CYP2C19*2 genetic polymorphism and incidence of in-stent restenosis in patients on clopidogrel: A matched case-control study

OBJECTIVES The cytochrome P450 2C19*2 (CYP2C19*2) genetic polymorphism is associated with reduced clopidogrel bioactivation, increasing the risk of atherothrombotic complications after percutaneous coronary intervention (PCI). In-stent restenosis (ISR) is a complication that limits the long-term prognosis of PCI. The aim was to investigate the association between presence of the CYP2C19*2 allele and ISR within one-year after PCI in patients prescribed dual antiplatelet therapy with aspirin and clopidogrel. METHODS Sixty patients with angiographically-confirmed drug eluting stent (DES)-ISR within 12 months post-PCI when on DAPT with aspirin and clopidogrel were retrospectively identified (Cases). Another 60 patients with no documented ISR post-PCI in the study period (Controls) were case-matched for age, gender, ethnicity, diabetes mellitus and estimated glomerular filtration rate value, and were invited for CYP2C19*2 genotyping. The association between presence of the CYP2C19*2 allele and ISR was analysed using the Fisher's Exact test and binary logistic regression. RESULTS Twenty-six (43.3%) cases and 5 (8.3%) controls were carriers of one or two CYP2C19*2 alleles. As to non-carrier status of the CYP2C19*2 allele, 34 (56.7%) cases and 55 (91.7%) controls were identified. The association between CYP2C19*2 carrier status and DES-ISR within one-year post-PCI was statistically significant (p<0.001) in both the univariate and multivariate analysis. CONCLUSIONS The proportion of patients who were carriers of one or two CYP2C19*2 alleles who presented with DES-ISR within one-year post-PCI while on clopidogrel was significantly higher compared to patients with no documented ISR.