Clinical, angiographic, and genetic factors associated with early coronary stent thrombosis

Impact of CYP2C19 polymorphism testing on the risk of stent thrombosis in patients with carotid artery stenting

OBJECTIVE

We aimed to identify the impact of CYP2C19 polymorphism testing on clinical outcomes in patients who have undergone carotid artery stenting (CAS).

METHODS

This was a single-center retrospective cohort study. CYP2C19 polymorphisms were identified based on the presence of two normal functional alleles in normal metabolizers (NMs), a normal functional allele and a nonfunctional allele in intermediate metabolizers and two nonfunctional alleles in poor metabolizers. Patients were recommended for the CYP2C19 polymorphism testing followed by the change in dual antithrombotic drugs (DAPT) at the discretion of the supervising physician. The primary clinical endpoint was stent thrombosis (ST). Logistic regression was used to evaluate the relative risk of clinical outcomes.

RESULTS

A total of 273 patients were included. The relative risk of ST was not reduced in patients who underwent CYP2C19 polymorphism testing than in patients without this test (3.1% vs. 3.9%, OR = 0.914, 95% CI = 0.218-3.841). The ST in NMs and non-NMs was 3.4% and 2.9%, respectively, and showing no reduction in NMs (OR = 1.145, 95% CI = 0.162-8.105). Changing DAPT did not reduce the relative risk of ST compared with non-changing (2.3% vs. 3.2%, OR = 1.604, 95% CI = 0.024-107.033).

CONCLUSIONS

CYP2C19 polymorphism was not related to stent thrombosis in patients with CAS.

Epoxidase inhibitor-aspirin resistance and the relationship with genetic polymorphisms: a review

Strokes are the leading cause of death in most regions of the world. Epoxidase inhibitors include the drug aspirin (acetylsalicylic acid). Aspirin is widely used as first-line treatment for the prevention of cardiovascular and cerebrovascular diseases in at-risk patients. However, patients using conventional doses of aspirin can still develop ischaemic cardiovascular and cerebrovascular diseases, a phenomenon known as aspirin resistance. The occurrence of aspirin resistance hinders the prevention and treatment of ischaemic cardiovascular and cerebrovascular diseases. There are many factors affecting aspirin resistance, such as sex, drug dose, metabolic disease, genetic polymorphisms, drug interactions and pharmacokinetics. Genetic polymorphism refers to the simultaneous and frequent presence of two or more discontinuous variants or genotypes or alleles in a population of organisms. Platelets contain a large number of highly polymorphic transmembrane glycoprotein receptors encoded by two or more isomeric alleles. Changes in gene polymorphisms in various pathways during platelet aggregation can lead to aspirin resistance. This narrative review describes the gene polymorphisms that have been demonstrated to be significantly associated with aspirin resistance. Research on the mechanisms of aspirin resistance and increased knowledge should provide accurate drug guidance in individuals that require first-line antiplatelet therapy.

High platelet reactivity strongly predicts early stent thrombosis in patients with drug-eluting stent implantation

Stent thrombosis (ST) is a fatal complication after percutaneous coronary intervention (PCI). The association between P2Y12 reaction unit (PRU) level and stent thrombosis occurrence remains unclear. Based on the multicenter, observational PTRG-DES (Platelet function and genoType-Related long-term proGnosis in DES-treated patients) registry of patients with drug-eluting stents (DES) implantation, a total of 11,714 patients with PRU values were analyzed. We sought to identify the predictors of early stent thrombosis (EST) and compared the primary outcome, a composite of cardiac death, myocardial infarction, and revascularization, between EST and non-EST groups. EST, defined as definite ST within 1 month after index PCI, occurred in 51 patients. PRU values were significantly higher in the EST group (263.5 ± 70.8 vs. 217.5 ± 78.7, p < 0.001). In multivariable analysis, PRU ≥ 252 (OR, 5.10; 95% CI 1.58-16.46; p = 0.006) and aspirin reaction unit ≥ 414 (OR 4.85; 95% CI 1.07-21.97; p = 0.040) were independent predictors of EST. The cumulative incidence of primary composite outcome at one year was significantly higher in the EST group (38.2% vs. 3.9%, Log-rank p < 0.001). In patients treated with clopidogrel after successful DES implantation, EST was associated with higher platelet reactivities, and a greater risk of cardiovascular events.Trial Registration: clinicaltrials.gov Identifier: NCT04734028.

Shortened Duration of Dual Antiplatelet Therapy Following Percutaneous Coronary Intervention: A Contemporary Clinical Review

Percutaneous coronary intervention with stent implantation is an integral aspect of minimally interventional cardiac procedures. The technology and techniques behind stent design and implantation have evolved rapidly over several decades. However, continued discourse remains around optimal peri- and post-interventional management with dual antiplatelet therapy to minimise both major cardiovascular or cerebrovascular events and iatrogenic bleeding risk. Standard guidelines around dual antiplatelet therapy historically recommended long-term dual antiplatelet therapy for 12 months (with consideration for >12 months in certain patients); however, emerging data and generational improvements in the safety of drug-eluting stents have ushered in a new era of short-term therapy to reduce the incidence of major bleeding events. This case review will provide an overview of the current state of guidelines around duration of dual antiplatelet therapy and examine recent updates and continued gaps in existing research.

Association between Q192R PON1 genetic polymorphism and major adverse cardiovascular events in patients treated with clopidogrel: an updated meta-analysis

BACKGROUND

Clopidogrel's responsiveness may be affected by the paraoxonase-1 (PON1) enzyme encoded by the Q192R PON1 genetic variant. We aimed to determine the aggregated risk of MACEs associated with carrying Q192R PON1 genetic variant in patients taking clopidogrel.

RESEARCH DESIGN AND METHODS

Different databases were searched systematically for eligible studies, and risk ratio (RR) was measured using RevMan software where P <0.05 was set statistically significant.

RESULTS

Nineteen studies were included consisting of 17,815 patients. It was found that patients carrying either homozygous or a combination of heterozygous and homozygous variants were not significantly associated with increased risk of MACEs compared to the non-carriers (QQ vs. RR: RR=0.99, 95% CI 0.69-1.42, P=0.96; QQ+QR vs RR; RR=1.05, 95% CI 0.82-1.35, P=0.70). The risk of MACEs was also not significantly different in other genetic model (QQ vs QR+RR) (RR=1.09, 95% CI 0.93-1.27, P=0.30). Further, bleeding events were not significantly different in different genetic models (QQ vs RR; RR=1.13, 95% CI 0.58-2.21, P=0.71; QQ+QR vs RR; RR=1.09, 95% CI 0.66-1.81, P=0.73; QQ vs QR+RR; RR=1.08, 95% CI 0.76-1.55, P=0.66).

CONCLUSIONS

The results suggest that the Q192R PON1 genetic polymorphism has no significant impact on the risk of MACEs or bleeding events in patients treated with clopidogrel.

Genetic Backgrounds Associated With Stent Thrombosis: A Pilot Study From a Percutaneous Coronary Intervention Registry

Background

Stent thrombosis (ST) is a rare, yet devastating, complication following percutaneous coronary intervention (PCI), with poorly understood pathophysiologic characteristics and genetic backgrounds.

Objectives

The authors performed a genome-wide association study to identify the common genetic loci associated with early stent thrombosis (EST) and late/very late ST (LST/VLST) in a contemporary Japanese multicenter PCI registry.

Methods

Among 8,642 PCI patients included in the registry, 42 who experienced stent thrombosis [EST (n = 15) and LST/VLST (n = 27)] were included (mean age, 67.6 ± 10.8 years; and 88.1% men). We conducted a genome-wide association study using the BioBank Japan patient population as the control (control #1: acute coronary syndrome [n = 29,542] and control #2: effort angina [n = 8,900]) to identify significant single nucleotide polymorphisms (SNPs) and evaluate the performance of polygenic risk scores (PRSs) for predicting these conditions.

Results

We compared patients with EST with controls #1 and #2 and identified SNPs (rs565401593 and rs561634568) in NSD1, and patients with LST/VLST with controls #1 and #2 and identified SNPs (rs532623294 and rs199546342) in GRIN2A. PRS for LST/VLST showed high predictive performance (area under the curve 0.83 [95% CI: 0.76-0.89] and 0.83 [95% CI: 0.77-0.89]), whereas PRS for EST showed modest predictive performance (area under the curve 0.71 [95% CI: 0.58-0.85] and 0.72 [95% CI: 0.58-0.85]).

Conclusions

We identified different genetic predispositions between EST and LST/VLST and demonstrated that the incorporation of PRS may aid in risk prediction of this highly fatal event.

Intravascular Imaging for Guiding In-Stent Restenosis and Stent Thrombosis Therapy

Advances in stent technology and the design of endovascular devices with thinner struts, anti-inflammatory and antithrombotic polymers, and better drug kinetics have enhanced the safety and efficacy of the second-generation drug-eluting stents and broadened their use in the therapy of high-risk patients and complex anatomies. However, despite these developments, in-stent restenosis and stent thrombosis remain the Achilles' heel of percutaneous coronary intervention, with their cumulative incidence reaching up to 10% at 5 years following percutaneous coronary intervention. The treatment of stent failure poses challenges and is associated with a worse prognosis than conventional percutaneous coronary intervention. Several studies have recently highlighted the value of intravascular imaging in identifying causes of stent failure, underscored its role in treatment planning, and registries have shown that its use may be associated with better clinical outcomes. The present review aims to summarize the evidence in the field; it discusses the value of intravascular imaging in identifying the mechanisms of in-stent restenosis and stent thrombosis in assessing the morphological characteristics of neointima tissue that appears to determine long-term outcomes in evaluating procedural results, and presents the findings of studies supporting its value in guiding therapy in stent failure.

The DNAm levels of CREB5 (cg11301281) were associated with clopidogrel resistance

Purpose

Clopidogrel resistance (CR) is mostly caused by interindividual variability of the platelet inhibition of clopidogrel, which may induce cardiovascular events. The aim of this research was to evaluate whether DNAm levels of CREB5 (cg01534253) are involved in CR among acute coronary syndrome (ACS) patients treated with clopidogrel.

Methods

72 patients(36 CR and 36 non‐CR) who underwent ACS were included in this study. The VerifyNow P2Y12 assay was selected to evaluate residual platelet reactivity, and bisulfite pyrosequencing methods was used to examine DNA methylation levels on cg01534253. Secondly, CREB5 mRNA expression was analyzed via quantitative real‐time PCR. Last, we employed logistic regression to test the interaction between genetic factors of CREB5 methylation and multiple clinical variables in CR patients.

Results

Subunit analysis indicated that for patients whose HbA1c levels were ≥6.5% or whose GLU levels were ≥7 mmol/L, lower methylation of cg01534253 indicated a poorer clopidogrel response. In addition, CREB5 mRNA expression was increased in CR patients with GLU levels ≥7 mmol/L. Moreover, regression analysis indicated that the values of albumin and uric acid were correlated with the incidence of CR.

Conclusions

Our findings were likely to provide fresh understanding for the new mechanism of platelet inhibition failure and promote individualized antiplatelet therapy.

High On-Treatment Platelet Reactivity as Predictor of Long-term Clinical Outcomes in Stroke Patients with Antiplatelet Agents

The purpose was to explore the value of high on-treatment platelet reactivity (HTPR) in predicting long-term clinical outcomes for stroke patients. The platelet reactivity was assayed after being treated with either 75 mg clopidogrel or 100 mg aspirin daily with VerifyNow System in stroke patients. HTPR for clopidogrel was defined as PRU ≥ 208, and that for aspirin was defined as ARU ≥ 550. CYP2C19 genotyping was performed using the Sequenom MassARRAY iPLEX platform. The primary endpoint was a composite of recurrent ischemic stroke, transient ischemic attack, myocardial infarction, or ischemic vascular death. The safety endpoint was bleeding. In the clopidogrel group, among 345 patients recruited, 174 of them were categorized as HTPR. A total of 270 patients were followed up for 54 months. There was a significant association between HTPR and the primary endpoint (HR_adj 2.13 [95% CI, 1.43-3.15], p < 0.001). Among the 314 participants genotyped for CYP2C19, 187 (59.6%) were classified as CYP2C19 loss-of-function allele carriers. Patients with at least 1 loss-of-function allele were more likely to present with HTPR (OR_adj 2.61 [95%CI, 1.43-4.77], p = 0.008), and had a higher risk of the primary endpoint (HR_adj 2.05 [95% CI, 1.30, 3.25], p = 0.002). In the aspirin group, among 140 patients recruited, 28 of them were categorized as HTPR. A total of 121 patients were followed up for 30 months. Similarly, there was a significant association between HTPR and the primary endpoint (HR_adj 3.28 [95% CI, 1.52-7.71], p = 0.002). HTPR is an independent risk factor for ischemic events during long-term follow-up in stroke patients. Platelet function testing is helpful to evaluate the effect of antiplatelet therapy for stroke patients.

Next-Generation Sequencing of CYP2C19 in Stent Thrombosis: Implications for Clopidogrel Pharmacogenomics

PURPOSE

Describe CYP2C19 sequencing results in the largest series of clopidogrel-treated cases with stent thrombosis (ST), the closest clinical phenotype to clopidogrel resistance. Evaluate the impact of CYP2C19 genetic variation detected by next-generation sequencing (NGS) with comprehensive annotation and functional studies.

METHODS

Seventy ST cases on clopidogrel identified from the PLATO trial (n = 58) and Mayo Clinic biorepository (n = 12) were matched 1:1 with controls for age, race, sex, diabetes mellitus, presentation, and stent type. NGS was performed to cover the entire CYP2C19 gene. Assessment of exonic variants involved measuring in vitro protein expression levels. Intronic variants were evaluated for potential splicing motif variations.

RESULTS

Poor metabolizers (n = 4) and rare CYP2C19*8, CYP2C19*15, and CYP2C19*11 alleles were identified only in ST cases. CYP2C19*17 heterozygote carriers were observed more frequently in cases (n = 29) than controls (n = 18). Functional studies of CYP2C19 exonic variants (n = 11) revealed 3 cases and only 1 control carrying a deleterious variant as determined by in vitro protein expression studies. Greater intronic variation unique to ST cases (n = 169) compared with controls (n = 84) was observed with predictions revealing 13 allele candidates that may lead to a potential disruption of splicing and a loss-of-function effect of CYP2C19 in ST cases.

CONCLUSION

NGS detected CYP2C19 poor metabolizers and paradoxically greater number of so-called rapid metabolizers in ST cases. Rare deleterious exonic variation occurs in 4%, and potentially disruptive intronic alleles occur in 16% of ST cases. Additional studies are required to evaluate the role of these variants in platelet aggregation and clopidogrel metabolism.

Assessing the Risks of Bleeding vs Thrombotic Events in Patients at High Bleeding Risk After Coronary Stent Implantation: The ARC-High Bleeding Risk Trade-off Model

Importance

Patients who are candidates for percutaneous coronary intervention (PCI) and are at high bleeding risk constitute a therapeutic challenge because they often also face an increased risk of thrombotic complications.

Objectives

To develop and validate models to predict the risks of major bleeding (Bleeding Academic Research Consortium [BARC] types 3 to 5 bleeding) and myocardial infarction (MI) and/or stent thrombosis (ST) for individual patients at high bleeding risk and provide assistance in defining procedural strategy and antithrombotic regimens.

Design, Setting, and Participants

This prognostic study used individual patient data from 6 studies conducted from July 1, 2009, to September 5, 2017, for 6641 patients at more than 200 centers in Europe, the US, and Asia who underwent PCI and were identified as being at high bleeding risk using the Academic Research Consortium criteria. In 1 year of follow-up (excluding periprocedural events), individual patient risks of MI and/or ST and major bleeding were evaluated using 33 baseline variables. To validate these models, a subgroup of 1458 patients at high bleeding risk from the ONYX ONE trial were analyzed. Statistical analysis was performed from February 1, 2019, to April 30, 2020.

Exposures

All patients underwent PCI with bare metal, drug-coated, or drug-eluting stent implants.

Main Outcomes and Measures

Forward, stepwise multivariable proportional hazards models were used to identify highly significant predictors of MI and/or ST and BARC types 3 to 5 bleeding.

Results

A total of 6641 patients (4384 men [66.0%]; median age, 77.9 years [interquartile range, 70.0-82.6 years]) were included in this study. Over 365 days, nonperiprocedural MI and/or ST occurred in 350 patients (5.3%), and BARC types 3 to 5 bleeding occurred in 381 patients (5.7%). Eight independent baseline predictors of risk of MI and/or ST and 8 predictors for risk of BARC types 3 to 5 bleeding were identified. Four of these predictors were in both risk models. Both risk models showed moderate discrimination: C statistic = 0.69 for predicting MI and/or ST and 0.68 for predicting BARC types 3 to 5 bleeding. Applying these same models to the validation cohort gave a similar strength of discrimination (C statistic = 0.74 for both MI and/or ST and BARC types 3-5 bleeding). Patients with MI and/or ST had a mortality hazard ratio of 6.1 (95% CI, 4.8-7.7), and those with BARC types 3 to 5 bleeding had a mortality hazard ratio of 3.7 (95% CI, 2.9-4.8) compared with patients free of both events. Taking these data into account, the risk scores facilitate investigation of the individual patient trade-off between these 2 risks: 2931 patients (44.1%) at high bleeding risk in the 6 studies had a greater risk of MI and/or ST than of BARC 3 to 5 bleeding, 1555 patients (23.4%) had a greater risk of BARC 3 to 5 bleeding than of MI and/or ST, and 2155 (32.4%) had a comparable risk of both events.

Conclusions and Relevance

In a large cohort of patients at high bleeding risk undergoing PCI, 2 prognostic models have been developed to identify individual patients' risk of major coronary thrombotic and bleeding events. In future clinical practice, using an application on a smartphone to evaluate the trade-off between these 2 quantifiable risks for each patient may help clinicians choose the most appropriate revascularization strategy and tailor the duration and intensity of antithrombotic regimens.

Ischemic stroke and myocardial ischemia in clopidogrel users and the association with CYP2C19 loss-of-function homozygocity: a real-world study

Reduced clopidogrel effectiveness in preventing recurrent myocardial ischemia following percutaneous coronary intervention has been demonstrated in CYP2C19 loss-of-function carriers. Less is known about the effect of CYP2C19 genotype on the effectiveness of clopidogrel for stroke prevention, particularly in Caucasians. This is a retrospective cohort study, in which we used the Clalit clinical database to follow genotyped clopidogrel initiators, for up to 3 years. Endpoint was a new primary discharge diagnosis of ischemic stroke; secondary endpoints were new primary discharge diagnoses of coronary angioplasty, myocardial infarction (MI), or a composite endpoint of: stroke, MI, or coronary angioplasty. After 3 years of follow up over 628 clopidogrel initiators, 2 out of 12 (16.7%) poor metabolizers, 9 out of 144 intermediate metabolizers (6.3%), and 29 out of 472 (6.1%) normal/rapid/ultrarapid metabolizers have been newly diagnosed with ischemic stroke. Poor metabolizer status was associated with higher risk for ischemic stroke, marginally significant in univariate analysis and in multivariable models; and higher risk for the composite outcome of stroke, myocardial infarction and coronary angioplasty, HR = 3.32 (1.35-8.17) p = 0.009, 2.86 (1.16-7.06) p = 0.02 (univariate and multivariate analyses, respectively). Poor metabolizer status was associated with higher risk for stroke HR = 5.80 (1.33-25.24) p = 0.019, HR = 4.13 (0.94-18.13) p = 0.06 (univariate and multivariate analyses, respectively) in patients who "survived" the first year, and were in the cohort 1-3 years. Caucasian treated with clopidogrel who are homozygote for the CYP2C19 loss-of function allele might be at increased risk for ischemic stroke, and for the composite outcome of ischemic stroke, myocardial infarction and coronary angioplasty.

Toward Brief Dual Antiplatelet Therapy and P2Y12 Inhibitors for Monotherapy After PCI

The optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention remains a controversial topic. The European Society of Cardiology and the American College of Cardiology/American Heart Association recommend at least 6 and 12 months of DAPT after PCI in patients with stable coronary artery disease or acute coronary syndrome, respectively. Although prolonging DAPT duration reduces ischemic events, it is associated with higher rates of bleeding and possible fatal outcomes. The DAPT score can be an important tool to identify patients who may still benefit from prolonged therapy. Nevertheless, several recent randomized controlled trials showed that shortening DAPT duration from 12 to 1-3 months reduces bleeding rates without significantly increasing ischemic event rates. These trials also suggested replacing acetylsalicylic acid (aspirin) with P2Y12 inhibitors after short-term DAPT. We review and compare past and present studies regarding DAPT and analyze the evidence favoring a short DAPT duration and the long-term single antiplatelet agent of choice.

Drug-eluting stent thrombosis: current and future perspectives

Over the past 40 years, the safety and efficacy of percutaneous coronary intervention has dramatically improved by overcoming several challenges. The introduction of drug-eluting stent (DES) in particular was a major breakthrough in interventional cardiology. Compared to bare-metal stents, first-generation DES (G1-DES) has dramatically reduced the rates of in-stent restenosis and subsequent target lesion revascularization. However, major safety concerns surrounding stent thrombosis (ST) emerged with G1-DES in clinical practice as a result of the high incidences of death, myocardial infarction, and repeat revascularization associated with ST. To overcome these limitations, second-generation DES (G2-DES) has been developed with an improved stent platform with thinner strut and biocompatible durable or biodegradable polymers. Indeed, G2-DES, when compared with G1-DES, has improved clinical outcomes by reducing the risk of late thrombotic events while maintaining anti-restenotic efficacy, whereas ST still occurs, even with the use of G2-DES. This review gives an overview of pathophysiology, risk factors, and outcomes of ST after DES implantation. Additionally, we discuss the management and prevention of ST.

Bioresorbable Scaffolds: Contemporary Status and Future Directions

Percutaneous coronary intervention, which is safe, effective, and timely, has become an important treatment for coronary artery diseases and has been widely used in clinical practice. However, there are still some problems that urgently need to be solved. Permanent vessel caging through metallic implants not only prevents the process of positive vessel remodeling and the restoration of vascular physiology but also makes the future revascularization of target vessels more difficult. Bioresorbable scaffolds (BRSs) have been developed as a potential solution to avoid the above adverse reactions caused by permanent metallic devices. BRSs provide temporary support to the vessel wall in the short term and then gradually degrade over time to restore the natural state of coronary arteries. Nonetheless, long-term follow-up of large-scale trials has drawn considerable attention to the safety of BRSs, and the significantly increased risk of late scaffold thrombosis (ScT) limits its clinical application. In this review, we summarize the current status and clinical experiences of BRSs to understand the application prospects and limitations of these devices. In addition, we focus on ScT after implantation, as it is currently the primary drawback of BRS. We also analyze the causes of ScT and discuss improvements required to overcome this serious drawback and to move the field forward.

Comparison between MassARRAY and pyrosequencing for CYP2C19 and ABCB1 gene variants of clopidogrel efficiency genotyping

Clopidogrel is one of the most frequently used drugs in patients to reduce cardiovascular events. Since patients with different genetic variations respond quite differently to clopidogrel therapy, the related genetic testing plays a vital role in its dosage and genetic testing related to clopidogrel therapy is currently considered as routine test worldwide. In this study, we aim to use two different methods MALDI-TOF mass spectrometry and pyrosequencing to detect gene variant of CYP2C19 and ABCB1. Six single nucleotides polymorphisms (SNP) within CYP2C19 (*2, *3, *4, *5, *17) and ABCB1 C3435T in 458 Chinese Han patients were determined using both MassARRAY and Pyrosequencing. Sanger sequencing was used for verification. Results of both methods were analyzed and compared. Allele frequencies of each SNP and distribution of different genotypes were calculated based on the MassARRAY and Sanger sequencing results. Both methods provided 100% call rates for gene variants, while results of six samples were different with two methods. With Sanger sequencing as the reference results, MassARRAY generated all the same results. The minor allele frequencies of the above six SNPs were 27.1% (CYP2C19*), 5.9% (CYP2C19*3), 0% (CYP2C19*4), 0% (CYP2C19*5), 1.1% (CYP2C19*17), 40.9% (ABCB1), respectively. MassARRAY provides accurate clopidogrel related genotyping with relatively high cost-efficiency, throughput and short time when compared with pyrosequencing.

Association Between ABCB1 Polymorphisms and Outcomes of Clopidogrel Treatment in Patients With Minor Stroke or Transient Ischemic Attack: Secondary Analysis of a Randomized Clinical Trial

Importance

Genetic variants of ABCB1 may affect intestinal absorption of clopidogrel bisulfate. However, it is unclear whether ABCB1 polymorphisms are associated with clopidogrel efficacy for minor ischemic stroke or transient ischemic attack (TIA).

Objectives

To investigate the association between ABCB1 polymorphisms and clopidogrel efficacy for minor stroke or TIA.

Design, Setting, and Participants

In this prespecified secondary analysis of the Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events (CHANCE) randomized clinical trial, 3010 patients with minor stroke or TIA at 73 sites in China with experience in conducting genetic studies were included from October 1, 2009, to July 30, 2012. The analysis was conducted on March 20, 2018. Four single-nucleotide polymorphisms (ABCB1 -154T>C [rs4148727], ABCB1 3435C>T [rs1045642], CYP2C19*2 [681G>A, rs4244285], and CYP2C19*3 [636G>A, rs4986893]) were genotyped among 2836 patients treated with clopidogrel plus aspirin (n = 1414) or aspirin alone (n = 1422). The association of ABCB1 genetic variants (-154 TC/CC and 3435 CT/TT) with clopidogrel efficacy was evaluated in the context of CYP2C19 status, another gene associated with clopidogrel efficacy.

Interventions

Patients in the CHANCE trial were randomized to treatment with clopidogrel combined with aspirin or to aspirin alone.

Main Outcomes and Measures

Primary efficacy outcome was stroke recurrence after 3 months. The safety outcome was any bleeding risk after 3 months.

Results

Among 2836 patients, the median age was 61.8 years (interquartile range, 54.4-71.1 years) and 1887 patients (66.5%) were male. A total of 2146 (75.7%) patients were carriers of ABCB1 -154 TC/CC (570 [20.1%]) or 3435 CT/TT (1851 [65.3%]) genotype. Clopidogrel plus aspirin treatment was associated with reduced risk of new stroke in patients with ABCB1 -154 TT and 3435 CC genotype (hazard ratio [HR], 0.43; 95% CI, 0.26-0.71) but not in those with ABCB1 -154 TC/CC or 3435 CT/TT genotype (HR, 0.78; 95% CI, 0.60-1.03) compared with aspirin (P = .04 for interaction). A combined association of ABCB1 and CYP2C19 polymorphisms with new stroke was observed. The risk of bleeding for clopidogrel plus aspirin treatment was not associated with the ABCB1 genotypes (2.3% and 1.3% vs 1.9% and 2.2%; P = .25 for interaction in patients with or without ABCB1 -154 TC/CC or 3435 CT/TT genotype).

Conclusions and Relevance

The ABCB1 polymorphism was associated with the reduced efficacy of clopidogrel plus aspirin treatment compared with aspirin among patients with minor ischemic stroke or TIA. Genetic polymorphism of ABCB1 should be considered when prescribing clopidogrel for these patients.

Trial Registration

ClinicalTrials.gov identifier: NCT00979589.

Drug-drug-gene interactions and adverse drug reactions

The economic and health burden caused by adverse drug reactions has increased dramatically in the last few years. This is likely to be mediated by increasing polypharmacy, which increases the likelihood for drug–drug interactions. Tools utilized by healthcare practitioners to flag potential adverse drug reactions secondary to drug–drug interactions ignore individual genetic variation, which has the potential to markedly alter the severity of these interactions. To date there have been limited published studies on impact of genetic variation on drug–drug interactions. In this review, we establish a detailed classification for pharmacokinetic drug–drug–gene interactions, and give examples from the literature that support this approach. The increasing availability of real-world drug outcome data linked to genetic bioresources is likely to enable the discovery of previously unrecognized, clinically important drug–drug–gene interactions.

Association of GCK gene DNA methylation with the risk of clopidogrel resistance in acute coronary syndrome patients

Backgrounds

Clopidogrel resistance (CR), which was manifested as the failure of platelet inhibition in clopidogrel treatment, was likely to lead to cardiovascular events. Our study was aimed to explore the contribution of DNA methylation in glucokinase (GCK) to the CR risk.

Methods

Among 36 CR and 36 non‐CR acute coronary syndrome (ACS) patients, the platelet functions were evaluated by VerifyNow P2Y12 assay (turbidimetric‐based optical detection) and DNA methylation levels on two fragments of the CGI from the GCK were investigated through bisulfite pyrosequencing methods. In addition, the GCK mRNA expression was analyzed via quantitative real‐time PCR. Lastly, the logistic regression was employed to test the interaction between GCK methylation and nongenetic variables in CR patients.

Results

Subunit analysis showed that in male patients without DM but suffering from dyslipidemia, the increased methylation of cg18492943 indicated a risk of poor clopidogrel response (male, NCR vs CR(%): 84.86 ± 6.29 vs 88.16 ± 4.32, P = .032; without DM, NCR vs CR (%): 84.66 ± 6.18 vs 88.16 ± 4.17, P = .029; and dyslipidemia, NCR vs CR (%): 83.81 ± 6.96 vs 88.39 ± 4.74, P = .042).In addition, GCK mRNA expression was reduced in CR patients without DM. Moreover, regression analysis indicated that the values of platelet distribution width (PDW), total cholesterol (TC), and uric acid (UA) were correlated with the incidence of CR, and hypertension lowered the CR risk.

Conclusions

A higher methylation of cg18492943 in GCK gene would lower the expression of GCK mRNA, which might contribute to CR in patients without DM. Meanwhile, PDW and TC might be risk factors in CR.

Advances in the Pharmacogenomics of Antiplatelet Therapy

BACKGROUND

Acute coronary syndrome (ACS) is a highly thrombotic state, and a sustained antiplatelet effect is vital to the prevention of thrombotic complications. Clopidogrel, the most widely used oral P2Y12 receptor antagonist in ACS, has attracted considerable attention because of significant variability in antiplatelet effect depending on the presence of CYP2C19 allele. Other P2Y12 receptor antagonists offer sustained and more predictable antiplatelet effects than clopidogrel albeit at an increased cost. Several studies have demonstrated the promising application of pharmacogenetics in choosing personalized antiplatelet therapy using the point-of-care genotype assays.

AREAS OF UNCERTAINTY

Guidelines regarding the genotype-guided approach to the selection of antiplatelet therapy have been conflicting, and studies evaluating the effect of pharmacogenetic-guided selection of antiplatelet therapy on the outcomes have demonstrated mixed results.

DATA SOURCES

A literature search was conducted using MEDLINE and EMBASE for studies reporting the association of pharmacogenetic-guided selection of antiplatelet therapy and the outcomes in patients with ACS until December 2018.

RESULTS

Presence of specific CYP2C19 allele significantly influences clopidogrel metabolism and associated outcomes in patients with ACS. Thrombotic and bleeding complications are more common in patients with loss-of-function (LOF) and gain-of-function (GOF) alleles, respectively. Although the pharmacogenetic-guided approach to the selection of antiplatelet therapy appears promising in ACS, studies have shown conflicting results, and direct randomized evidence linking this approach with the better outcomes is lacking.

CONCLUSIONS

Genotype-guided selection of antiplatelet therapy is expected to be useful in patients undergoing percutaneous coronary intervention (PCI) with a high risk of adverse outcomes. The patient-physician discussion should be an essential part of this decision-making process. Large-scale multicenter randomized controlled trials using the point-of-care genotype assay are needed to investigate this approach further before its use can be recommended in all comers.

Incidence, angiographic and clinical predictors, and impact of stent thrombosis: a 6-year survey of 6,545 consecutive patients

Objective

We sought to determine the incidence, angiographic predictors, and impact of stent thrombosis (ST).

Background

Given the high mortality after ST, this study emphasises the importance of ongoing efforts to identify angiographic predictors of ST.

Methods

All consecutive patients with angiographically confirmed ST between 2010 and 2016 were 1:4 matched for (1) percutaneous coronary intervention (PCI) indication and (2) index date ±6 weeks to randomly selected controls. Index PCI angiograms were reassessed by two independent cardiologists. A multivariable conditional logistic regression model was built to identify independent predictors of ST.

Results

Of 6,545 consecutive patients undergoing PCI, 55 patients [0.84%, 95% confidence interval (CI) 0.63–1.10%] presented with definite ST. Multivariable logistic regression identified dual antiplatelet therapy (DAPT) non-use as the strongest predictor of ST (odds ratio (OR) 10.9, 95% CI 2.47–48.5, p < 0.001), followed by: stent underexpansion (OR 5.70, 95% CI 2.39–13.6, p < 0.001), lesion complexity B2/C (OR 4.32, 95% CI 1.43–13.1, p = 0.010), uncovered edge dissection (OR 4.16, 95% CI 1.47–11.8, p = 0.007), diabetes mellitus (OR 3.23, 95% CI 1.25–8.36, p = 0.016), and residual coronary artery disease at the stent edge (OR 3.02, 95% CI 1.02–8.92, p = 0.045). ST was associated with increased rates of mortality as analysed by Kaplan-Meier estimates (27.3 vs 11.3%, p_log-rank < 0.001) and adjusted Cox proportional-hazard regression (hazard ratio 2.29, 95% CI 1.03–5.10, p = 0.042).

Conclusions

ST remains a serious complication following PCI with a high rate of mortality. DAPT non-use was associated with the highest risk of ST, followed by various angiographic parameters and high lesion complexity.

Electronic supplementary material

The online version of this article (10.1007/s12471-019-1253-2) contains supplementary material, which is available to authorized users.

Perioperative Bridging With Glycoprotein IIb/IIIa Inhibitors Versus Cangrelor: Balancing Efficacy and Safety

OBJECTIVE

To review the efficacy and safety of perioperative administration of intravenous (IV) antiplatelet agents as a substitute for oral P2Y₁₂ inhibitors and to provide clinicians guidance on optimal and cost-effective use of these medications.

DATA SOURCES

A MEDLINE literature search (1950 to November 2018) was performed using the key search terms abciximab, bridging, cangrelor, cardiac surgery, coronary artery bypass surgery, eptifibatide, intravenous antiplatelet agent, and tirofiban. Additional references were identified from a review of literature citations.

STUDY SELECTION AND DATA EXTRACTION

In all, 18 original research reports and case reports/series were included in the review.

DATA SYNTHESIS

Prevention of postoperative bleeding is critical to decrease morbidity and mortality after cardiac surgery. IV antiplatelet medications have short half-lives and are frequently used to substitute for oral P2Y₁₂ inhibitors to allow platelet function recovery before procedures. Functional recovery of platelets is delayed after abciximab discontinuation and increases postoperative bleeding risk. Eptifibatide and tirofiban have similar pharmacokinetic/pharmacodynamic properties and comparable efficacy and safety in the setting of perioperative bridging. Cangrelor may be considered in patients with renal insufficiency as decreased clearance of eptifibatide or tirofiban may increase the risk of postoperative bleeding. Relevance to Patient Care and Clinical Practice: Comparative studies of IV antiplatelet medications have not been published. Appropriate use of IV antiplatelet medications can prevent perioperative ischemic events and bleeding.

CONCLUSIONS

Eptifibatide, tirofiban, and cangrelor are preferred over abciximab as a perioperative bridge. The choice of agent should be tailored to clinical characteristics of the patient and institutional acquisition costs.

Percutaneous coronary interventions with the Absorb Bioresorbable vascular scaffold in real life: 1-year results from the FRANCE ABSORB registry

BACKGROUND

Several randomized studies have shown that bioresorbable vascular scaffold (BVS) technology is associated with an increased risk of stent thrombosis.

AIM

This study aimed to assess the rates of adverse outcomes at 1 year in patients treated with the Absorb BVS (Abbott Vascular, Santa Clara, CA, USA), using data from a large nationwide prospective multicentre registry (FRANCE ABSORB).

METHODS

All patients receiving the Absorb BVS in France were included prospectively in the study. Predilatation, optimal sizing and postdilatation were recommended systematically. The primary endpoint was a composite of cardiovascular death, myocardial infarction and target lesion revascularization at 1 year. Secondary endpoints were scaffold thrombosis and target vessel revascularization at 1 year.

RESULTS

A total of 2072 patients at 86 centres were included: mean age 55±11 years; 80% men. The indication was acute coronary syndrome (ACS) in 49% of cases. Predilatation and postdilatation were done in 93% and 83% of lesions, respectively. At 1 year, the primary endpoint occurred in 3.9% of patients, the rate of scaffold thrombosis was 1.5% and the rate of target vessel revascularization was 3.3%. In a multivariable analysis, diabetes and total Absorb BVS length>30mm were independently associated with the occurrence of the primary endpoint, whereas oral anticoagulation and total Absorb BVS length>30mm were independently associated with occurrence of scaffold thrombosis.

CONCLUSIONS

The Absorb BVS was implanted in a relatively young population, half of whom had ACS. Predilatation and postdilatation rates were high, and 1-year outcomes were acceptable.

The ABCB1, CYP2C19, CYP3A5 and CYP4F2 genetic polymorphisms and platelet reactivity in the early phases of acute coronary syndromes

Background

The aim was to study seven polymorphic markers of genes encoding proteins involved in the absorption, metabolism and pharmacokinetics of clopidogrel among patients with an acute coronary syndrome (ACS), who have undergone percutaneous coronary intervention (PCI).

Methods

Eighty-one ACS and PCI patients older than 18 years and treated with dual antiplatelet therapy were enrolled in the study. Platelet function testing and ABCB1, CYP2C19, CYP3A5 and CYP4F2 genotyping were performed. The predictive role of categorical variables, such as genotypes (carriers and non-carriers of polymorphism), on platelet reactivity (platelet reactivity units [PRU] platelet inhibition [PI]) was assessed by logistic regression (for categorical outcomes) and linear regression (for continuous outcomes) analysis. A p-value<0.05 was considered significant. The allele frequencies were estimated by gene counting, and Hardy-Weinberg equilibrium was tested using the chi-square test.

Results

Regarding clopidogrel response, 62 patients (76.5%) were clopidogrel responders and 19 were non-responders (23.5%). Mean PRU value and the percentage of platelet inhibition were 170.0±50.9 PRU and 28.6±19.9%, respectively. The effects of the CYP2C19*2 polymorphisms on PRU (166.0±50.8 vs. 190.7±48.2, p<0.038) and PI (30.6±20.0 vs. 18.1±16.3, p<0.013) were observed, and the rates of high platelet reactivity (HPR) were lower in CYP2C19*1/*1 than those in CYP2C19*1/*2+CYP2C19*2/*2 (16.2% vs. 53.8% p<0.0067). In comparison, no significant difference in PRU value and PI was observed at <5 days between the rest of polymorphisms (p>0.05). Based on the logistic regression analysis, CYP2C19*2 (OR: 4.365, CI: 1.25–17.67, p=0.022) was an independent predictor of HPR at <5 days, as was the stent diameter (OR: 0.219, CI: 0.002–0.229, p=0.049). The remaining polymorphisms had no influence.

Conclusions

The reactivity of the on-clopidogrel platelet in the early phase of ACS is influenced primarily by the CYP2C19 polymorphisms. We believe that the findings of the present study could supply additional evidence regarding the clinical appropriateness of the CYP2C19 genetic testing for designing suitable antiplatelet therapy in the early phase of ACS.

A Case Report of Cangrelor Bridge Therapy for a Diagnostic Bronchoscopy With Biopsy

Although premature discontinuation of dual antiplatelet therapy (DAPT) is associated with an increased risk of ischemic complications, patients may present with an urgent need for surgery that would require interruption of DAPT. Antiplatelet bridge therapy using cangrelor, an intravenous P2Y₁₂ inhibitor, has been studied as a potential option to ensure continuation of DAPT perioperatively. However, limited evidence exists supporting the off-label use of cangrelor bridge therapy to noncardiac procedures. We describe the case of a 67-year-old class 3 obese female on DAPT (aspirin and ticagrelor) for recent drug-eluting stent placement who required a bronchoscopy with biopsy for suspected lung cancer. Cangrelor bridge therapy was utilized both preoperatively and postoperatively without ischemic or bleeding complications, and the patient was subsequently able to begin radiation therapy after a confirmed diagnosis of lung cancer.

CYP2C19 and ABCB1 genetic polymorphisms correlate with the recurrence of ischemic cardiovascular adverse events after clopidogrel treatment

BACKGROUND

This study was aimed to investigate the correlation between CYP2C19 and ABCB1 polymorphisms and the recurrence of ischemic cardiovascular adverse events in patients with coronary artery disease treated with clopidogrel.

METHODS

A total of 168 patients with coronary heart disease who underwent PCI operation and received clopidogrel treatment were enrolled. Dual antiplatelet therapy was applied to the treatment of patients for 2 years. Thromboelastography was used to test the efficiency of blood coagulation. Polymerase chain reaction (PCR) was used to detect CYP2C19 and ABCB1 3435CT polymorphisms. One-year follow-up visit was carried out to record the incidence of cardiovascular adverse events after drug-eluting stent implantation was inset.

RESULTS

Follow-up visit results suggested that the patients with high on-treatment platelet reactivity (HPR) had a higher recurrence rate of cardiovascular adverse events after PCI operation and clopidogrel treatment. Gene polymorphism testing results indicated that patients with CYP2C19*3 had a significantly higher incidence of HPR, whereas CYP2C19*2 and ABCB1 3435CT were not significantly correlated with HPR. Multivariable logistic regression analysis showed that CYP2C19*3 might be an independent predictive factor of post-PCI HPR. In addition, CYP2C19*3 as well as post-PCI HPR could function as independent predictive factors of cardiovascular adverse events.

CONCLUSION

CYP2C19*3 polymorphism could be an important predictive factor of HPR and ischemic cardiovascular adverse events after clopidogrel treatment.

Platelet reactivity in human immunodeficiency virus infected patients on dual antiplatelet therapy for an acute coronary syndrome: the EVERE2ST-HIV study

Aim

To explore platelet reactivity on dual antiplatelet therapy (DAPT) of acute coronary syndrome (ACS) patients infected with HIV.

Methods and results

Acute coronary syndrome patients infected with HIV (n = 80) were matched to ACS patients without HIV (n = 160) on age, sex, diabetes, and DAPT (aspirin 100%, clopidogrel 68%, prasugrel 31%, ticagrelor 1%). Platelet reactivity was evaluated after ACS (>30 days) by measuring residual platelet aggregation (RPA) to aspirin and to P2Y12 inhibitors with light transmission aggregometry (LTA), VerifyNow aspirin assay (ARU), and P2Y12 assay (PRU) and with the VASP platelet reactivity index (VASP-PRI). Proportion of patients with high residual platelet reactivity (HPR) was evaluated. HIV-infected ACS patients had higher levels of platelet reactivity in response to P2Y12 inhibitors (RPA: 23.8 ± 2.7% vs. 15.3 ± 1.3%; P = 0.001; PRU: 132 ± 10 vs. 107.4 ± 6.6; P = 0.04; and VASP-PRI: 45.2 ± 2.6% vs. 32.0 ± 2.0%; P < 0.001) and to aspirin (RPA: 3.6 ± 1.5% vs. 0.4 ± 0.1%; P = 0.004 and ARU: 442 ± 11 vs. 407 ± 5; P = 0.002) compared with non-HIV. HIV-infection was independently associated with increased platelet reactivity regardless of the test used (RPA: P = 0.005; PRU: P < 0.001 and VASP-PRI: P < 0.001) and a higher proportion of HPR (OR = 7.6; P < 0.001; OR = 2.06; P = 0.06; OR = 2.91; P = 0.004, respectively) in response to P2Y12 inhibitors. Similar results were found with aspirin. Protease inhibitors use was associated with increased platelet reactivity and higher rate of HPR.

Conclusions

Acute coronary syndrome patients infected with HIV have increased levels of platelet reactivity and higher prevalence of HPR to P2Y12 inhibitors and aspirin than non-HIV patients. These results could provide potential explanations for the observed increase risk of recurrent ischemic events in the HIV-infected population.

Role of genetic testing in patients undergoing percutaneous coronary intervention

INTRODUCTION

Variability in individual response profiles to antiplatelet therapy, in particular clopidogrel, is a well-established phenomenon. Genetic variations of the cytochrome P450 (CYP) 2C19 enzyme, a key determinant in clopidogrel metabolism, have been associated with clopidogrel response profiles. Moreover, the presence of a CYP2C19 loss-of-function allele is associated with an increased risk of atherothrombotic events among clopidogrel-treated patients undergoing percutaneous coronary interventions (PCI), prompting studies evaluating the use of genetic tests to identify patients who may be potential candidates for alternative platelet P2Y12 receptor inhibiting therapies (prasugrel or ticagrelor). Areas covered: The present manuscript provides an overview of genetic factors associated with response profiles to platelet P2Y12 receptor inhibitors and their clinical implications, as well as the most recent developments and future considerations on the role of genetic testing in patients undergoing PCI. Expert commentary: The availability of more user-friendly genetic tests has contributed towards the development of many ongoing clinical trials and personalized medicine programs for patients undergoing PCI. Results of pilot investigations have shown promising results, which however need to be confirmed in larger-scale studies to support the routine use of genetic testing as a strategy to personalize antiplatelet therapy and improve clinical outcomes.

P2Y12 receptor inhibitors: an evolution in drug design to prevent arterial thrombosis

INTRODUCTION

P2Y12 inhibitors are a critical component of dual antiplatelet therapy (DAPT), which is the superior strategy to prevent arterialthrombosis in patients with acute coronary syndromes (ACS) and undergoing stent implantation.. Areas covered: Basic science articles, clinical studies, and reviews from 1992-2017 were searched using Pubmed library to collet impactful literature. After an introduction to the purinergic receptor biology, this review summarizes current knowledge on P2Y12 receptor inhibitors. Furthermore, we describe the subsequent improvements of next-generation P2Y12 receptor inhibitors facing the ambivalent problem of bleeding events versus prevention of arterial thrombosis in a variety of clinical settings. Therefore, we summarize data from relevant preclinical and clinical trials of currently approved P2Y12 receptor inhibitors (clopidogrel, prasugrel, ticagrelor, cangrelor) and provide strategies of drug switching and management of bleeding events. Expert opinion: An enormous amount of pharmacologic and clinical data is available for the application of P2Y12 receptor inhibitors. Today prasugrel, ticagrelor and clopidogrel are the standard of care drugs during dual antiplatelet therapy for ACS patients, but have considerable rates of bleeding. Recent and future clinical trials will provide evidence for subsequent escalation and de-escalation strategies of P2Y12 receptor inhibition. These data may pave the way for an evidence-based, individualized P2Y12 receptor inhibitor therapy.

[Coronary thrombosis: Physiopathology and treatment in the era of tailored medicine]

Coronary thrombosis remains the leading cause for cardiovascular death in France. Great advances have been made in the knowledge of the basic mechanism involved in coronary thrombogenesis and in antithrombotic treatments. They have led to substantial survival benefit after myocardial infarction and enabled development of tailored therapeutic strategies, especially for high-risk patients. Direct oral anticoagulants have now entered the game for secondary prevention after coronary thrombosis.

Platelet function testing in acute cardiac care – is there a role for prediction or prevention of stent thrombosis and bleeding?

The role of platelet function testing in acute coronary syndrome patients undergoing percutaneous coronary intervention remains controversial despite the fact that high platelet reactivity is an independent predictor of stent thrombosis and emerging evidence suggests also a link between low platelet reactivity and bleeding. In this expert opinion paper, the Study Group on Biomarkers in Cardiology of the Acute Cardiovascular Care Association and the Working Group on Thrombosis of the European Society of Cardiology aim to provide an overview of current evidence in this area and recommendations for practicing clinicians.

Antiplatelet Drug Regimen in Patients With Stent Thrombosis - Insights From the PESTO French Optical Coherence Tomography Registry

BACKGROUND

Stent thrombosis (ST) may be triggered by different phenomena, including underlying device abnormalities and modification of the antiplatelet therapy (APT) regimen. This work investigated the characteristics of APT regimens and their relationships with ST mechanisms among a large cohort of patients evaluated by optical coherence tomography (OCT).

METHODS AND RESULTS

A prospective multicenter registry was screened for patients with confirmed ST. OCT was performed after the initial intervention to the culprit lesion. ST was classified as acute (AST), subacute (SAST), late (LST) and very late (VLST). OCT records were analyzed in a central core laboratory. A total of 120 patients (median age 62 years, 89% male) were included in the study. VLST was the clinical presentation in 75%, LST in 6% and SAST+AST in 19% of the patients. Single APT (SAPT) was given in 61%, double APT (DAPT) in 27% and no APT in 12% of the cases at the time of the ST. A recent (≤15 days) APT modification was reported in 22% of the patients. An underlying mechanical abnormality was identified by OCT in 96.7% of the cases. Ruptured neoatherosclerotic lesions were significantly more frequent in patients without APT compared with the others.

CONCLUSIONS

ST mostly occurs in patients receiving DAPT or SAPT. Any underlying mechanical abnormality of ST can be involved, irrespective of the APT regimen.

Incidence of cardiovascular events and vascular interventions in patients with type 2 diabetes

OBJECTIVE

Diabetes mellitus is associated with an increased risk for cardiovascular morbidity and mortality. The vascular burden in terms of incidence of cardiovascular events (CVE) and vascular interventions is however poorly quantified. In this study we evaluated the incidence rates of CVE and vascular interventions in patients with type 2 diabetes (T2DM) with and without cardiovascular disease (CVD) in comparison to patients without type 2 diabetes.

RESEARCH DESIGN AND METHODS

In a cohort of 9.808 high-risk patients with and without cardiovascular disease and type 2 diabetes originated from the ongoing, single-center prospective SMART (Second Manifestations of ARTerial disease) cohort, the number and incidence rates of CVE and interventions were calculated. The incidence rates were adjusted for confounders using Poisson regression models. CVE were defined as vascular death, stroke and myocardial infarction (MI). Interventions were defined as percutaneous coronary intervention, coronary artery bypass grafting, percutaneous transluminal angioplasty or stenting of the peripheral arteries and amputation.

RESULTS

Patients with T2DM and CVD had a 4-fold higher incidence rate of CVE and a 8-fold higher incidence rate of vascular interventions compared to high-risk patients without T2DM and CVD after adjusting for confounders. The incidence rate for the composite of non-fatal MI, non-fatal stroke and vascular death was 5.8 per 1000person-years in patients without T2DM or CVD at baseline, 15.2 per 1000person-years in patients with T2DM but without CVD at baseline, 26.0 per 1000person-years in patients without T2DM but with CVD and 40.7 per 1000person-years in patients with both T2DM and CVD at baseline. A similar increasing incidence rate was seen for all vascular interventions from patients without T2DM or CVD to patients with both T2DM and CVD.

CONCLUSIONS

Patients with type 2 diabetes or CVD are subject to an increased incidence of cardiovascular events and interventions compared to high-risk patients without type 2 diabetes or vascular disease. Patients with type 2 diabetes and CVD have the highest incidence of new cardiovascular diseases and vascular interventions when compared to patients without type 2 diabetes and CVD. These results underline the need for optimal risk factor treatment as well as the need for new prevention and treatment strategies in this very high risk population.

Acute Coronary Stent Thrombosis in Modern Era: Etiology, Treatment, and Prognosis

Acute stent thrombosis (AST) is a rare but life-threatening complication of coronary artery stenting. AST remains a challenging task for cardiologists, despite the application of modern procedural techniques and dual-antiplatelet therapy strategies as well as improved understanding of the underlying pathophysiology. This review focuses on the prevalence, risk factors, prognosis, multiple potential underlying pathogenesis, knowledge gaps, and recommends diagnosis and individualized management strategies of AST.

A risk scoring system to predict coronary stent thrombosis

OBJECTIVE

Stent thrombosis (ST) is a potentially life-threatening complication of percutaneous coronary intervention (PCI). We aimed to develop a scoring system to predict the risk of ST following PCI.

RESEARCH DESIGN AND METHODS

Odds ratios (ORs) for risk factors associated with ST were identified from a meta-analysis based on a systematic literature review, and through consensus expert opinion (Delphi-RAND method). The combined ORs were used to calculate risk scores for acute (within 24 hours), early (within 30 days) and late (31 days to 1 year) ST. Risk scores were validated against patient-level data from the TRITON-TIMI 38 study. Twenty risk factors were identified.

RESULTS

The most highly predictive factor for early and late ST was "incomplete duration of dual antiplatelet therapy". Derived total risk scores ranged from 0 to 22 for acute and early ST, and from 0 to 20 for late ST. Increasing scores were associated with an increasing risk of ST when applied to trial data. Model discrimination was 0.60 (p = .0028), 0.67 (p < .0001) and 0.66 (p < .0001) for acute, early and late ST respectively, indicating good discriminatory power for predicting ST. Key limitations included a lack of published data on acute ST, resulting in a risk score for this time point being based predominantly on expert opinion, and that it was not possible to map all risk factors to variables collected in the TRITON-TIMI 38 study.

CONCLUSION

Our weighted scoring system may help to stratify ST risk and individualize antiplatelet therapy in patients undergoing PCI.

Associations between P2RY12 gene polymorphisms and risks of clopidogrel resistance and adverse cardiovascular events after PCI in patients with acute coronary syndrome

Clopidogrel resistance in patients with acute coronary syndrome (ACS) is one of the key causes of recurrent cardiovascular disease (CVD) events after percutaneous coronary intervention (PCI). Clopidogrel targets the platelet membrane receptor P2RY12 to inhibit platelet aggregation via adenosine diphosphate (ADP). This study aimed to investigate the relationships between P2RY12 polymorphisms and the risk of clopidogrel resistance and adverse CVD events after PCI. From January 2015 to December 2014, patients who had been diagnosed with ACS undergoing PCI and treated with clopidogrel were recruited for this prospective cohort study (N = 498). Data regarding demographics, medication intake, and ACS lesion were recorded, and whole blood samples were collected for biochemical tests, ADP-induced platelet aggregation ratio detection, and P2RY12 genotyping. P2RY12 genotyping was performed by polymerase chain reaction. The left ventricular ejection fraction was calculated by echocardiography. After 3 to 12 months of follow-up, data regarding any adverse CVD event or death were recorded. The allele frequencies for the T variation alleles in C34T and G52T of P2RY12 were 20.3% and 11.6%, respectively. Patients with T variations at C34T or G52T of P2RY12 had a significantly higher risk of clopidogrel resistance (C34T: P < 0.001; G52T: P = 0.003) and total cardiovascular events (C34T: P = 0.013; G52T: P = 0.018) compared to those with the wild-type genotype. Moreover, multivariable logistic regression showed that patients with the T variations in C34T (odds ratio [OR]: 2.89 (95% confidence interval [CI]: 1.48-5.64), P = 0.002) and G52T (OR: 3.68 [95% CI: 1.71-7.92], P = 0.001) also had a significantly higher risk of clopidogrel resistance. Also, the T variations in C34T (OR: 2.68 [95% CI: 1.07-6.73], P = 0.035) and G52T (OR: 5.64 [95% CI: 1.52-20.88], P = 0.010) significantly increased the risk of post-PCI CVD events after accounting for confounding factors. The P2RY12 gene polymorphisms C34T and G52T were significantly associated with a higher risk of clopidogrel resistance and sequential cardiovascular events in Chinese ACS patients after PCI.

The risk of clopidogrel resistance is associated with ABCB1 polymorphisms but not promoter methylation in a Chinese Han population

The goal of our study was to investigate the contribution of ABCB1 expression to the risk of clopidogrel resistance (CR). Platelets functions were measured using the Verify-Now P2Y12 assay. Applying Polymerase Chain Reaction–Restriction Fragment Length Polymorphism (PCR-RFLP), the single-nucleotide polymorphisms (SNPs) was tested. Using bisulphite pyrosequencing assay, we investigated the association of the ABCB1 DNA methylation levels and CR. It was shown that female, hypertension, and lower albumin levels increased the risk of CR (P<0.05). If patients did not have hypoproteinaemia or had hypertension, the SNP in rs1045642 was associated with CR (CC vs. TT: albumin ≥35, P = 0.042; hypertension, P = 0.045; C vs. T: albumin ≥35, P = 0.033; hypertension, P = 0.040). Additionally, the platelet inhibition of the CT+TT genotype in rs1128503 was larger than that of the CC genotype (P = 0.021). Multivariate logistic regression analysis showed that male, higher albumin and hsCRP decreased the risk of CR, and the stent size maybe positively correlated with CR. The SNP in rs1045642 was related to all-cause mortality (P = 0.024). We did not find any relationship between the methylation levels of the ABCB1 promoter and CR. In conclusions, our study indicated that ABCB1 polymorphisms might be useful in further evaluating the pathogenesis of CR.

Clopidogrel pharmacogenetics: Beyond candidate genes and genome-wide association studies

While it is well established that genetic variation is a significant contributor to interindividual variability in clopidogrel efficacy, candidate gene and genome-wide approaches have failed to reproducibly identify genetic determinants of antiplatelet response, apart from variants in CYP2C19, prompting the need for more innovative study designs. Herein, we highlight the potential benefit of exome sequencing of patients at the extremes of clopidogrel responsivity through examination of data reported in this issue of Clinical Pharmacology & Therapeutics.