Cytochrome P450 2C19 681G>A polymorphism and high on-clopidogrel platelet reactivity associated with adverse 1-year clinical outcome of elective percutaneous coronary intervention with drug-eluting or bare-metal stents

J Am Coll Cardiol. 2008 May 20;51(20):1925-34. doi: 10.1016/j.jacc.2007.12.056.


Objectives: We investigated whether the loss of function CYP2C19 681G>A *2 polymorphism is associated with high (>14%) residual platelet aggregation (RPA) on clopidogrel and whether high on-clopidogrel RPA impacts clinical outcome after elective coronary stent placement.

Background: The cytochrome P450 (CYP)-dependent conversion of clopidogrel to its active metabolite may contribute to the variability in antiplatelet effect of clopidogrel.

Methods: The study included 797 consecutive patients undergoing percutaneous coronary intervention, who were followed-up for 1 year. Adenosine-diphosphate-induced (5 mumol/l) RPA was assessed after a 600-mg loading dose and after the first 75-mg maintenance dose of clopidogrel before discharge. CYP2C19 genotype was analyzed by real-time polymerase chain reaction.

Results: Of the patients included, 552 (69.3%) were CYP2C19 wild-type homozygotes (*1/*1) and 245 (30.7%) carried at least one *2 allele. Residual platelet aggregation at baseline did not differ significantly between genotypes. On clopidogrel, RPA was significantly (p < 0.001) higher in *2 carriers than in wild-type homozygotes (23.0% [interquartile range (IQR) 8.0% to 38.0%] vs. 11.0% [IQR 3.0% to 28.0%] after loading; 11.0% [IQR 5.0% to 22.0%] vs. 7.0% [IQR 3.0% to 14.0%] at pre-discharge). Between *2 carriers and wild-type homozygotes, we found significant (p < 0.001) differences in the proportion of patients with RPA >14%, both after loading (62.4% vs. 43.4%) and at pre-discharge (41.3% vs. 22.5%). Residual platelet aggregation >14% at pre-discharge incurred a 3.0-fold increase (95% confidence interval 1.4 to 6.8; p = 0.004) in the 1-year incidence of death and myocardial infarction.

Conclusions: Patients carrying at least one CYP2C19*2 allele are more prone to high-on clopidogrel platelet reactivity, which is associated with poor clinical outcome after coronary stent placement (Effect of Clopidogrel Loading and Risk of PCI [EXCELSIOR]; NCT00457236).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Angioplasty, Balloon, Coronary / adverse effects*
  • Angioplasty, Balloon, Coronary / mortality
  • Aryl Hydrocarbon Hydroxylases / genetics*
  • Clopidogrel
  • Cytochrome P-450 CYP2C19
  • Drug-Eluting Stents / adverse effects
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mixed Function Oxygenases / genetics*
  • Myocardial Infarction / etiology
  • Myocardial Infarction / mortality
  • Platelet Aggregation / drug effects*
  • Platelet Aggregation Inhibitors / pharmacology*
  • Platelet Aggregation Inhibitors / therapeutic use
  • Polymorphism, Genetic*
  • Ticlopidine / analogs & derivatives*
  • Ticlopidine / pharmacology
  • Ticlopidine / therapeutic use
  • Treatment Outcome


  • Platelet Aggregation Inhibitors
  • Clopidogrel
  • Mixed Function Oxygenases
  • Aryl Hydrocarbon Hydroxylases
  • CYP2C19 protein, human
  • Cytochrome P-450 CYP2C19
  • Ticlopidine

Associated data