Anticoagulant therapy with enoxaparin is an effective alternative to heparin for patients with non-ST-elevation acute coronary syndromes, according to an article in the July 7th issue of The Journal of the American Medical Association.

International investigators with the Superior Yield of the New Strategy of Enoxaparin, Revascularization and Glycoprotein IIb/IIIa inhibitors (SYNERGY) trial compared the outcomes of patients treated with enoxaparin versus unfractionated heparin. Although previous trials had demonstrated the superiority of enoxaparin compared with unfractionated heparin for patients with non-ST-elevation acute coronary syndrome receiving medical therapy as primary treatment strategy, the value of enoxaparin as the principal anticoagulant regimen has been debated.

The SYNERGY trial was a randomized, multicenter, international trial conducted between August 2001 and December 2003. A total of 10,027 high-risk patients with non-ST-elevation acute coronary syndrome to be treated with an intended early invasive strategy were recruited. Participants received either subcutaneous enoxaparin (n=4,993) or intravenous unfractionated heparin (n=4,985), administered immediately after enrollment and continued until the patient required no further anticoagulation as judged by the treating physician.

The primary efficacy outcome was the composite clinical end point of death or nonfatal myocardial infarction during the first 30 days after randomization. The primary safety outcome was major bleeding or stroke.

The primary end point of death or nonfatal myocardial infarction in the first 30 days occurred in 14.0 percent of patients assigned to enoxaparin and 14.5 percent of patients assigned to unfractionated heparin. Enoxaparin was not superior to unfractionated heparin but fulfilled noninferiority criteria.

"No differences in ischemic events reported by the physician during percutaneous coronary intervention were observed between enoxaparin and unfractionated heparin, including similar rates of abrupt closure, threatened abrupt closure, unsuccessful intervention, or emergency coronary artery bypass graft surgery. Bleeding was modestly increased in patients assigned to enoxaparin," the researchers wrote.

"In high-risk patients with an intended early invasive treatment strategy, enoxaparin and unfractionated heparin are safe and effective alternatives as the antithrombin regimen. Enoxaparin has the advantages of convenience (fixed dosing without need for monitoring or intravenous infusion) and a trend toward a lower rate of nonfatal myocardial infarction with a modest excess of bleeding. As a first-line agent in the absence of changing antithrombin therapy during treatment, enoxaparin appears to be superior without an increased bleeding risk," the authors added.