Background and Objective: In symptomatic cerebral large artery disease, watershed infarcts may result from hemodynamic impairment or microembolism. Such patients often have a high risk of recurrence or deterioration. It is still not clear whether dual antiplatelet therapy reduce the risk of stroke recurrence. The aim of this subgroup analysis is to discuss whether dual antiplatelet therapy could decrease the one year stroke recurrence more effectively for minor stroke patients with watershed infarcts.
Methods: Patients enrolled in Clopidogrel in High-risk patients with Acute Non-disabling Cerebrovascular Events (CHANCE) trial and have magnetic resonance (MR) imaging data were included in this study. Diffusion-weighted imaging was obtained for detection of watershed infarcts. We assessed the interaction of the treatment effects of clopidogrel plus aspirin versus aspirin alone among patients with watershed infarcts or not.
Results: Of the 1089 patients with MR imaging data enrolled in the CHANCE trial, 831 (76.3%) patients with acute infarcts. Among patients with acute infarcts, 93 (11.19%) were watershed infarcts, 55 (59.14%) received dual antiplatelet therapy. Patients with watershed infarcts had higher rates of recurrent stroke (17.20% vs 10.70%, p=0.063) at 1 year. For patients with watershed infarcts, one-year stroke recurrence was 6 (10.91%) in clopidogrel plus aspirin group and 10 (26.32%) in placebo plus aspirin group. There was interaction between antiplatelet therapy and presence of watershed infarcts on the primary outcome of any stroke (p=0.0933). (Kaplan-Meier curves were showed in the figure).
Conclusions: For minor stroke patients with watershed infarcts, clopidogrel with aspirin may be more effective in decreasing 1-year stroke recurrence attributed to its potential mechanism of microembolism. Studies in other populations and subsequent analysis with adequate power are warranted to further verify such findings.