title: Expression of platelet surface receptors and early changes in platelet function in patients with STEMI treated with abciximab and clopidogrel versus clopidogrel alone.
abstract: BACKGROUND
  Platelets play a crucial role in the pathogenesis of acute coronary syndromes (ACS). The efficacy of antiplatelet treatment is pivotal in the success of percutaneous coronary intervention (PCI) performed in patients with ACS.
  
  
  OBJECTIVE
  The aim of the study was to investigate the effects of clopidogrel with or without abciximab on the expression of platelet surface receptors and platelet function in patients with ST-segment elevation myocardial infarction (STEMI) undergoing PCI.
  
  
  METHODS
  Thirty patients with STEMI were included in the study. During acute primary coronary intervention, patients received aspirin (acetylsalicylic acid) and clopidogrel in a loading dose of 300mg. Clopidogrel was the only antiplatelet therapy used by nine patients (group B). Twenty-one patients (group A) received additional abciximab. Blood samples were collected and analyzed twice: before and up to 22 hours after administration of antiplatelet therapy. The platelet aggregation was established as primary platelet-related hemostasis (closure time [CT] assessed using the PFA100 system). The absolute number of platelet surface antigens as CD41a, CD42a, CD42b, CD61, and CD62P were determined by flow cytometry analysis.
  
  
  RESULTS
  The study revealed a statistically significant increase in CT induced by adenosine diphosphate and adrenaline (epinephrine) +130 seconds (p < 0.0001) and +94 seconds (p < 0.0001), respectively, in group A patients post-therapy. While in group B the parameters of CT did not change after treatment. In addition, the absolute number of CD41a antigens (glycoprotein [GP] IIb/IIIa) increased significantly after treatment in group A. No significant changes were observed after treatment in the expression of CD62P (P-selectin) antigens in either treatment group. There was a significant reduction in the percentage of CD62P-positive platelets in group B after antiplatelet therapy.
  
  
  CONCLUSIONS
  The absolute number of GP IIb/IIIa receptors increases and platelets are not activated up to 12 hours after cessation of abciximab therapy. Treatment of STEMI patients undergoing PCI with a loading dose of clopidogrel reduces the percentage of active platelets but does not influence the CT.
authors: Institute of Cardiology and Institute of Haematology and Blood Transfusion in Warsaw, Warsaw, Poland. akonopka@ptkardio.pl
authors: Anna
authors: A
authors: Konopka
authors: Justyna
authors: J
authors: Spychalska
authors: Dariusz
authors: D
authors: Sitkiewicz
authors: Ewa
authors: E
authors: Zdebska
authors: Iwona
authors: I
authors: Pilichowska
authors: Walerian
authors: W
authors: Piotrowski
authors: Janina
authors: J
authors: Stepińska
mesh_terms: D000077284:Abciximab; D015906:Angioplasty, Balloon, Coronary; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D000077144:Clopidogrel; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D039661:Integrin beta3 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000188:drug therapy*; D019007:P-Selectin / Q000096:biosynthesis; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000096:biosynthesis*; D040201:Platelet Membrane Glycoprotein IIb / Q000096:biosynthesis; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000911:Antibodies, Monoclonal; C061248:ITGB3 protein, human; D007140:Immunoglobulin Fab Fragments; D039661:Integrin beta3; D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D040201:Platelet Membrane Glycoprotein IIb; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin; D000077284:Abciximab