Previous Antiplatelet Therapy on Ticagrelor-Aspirin and Clopidogrel-Aspirin Efficacy in Intracranial Artery Stenosis.

Abstract

Background and purpose: This study aims to investigate the effects of previous antiplatelet therapy on the efficacy and safety of ticagrelor-aspirin versus clopidogrel-aspirin among patients with and without intracranial artery stenosis (ICAS) using data from the Ticagrelor or Clopidogrel with Aspirin in High-Risk Patients with Acute Nondisabling Cerebrovascular Events-II (CHANCE-2) trial.

Methods: In this post-hoc analysis of the CHANCE-2 trial, patients who underwent intracranial artery imaging were included. The primary efficacy and safety outcomes were recurrent stroke and severe or moderate bleeding within 90 days.

Results: Among the 5,920 patients included, the median age was 64.8 years (interquartile range, 57.0-71.4), 2,004 (33.9%) were females, 2,385 (40.3%) had ICAS, and 701 (11.8%) had previous antiplatelet therapy before enrollment. There were significant interaction effects between previous antiplatelet therapy and dual-antiplatelet therapy regimens on the risk of recurrent stroke (P=0.003) in patients without ICAS but not in those with ICAS (P=0.557). Only in patients without ICAS without previous antiplatelet therapy, ticagrelor-aspirin therapy reduced the risk of stroke recurrence compared with clopidogrel-aspirin therapy (adjusted hazard ratio 0.47, 95% confidence interval 0.34-0.66, P<0.001). Similar effects were observed for the outcomes of composite vascular events and ischemic stroke at 3 months and 1 year. No significant differences in severe or moderate bleeding were observed between the groups.

Conclusion: In patients with minor stroke or high-risk transient ischemic attack carrying CYP2C19 loss-of-function alleles, those without ICAS and no history of previous antiplatelet therapy may have a better response to ticagrelor-aspirin therapy for reducing new stroke and composite vascular events.