Low molecular weight heparin for PCI ▸

Currently the risk of a major bleeding complication following a percutaneous coronary intervention (PCI) is estimated at 4–7% (SYNERGY, REPLACE-2). Low molecular weight heparins (LMWH) offer a number if benefits over unfractionated heparin that may be able to reduce this complication rate, such as having a more stable and predictable anticoagulant dose response. Only relatively small trials to date have evaluated the use of intravenous enoxaparin on post-PCI bleeding rates, and a meta-analysis of data from these trials suggested a non-significant trend toward a reduction in major bleeding with LMWH. To investigate this possibility further the STEEPLE (Safety and Efficacy of Enoxaparin in Percutaneous Coronary Intervention Patients, an International Randomized Evaluation) trial randomly assigned 3528 patients undergoing elective PCI to receive either enoxaparin (0.5 mg or 0.75 mg per kg body weight) or unfractionated heparin adjusted for activated clotting time. The primary end point was the incidence of major or minor bleeding that was not related to coronary artery bypass grafting. The main secondary end point was the percentage of patients in whom the target anticoagulation levels were reached. At a dose of 0.5 mg/kg enoxaparin was associated with a significant reduction in the rate of bleeding at 48 h, as compared with unfractionated heparin (5.9% v 8.5%; p = 0.01), but the higher dose of 0.75 mg/kg was not (6.5% v 8.5%; p = 0.051). Target anticoagulation levels were reached in significantly more patients who received enoxaparin (79% for 0.5 mg/kg dose, 92% of 0.75 mg/kg dose) than in those who received unfractionated heparin (20%; p<0.001). In conclusion, intravenous enoxaparin gave a more predictable anticoagulation response than unfractionated heparin, with the 0.5 mg/kg dose also giving reduced rates of bleeding. It must be noted, however, that the overall mortality rate of 1.0% in the 0.5 mg enoxaparin group is twice that expected for …