Abstract
BACKGROUND: Anterior circulation stroke (ACS) differs from posterior circulation stroke (PCS) in several aspects. We hypothesize that the risk of early neurologic deterioration (END) and its responses to clopidogrel plus aspirin versus aspirin alone may be different between stroke territories. METHODS AND RESULTS: This was a prespecified post hoc analysis of ATAMIS (Antiplatelet Therapy in Acute Mild to Moderate Ischemic Stroke) trial and included patients with definite infarct location who were classified into ACS and PCS according to stroke territory. Primary outcome was occurrence of END at 7 days, defined as ≥2-point increase in National Institutes of Health Stroke Scale score compared with baseline. We compared the treatment effects of clopidogrel plus aspirin versus aspirin alone in each stroke territory. From 3000 patients, 2431 eligible patients (1780 with ACS [910 assigned into clopidogrel plus aspirin and 870 assigned into aspirin alone] and 651 with PCS [371 assigned into clopidogrel plus aspirin and 280 assigned into aspirin alone]) were included. Median age was 66 years and 35.1% were women. The occurrence of END was higher in ACS than PCS (6.8% versus 3.8%, P=0.007). clopidogrel plus aspirin was associated with lower risk of END in ACS (risk difference [95% CI]: -2.4% [-4.1% to -0.8%], P=0.004), but not in PCS (risk difference [95% CI]: -0.6% [-2.7% to 1.5%], P=0.57). No significant interaction was found (P=0.69). CONCLUSIONS: Our study demonstrated END was higher in acute mild-to-moderate ischemic stroke with anterior circulation, who derived more benefit from clopidogrel plus aspirin than aspirin alone. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02869009.