CYP2C19 and transient ischemic attack: The results of the CHANCE-2 trial showed that in patients with minor stroke or high-risk TIA who carry the CYP2C19 LoF, using ticagrelor instead of clopidogrel in dual antiplatelet therapy can reduce the risk of stroke recurrence at 90 days. Subgroup analysis showed that patients with symptomatic intracranial arterial stenosis had a reduction in stroke recurrence. However, the result was not significant (HR 0.76, 95% CI 0.55 to 1.04).6 94