Low-molecular-weight heparin versus unfractionated heparin in acute ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention with drug-eluting stents

Abstract

Background Whether low-molecular-weight heparin (LMWH) is superior to unfractionated heparin (UFH) in acute ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) remains unclear. Methods A total of 3,372 STEMI patients who underwent primary PCI with DESs received either LMWH (n = 1,531 patients, subcutaneous enoxaparin 1 mg/kg, bid for 3-5 days plus reduced dose of UFH [ 50 U/kg] during PCI) or UFH alone (n = 1,841 patients, intravenous bolus injection of 5,000 U, followed by 24,000 U/d infusion for at least 48 hours). The bleeding events and clinical outcomes during in-hospital and at 8 months were compared. Results The incidences of major and minor bleeding events were similar between the 2 groups. Multivariable Cox regression analysis showed that LMWH group had lower incidences of cardiac death (adjusted odds ratio [OR] 0.55, 95% CI 0.39-0.77, P<.001), total death (adjusted OR 0.50, 95% CI 0.37-0.68, P<.001), and total major adverse cardiac events (adjusted OR 0.77, 95% CI 0.62-0.95, P=.017) at 8 months as compared with UFH group. Similar results were obtained across different subgroups including different DESs, age, and sex. Conclusions The LMWH enoxaparin combined with reduced dose of UFH (50 U/kg) administration as an adjunctive antithrombotic therapy in STEMI patients undergoing primary PCI with DESs seems to be safe and efficacious. However, randomized clinical trials are needed to confirm this conclusion. (Am Heart J 2010; 159: 684-690. e1.)