Atrial fibrillation and stroke: four treatment controversies.

Atrial fibrillation is an important cause of disabling ischemic stroke, and adjusted-dose warfarin is highly effective for prevention and remains the therapy of choice for high-risk patients. Ximelagatran, a novel oral anticoagulant, is clinically equivalent to warfarin for preventing stroke in patients with atrial fibrillation, but concerns about potential hepatic toxicity have precluded US Food and Drug Administration approval. Many patients with low-risk atrial fibrillation do not benefit substantially from anticoagulation, and these patients can be reliably identified using the CHADS2 stroke risk stratification scheme. A target International Normalized Ratio (INR) range of 2 to 3 is usually recommended for anticoagulation of patients with atrial fibrillation, but a lower INR target (2, range 1.6-2.5) may be a reasonable benefit/risk trade-off for primary prevention in those aged older than 75 years. Adding aspirin to adjusted-dose anticoagulation increases bleeding (including central nervous system bleeding), is of uncertain value, and should only be done after careful consideration and with vigorous efforts to control blood pressure.