Relationship between cytochrome P450 2C19*17 genotype distribution, platelet aggregation and bleeding risk in patients with blood stasis syndrome of coronary artery disease treated with clopidogrel.

OBJECTIVE: To assess the impact of cytochrome P450 (CYP) 2C19*17 allelic variant on platelet aggregation and bleeding risk in Chinese patients with blood stasis syndrome undergoing percutaneous coronary intervention (PCI) and treated with clopidogrel.

METHODS: A total of 520 patients with blood stasis syndrome undergoing PCI after pretreatment with 300 mg clopidogrel and aspirin were studied from July 2009 to April 2011 in Fujian Provincial Institute of Cardiovascular Diseases. CYP2C19*17 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. Platelet aggregation induced by 5μmol/L of adenosine diphosphate (ADP) was analyzed with platelet-rich plasma and platelet-poor plasma by turbidimetry method before and after 10 d of treatment with clopidogrel.

RESULTS: Bleeding events were observed in 5.96% of patients after thrombolysis for myocardial infarction, and the ratio of patients with CYP2C19*17 allele was 7.98%. The bleeding rate in patients carrying CYP2C19*17 allele, heterozygous (wt/*17) and homozygous (*17/*17), was higher than that in patients with wild-type homozygotes (wt/wt) (P<0.01). At baseline, ADP-induced light transmission at maximal aggregation, 5-min aggregation and disaggregation showed no significant difference among patients with the three different CYP2C19*17 genotypes. However, after 10-day administration of clopidogrel, values of ADP-induced platelet aggregation in *17/*17 and wt/*17 carriers were significantly decreased compared with the wild-type homozygotes (P<0.05, P<0.01); the inhibition rate of platelet aggregation was higher in patients carrying *17/*17 and wt/*17 than those only carrying wt/wt, and the same result was found in disaggregation of platelet after 10-day treatment (P<0.05, P<0.01). Patients with wt/*17 and *17/*17 allele of CYP2C19 showed a higher risk of bleeding than those with wild-type allele (P<0.01), and the occurrence of bleeding was highest in patients with CYP2C19*17 homozygotes.

CONCLUSION: CYP2C19*17 allele is associated with enhanced response to clopidogrel and an increased risk of bleeding in patients with blood stasis syndrome of coronary artery disease treated by clopidogrel.