Itrat, Ahmed

ABSTRACT Background and Purpose Neuroimaging of acute ischemic stroke (AIS) may provide clues to the underlying mechanism based on stroke location. Patients who experience stroke despite therapeutic anticoagulation provide a clinical challenge, and the subsequent preventive regimen may depend on the underlying stroke mechanism. We conducted a retrospective analysis of patients presenting with stroke despite anticoagulation (AC+) and compared their imaging findings to those of patients with stroke while not on anticoagulation (AC−). Methods Retrospectively, patients hospitalized with AIS were categorized as AC+ and AC− based on their prehospital anticoagulation use. A total of 119 patients met the inclusion criteria for AC+ strokes, which were compared to a random sample of 135 AC− patients during the same time frame. Imaging was dichotomized into embolic (ES) and nonembolic stroke (NES) groups. Descriptive analyses were used to compare imaging appearance between the two groups. Secondary analyses using multivariate logistic regression were used to identify risk factors for strokes in the AC+ group. Results ES were proportionally higher among the AC+ group compared to the AC− cohort. Atrial fibrillation was an independent predictor for breakthrough stroke among the entire cohort (adjusted OR 69.8 [21.1–291.8], p < 0.001), as well as a predictor for ES among those with AC+ stroke (adjusted OR 55.29 [14.4–286.2], p < 0.001). Conclusions AC+ patients have a higher proportion of embolic appearing strokes, suggesting incomplete response to anticoagulation rather than competing mechanisms as the cause of stroke in these patients. Further investigation into stroke mechanisms and management in this unique population is needed.