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Comparing Anti-Factor Xa and Activated Partial Thromboplastin Levels for Monitoring Unfractionated Heparin
Rebekah A Wahking1, Rachel H Hargreaves2, Sean M Lockwood2
11 Cincinnati Veterans Affairs Medical Center, Cincinnati, OH, USA.
The Annals of Pharmacotherapy
|March 1, 2019
Summary
Monitoring intravenous heparin (IV heparin) with anti-factor Xa (anti-Xa) levels, instead of activated partial thromboplastin time (aPTT), required higher doses but was safe and effective in veterans. This transition improved anticoagulation monitoring.
Area of Science:
- Pharmacology
- Clinical Medicine
- Health Services Research
Background:
- Activated partial thromboplastin time (aPTT) and anti-factor Xa (anti-Xa) are common laboratory tests for monitoring intravenous unfractionated heparin (IV heparin).
- Emerging evidence suggests anti-Xa levels may offer a more precise assessment of anticoagulation compared to aPTT.
- The Lexington Veterans Affairs Health Care System adopted anti-Xa monitoring in January 2017, shifting from aPTT.
Purpose of the Study:
- To evaluate the efficacy and safety of transitioning from aPTT to anti-Xa monitoring for IV heparin.
- To compare the IV heparin doses needed to achieve therapeutic goals between aPTT and anti-Xa monitoring protocols.
- To assess secondary outcomes including time to therapeutic goal, time within therapeutic range, and adverse events like bleeding.
Main Methods:
- A retrospective cohort study design was employed.
- Patients receiving IV heparin for at least 24 hours were divided into two groups: aPTT monitoring (August 2016–January 2017) and anti-Xa monitoring (February 2017–July 2017).
- Data on heparin dosage, time to therapeutic range, and adverse events were collected and compared.
Main Results:
- A total of 155 patients were analyzed.
- The anti-Xa group required significantly higher IV heparin doses to reach the therapeutic goal compared to the aPTT group.
- Despite higher doses, the anti-Xa group required fewer IV heparin rate adjustments, and monitoring was not linked to increased adverse events, including bleeding.
Conclusions:
- Higher IV heparin doses are necessary to achieve therapeutic anti-Xa levels in the veteran population transitioning from aPTT monitoring.
- The shift to anti-Xa monitoring for IV heparin appears to be a safe and effective practice in this patient cohort.
- Further research may be warranted to fully understand the implications in the largely unstudied veteran population.
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