Ineligibility for anticoagulation in patients with atrial fibrillation.

Although anticoagulation therapy markedly reduces the risk of stroke in patients with atrial fibrillation, up to 50% of these patients are deemed ineligible for anticoagulation. In this manuscript we provide a framework to assess the net clinical benefit of anticoagulation in patients with atrial fibrillation with an increased risk of bleeding. We also review recent data related to the novel oral anticoagulants targeting thrombin or factor Xa, and discuss how the introduction of these agents raises the distinction between eligibility for vitamin K antagonist therapy specifically, and eligibility for anticoagulation in general.