Am J Health Syst Pharm. 2020 Jul 28:zxaa143. doi: 10.1093/ajhp/zxaa143. Online ahead of print.
PURPOSE: To determine a patient's clinical course based on the use of an activated partial thromboplastin time (aPTT) or heparin anti-Xa assay when transitioning from rivaroxaban or apixaban to an unfractionated heparin infusion.
METHODS: A retrospective chart review was conducted to investigate how unfractionated heparin infusions were managed at a tertiary care hospital in the setting of recent apixaban or rivaroxaban administration. Patients were separated into 2 cohorts based on the chosen heparin infusion monitoring assay: heparin anti-Xa or aPTT. The primary composite outcome was total number of bleeding and thrombotic events; the secondary composite outcome was average incidence of heparin infusion holds and rate changes per patient.
RESULTS: Data were collected from 76 patients (heparin anti-Xa = 69, aPTT = 7). Due to the limited number of patients within the aPTT cohort, this data was excluded from the analysis, and heparin anti-Xa descriptive statistics were reported without statistical comparisons. In the heparin anti-Xa group, a total of 10 bleeds and 1 thrombus were discovered. Additionally, the average number of infusion holds and rate changes was 0.841 and 2.65 times per patient, respectively, for those patients monitored via heparin anti-Xa assay.
CONCLUSION: In the presence of a recently administered oral anti-Xa anticoagulant, more down-titrations occurred in the initial 6 hours of the heparin infusion when measuring anti-Xa activity, and most up-titrations occurred after 36 hours. Baseline heparin anti-Xa activity may be a useful tool to identify patients with residual plasma concentrations of apixaban and rivaroxaban to help better individualize heparin therapy.