger of bleeding complications. In clinical trials, aspirin provided effective prophylaxis in patients who were eligible to receive anticoagulation, such as those aged 75 years or younger; aspirin did not protect older women, who are vulnerable to intracranial hemorrhage from warfarin, or patients with previous stroke or transient ischemic attack who are at extraordinarily high risk for recurrent thromboembolism. This places clinicians on the horns of a dilemma-to anticoagulate with warfarin and expose patients to an increased risk of hemorrhagic stroke or to withhold anticoagulant therapy and its protection from ischemic stroke. One practical approach is to prescribe warfarin (target international normalized ratio, 2 to 3) to patients of any age at high risk for ischemic stroke, recommend aspirin (325 mg/d) to patients at low risk, and discuss the pros and cons of anticoagulant therapy with patients at intermediate risk.