Wan-Ting Huang, BCCCP, PharmD
Staff Pharmacist
UC San Diego Health
La Jolla, California
Disclosure information not submitted.
Kevin Nguyen, PharmD
PGY2 Internal Medicine Pharmacy Resident
UC San Diego Health, United States
Disclosure information not submitted.
Aakash Patel, PharmD, BCCCP
Inpatient Staff Pharmacist
UC San Diego Health, United States
Disclosure information not submitted.
Dmitri Lerner, PharmD, BCCCP
Pharmacist Specialist - Anticoagulation
UC San Diego Health, United States
Disclosure information not submitted.
Title: Utility of Apixaban or Rivaroxaban Anti-Xa Levels in Transitioning Patients to Heparin Infusions
Introduction/Hypothesis: Activated partial thromboplastin times and heparin-calibrated anti-Xa levels are used to monitor unfractionated heparin infusions. Direct oral anticoagulants (DOAC’s), such as apixaban or rivaroxaban, can impact these values and cause them to be unreliable parameters for heparin management. We hypothesized that evaluating a DOAC-calibrated anti-Xa level prior to initiating a heparin infusion would allow for a better determination of when to start the infusion and result in faster therapeutic anticoagulation.
Methods: This was a retrospective analysis over a two-year period of patients who received apixaban or rivaroxaban prior to a heparin infusion. The evaluation group included patients with an evaluation of a DOAC-calibrated anti-Xa level prior to a heparin infusion. The standard group included an equivalent number of matched patients who were transitioned to heparin infusion without an evaluation of a DOAC-calibrated anti-Xa level. The primary outcome was time to achieve two consecutive therapeutic measurements of anticoagulation after starting the heparin infusion. Secondary outcomes included the frequency of bleeding during or after the heparin infusion and the frequency of clotting during the hospital stay. For statistical analyses, student’s t-tests were used to analyze continuous variables and chi-squared tests were used to analyze categorical variables.
Results: Fifty-nine patients were included in each study group with similar baseline characteristics, except for the higher utilization of an increased bleeding risk heparin infusion protocol in the evaluation group (23.7% vs 6.8%; p=0.01). The mean times to stable therapeutic anticoagulation were similar at 29.4 hours for the evaluation group and 26.3 hours for the standard group (p=0.39). There was a trend of more patients in the evaluation group than in the standard group that met the primary outcome (74.6% vs 62.7%; p=0.16). Similar bleeding and clotting events occurred in 10.2% and 5.1% of patients in the evaluation group and in 8.5% and 0% of patients in the standard group, respectively (p=0.75; p=0.08).
Conclusions: By evaluating DOAC-calibrated anti-Xa levels, patients in the evaluation group had a higher bleeding risk but were able to achieve therapeutic anticoagulation in a similar time as the standard group.