Should We Use Bridging Therapy during Switching Patients from Warfarin to Novel Oral Anticoagulants?

Rivaroxaban is a new anticoagulant that was approved by the Food and Drug Administration in 2011 for stroke and systemic embolism prophylaxis in patients with nonvalvular atrial fibrillation. Several characteristics have made rivaroxaban an attractive alternative to warfarin: once-daily dosing, obviating the need for monitoring the international normalized ratio (INR), noninferiority to warfarin for preventing stroke in patients with atrial fibrillation, and comparatively lower risk of intracranial hemorrhage. Both The European Summary of Product Characteristics and the US Prescribing Information recommend to discontinue warfarin and to start rivaroxaban on the following day if the initial INR level is below 3.0, yet many clinics convert patient from warfarin to rivaroxaban when INR level is <2.0 due to increased risk of hemorrhage. Since there are no conventional coagulation measures to reliably demonstrate the level of anticoagulation in patients on rivaroxaban, there is an increased risk of adverse events, especially for patients with high ischemic burden. We report a case of acute ischemic stroke in a patient who switched from warfarin to rivaroxaban (20 mg once daily). A 68-year-old female patient with multiple co-morbidities was admitted to our clinic with ischemic stroke. After 1 week follow-up with parenteral anticoagulation in the neurology clinic, she was discharged with mild deficits and with dabigatran treatment (150 mg twice daily). Novel oral anticoagulants are attractive options for anticoagulation particularly in patients who are incompatible with warfarin therapy. On the other hand, physicians should be alert during switching patients from warfarin to novel oral anticoagulants.