In patients over age 75 years, these agents appear to be at least as effective as vitamin K antagonists: compared with warfarin, the direct oral factor Xa inhibitors apixaban and edoxaban have lower bleeding risks, rivaroxaban has similar bleeding risks, and dabigatran has higher risks for gastrointestinal bleeding but lower risks for intracranial bleeding. For cancer-associated VTE, edoxaban is as effective as subcutaneous dalteparin for the composite outcome of recurrent VTE or major bleeding, with less recurrent VTE but somewhat more major bleeding. None of the new oral anticoagulants have, however, demonstrated equivalent or superior efficacy and safety compared with traditional anticoagulants in thromboprophylaxis for patients with mechanical heart valves, and therefore their use in this setting is not recommended at this time.
REF. Goldman-Cecil medicine, 26th edition
