Background and Purpose: TIAregistry.org project showed that TIA and minor stroke patients with multiple acute infarctions (MAIs), which represent mechanisms of embolism, are at higher risk of recurrent stroke as compared to those with none or single acute infarction (SAI). We hypothesis that patient with MAIs may be more susceptible to dual antiplatelet therapy.
Methods: We compared clopidogrel plus aspirin with aspirin alone with regard to their effectiveness and safety for prevention of stroke recurrence among non-cardiac TIA and minor ischemic stroke patients with different infarction patterns (no acute infarction, SAI, or MAIs) in the imaging subgroup from the Clopidogrel in High-Risk Patients with Acute Non-disabling Cerebrovascular Events (CHANCE) trial. The efficacy and safety outcome were stroke recurrence and moderate-to-severe bleeding event at 90 days respectively.
Results: Overall, 1089 patients at 45 centers in CHANCE trial were included. The rate of recurrent stroke was 14.2%, 8.7%, and 2.0% in patients with MAIs, SAI and no infarction respectively at 90 days. Increased risk of stroke recurrence was observed in patients with MAIs (HR, 5.9; 95% CI, 2.3-15.2) and SAI (HR, 4.1; 95% CI, 1.6-10.7) (Figure A) as compared to those without infarction. The dual antiplatelet treatment was superior to aspirin alone for reducing the risk of recurrent stroke in patients with MAIs (HR 0.48; 95% CI, 0.25- 0.92; P= 0.03) but not in patients with SAI and without acute infarction with P=0.046 for interaction (Figure B-D). The effect of treatment assignment on bleeding did not vary among groups with different infarction patterns (P>0.05 for all).
Conclusions: Patients with MAIs had the highest risk for stroke recurrence among patients with different infarction patterns. Patients with MAIs may benefit the most clinically from dual antiplatelet therapy and dual antiplatelet therapy does not increase the risk of hemorrhage among any groups.