Abstract 135: Antiplatelet Therapy Following Ischemic Stroke - Continue or Change Pre-existing Therapy?

Abstract

Introduction: Antiplatelet therapy is routinely prescribed early after ischemic stroke. Many patients will already be taking antiplatelet therapy and it is unknown whether these patients should continue the same antiplatelet treatment or switch to a different regimen. We compared outcomes in patients who continued the same regimen after ischemic stroke to those who changed. Methods: Data from 10304 subjects were extracted from the Virtual International Stroke Trials Archive. 8550 subjects were excluded (12 incomplete data, 4823 no antiplatelet therapy recorded pre-stroke, 3715 no recorded antiplatelets post-stroke). Propensity score matching was employed to create a matched sample for comparison of those who continued the same regimen to those who changed. The nature of change in antiplatelet regimen was not explored. We compared the rate of recurrent stroke (primary endpoint), bleeding complications (defined as intracranial haemorrhage not including haemorrhagic transformation or any major bleed) and day-90 outcomes (using the modified Rankin and National Institutes of Health Stroke Scales). We used logistic regression analysis and adjusted for important clinical factors. Patients who suffered an outcome event prior to resuming antiplatelet therapy were not included in the analysis. Results: 963 subjects changed antiplatelet regimen post stroke and 791 continued the same regimen. In the propensity matched sample (n=791 per group), a recurrent ischemic event occurred in 3.7% of subjects who changed regimen and 3.8% who continued unchanged (OR=1.078; 95% CI 0.62-1.88, p=0.790). The odds of better functional outcome were higher in the change group according to both day-90 mRS (OR=1.31; 95% CI 1.07-1.59, p=0.008) and NIHSS. The rate of intracranial bleeding and major bleeding within the first 90 days was similar in both groups (1.2% vs. 1.2% (p=0.939) and 2.4% vs. 3.2% (p=0.409) respectively). Conclusion: In patients who suffer ischemic stroke whilst taking antiplatelets, a change in antiplatelet regimen was not associated with reduced recurrent stroke rate or bleeding. Day 90 functional outcome was better in the change group but this may be due to a confounding variable.