Stroke Recurrence and Antiplatelets in Posterior Versus Anterior Circulation Minor Stroke or Transient Ischemic Attack

Background: It is unclear whether infarct location affects stroke recurrence after index ischemic stroke. We aimed to compare the risk of stroke recurrence and the responses to dual antiplatelets with ticagrelor-aspirin versus clopidogrel-aspirin between patients with posterior circulation infarct (PCI) and those with anterior circulation infarct (ACI) after minor stroke or transient ischemic attack.Methods: Data were obtained from the double-blind CHANCE-2 trial (Ticagrelor or Clopidogrel With Aspirin in High-Risk Patients With Acute Nondisabling Cerebrovascular Events II), which was conducted across 202 centers in China from September 2019 to March 2021. Patients with positive diffusion-weighted imaging were included and classified into PCI and ACI groups according to the hyperintense lesions on diffusion-weighted imaging. The primary efficacy and safety outcomes were a new stroke and severe or moderate bleeding within 90 days, respectively.Results: A total of 4168 patients were included in this substudy, with 1427 PCI and 2741 ACI. During the 90-day follow-up, the risk of stroke recurrence in patients with PCI was similar to that with ACI (7.4% versus 8.3%; adjusted hazard ratio, 1.01 [95% CI, 0.79-1.29]; P=0.94). In comparison with clopidogrel-aspirin, ticagrelor-aspirin significantly reduced the risk of stroke recurrence in both the PCI (hazard ratio, 0.59 [95% CI, 0.40-0.89]; P=0.01) and ACI groups (hazard ratio, 0.65 [95% CI, 0.50-0.85]; P=0.002). There was no treatment-by-infarct location interaction (P value for interaction, 0.92). The risk of severe or moderate bleeding was similar between PCI and ACI patients (P=0.19). However, the risk of any bleeding increased on ticagrelor-aspirin than clopidogrel-aspirin treatment in PCI and ACI patients (P=0.02 and 0.002, respectively).Conclusions: Our study demonstrated that stroke recurrence was similar between PCI and ACI in patients with minor stroke or transient ischemic attack. Additionally, ticagrelor-aspirin was superior to clopidogrel-aspirin in reducing the risk of stroke within 90 days in both PCI and ACI patients.Registration:URL: ; Unique identifier: NCT04078737.

Automated summary

This study compared the risk of stroke recurrence and the responses to dual antiplatelets with ticagrelor-aspirin versus clopidogrel-aspirin between patients with posterior circulation infarct (PCI) and those with anterior circulation infarct (ACI). The study found that the risk of stroke recurrence was similar between PCI and ACI patients, and ticagrelor-aspirin was superior to clopidogrel-aspirin in reducing the risk of stroke in both PCI and ACI patients within 90 days.