CYP2C19*2 Allele Carrier Status and Coronary In-stent Restenosis: is There an Association?

Background and objective: The CYP2C19*2 allele is associated with reduced clopidogrel bioactivation, increasing the risk of complications after percutaneous coronary intervention (PCI), particularly stent thrombosis.Recently published data suggests that CYP2C19*2 allele carriers have a higher risk for in-stent restenosis (ISR) after endovascular treatment.Very few studies have investigated the relationship between CYP2C19*2 and coronary ISR, with no significant association reported.The objective of this study was to assess the relationship between CYP2C19*2 allele carrier status and coronary ISR.Methods: Patients with previous PCI with stenting and who were scheduled for elective PCI after coronary angiogram were recruited from the cardiac catheterization suite over a 12-month period.The angiography report of each patient was perused to identify patients requiring PCI due to ISR.For patients with angiography-confirmed ISR, date of previous PCI to the restenosed stent was noted.CYP2C19*2 genotyping was undertaken using a TaqMan ® Drug Metabolism assay.The association between CYP2C19*2 allele carrier status and incidence of coronary ISR within 1 year was assessed using Fisher's exact test (p < 0.05 significance) and by calculating the odds ratio (OR) with a 95% confidence interval (CI). Results:Of the 82 patients with previous PCI, 29 (35.4%) had angiography-confirmed ISR (12 carriers, 17 noncarriers of CYP2C19*2).In 13 (44.8%) of these patients, the restenosed stent was deployed within 1 year and the patients were on clopidogrel therapy at the time of repeat PCI (8 carriers, 5 non-carriers of CYP2C19*2).The association between CYP2C19*2 allele carrier status and ISR within 1 year was not statistically significant (Fisher's exact p = 0.067; OR: 4.80, 95% CI: 0.98-23.54,p = 0.053).Conclusions: Despite a higher proportion of CYP2C19*2 allele carriers exhibiting ISR within 1 year compared to non-carriers, the association was not statistically significant.This result may be attributed to the small sample size, and larger prospective studies are recommended to further assess this association.