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

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 Dietmar Trenk, Willibald Hochholzer, Martin F. Fromm, Ligia-Emilia Chialda, Andreas Pahl, Christian M. Valina, Christian Stratz, Peter Schmiebusch, Hans-Peter Bestehorn, Heinz Joachim Büttner, Franz-Josef Neumann In 797 consecutive patients undergoing elective coronary stent placement (percutaneous coronary intervention), we investigated the impact of the loss of function CYP2C19 681G>A 2 polymorphism on the antiplatelet effect of clopidogrel. Between 2 carriers (n = 245) and wild-type homozygotes (n = 552) we found significant (p < 0.001) differences in the proportion of patients with residual platelet aggregation induced by adenosine diphosphate 5 μmol/l (residual platelet aggregation) >14%, both after loading with 600 mg (62.4% vs. 43.3%) and after maintenance dosing 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.