Dual Antiplatelet Therapy and Outcomes in Acute Mild to Moderate Stroke With Versus Without Large-Artery Atherosclerosis Post Hoc Analysis of ATAMIS

Background We conducted a post hoc analysis of the ATAMIS (Antiplatelet Therapy in Acute Mild to Moderate Ischemic Stroke) trial to investigate whether the priority of clopidogrel plus aspirin to aspirin alone was consistent between patients with and without stroke pathogenesis of large-artery atherosclerosis (LAA). Methods and Results Patients with stroke classification randomized to a clopidogrel-plus-aspirin group and aspirin-alone group in a modified intention-to-treat analysis set of ATAMIS were classified into LAA and non-LAA subtypes. The primary outcome was early neurologic deterioration at 7 days, defined as a >2-point increase in National Institutes of Health Stroke Scale score compared with baseline, and safety outcomes were bleeding events and intracranial hemorrhage. We compared treatment effects in each stroke subtype and investigated the interaction. Among 2910 patients, 225 were assigned into the LAA subtype (119 in the clopidogrel-plus-aspirin group and 106 in the aspirin-alone group) and 2685 into the non-LAA subtype (1380 in the clopidogrel-plus-aspirin group and 1305 in the aspirin-alone group). Median age was 66 years, and 35% were women. A lower proportion of early neurologic deterioration was found to be associated with dual antiplatelet therapy in the LAA subtype (adjusted risk difference, -10.4% [95% CI, -16.2% to -4.7%]; P=0.001) but not in the non-LAA subtype (adjusted risk difference, -1.4% [95% CI, -2.6% to 0.1%]; P=0.06). No significant interaction was found (P=0.11). Conclusions Compared with the non-LAA subtype, patients with stroke of the LAA subtype may get more benefit from dual antiplatelet therapy with clopidogrel plus aspirin with respect to early neurologic deterioration at 7 days. Registration URL: clinicaltrials.gov; UnIque identifier: NCT02869009.