Effect of cytochrome P450 2C19 polymorphism on adverse cardiovascular events after drug-eluting stent implantation in a large Hakka population with acute coronary syndrome receiving clopidogrel in southern China

Effect of loss-of-function CYP2C19 variants on clinical outcomes in coronary artery disease patients treated with clopidogrel: A systematic meta-analysis approach

For many years, clopidogrel has been a commonly utilised antiplatelet drug in the management of coronary artery disease (CAD). It's thought that the CYP2C19 loss of function (LoF) polymorphism causes clopidogrel's poor metabolism, which eventually leads to resistance. Previous research produced extremely divergent and inconsistent results, making it impossible to draw definitive conclusions. Therefore, current, investigation was carried out to obtain definitive evidence from an updated meta-analysis on the connection between CYP2C19 LoF polymorphism and coronary artery event in patients treated with clopidogrel. 52,542 individuals with coronary artery disease who were receiving clopidogrel treatment were included in 87 carefully chosen trials from reliable databases that we used for our meta-analysis. According to our data, those who carry one or more CYP2C19 LoF alleles worldwide are much more likely to experience composite events and coronary artery events than people who do not carry these alleles, especially in Asian populations. Our meta-analysis observed that the global population, particularly Asians receiving clopidogrel treatment, is at risk of recurrent coronary artery events and composite events if they carry the CYP2C19 LoF alleles. Additional research is essential on alternative antiplatelet therapies for individuals who exhibit poor or intermediate metabolic activity. OBJECTIVES: 1.To systematically analyze the current evidence regarding the association of CYP2C19 variants with coronary artery disease (CAD). 2.To conduct a meta-analysis to investigate the association between loss of function (LoF) CYP2C19 modifications and CAD.

The polygenic implication of clopidogrel responsiveness: Insights from platelet reactivity analysis and next-generation sequencing

Clopidogrel is widely used worldwide as an antiplatelet therapy in patients with acute coronary disease. Genetic factors influence interindividual variability in response. Some studies have explored the polygenic contributions in the drug response, generating pharmacogenomic risk scores (PgxPRS). Importantly, these factors are less explored in underrepresented populations, such as Latin-American countries. Identifying patients at risk of high-on-treatment platelet reactivity (HTPR) is highly valuable in translational medicine. In this study we used a custom next-generation sequencing (NGS) panel composed of 91 single nucleotide polymorphisms (SNPs) and 28 genes related to clopidogrel metabolism, to analyze 70 patients with platelet reactivity values, assessed through closure time (CT). Our results demonstrated the association of SNPs with HTPR and non-HTPR, revealing the strongest associations with rs2286823 (OR: 5,0; 95% CI: 1,02-24,48; p: 0,03), rs2032582 (OR: 4,41; 95% CI: 1,20-16,12; p: 0,019), and rs1045642 (OR: 3,38; 95% CI: 0,96-11,9; p: 0,05). Bivariate regression analysis demonstrated the significant association of several SNPs with the CT value, a "surrogate" biomarker of clopidogrel response. Exploratory results from the LASSO regression model showed a high discriminatory capacity between HTPR and non-HTPR patients (AUC: 0,955), and the generated PgxPRS demonstrated a significant negative association between the risk score, CT value, and the condition of HTPR and non-HTPR. To our knowledge, our study addresses for the first time the analysis of the polygenic contribution in platelet reactivity using NGS and establishes PgxPRS derived from the LASSO model. Our results demonstrate the polygenic implication of clopidogrel response and offer insights applicable to the translational medicine of antiplatelet therapy in an understudied population.

Cilostazol plus Aspirin vs. Clopidogrel plus Aspirin in Acute Minor Stroke or Transient Ischemic Attack

AIM

This study compared the effectiveness, safety, and mortality risks between cilostazol plus aspirin and clopidogrel plus aspirin treatment for patients with acute minor ischemic stroke or transient ischemic attack (TIA).

METHODS

This retrospective cohort study employed a new-user design and utilized data from the nationwide Health and Welfare Database in Taiwan. Patients were included if they were discharged with newly initiated cilostazol plus aspirin or clopidogrel plus aspirin after primary acute minor ischemic stroke or TIA hospitalization between 2009 and 2018. Inverse probability of treatment weighting was applied to balance covariats between study groups. Effectiveness outcomes were the risks of acute ischemic stroke, acute myocardial infarction (AMI), TIA, and composite cardiovascular events; Safety outcomes were the risks of intracranial hemorrhage (ICH), gastrointestinal bleeding, and composite bleeding events; Mortality outcomes were the risks of fatal stroke, cardiovascular mortality, and all-cause mortality.

RESULTS

A total of 3,403 patients were included, of which 578 were treated with cilostazol plus aspirin and 2,825 were treated with clopidogrel plus aspirin. Cilostazol plus aspirin was associated with a higher risk of ICH (HR: 1.82; 95% CI: 1.16-2.84) compared to clopidogrel plus aspirin. No significant differences in the risks of effectiveness or mortality outcomes between the two groups were found.

CONCLUSIONS

The effectiveness and mortality of the two groups were similar for patients with acute minor ischemic stroke or TIA. However, cilostazol plus aspirin was associated with a higher risk of ICH compared to clopidogrel plus aspirin. Patients treated with cilostazol plus aspirin among this population should be monitored carefully to ensure their safety.

The Association between CYP2C19 Genetic Polymorphism and Prognosis in Patients Receiving Endovascular Therapy

Background

Potentially substantial impacts on the prognosis have been observed in individuals undergoing endovascular treatment due to cytochrome P450 2c19 (CYP2C19) polymorphism. In an attempt to improve prognosis and lower the recurrence rate, this study investigated the CYP2C19 polymorphism in acute ischemic stroke patients.

Materials and Methods

A retrospective analysis was performed on 292 patients with cerebral infarction who had acute endovascular recanalization at the Department of Neurology of Chongqing Hospital of Traditional Chinese Medicine between May 2017 and 2019. The patients were categorized into rapid-, medium-, and slow-metabolism groups based on CYP2C19 gene polymorphism, and their prognosis was monitored. In addition, the prognosis of 188 patients selectively receiving carotid artery stenting at a selected time was also observed.

Results

Among the 292 cerebral infarction cases receiving acute endovascular recanalization, the patients in the CYP2C19 rapid-metabolism group regularly took clopidogrel and aspirin combined with antiplatelet therapy and suffered from reoccurrence of apoplexy and cerebral hemorrhage; the 90-day good prognosis had a statistical difference (P < 0.05, prognostic assessment includes hospitalization and 6 months after discharge) and the other adverse events had no statistical difference (including mortality). The 188 patients selectively receiving carotid artery stenting had a recurrence of apoplexy, cerebral hemorrhage, and restenosis rate with a statistical difference (P < 0.05), and the other adverse events had no statistical difference.

Conclusions

In conclusion, the findings of the current study indicate that irrespective of whether patients are undergoing selective carotid artery stenting or acute endovascular recanalization, those with rapid CYP2C19 metabolism have a significantly lower likelihood of experiencing adverse prognostic events compared to those with intermediate and slow metabolism. Furthermore, this group also has a more favorable prognosis than the other two groups.

Ticagrelor vs Clopidogrel in Acute Myocardial Infarction Patients With a History of Ischemic Stroke

OBJECTIVE

To investigate whether use of ticagrelor compared to clopidogrel is associated with different risks for thrombotic events or major bleeding among acute myocardial infarction (AMI) patients with a prior history of acute ischemic stroke.

PATIENTS AND METHODS

This retrospective cohort study used the Health and Welfare Database in Taiwan. Stroke patients prescribed ticagrelor plus aspirin or clopidogrel plus aspirin after a primary hospitalization for AMI between July 1, 2013, and December 31, 2018, were included. Inverse probability of treatment weighting was applied to balance covariates between treatment groups. The primary effectiveness outcome included a composite measure of AMI, acute ischemic stroke, or all-cause mortality. The primary safety outcome included a composite measure of intracranial hemorrhage (ICH) and major gastrointestinal bleeding. The secondary effectiveness and safety outcomes comprised each of the individual components that make up the primary effectiveness and safety outcomes, respectively.

RESULTS

A total of 1691 eligible patients were included in the study, of whom 734 (43.4%) received ticagrelor plus aspirin and 957 received clopidogrel plus aspirin. There were no significant differences observed in the primary and secondary effectiveness outcomes between the two study groups. However, the use of ticagrelor was associated with a higher risk of ICH (ticagrelor: 8.68 per 1000 person-year; clopidogrel: 2.17 per 1,000 person-year; HR, 3.34; 95% CI, 1.27 to 8.81, P = .01) compared with clopidogrel.

CONCLUSION

In AMI patients with a history of acute ischemic stroke, the risks of cardiovascular events were comparable between ticagrelor plus aspirin and clopidogrel plus aspirin. However, ticagrelor was associated with a higher risk of ICH. Ticagrelor should be used cautiously in AMI patients with a history of acute ischemic stroke.

Dosage optimization of clopidogrel via a precision medicine approach: the way forward

Clopidogrel is a prodrug chiefly metabolized by the hepatic isoenzyme CYP2C19 to its active metabolite that inhibits the platelet aggregation. It has been proven in many populations that the genetic polymorphism of CYP2C19 has influence on the pharmacokinetic and or pharmacodynamics of this drug and resulting in high inter-individual variability in the treatment outcomes. As CYP2C19 genetic polymorphism is highly prevalent among the Asian population, the influence of the same on the pharmacokinetics and; thereby, the pharmacodynamics of clopidogrel needs more attention. Using the pharmacogenetic information for drug therapy could help overcome these issues and to optimize the dosage regimen of clopidogrel, this review advocates the precision medicine approach for reducing the clopidogrel resistance and adverse cardiovascular events.

Associations of Gene Polymorphisms and Prognosis in Highly Adherent to Treatment Patients After Myocardial Infarction

Aim. To evaluate the influence of genetic factors on the risk of developing a combined endpoint, during a one-year supervision of patients, who had myocardial infarction and highly adherent to drug therapy.

Material and methods. The research included 250 patients with high adherence to treatment with myocardial infarction, using the method of polymerase chain reaction we determined the polymorphisms Thr174Met and Met235Thr in the AGT gene, Arg389Gly and Ser49Gly in the ADRB1 gene, Ser447Ter in the LPL gene and Leu28Pro in the APOE gene, Trp212Ter and G681A in the CYP2C19 gene, and then we evaluated their influence on the prognosis.

Results. A significant influence on the risk of developing combined endpoint was noticed for the polymorphism of CYP2C19 (G681A) gene. For the GA genotype of the CYP2C19 gene (G6881A), the OR of developing an unsuccessful outcome was 1.97 (95 % CI 1.05 — 3.69) (P = 0.03). For сarrier-state of A allele the OR was 1.46 (95 % CI 1.06 — 3.64) (P = 0.03).

 Conclusion. The results received indicate the need for individual approach for the choice of drugs from the group of inhibitors P2Y12-receptors for dual antiplatelet therapy, and if clopidogrel is chosen it is necessary to resolve the issue of pharmacogenetic testing for CYP2C19.

Risk of stroke in CYP2C19 LoF polymorphism carrier coronary artery disease patients undergoing clopidogrel therapy: An ethnicity-based updated meta-analysis

BACKGROUND

Antiplatelet agent clopidogrel has been widely used for stroke management for many years, although resistance to clopidogrel may increase the chance of stroke recurrence. CYP2C19 loss-of-function (LoF) polymorphism is assumed to be responsible for the poor metabolism of clopidogrel that ultimately turns to resistance. Previous publications could not provide firm evidence due to highly conflicting and heterogeneous outcomes.

AIM

To get clear evidence from an updated meta-analysis on CYP2C19 LoF polymorphism association with stroke risk in clopidogrel treated patients, this study has been performed.

METHODS

We conducted a meta-analysis with 72 selected studies from authentic databases, including 40,035 coronary artery disease patients treated with clopidogrel.

RESULTS

This analysis showed that the worldwide carrier of one or more CYP2C19 LoF alleles had a significantly higher risk of stroke and composite events than the non-LoF carriers (RR=1.78, 95% CI=1.52-2.07, p<0.00001 and RR=1.39, 95% CI=1.26-1.54, p<0.00001, respectively). Besides, subgroup analysis showed that Asian CYP2C19 LoF carriers had a significantly increased risk of stroke (RR=1.91, 95% CI=1.60-2.28, p<0.00001) while the risk of composite events was significantly higher in all ethnic populations (Asian: RR=1.58, 95% CI=1.32-1.89, p<0.00001; Caucasian: RR=1.27, 95% CI=1.08-1.50, p=0.003; Hispanic and others: RR=1.21, 95% CI=1.09-1.34, p=0.0003).

CONCLUSION

Our meta-analysis confirmed that the presence of CYP2C19 LoF alleles increases the risk of stroke and composite events recurrence in the worldwide population, especially in Asians undergoing clopidogrel treatment. Alternative antiplatelet therapy should be investigated thoroughly for the intermediate and poor metabolizers.

Association between CYP2C19 polymorphisms and clinical outcomes in patients undergoing stent procedure for cerebral artery stenosis

We investigated the effect of CYP2C19 polymorphisms on the clinical outcomes of clopidogrel therapy in patients after stenting procedure for cerebral artery stenosis in northeast China. 568 patients performed CYP2C19 genotype screening in the neurosurgery department of our hospital; 154 patients were finally recruited according to the inclusion and exclusion criteria, and followed-up for 6 months. Ischemic events including (1) transient ischemic attack (TIA); (2) stent thrombosis; (3) ischemic stroke; and (4) death were defined as primary clinical endpoints. The frequencies of CYP2C19*1, *2 and *3 alleles in 568 patients were 63.1%, 31.1% and 5.8%, respectively. 154 patients were classified into extensive (65 patients; 42.2%), intermediate (66 patients; 42.9%), and poor (23 patients; 14.9%) metabolizer groups. A χ2 test showed a significant difference in primary clinical endpoints at 6 months (P = 0.04), and a multivariate Cox regression analysis indicated that the CYP2C19 loss-of-function (LOF) alleles associated with post-procedure prognosis. The Kaplan-Meier curve revealed that there was no significant difference in ischemic events between *2 and *3 alleles carriers. Our study verifies that CYP2C19 *2 and *3 have significant impact on the clinical outcomes of clopidogrel therapy in patients with stenting procedure for cerebral artery stenosis in China.

Functional genetic variations of CYP2C19 promoter from patients with gastroesophageal reflux disease

BACKGROUND

Gastroesophageal reflux disease (GERD) is a chronic, progressive condition, and its prevalence is increasing worldwide. The risk factors for GERD are complex and the pathogenesis of GERD has not been fully elucidated. As acid-suppressive drugs, proton pump inhibitors (PPIs) are commonly used to treat GERD; after being metabolized by CYP2C19 in the human liver, the blood concentration of PPIs gradually decreases. Previous studies have shown that CYP2C19 gene polymorphism leads to considerable individual differences of PPIs in terms of metabolic rate and efficacy.

AIM

To identify potential variations in CYP2C19 promoter from patients (normal metabolizers, NMs, *1/*1) with GERD, verify the activity of promoter with variations in HEK 293T, and analyze the correlation between variations in CYP2C19 promoter and PPI treatment effect for GERD in the Chinese population.

METHODS

A total of 163 patients with sporadic GERD were collected. After diagnostic treatment with PPIs, the symptom score decreased by 50%, but the symptoms did not completely disappear in the study group (n = 82). In the control group (n = 81), the symptoms completely disappeared after treatment. The CYP2C19 genotype of all patients was detected as *1/*1. The PCR and Sanger sequencing were used to identify variations in the CYP2C19 promoter. The luciferase activities of pGL3 basic-CYP2C19 promoters with or without variation were detected by dual-luciferase assay.

RESULTS

Three novel heterozygous variations were identified in the CYP2C19 gene promoters isolated from three NM patients with GERD: g.94761364 T>A, g.94762112 T>A, and g.94762514 G>T. Compared to the wild type, the transcriptional activity of the CYP2C19 promoter with g.94761364 T>A was significantly increased (P = 0.034).

CONCLUSION

The transcriptional activity of the CYP2C19 promoter is significantly increased in the presence of g.94761364 T>A, which may further affect the metabolism and blood concentration of PPIs. This finding provides a new insight for the medication and treatment of GERD patients in the Chinese population.

Association of FMO3 rs1736557 polymorphism with clopidogrel response in Chinese patients with coronary artery disease

PURPOSE

Dual antiplatelet therapy with aspirin and clopidogrel is commonly used for coronary artery disease (CAD) patients undergoing percutaneous coronary intervention to prevent stent thrombosis and ischemic events. However, some patients show high on-treatment platelet reactivity (HTPR) during clopidogrel therapy. Genetic factors such as loss-of-function variants of CYP2C19 are validated to increase the risk of HTPR. Flavin-containing monooxygenase 3 (FMO3) is reported to be associated with potency of platelet responsiveness and thrombosis. This study aimed to explore the association between FMO3 rs1736557 polymorphism and clopidogrel response.

METHODS

Five hundred twenty-two Chinese CAD patients treated with dual antiplatelet therapy were recruited from Xiangya Hospital. After oral administration of 300 mg loading dose (LD) clopidogrel for 12-24 h or 75 mg daily maintenance dose (MD) clopidogrel for at least 5 days, the platelet reaction index (PRI) was determined by vasodilator-stimulated phosphoprotein-phosphorylation assay. FMO3 rs1736557, CYP2C19*2, and CYP2C19*3 polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Mean PRI value was significantly higher in CYP2C19 poor metabolizers (PMs) and intermediate metabolizers (IMs) than the extensive metabolizers (EMs) (p < 0.001). In addition, FMO3 rs1736557 AA homozygotes showed significantly lower PRI as compared with carriers of the major rs1736557 G allele in the entire cohort and in the MD cohort (p = 0.011, p = 0.008, respectively). The risk of HTPR was decreased significantly in carriers of the rs1736557 A allele (AA vs GG: OR = 0.316, 95% CI: 0.137-0.726, p = 0.005; AA vs GA: OR = 0.249, 95% CI: 0.104-0.597, p = 0.001; AA vs GG+GA: OR = 0.294, 95% CI: 0.129-0.669, p = 0.002), and the association was observed mainly in patients carrying the CYP2C19 LOF allele and in those administered with MD.

CONCLUSION

The FMO3 rs1736557 AA genotype was related to an increased the antiplatelet potency of clopidogrel in Chinese CAD patients. Additional studies are required to verify this finding.

The impact of cytochrome 450 and Paraoxonase polymorphisms on clopidogrel resistance and major adverse cardiac events in coronary heart disease patients after percutaneous coronary intervention

Background

Clopidogrel is an inactive prodrug, it catalyzed into its active form by Cytochrome 450 and Paraoxonase-1(PON-1). polymorphisms of genes encoding these enzymes will affect the efficacy of Clopidogrel. The main objective of our study was to investigate the association of CYP2C19*2, CYP2C19*3 and PON-1Q192R polymorphisms with Clopidogrel resistance and major adverse cardiac events in Jin Hua district in the middle of Zhe Jiang Province in China.

Methods

One hundred sixty coronary heart disease patients with percutaneous coronary intervention, who were followed-up for 1 year, were enrolled in our study. These patients were co-administered aspirin 100 mg/d and clopidogrel 75 mg/d following a loading dose of 300 mg. The ADP-induced platelet aggregation rate was measured by Platelet aggregator. Genotypes of CYP2C19*2, CYP2C19*3, PON-1Q192R were determined using Sanger sequencing in all patients. Various clinical data were collected.

Results

The frequencies of CYP2C19*2, CYP2C19*3 and PON-1Q192R homozygous mutant genotypes were significantly lower in non-responders than those in responders. After for all variables, CYP2C19*2, CYP2C19*3 and PON-1Q192R independently increased the risk of clopidogrel resistance with adjusted ORs 46.65(95% CI,1.77–25.04; p = 0.005); 22.74(95% CI, 3.11–166.27; p = 0.002); 5.69 (95% CI,1.06–30.47; p = 0.042). Over a follow-up of 12 months, the incidence of major adverse cardiac events (MACE) in CYP2C19*1/*2, *1/*3, *2/*2, *2/*3 was significantly higher than no mutant genotype (18/40vs.2/63,3/9vs.2/63, 11/6vs.2/63, 7/1vs2/63, respectively). There was no significant correlation between PON-1Q192R mutant allele and MACE.

Conclusion

Our study was first time to report on CYP2C19 and PON-1 polymorphisms in Jin Hua population in the middle of Zhe Jiang province in China. The carriage of CYP2C19*2 or *3 mutant allele significantly reduced the platelet response to clopidogrel and increase the MACE. The carriage of PON-1 mutant allele also significantly reduced the platelet response to clopidogrel, but would not increase the major adverse cardiac events after 1 year follow-up.

Trial registration

ChiCTR, ChiCTR1800018316. Registered 11 September 2018 – prospective registered, http://www.chictr.org.cn/edit.aspx?pid=30927&htm=4.

The effect of the CYP2C19*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 (CYP2C19*2) on ischemic and bleeding events in the Chinese Han population.

MATERIAL AND METHODS

Patients after coronary artery stenting were enrolled for genotyping CYP2C19*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) CYP2C19*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%, p < 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 (p = 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 (p = 0.013). Also, 2.2%, 1.6% and 0% of patients experienced bleeding events in GG, GA and AA genotype groups (p = 0.153 for trend). No independent association of CYP2C19*2 genotype and bleeding events was observed.

CONCLUSIONS

Genotyping of CYP2C19*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.

Association of N6AMT1 rs2254638 Polymorphism With Clopidogrel Response in Chinese Patients With Coronary Artery Disease

Dual antiplatelet treatment with aspirin and clopidogrel is the standard therapy for patients undergoing percutaneous coronary intervention (PCI). However, a portion of patients suffer from clopidogrel resistance (CR) and consequently with recurrence of cardiovascular events. Genetic factors such as loss-of-function variants of CYP2C19 contribute a lot to CR. Recently, the N-6-adenine-specific DNA methyltransferase 1 (N6AMT1) rs2254638 polymorphism is reported to be associated with clopidogrel response. To validate the association between N6AMT1 rs2254638 polymorphism and clopidogrel response, 435 Chinese CAD patients receiving aspirin and clopidogrel were recruited. N6AMT1 rs2254638 and CYP2C19^*2/^*3 polymorphisms were genotyped. Platelet reaction index (PRI) was measured by VASP-phosphorylation assay after treated with a 300 mg loading dose (LD) clopidogrel or 75 mg daily maintenance dose (MD) clopidogrel for at least 5 days. There was a significant difference in PRI between LD cohort and MD cohort. Carriers of CYP2C19^*2 allele showed significantly increased PRI in the entire cohort and in respective of the MD and LD cohorts (p < 0.001, p = 0.003, p < 0.001, respectively). However, carriers of CYP2C19^*3 allele exhibited significantly higher PRI only in the entire cohort and LD cohort (p = 0.023, p = 0.023 respectively). PRI value was significantly higher in CYP2C19 PM genotyped patients as compared with those carrying the IM genotypes and EM genotype (p < 0.001). Besides, carriers of the rs2254638 C allele showed significantly higher PRI in entire cohort and in the LD cohort (p = 0.023, p = 0.008, respectively). When the patients were grouped into clopidogrel resistance (CR) and non-clopidogrel resistance (non-CR) groups, CYP2C19^*2 was associated with increased risk of CR in the entire cohort, the LD cohort and the MD cohort (p < 0.001, p < 0.001, and p = 0.019, respectively). Carriers of the rs2254638 C allele also showed increased risk of CR in the entire cohort and the LD cohort (p = 0.024, and p = 0.028, respectively). N6AMT1 rs2254638 remained as a strong predictor for CR (TC vs. TT: OR = 1.880, 95% CI = 1.099–3.216,p = 0.021; CC vs. TT: OR = 1.930, 95% CI = 1.056-3.527, p = 0.032; TC + CC vs. TT: OR = 1.846, 95%CI = 1.126–3.026, p = 0.015) after adjustment for confounding factors. Our study confirmed the influence of CYP2C19^*2 and rs2254638 polymorphisms on clopidogrel resistance in Chinese CAD patients. Both CYP2C19^*2 and N6AMT1 rs2254638 polymorphism may serve as independent biomarkers to predict CR.