Testing for CYP2C9 Before Anticoagulant Therapy

Excerpt

Authors Reply: We share Dr. Jolobe’s sentiment that appropriate tools must be developed to better characterize the risk of bleeding, particularly intracerebral hemorrhage, for patients with indications for oral anticoagulant therapy. Indeed, the increased use of warfarin anticoagulation for prevention of thromboembolic stroke in patients with atrial fibrillation (AF) has produced significant benefits, but has also resulted in an estimated quintupling of the incidence of warfarin-associated intracerebral hemorrhage (ICH).1 Warfarin-associated ICH now comprises roughly 20% of all ICH. Furthermore, among patients with ICH, warfarin is associated with a doubling in the case fatality rate at 3 months and an increase in poor neurological outcomes.2 There is suggestive evidence that the risk-adjusted incidence of cardioembolic ischemic stroke in patients with atrial fibrillation has declined over the past 2 decades, perhaps in response to more aggressive treatment of underlying risk factors such as hypertension and hyperlipidemia.3‐5 As a result, the balance between the risk and benefit of anticoagulation therapy in patients with non-valvular atrial fibrillation may be shifting. These two trends, the increasing incidence of warfarin-associated ICH and the decreasing risk of cardioembolic ischemic stroke in patients with AF, underscore the imperative to develop better tools to predict the risk of warfarin-associated ICH to improve “personalized” decision-making about anticoagulant therapy for patients with AF. …