(962) Rethinking Reversal: The Underappreciated Risk of Thrombotic Complications After Andexanet Alfa Use

Introduction: Current paradigms call for early reversal of apixaban in anticoagulation-associated traumatic intracranial hemorrhage (tICH) to prevent worse outcomes associated with hematoma expansion. This comes with the risk of increased thrombotic events, but the true severity of these events is underreported, limiting the ability of clinicians to perform an accurate risk-benefit analysis. Here, we report on a patient with a devastating thrombotic complication after reversal of apixaban with Andexanet alfa, underscoring the need for more nuanced understanding of hemorrhagic and thrombotic risks.

Description: A 91-year-old woman with atrial fibrillation on apixaban, hypertension, hyperlipidemia, and a history of bladder cancer in remission presented from home to the emergency department 4 days after an unwitnessed ground level fall due to developing headache, right posterior ear bruising, and new inability to get out of bed unassisted. The patient was alert, oriented to baseline, had normal cranial nerves, and 4/5 extremity strength. Computed tomography (CT) head without contrast was obtained and notable for right temporal bone fracture, multifocal subarachnoid hemorrhage, intraparenchymal contusions, and trace subdural hemorrhage without midline shift or herniation. In accordance with the hospital pathway, she was reversed with 880mg (low dose) of Andexanet alfa and admitted to the surgical ICU for neurologic monitoring. 12 h later she was noted to be less responsive, and exam was concerning for acute stroke. Head imaging showed a culprit proximal right M1 occlusion with associated infarct core of 89mL. She was managed medically and discharged to a long-term care facility with percutaneous gastrostomy on hospital day 23.

Discussion: Andexanet alfa has been shown to improve hemostasis and reduce hematoma expansion in anticoagulation-associated tICH, at the cost of increased thrombotic complications. Emerging evidence suggests that reversal itself can constitute a prothrombotic event, a possible etiology in our patient as she had been anticoagulated and lacked intracardiac thrombi or right to left shunt. This case report shows that reversal carries significant risk of morbidity, and thus more nuanced guidelines around the decision to reverse might be beneficial while further safety data is obtained.