Anticoagulation Therapy in Non–ST-Segment Elevation Acute Coronary Syndrome

Abstract

Non-ST-segment elevation acute coronary syndrome (NSTE-ACS) affects over 500 000 patients in the United States each year. This condition spans a clinical spectrum from unstable angina pectoris (biomarker negative) to non-ST-segment elevation myocardial infarction (biomarker positive). The syndrome results from disruption of the fibrous cap of an unstable atherosclerotic coronary plaque, leading to thrombus formation and partial or total occlusion of the coronary vessel.Clinical research has focused on parenteral anticoagulation as a potential therapeutic intervention. Clinical trials 1,2 with unfractionated heparin, low-molecular-weight heparin, and the pentasaccharide fondaparinux reported clinical benefit, and consequently clinical practice guidelines recommend the immediate use of these agents in all patients with NSTE-ACS.However, the pivotal clinical trials 1,2 that established the efficacy of parenteral anticoagulation in NSTE-ACS were performed before the routine use of dual antiplatelet therapy, advanced coronary artery stenting, and use of the radialartery approach to percutaneous coronary intervention, all of which have done much to improve outcomes in NSTE-ACS. The question therefore arises as to whether parenteral anticoagulation therapy adds significantly to these modern approaches to treatment.