Background: P2Y12-ADP receptor blockade during percutaneous coronary intervention (PCI) is critical to prevent thrombotic events. In patients under chronic P2Y12 blockers, the use of additional loading dose (LD) before an elective PCI is debated. We aimed to investigate the rate of high on-treatment platelet reactivity (HTPR) in patients undergoing elective PCI during chronic clopidogrel or ticagrelor therapy.
Methods and results: We performed a sub-group analysis of a randomized trial comparing ticagrelor and clopidogrel in acute coronary syndrome (ACS) patients undergoing PCI. Multi-vessel disease patients requiring a staged PCI one month after the ACS were included. The VASP (vasodilatatory phosphoprotein) index, which is a specific and reproducible platelet assay to measure P2Y12-ADP receptor activity, was used to assess the biological efficacy of the maintenance dose (MD) of ticagrelor and clopidogrel before PCI. Forty-one patients in each group of randomization required a staged PCI. They were similar regarding the baseline demographic, clinical and angiographic characteristics. The mean VASP index in the ticagrelor group was 20.7±8.8% compared to 51.8±17% in the clopidogrel group (p<0.001) before PCI. No patients had a VASP index ≥50% in the ticagrelor group compared to 56% in the clopidogrel group (p<0.001). Following PCI the rate of peri-procedural MI was higher in the clopidogrel group (p=0.02).
Conclusions: Unlike clopidogrel MD, ticagrelor MD achieves an optimal PR inhibition in all patients during a staged PCI.
Keywords: High on-treatment platelet reactivity; Loading dose; Myocardial infarction; P2Y12-ADP receptor; Percutaneous coronary intervention.
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