Stronger inhibitory effects of ticagrelor plus aspirin compared with clopidogrel plus aspirin on arachidonic acid induced platelet aggregation in patients with acute coronary syndrome with PCI

Antagonists of the Adenosine Diphosphate (ADP) receptor, P2Y12, may inhibit platelet aggregation as a result of stimulation with arachidonic acid (AA). The potent P2Y12 blocker, Ticagrelor has greater anti-platelet effects than Clopidogrel. We explored the effects of Ticagrelor versus Clopidogrel on mean maximum aggregation ratios (MAR%) in response to AA stimulation in patients receiving aspirin in conventional doses. A total of 613 acute coronary syndrome (ACS) patients were followed from October 2017 to October 2018. At the one- and six-month follow-up visit, mean AA-MAR% was lower in the Ticagrelor group when compared with the Clopidogrel group (28.9% vs 31.7%, 28.4% vs 31.0%, p<0.001 and p=0.001, respectively). BARC1-2 bleeding occurred with greater frequency with Ticagrelor than in patients treated with Clopidogrel (29.3% vs 9.5%, p<0.001; 23.5% vs 9.3%, p<0.001). Excessive platelet inhibition and decreased AA-MAR% were considered the main reasons for the severe subcutaneous/dermal bleeding in Ticagrelor treated patients.