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
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
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.
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.