Abstract 1800: Unfractionated Heparin Dosing and Major Bleeding in Non-ST-Segment Elevation Acute Coronary Syndromes

Abstract

Background : Unfractionated heparin (UFH) is a mainstay in the treatment of ACS, but failure to adjust UFH dosing based on pt weight is common. Methods : We used data from 31,445 high-risk ACS pts in 420 CRUSADE hospitals to assess initial UFH bolus and infusion doses relative to guidelines recommendations (60–70 U/Kg bolus and 12–15 U/Kg/h infusion). We evaluated the following: UFH excess dosing (>70 U/kg bolus or >15 U/kg/min infusion) vs. no excess dosing; excess dosing and major bleeding, overall and in subgroups; and factors associated with excess dosing. Results : An excess dose of UFH was given 35% of the time (8.9% excess infusion, 9.0% excess bolus, 17.1% both); more often to women, elderly, and those with low body weight (Figure). There was a digit preference for bolus doses of 5000 U (37%), and infusion doses of 1000 U/h (45%). The factors most associated with excess dosing were older age (OR 1.11, 95% CI 1.08–1.15) and female sex (OR 1.45, 95% CI 1.33–1.59). Although individually excess bolus (OR 1.03, 95% CI 1.00–1.06) and excess infusion (OR 1.16, 95% CI 1.05–1.28) each contribute to bleeding, considered together only excess infusion remained significantly associated with bleeding (OR 1.13, 95% CI 1.01–1.26). Although women and elderly bleed more, the relationship between UFH dose (bolus and infusion individually) and major bleeding did not vary across sex and age. Conclusion : In high-risk NSTE ACS pts, both UFH bolus and infusion dosing is often outside the recommended range. Excess dosing is common among elderly and women and is related to increased bleeding. Attention to dosing by weight rather than one-size-fits-all bolus and infusion dosing should improve safety in the use of UFH.