title: Impact of bivalirudin or unfractionated heparin on platelet aggregation in patients pretreated with 600 mg clopidogrel undergoing elective percutaneous coronary intervention.
abstract: OBJECTIVE
  The aim of this study was to assess the impact of bivalirudin or unfractionated heparin (UFH) on platelet aggregation in patients, pretreated with a 600 mg loading dose clopidogrel, undergoing elective percutaneous coronary intervention (PCI).
  
  
  RESULTS
  Patients (n = 100) were recruited consecutively in the setting of a double-blind, randomized trial. Bivalirudin or UFH was administered during PCI. Blood was drawn immediately before PCI, following administration of bivalirudin or UFH directly after PCI, and 24 h after PCI. Adenosine diphosphate (ADP)-induced platelet aggregation was assessed with light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA). Before PCI, ADP-induced platelet aggregation was similar in UFH and bivalirudin patients (P = 0.99 for LTA; P = 0.28 for MEA). Administration of bivalirudin during PCI resulted in significant additional suppression of platelet aggregation (P = 0.012 for LTA; P = 0.008 for MEA). Administration of UFH did not have a significant influence on platelet aggregation (P = 0.42 for LTA; P = 0.78 for MEA). Platelet aggregation was again similar in the two groups 24 h after PCI (P > 0.05 for LTA and MEA).
  
  
  CONCLUSIONS
  Bivalirudin, given during PCI in patients pretreated with 600 mg of clopidogrel, is in contrast to UFH associated with further inhibition of platelet aggregation.
authors.affiliation: Deutsches Herzzentrum and 1. Medizinische Klinik rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Sibbing
authors.forename: Gabriele
authors.initials: G
authors.lastname: Busch
authors.forename: Siegmund
authors.initials: S
authors.lastname: Braun
authors.forename: Stefan
authors.initials: S
authors.lastname: Jawansky
authors.forename: Albert
authors.initials: A
authors.lastname: Schömig
authors.forename: Adnan
authors.initials: A
authors.lastname: Kastrati
authors.forename: Ilka
authors.initials: I
authors.lastname: Ott
authors.forename: Nicolas
authors.initials: N
authors.lastname: von Beckerath
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D000925:Anticoagulants / Q000008:administration & dosage*; D000077144:Clopidogrel; D004311:Double-Blind Method; D005260:Female; D006493:Heparin / Q000008:administration & dosage; D006629:Hirudins / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D010446:Peptide Fragments / Q000008:administration & dosage*; D019990:Perioperative Care; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D010979:Platelet Function Tests / Q000379:methods; D011292:Premedication; D011994:Recombinant Proteins / Q000008:administration & dosage; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives
chemical_list: D000925:Anticoagulants; D006629:Hirudins; D010446:Peptide Fragments; D010975:Platelet Aggregation Inhibitors; D011994:Recombinant Proteins; D000244:Adenosine Diphosphate; D006493:Heparin; D000077144:Clopidogrel; D013988:Ticlopidine; C074619:bivalirudin