Comparison of enoxaparin versus heparin during elective percutaneous coronary intervention performed with either eptifibatide or tirofiban (the ACTION Trial).

Limited data are available with regard to the pharmacodynamics and safety of combining enoxaparin with glycoprotein IIb/IIIa inhibition during elective percutaneous coronary interventions (PCIs). We randomized 200 patients to receive open-label enoxaparin (0.75 mg/kg intravenous bolus) or unfractionated heparin (60 U/kg intravenous bolus) and eptifibatide or tirofiban during PCI. This yielded 4 groups of combination therapy (50 patients/group). The first 10 patients per group had anti-Xa activity and inhibition of platelet aggregation measured at baseline, and at 5 minutes, 10 minutes, 4 hours, and 24 hours. All patients received aspirin and clopidogrel therapy before PCI. Patients who received enoxaparin and heparin achieved therapeutic peak anti-Xa activity observed shortly after drug administration. At 4 hours, a differential anticoagulant effect was observed, with patients who received enoxaparin having a more gradual decrease in anti-Xa activity. Patients who received eptifibatide achieved >80% inhibition of platelet aggregation soon after initiation of therapy more often than did those who received tirofiban. Type of heparin did not affect inhibition of platelet aggregation. Compared with patients who received heparin, periprocedural myocardial infarction and bleeding events occurred less frequently among those who received enoxaparin (14% vs 8% and 10% vs 5%); however, these differences were not statistically significant. Three cases of intraprocedural thrombus occurred among patients who received enoxaparin. Two patients received concomitant tirofiban therapy. Compared with unfractionated heparin, similar levels of anticoagulation and platelet inhibition are achieved with enoxaparin when concomitant therapy with eptifibatide or tirofiban is used during elective PCI, without an observed increase in early bleeding events or periprocedural ischemic complications.