Utility of a weight-based heparin nomogram for patients with acute coronary syndromes

Abstract

Background: Unfractionated heparin has been pivotal in the management of acute coronary syndromes (ACS), and continues to be used widely despite the emerging role of low molecular weight heparins (LMWH). The apparent superiority of LMWH over unfractionated heparin may, at least partially, reside in its more predictable achievement of therapeutic effect, with high rates of non-therapeutic activated partial thromboplastin time (APTT) results being observed in the intravenous heparin treatment groups. Aim: To evaluate the impact of introduction of a weight-based heparin nomogram developed for use in patients with ACS on frequency of ‘therapeutic’ APTT results. Methods: The effectiveness of an existing non-weightbased heparin nomogram in achieving a therapeutic APTT was compared sequentially with that of a weight-based heparin nomogram in 89 and 84 consecutive patients admitted with a diagnosis of ACS. Results: Patients in whom heparin dosage adjustment was weight based rapidly achieved therapeutic APTT. The median time to achieve an APTT within the target range was 8.75 h in the weight-based group versus >24 h in the non-weight-based group. Utilization of a weight-based nomogram was associated with markedly increased proportions of readings within the therapeutic APTT range at 6 h and at 24 h (51% vs. 26% and 72% vs. 36%, respectively). Conclusions: The current study confirms the marked superiority of the weight-based heparin regimen for treatment of patients with ACS. The nomogram dramatically facilitated the attainment of therapeutic APTT, and may represent the optimal method for titration of heparin dosage to individual heparin requirements in patients with ACS.