Prehospital administration of enoxaparin before primary angioplasty for ST-elevation acute myocardial infarction

We hypothesized that primary percutaneous coronary intervention (PCI) could be performed with prehospital injections of enoxaparin for ST segment elevation myocardial infarction (STEMI). Enoxaparin has been studied in combination with fibrinolysis in STEMI, but has not been evaluated as anticoagulant regimen for primary PCI. In a prospective registry, 143 consecutive patients with STEMI received prehospital 0.5 mg/kg intravenous (IV) bolus followed by 1 mg/kg subcutaneous enoxaparin before immediate transport for PCI. We focused on anti-Xa activities before and after PCI, bleedings, infarct-related artery patency, and major adverse cardiac events at day 30. Anti-Xa activity was at the target level (>0.5 IU/ml) in 99% of patients during PCI, and in 100% 4 hr after injections; over-anticoagulation (>1.5 IU/ml) was noted in 9 and 2%, respectively at start and 4 hr after injections. Bleeding complications with enoxaparin were rare : major in 1.4% (no intracranial hemorrhages), minor in 2.1%. A patent infarct-related artery (TIMI 2 + 3) was observed in 40.6% of the patients before PCI. TIMI 3 flow was obtained in 88.1% of the cases after PCI. Major adverse cardiac events at 30 days occurred in 5.6 % of cases: death 2.8%, reinfarction 3.5%, and target lesion revascularisation 3.5%. Prehospital IV and subcutaneous enoxaparin provides simple and rapid anticoagulation for PCI in STEMI patients. Enoxaparin dose needs to be reduced regarding the 9% of over-anticoagulation. This study suggests the potential of enoxaparin as an alternative anticoagulant regimen for primary PCI. © 2006 Wiley-Liss, Inc.