The effect of the *2 allele on cardiovascular outcomes in patients with coronary artery stenting: a prospective study.

Introduction: The aim of the study was to evaluate the effects of cytochrome P450 2C19*2 (*2) on ischemic and bleeding events in the Chinese Han population.

Material And Methods: Patients after coronary artery stenting were enrolled for genotyping *2. Platelet reactivity 4 weeks after stent implantation was compared between different genotype groups. Ischemic and bleeding events were compared after 6 months' follow-up.

Results: A total of 255 patients were enrolled and 57.7% and 42.3% of patients presented with stable angina and acute coronary syndrome, respectively. The prevalence of homozygous (AA) and heterozygous (GA) *2 variants was 3.5% and 24.7% respectively, and the prevalence of wild type (GG) was 71.8%. Compared to GG and GA genotype groups, the absolute platelet activity reduction was significantly lower in AA genotype (GG 43.6 ±7.8%, GA 31.9 ±6.5%, and AA 24.8 ±5.3%, < 0.01 for trend). After 6 months' follow-up, 3.3%, 4.8% and 11.1% of patients experienced ischemic events in GG, GA and AA genotype groups, respectively ( = 0.003 for trend). After adjusting for traditional risk factors, AA genotype was significantly associated with ischemic events, with hazard ratio 1.19 and 95% confidence interval 1.08-1.30 ( = 0.013). Also, 2.2%, 1.6% and 0% of patients experienced bleeding events in GG, GA and AA genotype groups ( = 0.153 for trend). No independent association of *2 genotype and bleeding events was observed.

Conclusions: Genotyping of *2 may be useful to guide antiplatelet treatment in the Chinese Han population. Randomized controlled trials are warranted to investigate whether genotype-guided antiplatelet treatment could reduce ischemic events.