Dual antiplatelet therapy guided by platelet function testing

Current Strategies to Guide the Antiplatelet Therapy in Acute Coronary Syndromes

The role of antiplatelet therapy in patients with acute coronary syndromes is a moving target with considerable novelty in the last few years. The pathophysiological basis of the treatment depends on platelet biology and physiology, and the interplay between these aspects and clinical practice must guide the physician in determining the best therapeutic options for patients with acute coronary syndromes. In the present narrative review, we discuss the latest novelties in the antiplatelet therapy of patients with acute coronary syndromes. We start with a description of platelet biology and the role of the main platelet signal pathways involved in platelet aggregation during an acute coronary syndrome. Then, we present the latest evidence on the evaluation of platelet function, focusing on the strengths and weaknesses of each platelet's function test. We continue our review by describing the role of aspirin and P2Y12 inhibitors in the treatment of acute coronary syndromes, critically appraising the available evidence from clinical trials, and providing current international guidelines and recommendations. Finally, we describe alternative therapeutic regimens to standard dual antiplatelet therapy, in particular for patients at high bleeding risk. The aim of our review is to give a comprehensive representation of current data on antiplatelet therapy in patients with acute coronary syndromes that could be useful both for clinicians and basic science researchers to be up-to-date on this complex topic.

Personalised antiplatelet therapies for coronary artery disease: what the future holds

Coronary artery disease (CAD) is one of the leading causes of death globally, and antiplatelet therapy is crucial for both its prevention and treatment. Antiplatelet drugs such as aspirin and P2Y12 inhibitors are commonly used to reduce the risk of thrombotic events, including myocardial infarction, stroke, and stent thrombosis. However, the benefits associated with the use of antiplatelet drugs also come with a risk of bleeding complications. The ever-growing understanding of the poor prognostic implications associated with bleeding has set the foundations for defining strategies that can mitigate such safety concern without any trade-off in antithrombotic protection. To this extent, personalised antiplatelet therapy has emerged as a paradigm that optimizes the balance between safety and efficacy by customizing treatment to the individual patient's needs and risk profile. Accurate risk stratification for both bleeding and thrombosis can aid in selecting the optimal antiplatelet therapy and prevent serious and life-threatening outcomes. Risk stratification has traditionally included clinical and demographic characteristics and has expanded to incorporate angiographic features and laboratory findings. The availability of bedside platelet function testing as well as rapid genotyping assays has also allowed for a more individualized selection of antiplatelet therapy. This review provides a comprehensive overview of the current state of the art and future trends in personalised antiplatelet therapy for patients with CAD, with emphasis on those presenting with an acute coronary syndrome and undergoing percutaneous coronary revascularization. The aim is to provide clinicians with a comprehensive understanding of personalised antiplatelet therapy and facilitate informed clinical decision-making.

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.

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.

Antiplatelet therapy after percutaneous coronary intervention

Antiplatelet therapy is key to reducing local thrombotic complications and systemic ischaemic events among patients undergoing percutaneous coronary interventions (PCI), but it is inevitably associated with increased bleeding. The continuous refinement in stent technologies, together with the high incidence of ischaemic recurrences after PCI and the understanding of prognostic implications associated with bleeding, have led to a substantial evolution in antiplatelet treatment regimens over the past decades. Numerous investigations have been conducted to better stratify patients undergoing PCI according to their ischaemic and bleeding risks and to implement antithrombotic regimens accordingly. Evidence from these investigations have resulted in a number of antithrombotic treatment options as recommended by recent guidelines. In this State-of-the-Art review we provide the rationale, summarise the evidence, and discuss current and future directions of antiplatelet treatment regimens after PCI.

Role of platelet function and genetic testing in patients undergoing percutaneous coronary intervention

Dual antiplatelet therapy (DAPT) represents the standard of care for patients undergoing percutaneous coronary intervention (PCI). Increasing evidence indicates that a "one-size-fits-all" approach with the use of a standard DAPT regimen for all patients undergoing PCI could lead to either suboptimal efficacy or prohibitively high bleeding in specific cohorts of patients. Moreover, the broad interindividual variability in response to P2Y₁₂ inhibitors can impact outcomes and resource utilization. Among the strategies proposed to provide a more balanced trade-off between bleeding and ischemic events at a single patient level, a guided selection of P2Y₁₂ inhibitors, by using platelet function or genetic testing, has shown promising results. In this review, we provide a focused summary of the rationale and evidence on the use of platelet function and genetic testing-guided antiplatelet therapy, and we explore the implications for their use in the modern setting of patients undergoing PCI.

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.

Antiplatelet therapy in percutaneous coronary intervention: latest evidence from randomized controlled trials

PURPOSE OF REVIEW

Antiplatelet therapy is key to reduce systemic and local thrombotic events among patients undergoing percutaneous coronary interventions (PCI). Antiplatelet treatment regimens have been subject to continuous changes over the years, with a dual antiplatelet therapy (DAPT), consisting of aspirin and a P2Y12 inhibitor representing the cornerstone of treatment in these patients.

RECENT FINDINGS

The need for less aggressive antithrombotic drugs to prevent local ischemic events with newer generation drug-eluting stent together with the increased understanding of the prognostic relevance of bleeding events in PCI patients, have prompted investigations aimed at identifying antiplatelet treatment regimens associated with a more favorable balance between ischemic and bleeding risks. Several key randomized controlled trials (RCTs) on antiplatelet regimens in patients undergoing PCI have been recently reported resulting in updates in practice guidelines.

SUMMARY

This manuscript provides an overview of the advancements in the field deriving from key RCTs on antiplatelet regimens in patients undergoing PCI.

Evolution of antithrombotic therapy in patients undergoing percutaneous coronary intervention: a 40-year journey

Since its introduction in 1977, percutaneous coronary intervention has become one of the most commonly performed therapeutic procedures worldwide. Such widespread diffusion, however, would have not been possible without a concomitant evolution of the pharmacotherapies associated with this intervention. Antithrombotic agents are fundamental throughout the management of patients undergoing coronary stent implantation, starting from the procedure itself to the long-term prevention of cardiovascular events. The last 40 years of interventional cardiology have seen remarkable improvements in both drug therapies and device technologies, which largely reflected a progressive understanding of the pathophysiological mechanisms of coronary artery disease, as well as procedure- and device-related adverse events. The purpose of this article is to provide an overview of the important milestones in antithrombotic pharmacology that have shaped clinical practice of today while also providing insights into knowledge gaps and future directions.

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.

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.

High glycated albumin is an independent predictor of low response to clopidogrel in ACS patients: a cross-sectional study

BACKGROUND

Glycated albumin (GA) is a marker of short-term glycemic control and is strongly associated with the occurrence of diabetes. Previous studies have shown an association between GA and the effect of clopidogrel therapy on ischemic stroke. However, limited information is available regarding this relationship in acute coronary syndrome (ACS) patients. In this study, we evaluated the effect of GA on platelet P2Y12 inhibition by clopidogrel in patients with ACS.

METHODS

Consecutive Chinese patients with ACS who received loading or maintenance doses of clopidogrel in addition to aspirin were recruited. At least 12 h after the patient had taken the clopidogrel dose, thromboelastography (TEG) and light transmittance aggregometry (LTA) were used to calculate the quantitative platelet inhibition rate to determine clopidogrel-induced antiplatelet reactivity. A prespecified cutoff of the maximum amplitude of adenosine diphosphate (ADP)-induced platelet-fibrin clot strength > 47 mm plus an ADP-induced platelet inhibition rate < 50% assessed by TEG or ADP-induced platelet aggregation > 40% assessed by LTA to indicate low responsiveness to clopidogrel were applied for evaluation. Patients were categorized into two groups based on a GA level of 15.5%, the cutoff point indicating the development of early-phase diabetes. Multivariate linear regression analysis was used to assess the interaction of GA with clopidogrel antiplatelet therapy.

RESULTS

A total of 1021 participants were evaluated, and 28.3% of patients (289 of 1021) had low responsiveness to clopidogrel assessed by TEG. In patients with elevated GA levels, low responsiveness to clopidogrel assessed by TEG was observed in 33.7% (139 of 412) of patients, which was a significantly higher rate than that in the lower-GA-level group (24.6%, P = 0.002). According to multivariate linear regression analysis, a GA level > 15.5% was independently associated with low responsiveness to clopidogrel after adjustment for age, sex and other conventional confounding factors. This interaction was not mediated by a history of diabetes mellitus. A GA level ≤ 15.5% was associated with a high positive value [75.4%, 95% CI 73.0-77.6%] for predicting a normal responsiveness to clopidogrel.

CONCLUSIONS

GA could be a potential biomarker to predict the effects of clopidogrel antiplatelet therapy in ACS patients and might be a clinical biomarker to guide DAPT de-escalation.

Point-of-care platelet function tests: relevance to arterial thrombosis and opportunities for improvement

Studies using whole blood platelet aggregometry as a laboratory research tool, provided important insights into the mechanism and modulators of platelet aggregation. Subsequently, a number of point-of-care (POC) platelet function tests (PFTs) were developed for clinical use, based on the concept that an individual’s thrombotic profile could be assessed in vitro by assessing the response to stimulation of platelet aggregation by specific, usually solo agonists such as adenosine diphosphate (ADP), collagen and thrombin. However, adjusting antiplatelet medication in order to improve the results of such POC PFTs has not translated into a meaningful reduction in cardiovascular events, which may be attributable to important differences between the POC PFT techniques and in vivo conditions, including patient-to-patient variability. Important limitations of most tests include the use of citrate-anticoagulated blood. Citrate directly and irreversibly diminishes platelet function and even after recalcification, it may result in altered platelet aggregation in response to ADP, epinephrine or collagen, and interfere with thrombin generation from activated platelets. Furthermore, most tests do not employ flowing blood and therefore do not assess the effect of high shear forces on platelets that initiate, propagate and stabilize arterial thrombi. Finally, the effect of endogenous thrombolysis, due to fibrinolysis and dislodgement, which ultimately determines the outcome of a thrombotic stimulus, is mostly not assessed. In order to accurately reflect an individual’s predisposition to arterial thrombosis, future tests of thrombotic status which overcome these limitations should be used, to improve cardiovascular risk prediction and to guide pharmacotherapy.

De-escalation therapy after acute coronary syndrome: is it reasonable to switch from prasugrel (or ticagrelor) to clopidogrel early?

Dual antiplatelet treatment (DAPT) is the treatment of choice to prevent atherothrombotic events in patients with acute coronary syndrome (ACS) treated with percutaneous interventions (PCIs). The availability of different P2Y12 inhibitors set the stage for costum made DAPT, as to achieve the highest profile of safety and efficacy. The de-escalation therapy for the newer and more powerful antiplatelet drugs, such as ticagrelor and prasugrel, to clopidogrel, is a strategy for patients with recent ACS, unfit for continuing DAPT for their high risk of bleeding, or side effects, or socio-economic reasons, but without a prohibitive ischaemic risk. There is a need for compelling clinical evidences able to provide the clinical cardiologist with the necessary information to decide the best antiplatelet strategy for each individual patient.

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]).

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.

Antithrombotic pharmacotherapy after transcatheter aortic valve implantation: an update

Introduction: Transcatheter aortic valve implantation (TAVI) is the treatment of choice for a large proportion of patients with severe aortic stenosis. Despite numerous technological and clinical advances, TAVI remains associated with thrombotic complications requiring antithrombotic pharmacotherapy, which exposes to the risk of bleeding, especially in elderly individuals. The optimal antithrombotic regimen following TAVI is uncertain and several investigations are ongoing. Areas covered: Clinical guidelines are mostly driven by observational trials and experts' opinions, thus resulting into low-grade level of evidence. The aim of the current review is to critically explore the epidemiology, pathophysiology and prognostic value of thrombotic and bleeding events after TAVI, and to review the current literature on antithrombotic strategies following the procedure. Expert opinion: Thrombotic and bleeding events remain major complications occurring in the frail population that is currently offered TAVI. Waiting for upcoming evidence from ongoing randomized clinical trials, tailoring antithrombotic therapies based on patients' characteristics, values and circumstances is a preferable approach.

Laboratory Monitoring of Platelet P2Y12 Receptor Inhibitors and Reversal of Antiplatelet Agents

OBJECTIVES

To review the use of laboratory tests for antiplatelet agents to determine escalation of antiplatelet therapy and for emergent reversal of P2Y12 inhibitors.

METHODS

A case scenario and review of cardiovascular and neurointerventional literature are described.

RESULTS

In cardiovascular disease patients, large randomized trials failed to demonstrate superiority of tailored antiplatelet regimens using the VerifyNow P2Y12 assay, where earlier studies had shown promise. Platelet transfusions restored platelet function measured by vasodilator-stimulated phosphoprotein, light transmission aggregometry, or thromboelastography but not VerifyNow P2Y12, with the most restoration for clopidogrel and the least for ticagrelor.

CONCLUSIONS

Current evidence does not support changing antiplatelet therapy based on the results of platelet function monitoring tests. For emergent reversal of P2Y12 inhibitors, test method can affect platelet dosing recommendations, as different methods may give different results.

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).