Role of genetic testing in patients undergoing percutaneous coronary intervention

Targeted next-generation sequencing panel to investigate antiplatelet adverse reactions in acute coronary syndrome patients undergoing percutaneous coronary intervention with stenting

Antiplatelet therapy, the gold standard of care for patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI), is one of the therapeutic approaches most associated with the development of adverse drug reactions (ADRs). Although numerous studies have shown that pharmacological intervention based on a limited number of high-evidence variants (primarily CYP2C19*2 and *3) can reduce the incidence of major adverse cardiovascular events (MACEs), ADRs still occur at variable rates (10.1 % in our case) despite personalized therapy. This study aimed to identify novel genetic variants associated with the endpoint of MACEs 12 months after PCI by designing and analyzing a targeted gene panel. We sequenced 244 ACS-PCI-stent patients (109 with event and 135 without event) and 99 controls without structural cardiovascular disease and performed an association analysis to search for unexpected genetic variants. No single nucleotide polymorphisms reached genomic significance after correction, but three novel variants, including ABCA1 (rs2472434), KLB (rs17618244), and ZNF335 (rs3827066), may play a role in MACEs in ACS patients. These genetic variants are involved in regulating high-density lipoprotein levels and cholesterol deposition, and as they are regulatory variants, they may affect the expression of nearby lipid metabolism-related genes. Our findings suggest new targets (both at the gene and pathway levels) that may increase susceptibility to MACEs, but further research is needed to clarify the role and impact of the identified variants before these findings can be incorporated into the therapeutic decision-making process.

Smoking and outcomes following personalized antiplatelet therapy in chronic coronary syndrome patients: A substudy from the randomized PATH-PCI trial

BACKGROUND

This is a sub-analysis of the Personalized Antithrombotic Therapy for Coronary Heart Disease after PCI (PATH-PCI) trial in China to explore the relationship between smoking and outcomes following personalized antiplatelet therapy (PAT) in chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI).

METHODS

As a single-center, prospective, randomized controlled and open-label trial, the PATH-PCI trial randomized CCS patients undergoing PCI into standard group or personalized group guided by a novel platelet function test (PFT), from December 2016 to February 2018. All patients were divided into smokers and nonsmokers according to their smoking status. Subsequently, we underwent a 180-day follow-up evaluation. The primary endpoint was the net adverse clinical events (NACE).

RESULTS

Regardless of smoking status, in the incidence of NACE, there was a reduction with PAT but that the reductions are not statistically significant. In the incidence of bleeding events, we found no statistically significant difference between two groups (smokers: 2.0% vs. 1.4%, HR = 1.455, 95% confidence interval [CI]: 0.595-3.559, p = .412; nonsmokers: 2.2% vs. 1.8%, HR = 1.228, 95% CI: 0.530-2.842, p = .632). In smokers, PAT reduced major adverse cardiac and cerebrovascular events (MACCE) by 48.7% (3.0% vs. 5.9%, HR = 0.513, 95% CI: 0.290-0.908, p = .022), compared with standard antiplatelet therapy (SAT). PAT also reduced the major adverse cardiovascular events (MACE) but there was no statistically difference in the reductions (p > .05). In nonsmokers, PAT reduced MACCE and MACE by 51.5% (3.3% vs. 6.7%, HR = 0.485, 95% CI: 0.277-0.849, p = .011) and 63.5% (1.8% vs. 4.9%, HR = 0.365, 95% CI: 0.178-0.752, p = .006), respectively. When testing p-values for interaction, we found there was no significant interaction of smoking status with treatment effects of PAT (pint-NACE  = .184, pint-bleeding  = .660).

CONCLUSION

Regardless of smoking, PAT reduced the MACE and MACCE, with no significant difference in bleeding. This suggests that PAT was an recommendable regimen to CCS patients after PCI, taking into consideration both ischemic and bleeding risk.

The Impact of CYP2C19 Genotype on the Platelet Reactivity Index (PRI) among Chronic Coronary Syndromes (CCS) Patients Undergoing Percutaneous Coronary Intervention (PCI): Affectability of Rapid Genetic Testing

BACKGROUND

In the Asian population, the presence of the CYP2C19 loss-of-function (LOF) allele is a known genetic variation. This allele is associated with a reduced capacity to metabolize clopidogrel into its active forms through the CYP2C19 enzyme, resulting in diminished platelet inhibition and an elevated risk of recurrent cardiovascular events. Regulatory authorities have recommended an alternative P2Y12 inhibitor, ticagrelor, for individuals carrying the LOF allele. Consequently, this study seeks to assess the impact of the CYP2C19 genotype on the Platelet reactivity index (PRI) using a rapid genetic testing approach in Asian patients with chronic coronary syndromes (CCS) who undergo percutaneous coronary intervention (PCI).

METHODS

This prospective study employed a parallel design, single-center design, and randomized approach. Genotyping for the CYP2C19*2 and *3 polymorphisms was conducted using the Nested Allele-Specific Multiplex PCR (NASM-PCR) technique. Patients meeting the inclusion criteria underwent genotyping for CYP2C19 polymorphisms. Following PCI, patients were randomly assigned to receive either ticagrelor or clopidogrel. PRI assessments were performed four hours after loading dose administration. The trial was registered with ClinicalTrials.gov under the identifier NCT05516784.

RESULTS

Among the 94 patients recruited for the study, 40 (42.55%) were identified as carriers of the LOF allele for CYP2C19*2 and *3 (*1/*2, *2/*2, *1/*3). Out of the 84 patients evaluated for PRI (44 receiving clopidogrel and 40 receiving ticagrelor), 21 (47.7%) of the clopidogrel group and 39 (97.5%) of the ticagrelor group exhibited a favorable response to antiplatelet therapy (PRI < 50). Patients treated with ticagrelor demonstrated superior antiplatelet responses compared to those receiving clopidogrel, regardless of LOF carrier status (P = 0.005 and < 0.001 for non-LOF and LOF carriers, respectively).

CONCLUSION

NASM-PCR as a rapid genetic test holds promise for personalizing antiplatelet therapy in Asian CCS patients.

Advances and Perspectives in methods for identifying high platelet reactivity

Antiplatelet therapy is the foundational treatment for the prevention and treatment of coronary and cerebrovascular ischemic events in patients with coronary heart disease, ischemic stroke, and transient ischemic attack (TIA). However, with more and more studies reporting an increased risk of thrombosis in some patients due to poor response to therapeutic agents, the selection of appropriate P2Y12 inhibitors has become a major challenge that needs to be addressed urgently. Currently, commonly used oral P2Y12 inhibitors include clopidogrel, ticagrelor, and prasugrel. Assessing patients' risk factors before the development of treatment regimens by effectively predicting the risk of high platelet reactivity with specific P2Y12 inhibitors in advance to avert the occurrence of major adverse cardiovascular and cerebrovascular events (MACCE) is the key point to the problem. Up to now, methods available for predicting platelet reactivity include genetic testing, platelet function testing, and risk scores. This review provides a summarization of the existent available identification methods and analyzes the advantages and drawbacks of different methods in specific clinical settings, intending to guide the rational clinical application of P2Y12 receptor inhibitors.

Guided vs. conventional anti-platelet therapy for patients with acute coronary syndrome: A meta-analysis of randomized controlled trials

Background

Whether guided antiplatelet therapy in patients with acute coronary syndrome (ACS) is effective in improving net clinical benefits compared with conventional antiplatelet therapy remains controversial. Therefore, we assessed the safety and efficacy of guided antiplatelet therapy in patients with ACS and undergoing percutaneous coronary intervention.

Method

We searched PubMed, EMBASE, and Cochrane Library databases to select the relevant randomized controlled trials comparing the guided and conventional antiplatelet therapy in patients with ACS. The primary and safety outcomes are major adverse cardiovascular events (MACE) and major bleeding, respectively. The efficacy outcomes included myocardial infarction, stent thrombosis, all-cause death, and cardiovascular death. We selected the relative risk (RR) and 95% confidence intervals (CIs) as effect size and calculated it using the Review Manager software. In addition, we evaluated the final results by trial sequential analysis (registered by PROSPERO, CRD 42020210912).

Results

We selected seven randomized controlled trials and included 8,451 patients in this meta-analysis. Guided antiplatelet therapy can significantly reduce the risk of MACE (RR 0.64, 95% CI 0.54-0.76, P < 0.00001), myocardial infarction (RR 0.62, 95% CI 0.49-0.79, P = 0.0001), all-cause death (RR 0.61, 95% CI 0.44-0.85, P = 0.003), and cardiovascular death (RR 0.66, 0.49-0.90, P = 0.009). In addition, there is no significant difference between the two groups in stent thrombosis (RR 0.67, 95% CI 0.44-1.03, P = 0.07) and major bleeding (RR 0.86, 95% CI 0.65-1.13, P = 0.27). The subgroup analysis showed that the guided group based on genotype tests could bring benefits in MACE and myocardial infarction.

Conclusions

The guided antiplatelet therapy is not only associated with a comparable risk of bleeding but also with a lower risk of MACE, myocardial infarction, all-cause death, cardiovascular death, and stent thrombosis than the conventional strategy in patients with ACS.

Short dual antiplatelet therapy and dual antiplatelet therapy de-escalation after primary percutaneous intervention: For whom and how

Dual antiplatelet therapy (DAPT) for 6-12 months, followed by lifelong aspirin monotherapy is considered an effective standard therapy for the prevention of thrombo-ischemic events in patients with acute and chronic coronary syndrome (ACS, CCS) undergoing percutaneous coronary intervention (PCI) or after a primarily conservative treatment decision. In ACS patients, the stronger P2Y12-inhibitors ticagrelor or prasugrel are recommended in combination with aspirin unless the individual bleeding risk is high and shortening of DAPT is warranted or clopidogrel is preferred. However, also in patients at low individual bleeding risk, DAPT is associated with a higher risk of bleeding. In recent years, new antithrombotic treatment strategies, such as shortening DAPT followed by early P2Y12-inhibitor monotherapy and de-escalating DAPT from potent P2Y12-inhibitors to clopidogrel by maintaining DAPT duration time, have been investigated in clinical trials and shown to reduce bleeding complications in cardiovascular high-risk patients without negative effects on ischemic events. In this review, we summarize the current knowledge and discuss its implication on future antithrombotic strategies in terms of a personalized medicine.

Sex Differences in Clopidogrel Effects Among Young Patients With Acute Coronary Syndrome: A Role for Genetics?

Background

Poorer health outcomes experienced by young women with acute coronary syndrome may be related to sex differences in the safety and efficacy of antiplatelet agents, such as clopidogrel. Polymorphisms in drug metabolism enzyme (cytochrome P450 [CYP] family) genes are independent factors for the variability in response to clopidogrel. However, a sex-specific impact of genetics to explain worse clinical outcomes in women has not been explored extensively. Therefore, our objective was to determine whether an interaction of sex with CYP variants occurs among users of clopidogrel, and if so, its impact on 1-year adverse clinical outcomes.

Methods

We used data from a combined cohort of 2272 patients (median age 49 years; 56% female) hospitalized for acute coronary syndrome. We examined interactions between sex and CYP variants among clopidogrel users at admission and discharge to assess associations with 1-year readmission due to cardiac events.

Results

The case-only analysis of 177 participants on clopidogrel at the time of presentation showed that the risk of an atherothrombotic event was greater in female carriers of the CYP2C9∗3 loss-of-function allele (odds ratio = 3.77, 95% confidence interval = 1.54-9.24). The results of the multivariable logistic regression model for users of clopidogrel at discharge (n = 1733) indicated that women had significantly higher risk of atherothrombotic readmissions at 1 year (odds ratio = 1.55, 95% confidence interval = 1.16-2.07), compared to the risk for men, but the loss-of-function alleles, either individually or through a genetic risk score, were not associated with 1-year readmissions.

Conclusion

This study highlights the need for an improved understanding of the role of sex-by-gene interactions in causing sex differences in drug metabolism.

Escalation and De-Escalation of Antiplatelet Therapy after Acute Coronary Syndrome or PCI: Available Evidence and Implications for Practice

Dual antiplatelet therapy (DAPT) is the gold standard for the antithrombotic management of patients with an acute coronary syndrome (ACS) or undergoing percutaneous coronary intervention (PCI). Implementation of intensified or prolonged DAPT regimens has proven to lower the risk of ischemic events but at the expense of increased bleeding. Importantly, bleeding is a predictor of poor prognosis. Risk stratification and selection of tailored antiplatelet strategies to maximize the net clinical benefit in individual patients with ACS or undergoing PCI is therefore potentially beneficial. Recently, novel approaches including DAPT de-escalation or escalation have been proposed as possible alternatives to standard DAPT. These strategies, which are generally based on patient's risk profile, genetics, and/or platelet function have been proposed to offer more tailored treatments in patients with ACS or PCI, with the ultimate goal of providing adequate ischemic protection while mitigating the risk of bleeding. This review summarizes the available evidence on DAPT de-escalation or escalation (both guided and unguided) and discusses the practical implications of these strategies in the contemporary management of patients with ACS and/or undergoing PCI.

De-escalation of antiplatelet therapy in acute coronary syndromes: Why, how and when?

The synergistic blockade of the key platelet signaling pathways of cyclooxygenase-1 blockade and P2Y12 signaling by combining aspirin plus a potent P2Y12 inhibitor (prasugrel or ticagrelor), the so called dual antiplatelet treatment (DAPT), has represented the antithrombotic regimen of choice in patients with acute coronary syndrome (ACS) for nearly a decade. Nevertheless, the use of such antiplatelet treatment regimen, while reduced the risk of thrombotic complications, it is inevitably associated with increased bleeding and this risk may outweigh the benefit of a reduction of ischemic events in specific subgroup of patients. In light of the adverse prognostic implications of a bleeding complication, there has been a great interest in the development of antiplatelet regimens aimed at reducing bleeding without any trade-off in ischemic events. The fact that the ischemic risk is highest in the early phase after an ACS while the risk of bleeding remains relatively stable over time has represented the rationale for the implementation of a more intense antithrombotic regimen early after an ACS, followed by a less intense antithrombotic regimen thereafter. This practice, known as a "de-escalation" strategy, represents one of the more promising approaches for personalization of antithrombotic therapy in ACS. In this review we discuss the rationale, appraise the evidence and provide practical recommendations on the use of a de-escalation strategy of antiplatelet therapy in patients with an ACS.

Precision medicine in interventional cardiology: implications for antiplatelet therapy in patients undergoing percutaneous coronary intervention

Precision medicine is a medical model that proposes the customization of medical treatments to the individual patient, as opposed to a one-drug-fits-all model. Such a "personalized medicine" approach has been widely adopted in several medical fields, such as cancer medicine, but the implementation of precision medicine in cardiovascular medicine has not been similarly straightforward. Because pharmacogenomics plays an important role in the safety and efficacy of cardiovascular drug therapy, there has been a great interest in the use of tools aiming at personalizing antiplatelet therapy. Moreover, antiplatelet therapy is essential for the treatment of cardiovascular patients to reduce the risk of thrombotic complications, particularly those undergoing percutaneous coronary intervention, but it is inevitably associated with increased bleeding risk. In this review, the authors discuss the rationale, summarize the evidence and discuss the current and future directions for the personalization of antiplatelet treatment regimens in patients undergoing percutaneous coronary intervention.

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.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights from 2021

This special article is the fourteenth in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the Editor-in-Chief, Dr. Kaplan, and the editorial board for the opportunity to continue this series; namely, the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2021 are outlined in this introduction, and each highlight is reviewed in detail in the main body of the article. The literature highlights in the specialty for 2021 begin with an update on structural heart disease, with a focus on updates in arrhythmia and aortic valve disorders. The second major theme is an update on coronary artery disease, with discussion of both medical and procedural management. The third major theme is focused on the perioperative management of patients with COVID-19, with the authors highlighting literature discussing the impact of the disease on the right ventricle and thromboembolic events. The fourth and final theme is an update in heart failure, with discussion of diverse aspects of this area. The themes selected for this fourteenth special article are only a few of the diverse advances in the specialty during 2021. These highlights will inform the reader of key updates on a variety of topics, leading to improvement of perioperative outcomes for patients with cardiothoracic and vascular disease.

Genetic testing in patients undergoing percutaneous coronary intervention: rationale, evidence and practical recommendations

INTRODUCTION

Clopidogrel is the most frequently utilized P2Y12 inhibitor and is characterized by broad interindividual response variability resulting in impaired platelet inhibition and increased risk of thrombotic complications in a considerable number of patients. The potent P2Y12 inhibitors, prasugrel and ticagrelor, can overcome this limitation but at the expense of an increased risk of bleeding. Genetic variations of the cytochrome P450 (CYP) 2 C19 enzyme, a key determinant in clopidogrel metabolism, have been strongly associated with clopidogrel response profiles prompting investigations of genetic-guided selection of antiplatelet therapy.

AREAS COVERED

The present manuscript focuses on the rationale for the use of genetic testing to guide the selection of platelet P2Y12 inhibitors among patients undergoing percutaneous coronary intervention (PCI). Moreover, a comprehensive appraisal of the available evidence and practical recommendations is provided.

EXPERT COMMENTARY

Implementation of genetic testing as a strategy to guide the selection of therapy can result in escalation (i.e. switching to prasugrel or ticagrelor) or de-escalation (i.e. switching to clopidogrel) of P2Y12 inhibiting therapy. Most recent investigations support the clinical benefit of a genetic guided selection of antiplatelet therapy in patients undergo PCI. Integrating the results of genetic testing with clinical and procedural variables represents a promising strategy for a precision medicine approach for the selection of antiplatelet therapy among patients undergoing PCI.

Guided versus standard antiplatelet therapy in patients undergoing percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Whether guided selection of antiplatelet therapy in patients undergoing percutaneous coronary intervention (PCI) is effective in improving outcomes compared with standard antiplatelet therapy remains controversial. We assessed the safety and efficacy of guided versus standard selection of antiplatelet therapy in patients undergoing PCI.

METHODS

For this systematic review and meta-analysis, from Aug 20 to Oct 25, 2020, we searched MEDLINE (via PubMed), Cochrane, Embase, and Web of Science databases for randomised controlled trials and observational studies published in any language that compared guided antiplatelet therapy, by means of platelet function testing or genetic testing, versus standard antiplatelet therapy in patients undergoing PCI. Two reviewers independently assessed study eligibility, extracted the data, and assessed risk of bias. Risk ratios (RRs) and 95% CIs were used with random-effects or fixed-effect models according to the estimated heterogeneity among studies assessed by the I² index. Coprimary endpoints were trial-defined primary major adverse cardiovascular events and any bleeding. Key secondary endpoints were all-cause death, cardiovascular death, myocardial infarction, stroke, definite or probable stent thrombosis, and major and minor bleeding. This study is registered with PROSPERO (CRD42021215901).

FINDINGS

3656 potentially relevant articles were screened. Our analysis included 11 randomised controlled trials and three observational studies with data for 20 743 patients. Compared with standard therapy, guided selection of antiplatelet therapy was associated with a reduction in major adverse cardiovascular events (RR 0·78, 95% CI 0·63-0·95, p=0·015) and reduced bleeding, although not statistically significant (RR 0·88, 0·77-1·01, p=0·069). Cardiovascular death (RR 0·77, 95% CI 0·59-1·00, p=0·049), myocardial infarction (RR 0·76, 0·60-0·96, p=0·021), stent thrombosis (RR 0·64, 0·46-0·89, p=0·011), stroke (RR 0·66, 0·48-0·91, p=0·010), and minor bleeding (RR 0·78, 0·67-0·92, p=0·0030) were reduced with guided therapy compared with standard therapy. Risks of all-cause death and major bleeding did not differ between guided and standard approaches. Outcomes varied according to the strategy used, with an escalation approach associated with a significant reduction in ischaemic events without any trade-off in safety, and a de-escalation approach associated with a significant reduction in bleeding, without any trade-off in efficacy.

INTERPRETATION

Guided selection of antiplatelet therapy improved both composite and individual efficacy outcomes with a favourable safety profile, driven by a reduction in minor bleeding, supporting the use of platelet function or genetic testing to optimise the choice of agent in patients undergoing PCI.

FUNDING

None.

Clopidogrel Versus Ticagrelor or Prasugrel After Primary Percutaneous Coronary Intervention According to CYP2C19 Genotype: A POPular Genetics Subanalysis

[Figure: see text].

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.

P2Y12 inhibitors in neuroendovascular surgery: An opportunity for precision medicine

INTRODUCTION

Dual antiplatelet therapy (DAPT), primarily the combination of aspirin with a P2Y12 inhibitor, in patients undergoing intravascular stent or flow diverter placement remains the primary strategy to reduce device-related thromboembolic complications. However, selection, timing, and dosing of DAPT is critical and can be challenging given the existing significant inter- and intraindividual response variations to P2Y12 inhibitors.

METHODS

Assessment of indexed, peer-reviewed literature from 2000 to 2020 in interventional cardiology and neuroendovascular therapeutics with critical, peer-reviewed appraisal and extraction of evidence and strategies to utilize DAPT in cardio- and neurovascular patients with endoluminal devices.

RESULTS

Both geno- and phenotyping for DAPT are rapidly and conveniently available as point-of-care testing at a favorable cost-benefit ratio. Furthermore, systematic inclusion of a quantifying clinical risk score combined with an operator-linked, technical risk assessment for potential adverse events allows a more precise and individualized approach to new P2Y12 inhibitor therapy.

CONCLUSIONS

The latest evidence, primarily obtained from cardiovascular intervention trials, supports that combining patient pharmacogenetics with drug response monitoring, as part of an individually tailored, precision medicine approach, is both predictive and cost-effective in achieving and maintaining individual target platelet inhibition levels. Indirect evidence supports that this gain in optimizing drug responses translates to reducing main adverse events and overall treatment costs in patients undergoing DAPT after intracranial stent or flow diverting treatment.

Clopidogrel Resistance Is Associated With DNA Methylation of Genes From Whole Blood of Humans

Antiplatelet therapy has become a cornerstone in the treatment of coronary heart disease (CHD). However, due to high-residual-platelet-reactivity, clopidogrel resistance (CR) is a common phenomenon, and it is rarely known about the relationship between CR and epigenetic changes. This study compared the whole genomic methylation patterns of blood samples from patients with CR (n = 6) and non-CR (n = 6) with the Human Methylation 850K BeadChip assay. We explored differentially methylated CpG sites, genes, and pathways using bioinformatics profiling. The CR and control groups showed significantly different DNA methylation at 7,098 sites, with 979 sites showing hypermethylation and 6,119 sites showing hypomethylation. The pyrosequencing method was used to validate four differentially methylated CpG loci (cg23371584, cg15971518, cg04481923, cg22507406), confirming that DNA methylation was associated with the risk of CR (30 CR vs. 30 non-CR). The relative mRNA expression of the four genes (BTG2, PRG2, VTRNA2-1, PER3) corresponding to the loci above was also associated with CR, suggesting that alterations in DNA methylation may affect the expression of these four genes, eventually resulting in CR. Additionally, differentially methylated sites are partially related to genes and pathways that play key roles in process of circadian entrainment, insulin secretion, and so on. Hence, the mechanism and biological regulation of CR might be reflected through these epigenetic alterations, but future research will need to address the causal relationships.

Safety and efficacy of P2Y12 inhibitor monotherapy in patients undergoing percutaneous coronary interventions

Introduction: Antiplatelet therapy represents a key strategy for the prevention of thrombotic complications in patients with both acute and chronic coronary syndromes, particularly those undergoing percutaneous coronary intervention (PCI). Nevertheless, dual antiplatelet therapy (DAPT) is associated with a bleeding risk proportionate to its duration. Ever growing appreciation of the prognostic implications associated with bleeding and the development of safer stent platforms over the past years have led to a number of novel antiplatelet treatment strategies being tested among patients undergoing PCI. Areas covered: P2Y₁₂ inhibitor monotherapy after ashort course DAPT has emerged as ableeding reduction strategy to mitigate such risk while still preventing thrombotic complications. In this review we describe the latest evidence regarding the safety and efficacy of P2Y₁₂ inhibitor monotherapy in patients undergoing PCI in different clinical settings. Expert opinion: P2Y₁₂ inhibitor monotherapy after a brief period of DAPT has emerged as an effective approach to reduce the risk of bleeding without any tradeoff in efficacy (i.e., thrombotic complications). This strategy has shown consistent findings in a number of different clinical settings of patients undergoing PCI. Nevertheless, unanswered questions on the ideal patient and the precise P2Y₁₂ monotherapy regimen warrant further investigation.

The need of a multicomponent guiding approach to personalize clopidogrel treatment

Patients bearing polymorphisms termed CYP2C19 loss of function (LoF) alleles and ABCB1-C3435T may do not properly respond to standard dosage of clopidogrel and have an increased risk of thrombosis. Moreover, co-administration of proton pump inhibitors (PPIs) and clopidogrel may attenuate the antiplatelet effect. The role of pharmacogenetics and PPIs/clopidogrel drug-drug interaction has been extensively investigated in patients with acute coronary syndrome after stent implantation (ACS/PCI), while data in patients undergoing vascular surgery are scarce. Here we have performed a systematic review to evaluate the available literature in such a clinical setting and have discussed the controversies about the use of CYP2C19 pharmacogenetics and platelet function testing to personalize clopidogrel treatment. In addition, we have made a comparison of the literature data with our findings concerning patients eligible for vascular surgery and treated with clopidogrel, in whom we used a combined management based on the CYP2C19 and ABCB1 pharmacogenetic testing with monitoring of therapeutic adherence and PPIs-clopidogrel interaction. Both our data and those produced during both observational studies and randomized clinical trials confirm the validity of pharmacogenetics to personalize clopidogrel treatment and stress the importance to make a drug monitoring considering all the known variables, potentially responsible for treatment failure. However, the American Heart Association and the European Cardiovascular Society recommend against the routine use of clopidogrel pharmacogenetic testing. An update of the international guidelines on antiplatelet therapy, incorporating the evidence related to CYP2C19 pharmacogenetics and PPIs-clopidogrel drug-drug interactions is warranted both in ACS/PCI patients and subjects undergoing vascular surgery.

Impact of the CYP2C19*17 Allele on Outcomes in Patients Receiving Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention

Genotyping for CYP2C19 no function alleles to guide antiplatelet therapy after percutaneous coronary intervention (PCI) improves clinical outcomes. Although results for the increased function CYP2C19*17 allele are also reported, its clinical relevance in this setting remains unclear. A collaboration across nine sites examined antiplatelet therapy prescribing and clinical outcomes in 3,342 patients after implementation of CYP2C19-guided antiplatelet therapy. Risk of major atherothrombotic and bleeding events over 12 months after PCI were compared across cytochrome P450 2C19 isozyme (CYP2C19) metabolizer phenotype and antiplatelet therapy groups by proportional hazards regression. Clopidogrel was prescribed to a similar proportion of CYP2C19 normal (84.5%), rapid (82.9%), and ultrarapid metabolizers (80.6%) (P = 0.360). Clopidogrel-treated normal metabolizers (20.4 events/100 patient-years; adjusted hazard ratio (HR) 1.00, 95% confidence interval (CI), 0.75-1.33, P = 0.993) and clopidogrel-treated rapid or ultrarapid metabolizers (19.1 events/100 patient-years; adjusted HR 0.95, 95% CI, 0.69-1.30, P = 0.734) exhibited no difference in major atherothrombotic events compared with patients treated with prasugrel or ticagrelor (17.6 events/100 patient-years). In contrast, clopidogrel-treated intermediate and poor metabolizers exhibited significantly higher atherothrombotic event risk compared with prasugrel/ticagrelor-treated patients (adjusted HR 1.56, 95% CI, 1.12-2.16, P = 0.008). When comparing clopidogrel-treated rapid or ultrarapid metabolizers to normal metabolizers, no difference in atherothrombotic (adjusted HR 0.97, 95% CI, 0.73-1.29, P = 0.808) or bleeding events (adjusted HR 1.34, 95% CI, 0.83-2.17, P = 0.224) were observed. In a real-world setting of genotype-guided antiplatelet therapy, the CYP2C19*17 allele did not significantly impact post-PCI prescribing decisions or clinical outcomes. These results suggest the CYP2C19 *1/*17 and *17/*17 genotypes have limited clinical utility to guide antiplatelet therapy after PCI.

Clopidogrel drug interactions: a review of the evidence and clinical implications

INTRODUCTION

Patients with cardiovascular disease are commonly affected by a number of comorbidities leading to a high prevalence of polypharmacy. Polypharmacy increases the probability of drug-drug interactions (DDIs). Amongst these, DDIs involving clopidogrel, the most commonly utilized platelet P2Y₁₂ inhibitor, is a topic of potential clinical concern.

AREAS COVERED

This article reviews DDIs between clopidogrel and drugs which are widely used in clinical practice. In particular, drugs shown to interfere with the pharmacodynamic and pharmacokinetic effects of clopidogrel and the clinical implications of these findings are reviewed. These drugs include inhibitors of gastric acid secretion, statins, calcium channel blockers, antidiabetic agents, and antimicrobial agents. For the references, we searched PubMed, EMBASE, or the Cochrane Library.

EXPERT OPINION

Clopidogrel-drug interactions are common. Most of these DDIs are limited to laboratory findings showing an impact on clopidogrel-induced antiplatelet effects. While variability in clopidogrel-induced antiplatelet effects is known to affect clinical outcomes, with high platelet reactivity being associated with thrombotic complications among patients undergoing coronary stenting, most studies assessing the clinical implications of clopidogrel-drug interactions have not shown to significantly affect outcomes. However, awareness of these DDIs remains important for optimizing the selection of concomitant therapies.

Prasugrel Versus Ticagrelor in Patients With CYP2C19 Loss-of-Function Genotypes: Results of a Randomized Pharmacodynamic Study in a Feasibility Investigation of Rapid Genetic Testing

The feasibility of rapid genetic testing in patients undergoing percutaneous coronary intervention (PCI) and the comparison of the pharmacodynamic effects of prasugrel versus ticagrelor among carriers of cytochrome P450 2C19 loss-of-function alleles treated with PCI has been poorly explored. Rapid genetic testing using the Spartan assay was shown to be feasible and provides results in a timely fashion in a real-world setting of patients undergoing coronary angiography (n = 781). Among patients (n = 223, 28.5%), carriers of at least 1 loss-of-function allele treated with PCI (n = 65), prasugrel, and ticagrelor achieve similar levels of platelet inhibition. (A Pharmacodynamic Study Comparing Prasugrel Versus Ticagrelor in Patients Undergoing PCI With CYP2C19 Loss-of-function [NCT02065479]).

Efficacy and safety of clopidogrel versus prasugrel and ticagrelor for coronary artery disease treatment in patients with CYP2C19 LoF alleles: a systemic review and meta-analysis

AIM

We performed a systematic review and meta-analysis to compare the efficacy and safety of ticagrelor and prasugrel with those of clopidogrel in CYP2C19 reduced-metabolizers.

METHODS

PubMed, Cochrane and Web of Science were systematically searched for randomized controlled trials or cohort studies up to January 2020. The primary endpoint was major adverse cardiovascular events (MACE), including cardiovascular (CV) death, all-cause death, myocardial infarction (MI), stent thrombosis and stroke. The secondary endpoint was bleeding. Pooled effects were measured by relative risk (RR) with 95% confidence intervals (CIs). Publication bias was evaluated with Egger's regression test and adjusted by trim and fill method.

RESULTS

Twelve studies comprising 5829 CV patients with CYP2C19 loss-of-function alleles were included. Patients who received ticagrelor or prasugrel showed a lower risk of MACE than those who received clopidogrel (RR 0.524; 95% CI: 0.375, 0.731). The former also had lower risks of CV death (RR 0.409; 95% CI: 0.177, 0.946), all-cause death (RR 0.441; 95% CI: 0.263, 0.739), MI (RR 0.554; 95% CI: 0.414, 0.741) and stent thrombosis (RR 0.587; 95% CI: 0.348, 0.988) than the latter patient group. The risk of stroke was not significantly different between patients receiving the alternatives and those receiving clopidogrel (RR 0.605; 95% CI: 0.257, 1.425). Major and minor bleeding risk was not significantly different between patients treated with alternatives and clopidogrel (RR 1.019; 95% CI: 0.827, 1.260 and RR 1.235; 95% CI: 0.581, 2.628, respectively).

CONCLUSION

CYP2C19 reduced-metabolizers can expect better clinical outcome on using prasugrel or ticagrelor rather than clopidogrel.

Concepts Driving Pharmacogenomics Implementation Into Everyday Healthcare

Pharmacogenomics (PGx) is often promoted as the domain of precision medicine with the greatest potential to readily impact everyday healthcare. Rapid advances in PGx knowledge derived from extensive basic and clinical research along with decreasing costs of laboratory testing have led to an increased interest in PGx and expectations of imminent clinical translation with substantial clinical impact. However, the implementation of PGx into clinical workflows is neither simple nor straightforward, and comprehensive processes and multidisciplinary collaboration are required. Several national and international institutions have pioneered models for implementing clinical PGx, and these initial models have led to a better understanding of unresolved challenges. In this review, we have categorized and explored the most relevant of these challenges to highlight potential gaps and present possible solutions. We describe the ongoing need for basic and clinical research to drive further developments in evidence-based medicine. Integration into daily clinical workflows introduces new challenges requiring innovative solutions; specifically those related to the electronic health record and embedded clinical decision support. We describe advances in PGx testing and result reporting and describe the critical need for increased standardization in these areas across laboratories. We also explore the complexity of the PGx knowledge required for clinical practice and the need for educational strategies to ensure adequate understanding among members of current and future healthcare teams. Finally, we evaluate knowledge obtained from previous implementation efforts and discuss how to best apply these learnings to future projects. Despite these challenges, the future of precision medicine appears promising due to the rapidity of recent advances in the field and current multidisciplinary efforts to effectively translate PGx to everyday clinical practice.

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.

Pharmacodynamics During Transition Between Platelet P2Y12 Inhibiting Therapies

Several platelet P2Y₁₂ inhibiting agents, both oral and intravenous, are available for clinical use. The oral P2Y₁₂ inhibitors comprise clopidogrel, prasugrel, and ticagrelor. Cangrelor is the only intravenous P2Y₁₂ inhibitor. Numerous pharmacodynamic studies have been performed to assess the impact of P2Y₁₂ inhibitor switching on platelet reactivity profiles and to define the optimal strategy if switching is needed, with the goal of minimizing the risk of having inadequate platelet inhibition due to potential drug-drug interactions occurring during the drug overlap phase. This article provides an overview of pharmacodynamic studies assessing switching between P2Y₁₂ inhibitors and recommendations on switching modalities based on these findings.

Personalized antiplatelet therapy in patients with coronary artery disease undergoing percutaneous coronary intervention: A network meta-analysis of randomized clinical trials

OBJECTIVES

This study aimed to evaluate the efficacy and safety of genotype- and phenotype-guided intensified antiplatelet therapy compared with conventional therapy in patients undergoing stent implantation.

BACKGROUND

Although potent P2Y₁₂ receptor inhibitors are recommended for percutaneous coronary intervention (PCI)-treated acute coronary syndrome, their usage is limited by a high bleeding risk. Therefore, personalized antiplatelet therapy could provide a valuable foundation for selection of antiplatelet therapy in this population.

METHODS

We conducted a Bayesian network meta-analysis for all randomized clinical trials (RCTs) that evaluated genotype- and/or phenotype-guided therapy in PCI-treated coronary artery disease.

RESULTS

Thirteen RCTs were included with a total of 6,845 patients. The results showed no significant differences in major adverse cardiovascular events (MACE) between the treatment options ((genotype guided vs. standard of care; OR 0.64; 95% CI: 0.38-1.05) and (phenotype vs. standard of care; OR 0.93; 95% CI: 0.54-1.37)). In addition, no significant differences were demonstrated in bleeding events ((genotype guided vs. standard of care; OR 0.73; 95% CI: 0.45-1.25) and (phenotype vs. standard of care; OR 0.90; 95% CI: 0.62-1.39)).

CONCLUSIONS

In this mixed treatment meta-analysis of RCTs, neither genotype- nor phenotype-guided antiplatelet therapy in patients with PCI-treated coronary artery disease was superior to conventional therapy.

De-escalation from ticagrelor to clopidogrel in acute coronary syndrome patients: a systematic review and meta-analysis

De-escalation from ticagrelor to clopidogrel in acute coronary syndrome (ACS) may occur for a variety of reasons, including side effects (bleeding and non-bleeding) and costs. This study sought to assess the prevalence of de-escalation from ticagrelor to clopidogrel and the occurrence of adverse clinical outcomes following de-escalation. We conducted a systematic review of clinical trials and real-world studies in ACS patients treated with ticagrelor. Real-world data on the prevalence of de-escalation during hospitalization or at discharge, after hospital discharge, and during the whole study period were included for meta-analysis. Major adverse cardiovascular events (MACE) and bleeding events occurring after de-escalation were also assessed. A total of 12 studies were eligible for meta-analysis of the prevalence of de-escalation. De-escalation from ticagrelor to clopidogrel therapy occurred with a mean prevalence of 19.8% [95% confidence interval (CI) 11.2-28.4%]. De-escalation occurred more frequently in-hospital or at discharge than after hospital discharge (23.7% vs. 15.8%). For assessment of clinical outcomes, a total of six studies were eligible for meta-analysis. Mean rate of MACE for patients with de-escalation was 2.1% (95% CI 1.1-4.1%) and the rate of major bleeding events was 1.3% (95% CI 0.4-4.5%). In conclusion, de-escalation commonly occurs in real-world practice. Although rates of major cardiovascular and bleeding events in this analysis were generally low, the profile of patients suitable for de-escalation, the impact of de-escalation on adverse clinical outcomes and how this is affected by the timing after index ACS warrants further large-scale investigation.

CYP2C19 pharmacogenetics in patients undergoing coronary stent placement: Is it time to test everyone?

Although there are no current guidelines for when to test patients for CYP2C19 loss of function alleles, the current state of evidence suggests that testing high-risk patients should be considered. Based on this meta-analysis, there is no reduction in major adverse cardiovascular events (MACE) in patients that receive genotype-guided antiplatelet therapy, but there is a significant reduction in MACE when including only patients who present with acute coronary syndromes and a significant reduction in myocardial infarction. Genotype-guided therapy shows promise but requires further study to solidify this approach, and to determine which patients derive the most benefit.

Cardiovascular Risk Reduction: A Pharmacotherapeutic Update for Antiplatelet Medications

This update presents evidence for new antiplatelet therapies including modified P2Y₁₂ inhibitors and a new class of thromboxane antagonists. Discussed are emerging data on established antihyperlipidemic medications that support an additional antiplatelet effect. Current information about the effectiveness of several bleeding reversal agents is discussed, and the concept of personalized antiplatelet therapy, wherein selection of an antiplatelet therapy is based on genetic factors or laboratory testing that predict response to therapy and risk of adverse effects. Finally, future drug targets are introduced and drug interactions that can be leveraged to design more effective and safe antiplatelet therapies are described.

Candidate gene and pathway analyses identifying genetic variations associated with prasugrel pharmacokinetics and pharmacodynamics

AIM

We aimed to investigate the genetic polymorphisms and pharmacogenetic variability associated with the pharmacodynamics (PD) and pharmacokinetics (PK) of prasugrel, in healthy Han Chinese subjects.

PATIENTS & METHODS

Healthy, native, Han Chinese subjects (n = 36) aged 18 to 45 years with unknown genotypes were included. All subjects received a loading dose (LD) on day 1 and a maintenance dose (MD) from day 2 until day 11. Candidate gene association and gene-set analysis of biological pathways related to prasugrel and platelet activity were analyzed.

RESULTS

28 SNPs of 17 candidate genes previously associated with prasugrel or platelet activity were selected after a literature search. In the 30 mg LD groups (n = 24), ITGA2-rs28095 was found to be significantly associated with the P2Y12 reaction unit (PRU) value at 24 h after the LD (p = 0.015). 165 study genes related to platelet activation-related processes and prasugrel activity were selected from the MSigDB database, including curated gene sets from KEGG, Bio Carta, and Gene Cards. 14 SNPs of 9 genes were found to be significantly correlated both at 24 h and 12 days after LD: ADAMTSL1, PRKCA, ITPR2, P2RY12, P2RY14, PLCB4, PRKG1, ADCY1, and LYN. Seven SNPs of 6 protein-coding genes associated with area under the concentration-time curve (AUC0-tlast) were significantly identified among the 47 selected genes, including ADAMTSL1, CD36, P2RY1, PCSK9, PON1, and SCD.

CONCLUSION

These results show that genetic variation affects the PK and PD of prasugrel in normal individuals. Further studies with larger sample sizes are required to explore whether the SNPs are associated only with prasugrel activity or also with cardiovascular events and all-cause mortality.

Multisite Investigation of Strategies for the Implementation of CYP2C19 Genotype-Guided Antiplatelet Therapy

CYP2C19 genotype-guided antiplatelet therapy following percutaneous coronary intervention is increasingly implemented in clinical practice. However, challenges such as selecting a testing platform, communicating test results, building clinical decision support processes, providing patient and provider education, and integrating methods to support the translation of emerging evidence to clinical practice are barriers to broad adoption. In this report, we compare and contrast implementation strategies of 12 early adopters, describing solutions to common problems and initial performance metrics for each program. Key differences between programs included the test result turnaround time and timing of therapy changes, which are both related to the CYP2C19 testing model and platform used. Sites reported the need for new informatics infrastructure, expert clinicians such as pharmacists to interpret results, physician champions, and ongoing education. Consensus lessons learned are presented to provide a path forward for those seeking to implement similar clinical pharmacogenomics programs within their institutions.

Synthesis of a Novel Series of Amino Acid Prodrugs Based on Thienopyridine Scaffolds and Evaluation of Their Antiplatelet Activity

The thienopyridines class of drugs used as P2Y₁₂ receptor antagonists plays a vital role in antiplatelet therapy. To further optimized this compound class, we designed and synthesized a series of amino acid prodrugs of 2-hydroxytetrahydrothienopyridine. All compounds were then evaluated for their inhibitory effect on ADP-induced platelet aggregation in rats and then ED₅₀ and bleeding time of the most potent compounds were compared with commercial drugs. The results showed compound 5c could be a potent and safe candidate for further research.

Clinical implementation of rapid CYP2C19 genotyping to guide antiplatelet therapy after percutaneous coronary intervention

BACKGROUND

The CYP2C19 nonfunctional genotype reduces clopidogrel effectiveness after percutaneous coronary intervention (PCI). Following clinical implementation of CYP2C19 genotyping at University Florida (UF) Health Shands Hospital in 2012, where genotype results are available approximately 3 days after PCI, testing was expanded to UF Health Jacksonville in 2016 utilizing a rapid genotyping approach. We describe metrics with this latter implementation.

METHODS

Patients at UF Health Jacksonville undergoing left heart catheterization with intent to undergo PCI were targeted for genotyping using the Spartan RX™ system. Testing metrics and provider acceptance of testing and response to genotype results were examined, as was antiplatelet therapy over the 6 months following genotyping.

RESULTS

In the first year, 931 patients, including 392/505 (78%) total patients undergoing PCI, were genotyped. The median genotype test turnaround time was 96 min. Genotype results were available for 388 (99%) PCI patients prior to discharge. Of 336 genotyped PCI patients alive at discharge and not enrolled in an antiplatelet therapy trial, 1/6 (17%) poor metabolizers (PMs, with two nonfunctional alleles), 38/93 (41%) intermediate metabolizers (IMs, with one nonfunctional allele), and 119/237 (50%) patients without a nonfunctional allele were prescribed clopidogrel (p = 0.110). Clopidogrel use was higher among non-ACS versus ACS patients (78.6% vs. 42.2%, p < 0.001). Six months later, among patients with follow-up data, clopidogrel was prescribed in 0/4 (0%) PMs, 33/65 (51%) IMs, and 115/182 (63%) patients without a nonfunctional allele (p = 0.008 across groups; p = 0.020 for PMs versus those without a nonfunctional allele).

CONCLUSION

These data demonstrate that rapid genotyping is clinically feasible at a high volume cardiac catheterization facility and allows informed chronic antiplatelet prescribing, with lower clopidogrel use in PMs at 6 months. Trial registration ClinicalTrials.gov Identifier: NCT02724319; registered March 31, 2016; https://www.clinicaltrials.gov/ct2/show/NCT02724319?term=angiolillo&rank=7.

Pharmacogenomic Approach to Selecting Antiplatelet Therapy in Patients With Acute Coronary Syndromes: The PHARMCLO Trial

BACKGROUND

Although clopidogrel is still frequently used in patients with acute coronary syndromes (ACS), its efficacy is hampered by interpatient response variability caused by genetic polymorphisms associated with clopidogrel's metabolism.

OBJECTIVES

The goal of this study was to evaluate whether selecting antiplatelet therapy (clopidogrel, prasugrel, or ticagrelor) on the basis of a patient's genetic and clinical characteristics leads to better clinical outcomes compared with the standard of care, which bases the selection on clinical characteristics alone.

METHODS

Patients hospitalized for ACS were randomly assigned to standard of care or the pharmacogenomic arm, which included the genotyping of ABCB1, CYP2C19*2, and CYP2C19*17 using an ST Q3 system that provides data within 70 min at each patient's bedside. The patients were followed up for 12 ± 1 month for the primary composite endpoint of cardiovascular death and the first occurrence of nonfatal myocardial infarction, nonfatal stroke, and major bleeding defined according to Bleeding Academic Research Consortium type 3 to 5 criteria.

RESULTS

After enrolling 888 patients, the study was prematurely stopped. Clopidogrel was used more frequently in the standard-of-care arm (50.7% vs. 43.3%), ticagrelor in the pharmacogenomic arm (42.6% vs. 32.7%; p = 0.02), and prasugrel was equally used in both arms. The primary endpoint occurred in 71 patients (15.9%) in the pharmacogenomic arm and in 114 (25.9%) in the standard-of-care arm (hazard ratio: 0.58; 95% confidence interval: 0.43 to 0.78; p < 0.001).

CONCLUSIONS

A personalized approach to selecting antiplatelet therapy for patients with ACS may reduce ischemic and bleeding events. (Pharmacogenetics of Clopidogrel in Patients With Acute Coronary Syndromes [PHARMCLO]; NCT03347435).