Abstract P260: Ischemic Strokes on Direct Oral Anticoagulants
Introduction: The objective of our study was to identify the underlying causes of acute ischemic strokes (AIS) in patients prescribed direct oral anticoagulants (DOACs). Methods: This is a retrospective study of patients presenting to a large urban comprehensive stroke center from December 1, 2019 to May 31, 2020 who were prescribed DOACs at the index event. Two board-certified vascular neurologists independently reviewed medical charts including patient baseline characteristics, laboratory results, stroke mechanism, and patient-reported adherence. DOAC “failure” was defined as AIS occurring in the setting of self-reported adherence to the FDA-indicated dosing regimen. Results: Of 302 AIS patients admitted during the study period, 18 (6.0%) patients had AIS while on DOACs. Median age was 82 (IQR 72, 86) years, 9 (50%) were black and 14 (78%) were female. Eight patients (44%) presented within the IV Alteplase window and 5 (28%) patients presented with large vessel occlusion. At the time of stroke, 13 (72%) patients were on apixaban, 4 (22%) were on rivaroxaban and 1 (6%) on dabigatran. Atrial fibrillation (mean CHADS-VASc score 4.7) was the most common indication for DOAC (72%), followed by deep venous thrombosis (17%), and embolic stroke (11%). The most frequent causes of AIS on DOACs were underdosing in patients ≥ 80 years (n=6), known active malignancy (n=5), and non-adherence (n=4). The remaining cases included procedure-related discontinuation of the DOAC (n=1), symptomatic extracranial internal carotid artery stenosis (n=1), and unknown cause (n=1). Overall, the frequency of DOAC “failure” was 39%. In 6 (33%) patients, the initial anticoagulant was switched to an alternative anticoagulant at discharge. Conclusion: In this cohort of patients who had AIS while on DOAC therapy, 39% of cases were attributed to DOAC “failure” and primarily occurred in patients with active malignancy. Underdosing in the elderly and non-adherence remained the leading cause of AIS in patients on DOAC. Our findings highlight the importance of accurate dosing in the elderly and reinforcing adherence to medications. Further studies are needed to understand the role of DOACs in patients with active malignancy.