The need for new oral anticoagulants in clinical practice.

Atrial fibrillation, the most clinically important arrhythmia, is a considerable independent risk factor for the development of stroke. Vitamin K antagonists, primarily warfarin, are the only oral anticoagulants currently available for the long-term prevention of stroke in patients with atrial fibrillation. Although there is considerable evidence that warfarin reduces the risk of stroke in patients with atrial fibrillation, it is associated with various challenges to its use in routine clinical practice. Numerous studies have shown that it is underused in patients with atrial fibrillation, particularly elderly patients who would seem to benefit the most. Many physicians appear hesitant to prescribe warfarin for patients with atrial fibrillation because they are unconvinced that the benefits seen in clinical trials will actually translate into their everyday practice. As a result, there is a pressing need for convenient new, well-tolerated and effective oral anticoagulants that do not require frequent dose adjustment and routine coagulation monitoring.