OASIS-5 and OASIS-6 Trials Combined Analysis - OASIS-5 and OASIS-6 Trials Combined Analysis


The goal of the pooled analysis was to evaluate treatment with fondaparinux across the spectrum of acute coronary syndromes.

Study Design

Patients Enrolled: 32170
Mean Patient Age: Mean age 65 years
Female: 34

Patient Populations:

Enrollment in OASIS-5 or OASIS-6 trials

Drug/Procedures Used:

Data were pooled from the OASIS-5 and OASIS-6 trials. In OASIS-5, patients with non-ST elevation acute coronary syndromes were randomized to fondaparinux (2.5 mg/d, n = 10,057) or enoxaparin (1.0 mg/kg twice daily, n = 10,021). In OASIS-6, patients with ST elevation myocardial infarction (MI) were randomized to either fondaparinux (2.5 mg/d for up to 8 days or hospital discharge; n = 6,036) or control (n = 6,056). Patients were classified as stratum 1, meaning unfractionated heparin (UFH) was not indicated, or stratum 2, meaning UFH was indicated. Patients in stratum 1 received fondaparinux or placebo; patients in stratum 2 received fondaparinux or UFH.

Principal Findings:

In the pooled analysis, 16,093 patients were randomized to fondaparinux and 16,077 were randomized to control. Aspirin was used in 97% of patients and clopidogrel in 67% of patients. During the index hospitalization, percutaneous coronary intervention (PCI) was performed in 35% of patients and coronary artery bypass grafting in 6%.

At 30-day follow-up, the composite of death, MI, or stroke occurred in 8.0% of the fondaparinux group and 9.1% of the control group (p < 0.001). Among the components of the composite, death at 30 days occurred in 4.8% of the fondaparinux group and 5.6% of the control group (p = 0.002), MI in 3.4% and 3.7% (p = 0.073), and stroke in 0.8% and 1.0% (p = 0.49), respectively. Major bleeding at 9 days occurred in 2.1% of the fondaparinux group and 3.4% of the control group (p < 0.001).

Among patients undergoing nonprimary PCI (n = 6,634; analysis excludes primary PCI patients), there was no difference between groups in the rate of death, MI, or stroke at 30 days for fondaparinux compared with enoxaparin/UFH (8.0% each, p = 0.97). Catheter thrombosis occurred more frequently in the fondaparinux group than the enoxaparin/UFH group (0.9% vs. 0.2%, hazard ratio 3.58, p < 0.001). Major bleeding occurred in 2.9% of the fondaparinux group and 5.5% of the enoxaparin/UFH group (p < 0.001).


Among patients with acute coronary syndromes, treatment with fondaparinux was associated with a lower rate of the composite of death, MI, or stroke at 30 days compared with the control group, which was a mixture of no antithrombin, UFH, and enoxaparin. Additionally, major bleeding was lower with fondaparinux compared with control. There was no efficacy benefit with fondaparinux in the PCI cohort, but catheter thrombosis was increased with fondaparinux.


Mehta SR, Boden WE, Eikelboom JW, et al. Antithrombotic therapy with fondaparinux in relation to interventional management strategy in patients with ST- and non-ST-segment elevation acute coronary syndromes: an individual patient-level combined analysis of the Fifth and Sixth Organization to Assess Strategies in Ischemic Syndromes (OASIS 5 and 6) randomized trials. Circulation. 2008 Nov 11;118(20):2038-46.

Presented by SR Mehta, European Society of Cardiology Scientific Congress, September 2006.

Clinical Topics: Acute Coronary Syndromes, Anticoagulation Management, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Anticoagulation Management and ACS, Aortic Surgery, Interventions and ACS

Keywords: Polysaccharides, Myocardial Infarction, Acute Coronary Syndrome, Stroke, Follow-Up Studies, Enoxaparin, Thrombosis, Heparin, Coronary Artery Bypass, Percutaneous Coronary Intervention

< Back to Listings