Comparison of the anticoagulant intensities of fondaparinux and enoxaparin in the organization to assess strategies in acute ischemic syndromes (OASIS)‐5 trial

BACKGROUND: In the OASIS-5 trial, fondaparinux reduced major bleeding with similar short-term efficacy as enoxaparin but lowered death and stroke during long-term follow-up. The mechanism of lower bleeding and improved efficacy with fondaparinux is uncertain. METHODS AND RESULTS: We compared the anti-Xa concentration (reflecting drug levels), Xa clot time (reflecting anticoagulant effect) and endogenous thrombin potential (ETP; a global test of …