Studies on antiplatelet effect of ticagrelor/aspirin and clopidogrel/aspirin in patients with acute minor stroke and transient ischemic attack (TIA) stratified by CYP2C19 metabolizer status is limited. We gained data from the Platelet Reactivity In Non-disabling Cerebrovascular Events study. Platelet reactivity was tested at baseline, 2 hours, 24 hours, 7 days and 90 days after initial dose, including high on-treatment platelet reactivity (HOPR), which was defined as P2Y12 reaction unit >208, and percentage inhibition of platelet aggregation (IPA). A total of 365 patients were included. There were 199 (54.5%) individuals classified as carriers of CYP2C19 loss-of-function alleles. For carriers and non-carriers, the proportions of HOPR were significantly lower in those with ticagrelor/aspirin compared with those with clopidogrel/aspirin at 2 hours, 24 hours, 7 days, respectively (all p<0.05). IPA was higher at all time points except at baseline in patients with ticagrelor/aspirin compared with those with clopidogrel/aspirin in both carriers and non-carriers of CYP2C19 lose-of-function alleles (all p<0.05). Our findings showed that ticagrelor/aspirin therapy possessed greater platelet inhibition and more rapid onset in platelet inhibition compared with clopidogrel/aspirin therapy both in carriers and non-carriers of CYP2C19 lose-of-function alleles with acute minor stroke or TIA.
Keywords: antiplatelet; clopidogrel; high platelet reactivity; inhibition of platelet aggregation; ticagrelor.