Background and Purpose- This study aimed to compare the effectiveness of dual antiplatelet
therapy with
clopidogrel-
aspirin to that of
aspirin monotherapy in patients with acute minor
cerebral ischemia using a prospective, nationwide, multicenter,
stroke registry database in South Korea. Methods- CHANCE trial (
Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events)-like patients who met eligibility criteria modeled on the CHANCE trial eligibility criteria, including (1) acute minor
ischemic stroke defined as National Institutes of Health
Stroke Scale score ≤3 or lesion positive
transient ischemic attack within 24 hours of onset and (2) noncardioembolic
stroke mechanism. Propensity scores using the inverse probability of treatment weighting was used to adjust for baseline imbalances. The primary outcome was the composite of all
stroke (ischemic and hemorrhagic),
myocardial infarction, and vascular death by 3 months. Results- Among 5590 patients meeting the eligibility criteria, age was 64±13 year and 62.6% were male.
Aspirin and combination of
clopidogrel-
aspirin were administered in 66.1% and 33.9% of patients, respectively. In unadjusted analysis, rates of the 3-month primary vascular event outcome were lower with
clopidogrel-
aspirin versus
aspirin, 9.9% versus 12.2% (hazard ratio, 0.79 [0.67-0.95]). In propensity-weighted Cox proportional hazards regression with robust estimation,
clopidogrel-
aspirin was associated with a lower risk of the primary vascular event outcome (hazard ratio, 0.76 [0.63-0.92]) and all
stroke events (hazard ratio, 0.74 [0.61-0.90]). Among 6 predefined subgroup analyses, 3 showed potential modification of treatment effect, with lesser benefit associated with the absence of prior antiplatelet use (Pinteraction=0.01) and younger age (<75 years, Pinteraction=0.07), and absence of benefit associated with small vessel occlusion subtype (Pinteraction=0.08). Conclusions- Dual antiplatelet
therapy with
aspirin and
clopidogrel was associated with reduced
stroke,
myocardial infarction, and vascular death in the 3 months following a presenting minor, noncardioembolic
ischemic stroke. Benefits may be particularly magnified in patients with a history of prior antiplatelet
therapy, older age, and nonsmall vessel disease
stroke mechanism.