Clopidogrel Versus Ticagrelor in the Treatment of Patients Undergoing Percutaneous Coronary Intervention: Effects on Platelet Function Assessed by Platelet Function Tests and Mean Platelet Volume.

Background: Knowledge on the pharmacodynamic effects of antiplatelet drugs including clopidogrel and ticagrelor on Asian patients is scarce. We aim to evaluate the effects of the two drugs on platelet reactivity in the treatment of Chinese patients who underwent percutaneous coronary intervention (PCI), using two platelet function tests (PFT). Meanwhile, the relationship between mean platelet volume (MPV), a routinely index of platelet size, and high on-treatment platelet reactivity (HPR) is also investigated.Methods: Patients receiving dual antiplatelet therapy (DAPT) treatment were scheduled for the assessment of platelet reactivity at 2-3 days after PCI. Two PFTs, light transmission aggregometry (LTA) and vasodilator-stimulated phosphoprotein (VASP) assay, were applied in the evaluation of platelet reactivity. MPV was measured simultaneously.Results: The final study population included the traditional therapy group with aspirin and clopidogrel (n = 46) and the new therapy group with aspirin and ticagrelor (n = 66). In the new therapy group, the value of platelet aggregation assessed by LTA was obviously lower than that in the traditional therapy group (P < 0.001). The platelet reactivity index (PRI) level at VASP test was also markedly lower in the group given the new therapy (P < 0.001). It presented significant difference of HPR rates between the two groups. MPV showed a potent ability in predicting the presence of HPR at VASP assay (AUC = 0.788, 95% CI: 0.701-0.875, P < 0.001) in receiver-operating characteristic curve analysis.Conclusions: Compared with clopidogrel, ticagrelor has dramatically greater antiplatelet effect, with a superiority of suppressing platelet function and a lower HPR rates. In addition, there existed a significantly independent association between MPV and high prevalence of HPR at VASP assay.