Antiplatelet effects of ticagrelor versus clopidogrel after coronary artery bypass graft surgery: A single-center randomized controlled trial

Objective: The study objective was to compare the onset of platelet inhibition (inhibition of platelet aggregation) between ticagrelor 90 mg twice per day and clopidogrel 75 mg once per day in patients receiving coronary artery bypass grafting. Methods: In a single-center, randomized, open-label study, 140 patients receiving coronary artery bypass grafting were randomly assigned to the aspirin + ticagrelor group or the aspirin + clopidogrel group in a 1:1 ratio. Participants in the aspirin + ticagrelor group took aspirin 100 mg once per day and ticagrelor 90 mg twice per day. Participants in the aspirin + clopidogrel group took aspirin 100 mg once per day and clopidogrel 75 mg once per day. Platelet function was determined before study treatment (0 hours); at 2 hours, 8 hours, 24 hours, and 72 hours after medication; and during follow-up at 30 days after surgery. Results: Inhibition of platelet aggregation at 2 hours after the first drug administration was greater for the aspirin + ticagrelor group than for the aspirin + clopidogrel group (34.2% [interquartile range, 9.1-66.0] vs 5.3% [interquartile range, -14.3-22.0], P < .001) and at all times in the study period (P < .001). More patients reached inhibition of platelet aggregation maximum within 24 hours in the aspirin + ticagrelor group than in the aspirin + clopidogrel group (52.9% vs 27.5 % , P = .006). The average inhibition of platelet aggregation maximum from 2 to 24 hours was still greater in the aspirin + ticagrelor group than in the aspirin + clopidogrel group (72.3% +/- 15.4% vs 49.2% +/- 46.8%, P < .001). There were no differences in terms of bleeding or major adverse cardiac events between the 2 groups. Conclusions: In patients receiving coronary artery bypass grafting, the onset of action was faster and the peak inhibition of platelet aggregation was higher with ticagrelor than with clopidogrel.