title: Cytochrome 2C19*17 allelic variant, platelet aggregation, bleeding events, and stent thrombosis in clopidogrel-treated patients with coronary stent placement.
abstract: BACKGROUND
  The cytochrome P450 (CYP) 2C19 isoenzyme plays an important role in clopidogrel metabolization. A recently explored CYP2C19*17 allelic variant has been linked to increased transcriptional activity, resulting in extensive metabolization of CYP2C19 substrates, which may lead to an enhanced platelet response to clopidogrel treatment. The aim of this study was to assess the impact of CYP2C19*17 on ADP-induced platelet aggregation, the risk of bleeding, and stent thrombosis in clopidogrel-treated patients undergoing percutaneous coronary intervention.
  
  
  RESULTS
  The study population included 1524 patients undergoing percutaneous coronary intervention after pretreatment with 600 mg clopidogrel. Genotypes were determined with a TaqMan assay. ADP-induced platelet aggregation was assessed on a Multiplate analyzer. The primary clinical safety end point was the 30-day incidence of bleeding defined according to Thrombolysis in Myocardial Infarction criteria, and the primary clinical efficacy end point was the 30-day incidence of stent thrombosis. For both heterozygous (*wt/*17; n=546) and homozygous (*17/*17; n=76) allele carriers, significantly lower ADP-induced platelet aggregation values were found compared with wild-type homozygotes (*wt/*wt; n=902; P=0.039 and P=0.008, respectively). CYP2C19*17 allele carriage was significantly associated with an increased risk of bleeding; the highest risk was observed for CYP2C19*17 homozygous patients (P=0.01, chi(2) test for trend). Multivariate analysis confirmed the independent association of CYP2C19*17 allele carriage with platelet aggregation values (P<0.001) and the occurrence of bleeding (P=0.006). No significant influence of CYP2C19*17 on the occurrence of stent thrombosis was found (P=0.79).
  
  
  CONCLUSIONS
  CYP2C19*17 carrier status is significantly associated with enhanced response to clopidogrel and an increased risk of bleeding.
authors.affiliation: Deutsches Herzzentrum München, Lazarettstrasse 36, 80636 München, Germany. dirk@sibbing.net
authors.forename: Dirk
authors.initials: D
authors.lastname: Sibbing
authors.forename: Werner
authors.initials: W
authors.lastname: Koch
authors.forename: Daniela
authors.initials: D
authors.lastname: Gebhard
authors.forename: Tibor
authors.initials: T
authors.lastname: Schuster
authors.forename: Siegmund
authors.initials: S
authors.lastname: Braun
authors.forename: Julia
authors.initials: J
authors.lastname: Stegherr
authors.forename: Tanja
authors.initials: T
authors.lastname: Morath
authors.forename: Albert
authors.initials: A
authors.lastname: Schömig
authors.forename: Nicolas
authors.initials: N
authors.lastname: von Beckerath
authors.forename: Adnan
authors.initials: A
authors.lastname: Kastrati
mesh_terms: D000368:Aged; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics* / Q000378:metabolism; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000628:therapy*; D003328:Coronary Thrombosis / Q000517:prevention & control*; D065731:Cytochrome P-450 CYP2C19; D005260:Female; D005500:Follow-Up Studies; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006470:Hemorrhage / Q000453:epidemiology*; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010974:Platelet Aggregation / Q000235:genetics*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011110:Polymorphism, Genetic / Q000235:genetics; D012307:Risk Factors; D015607:Stents; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D013988:Ticlopidine