OASIS-5 Trial

Trial Details:

Acronym: Organization to Assess Strategies in Ischemic Syndromes

Purpose: To evaluate the efficacy of fondaparinux (Arixtra) versus enoxaparin (Lovenox) for anticoagulation during unstable angina and non-ST elevation myocardial infarction, specifically to assess bleeding risk comparison.

Format: Double blind, multicenter, randomized control trial

Treatment Group: Fondaparinux 2.5 mg SQ daily

Control Group: Enoxaparin 1 mg/kg twice daily

Number of Patients: 20,078

Inclusion Criteria:

  • Within 24 hours of symptom onset
  • At least 2 of the 3 following criteria:
    • > 60 years old
    • Elevated troponin I or creatine kinise MB
    • ECG changes consistent with ischemia

Exclusion Criteria:

  • Contraindication to the study drugs
  • Recent intracranial hemorrhage
  • Other indication for anticoagulation (i.e. pulmonary embolus or mechanical heart valve)
  • Serum creatinine > 3 mg/dL

Follow-up: Between 90 and 180 days

Primary Endpoint: Composite endpoint of all-cause mortality, myocardial infarction or refractory ischemia

Secondary Endpoint: There were evaluated at 30 days and upon study completion

  • All cause mortality or myocardial infarction
  • All cause mortality, myocardial infarction and refractory ischemia
  • All cause mortality alone
  • Myocardial infarction alone
  • Refractory ischemia alone


Patients with unstable angina and non-ST elevation myocardial infarction were randomized to either fondaparinux versus enoxaparin. Fondaparinux had a significant reduction in major bleeding (50%), similar risk of ischemic events and a reduced mortality compared to enoxaparin.

For the subgroup of patients undergoing PCI, there was also reduced major bleeding, however there was an increase in catheter thrombosis. This can be reduced by using unfractionated heparin during PCI.

Original Publication:

Mehta SR, et al. J Am Coll Cardiol. 2007;doi:10.1016/j.jacc.2007.07.042.

Yusuf S, et al. N Engl J Med, 2006;doi:10.1056/NEJMoa055443.