CYP2C19 and ischemic stroke: The present study prospectively recruited patients with ischemic stroke and clopidogrel prescription and found that (1) HCPR was associated with short-term (within 21 days) recurrent events, and (2) factors including high platelet P2Y12 reactivity at baseline, impaired kidney function, and CYP2C19 LoF allele carriers were independently and significantly associated with HCPR.