PGY2 internal Medicine Pharmacy Residency

Direct Oral to Parenteral Anticoagulants: Role of Factor Xa inhibitor-Specific Anti-Xa Concentrations

Corey V. Dinunno, PharmD; Chelsea N. Lopez, PharmD, BCCCP; Luma Succar, PharmD, BCCCP; Duc T. Nguyen, MD, PhD; Edward A. Graviss, PhD, MPH; Eric Salazar, MD, PhD; Kevin R. Donahue, PharmD, BCPS

PURPOSE increasing use of oral factor Xa inhibitors (FXaI) has led to increased interest in the clinical utility of laboratory monitoring to enhance safety and efficacy. Particularly, use of oral FXaI anti-Xa concentrations has gained traction and has been advocated for several indications, but limited studies have explored its role in guiding inpatient transitions from oral to parenteral anticoagulants. Therefore, additional data on such approaches are warranted to help balance bleed and thrombotic risks in the higher acuity inpatient setting. This study sought to compare two strategies for oral-to-parenteral anticoagulant transitions: FXaI anti-Xaguided versus standard of care (i.e., per-package insert).

METHODS Hospitalized patients converted from an oral FXaI (apixaban or rivaroxaban) to therapeutic parenteral anticoagulation with or without FXaI anti-Xa concentration guidance were reviewed. The primary outcome of major bleeding, according to international Society on Thrombosis and Hemostasis criteria, was compared between groups. Cox proportional hazard modeling was used to evaluate patient characteristics associated with the major bleeding events.

RESULTS

A total of 845 patients met inclusion criteria. Major bleeding was significantly lower in the concentration-guided vs. the non-concentration-guided group (4.8% vs. 11.7%; p<0.001). There were no differences between the groups in thromboembolic complications (2.4% vs. 2.7%; p=0.73) despite a significantly longer time from last oral FXaI dose to parenteral anticoagulant initiation in the concentrationguided group (27.9 hours vs. 15.1 hours; p<0.001).

CONCLUSION

This analysis suggests using FXaI anti-Xa concentrations to guide transition from oral to parenteral anticoagulants may be beneficial in reducing major bleeds in select patient populations.

PGY2 INTERNAL MEDICINE PHARMACY RESIDENCY

Corey Dinunno, PharmD

Corey earned his PharmD from the University of Connecticut College of Pharmacy in 2020. He completed his PGY1 residency at Houston Methodist Hospital. Following completion of his PGY2 residency, Corey has accepted a position as an Acute Care Clinical Pharmacy Specialist at Houston Methodist Hospital. Primary project preceptor: Chelsea N. Lopez, PharmD, BCCCP

Presented at 2021 Virtual Vizient Pharmacy Network and 2022 Midwest Pharmacy Residents Conference.