Risk Factors Associated with Thrombus Development Following Pharmacologic Anticoagulation Reversal with Coagulation Factor Xa [Recombinant], Inactivated-zhzo.

Background: Andexanet alfa (AA), a recombinant coagulation factor Xa, is approved as an antidote for the treatment of bleeding secondary to rivaroxaban and apixaban. While thromboembolism may serve as a risk with reversal of therapeutic anticoagulation, several landmark trials demonstrate higher rates with AA versus usual care. Objective: The purpose of this study was to identify independent patient-specific and hospital-associated risk factors corresponding to the development of thrombus in patients who have received AA. Methods: This was a retrospective cohort study conducted across six institutions comprised of academic and community settings. Patients aged 18 years and older who received AA from November 1, 2021 through June 30, 2024 during an inpatient hospitalization were included. The primary outcome evaluated the presence of select risk factors on thrombus development within 45 days of AA administration. Results: One hundred thirty-eight patients met inclusion criteria. Identification of thrombus occurred in 19/138 (13.8%) after receiving AA. Of the risk factors evaluated, a multivariate analysis demonstrated major surgery within 30 days of reversal (OR 3.72, 95% CI: 1.14-12.08, P = .03) served as a strong predictor for the development of thrombus after AA administration. Conclusion: A strong association existed between major surgery within 30 days and thrombotic complications following AA administration. Larger studies are needed to validate these findings and refine risk stratification post-AA administration.