Abstract WP207: Switching Antiplatelets In Breakthrough Ischemic Stroke: Long Term Outcomes And Safety

Introduction: Previous studies have shown that switching antiplatelets after having an ischemic stroke on aspirin may have better outcomes. However, these studies included patients who were switched to dual antiplatelets, which have an established benefit in the immediate post-stroke period. The purpose of this study is to assess outcomes in patients who continue aspirin versus switch to clopidogrel after having a cerebrovascular event on aspirin. Methods: We retrospectively identified patients within 14 Southern California hospitals using ICD-9 and ICD-10 codes who had a diagnosis of ischemic stroke on aspirin from January 2017-December 2019. Outcomes included recurrent hospital admission or emergency room visit for ischemic stroke, TIA, or intracranial hemorrhage up to two years post index event. Patients were grouped by which antiplatelet was prescribed at discharge. Those prescribed dual antiplatelets or an anticoagulant were excluded. Cox regression analysis was used to estimate risk of readmission. Results: Of the 580 patients who met the inclusion criteria, 372 (64%) continued aspirin and 208 (36%) switched to clopidogrel. Those with coronary artery disease (55.0% versus 45.0%, p = 0.015), dyslipidemia (61.4% versus 38.6%, p = 0.001), diabetes (59.5% versus 40.5%, p = 0.007), and a higher NIHSS score (mean 6.06 +/- 6.96 SD versus 4.08 +/- 4.32 SD, p = 0.001) were more likely to be discharged on aspirin. There were no differences in recurrent ischemic stroke {18.8% versus 15.4%, HR 1.12 (95% CI, 0.74-1.72), p = 0.587}, ischemic stroke plus TIA {19.9% versus 18.3%, HR (95% CI, 0.84-1.86), p = 0.253}, systemic embolism {25.5% versus 21.6%, HR 1.16 (95% CI, 0.82-1.66), p = 0.413} or intracranial hemorrhage {3.2% versus 2.4%, HR 0.94 (95% CI, 0.34-2.70), p = 0.919} between those discharged on aspirin versus clopidogrel, respectively. Conclusion: This study suggests that switching antiplatelets after having an ischemic stroke on aspirin may not be warranted.