Use of Heparins in Non-ST-Elevation Acute Coronary Syndromes

PURPOSE: We describe the use of antithrombotic therapy in the management of patients with acute coronary syndromes. METHODS: Patients from the Global Registry of Acute Coronary Events, a multinational coronary disease registry, were characterized according to the early and continued use of low-molecular-weight heparin, unfractionated heparin, any crossover of heparin therapy (change in early vs late heparin treatment), and no heparin treatment. Hospital outcomes were analyzed according to the heparin treatment and the timing of percutaneous coronary interventions. RESULTS: Data from 23,172 patients with non-ST-segment elevation myocardial infarction or unstable angina were analyzed. A total of 8791 patients were treated with low-molecular-weight heparin within the first 24 hours and continued thereafter; 4076 patients received unfractionated heparin; 2953 patients received neither heparin therapy; and 7352 patients received crossover heparin treatment. Concomitant treatment, including early or late percutaneous coronary intervention, varied according to the type of heparin therapy. Patients treated with a crossover therapy were more likely to undergo percutaneous coronary intervention. The rates of major bleeding and death were lower with low-molecular-weight heparin (1.4% and 1.8%, respectively) compared with unfractionated heparin (1.9% and 2.5%, respectively), crossover heparin (2.0% and 2.3%, respectively), or neither heparin (1.5% and 2.4%, respectively). CONCLUSIONS: There is significant variability in heparin use in patients with acute coronary syndromes. Heparin type and use seem to be related to the timing and use of percutaneous coronary interventions. The early use of low-molecular-weight heparin in the setting of an acute coronary syndrome is associated with better short-term outcomes.