Examining an Interaction Between Plasma Exchange and Apixaban Resulting in an Acute Ischemic Stroke

Objective: Therapeutic drug monitoring is not routinely considered necessary in patients undergoing plasma exchange; however, it is possible for serum concentrations of select medications to be impacted by this procedure. Case: We describe a 50-year-old patient who presented to our facility with new onset aphasia and right-sided weakness. Despite presenting with a National Institute of Health Stroke Severity (NIHSS) score of 23, the patient did not receive fibrinolytic therapy due to his being anticoagulated with apixaban for atrial fibrillation. The patient instead underwent an emergent thrombectomy which resulted in a post-operative Thrombolysis in Cerebral Infarction (TICI) score of 3. The patient had a significant past medical history including numerous previous strokes necessitating assistance with activities of daily living, atrial fibrillation, chronic kidney disease, and thrombocytopenic purpura, for which he was receiving twice weekly plasma exchange and immunomodulatory therapy. The patient's last plasma exchange session was approximately 24 hours prior to admission, leading us to hypothesize that the patient's plasma exchange may have been implicated in the removal of apixaban from the serum and precipitating a stroke. Discussion/Conclusions: Heterogeneity of data exists when evaluating the effect of plasma exchange on apixaban. Although the drug properties of apixaban, including its low volume of distribution and high plasma protein binding capacity, support the notion that it may be vulnerable to removal through plasma exchange, only one other case report has been published on this phenomenon.