Unfractionated heparin anticoagulation using estimated blood volume based dosing versus weight-based dosing in a Veteran population

Abstract

Objective. The purpose of this study is to compare estimated blood volume (EBV) versus weight-based (WB) dosing of unfractionated heparin in terms of safety and ability to achieve therapeutic antifactor-Xa (AF-Xa) levels. Methods. This was a retrospective, cohort study including 32 male veterans who received UFH. Primary outcome measures included time until therapeutic anticoagulation, number of adjustments needed to achieve therapeutic anticoagulation, median AF-Xa levels and the percentage of patients who were therapeutic after the first and second levels. Safety was determined as the incidence of major and minor bleeding. Results. EBV dosing may be associated with a decrease in the average time to therapeutic range (20.4 ± 16.7 hours with EBV vs. 26.8 ± 26 hours with WB; p = 0.404) and an increase in the percentage of patients achieving therapeutic anticoagulation after the first AF-Xa level (50% with EBV vs. 35.7% with WB; p = 0.611) although these results were not statistically significant. WB dosing required fewer adjustments (2.7 ± 2.9 with WB vs. 4 ± 2.6 with EBV; p = 0.192) with more patients within the therapeutic range after the second AF-Xa level (42.9% with WB vs. 33.3% with EBV; p = 0.897). There was one major and three minor bleeds in the WB dosing group versus one minor bleed for the EBV dosing cohort (p = 0.438 and p = 0.323, respectively). Conclusion. EBV dosing achieved quick therapeutic anticoagulation with less bleeding compared to WB dosing in a veteran population. Due to the study's limitations, larger, randomized, comparative trials are needed to confirm our findings.