Analysis on expression of platelet surface receptors and changes in platelet function in patients with STEMI treated with tirofiban and clopidogrel versus clopidogrel alone

Objective The aim of the investigation is to compare the effects of clopidogrel with or without tirofiban on the expression of platelet surface receptors and platelet function in patients with ST-segment elevation myocardial infarction(STEMI) undergoing percutaneous coronary intervention(PCI).Methods Totally 32 patients with STEMI were included in the study.During acute primary coronary intervention,patient received aspirin and clopidogrel in a loading dose of 300 mg.Clopidogrel was the only antiplatelet therapy used by the patients in clopidogrel group.The patients in the tirofiban group received additional of tirofiban.Blood samples were collected and analyzed twice: before and up to 24 hours after administration of antiplatelet therapy.The platelet aggregation was established as primary platelet-related hemostasis.The absolute numbers of platelet surface antigens were determined by flow cytometry analysis.Result The study revealed that no significant changes were observed in prothrombin time and partial thromboplastin time in each group before and after treatment,and there was no significant diference after treatment between each group.There was significant increase in closure time(CT) induced by adenosine and adrenaline 120 seconds and 94 seconds respectively in the clopidogrel group post-therapy.While in the tirofiban group the parameters of CT did not change after treatment.The percentage of activated platelets decreased in each group after treatment,but significant different were observed between both group.In addition the absolute number of CD41a antigens increased significantly after treatment in the tirofiban group.Conclusions Ttirofiban and clopidogrel therapy increase the absolute number of GP IIb/IIIa receptors and inhibit the activation of platelets more in the STEMI patients undergoing PCI compared with the treatment of clopidogrel without tirofiban,but both do not influence the CT.