Updated Expert Consensus Statement on Platelet Function and Genetic Testing for Guiding P2Y12 Receptor Inhibitor Treatment in Percutaneous Coronary Intervention

Recent Advances in Antiplatelet Therapy in Complex Percutaneous Coronary Intervention

Antithrombotic therapy is the cornerstone of secondary cardiovascular prevention after percutaneous coronary intervention (PCI). Improvements in drug-eluting stent (DES) design and materials over the last 2 decades have prompted the development of new antithrombotic strategies. Current guidelines recommend to tailor dual antiplatelet therapy (DAPT) according to clinical presentation and individual ischemic and bleeding risk. Given the growing number of complex PCI procedures performed nowadays, it is a priority to define the optimal antithrombotic treatment in this challenging patient subset. In this review article, we sought to summarize and discuss the current evidence on antiplatelet therapy in patients undergoing complex PCI.

Effects of DPP4 Inhibitor in Platelet Reactivity and Other Cardiac Risk Markers in Patients with Type 2 Diabetes and Acute Myocardial Infarction

Background: The management of acute myocardial infarction (AMI) presents several challenges in patients with diabetes, among them the higher rate of recurrent thrombotic events, hyperglycemia and risk of subsequent heart failure (HF). The objective of our study was to evaluate effects of DPP-4 inhibitors (DPP-4i) on platelet reactivity (main objective) and cardiac risk markers. Methods: We performed a single-center double-blind randomized trial. A total of 70 patients with type 2 diabetes (T2DM) with AMI Killip ≤2 on dual-antiplatelet therapy (aspirin plus clopidogrel) were randomized to receive sitagliptin 100 mg or saxagliptin 5 mg daily or matching placebo. Platelet reactivity was assessed at baseline, 4 days (primary endpoint) and 30 days (secondary endpoint) after randomization, using VerifyNow Aspirin™ assay, expressed as aspirin reaction units (ARUs); B-type natriuretic peptide (BNP) in pg/mL was assessed at baseline and 30 days after (secondary endpoint). Results: Mean age was 62.6 ± 8.8 years, 45 (64.3%) male, and 52 (74.3%) of patients presented with ST-segment elevation MI. For primary endpoint, there were no differences in mean platelet reactivity (p = 0.51) between the DPP-4i (8.00 {−65.00; 63.00}) and placebo (−14.00 {−77.00; 52.00}) groups, as well in mean BNP levels (p = 0.14) between DPP-4i (−36.00 {−110.00; 15.00}) and placebo (−13.00 {−50.00; 27.00}). There was no difference between groups in cardiac adverse events. Conclusions: DPP4 inhibitor did not reduce platelet aggregation among patients with type 2 diabetes hospitalized with AMI. Moreover, the use of DPP-4i did not show an increase in BNP levels or in the incidence of cardiac adverse events. These findings suggests that DPP-4i could be an option for management of T2DM patients with acute MI.

Current and Future Insights for Optimizing Antithrombotic Therapy to Reduce the Burden of Cardiovascular Ischemic Events in Patients with Acute Coronary Syndrome

The pharmacological treatment strategies for acute coronary syndrome (ACS) in recent years are constantly evolving to develop more potent antithrombotic agents, as reflected by the introduction of more novel P2Y₁₂ receptor inhibitors and anticoagulants to reduce the ischemic risk among ACS patients. Despite the substantial improvements in the current antithrombotic regimen, a noticeable number of ACS patients continue to experience ischemic events. Providing effective ischemic risk reduction while balancing bleeding risk remains a clinical challenge. This updated review discusses the currently approved and widely used antithrombotic agents and explores newer antithrombotic treatment strategies under development for the initial phase of ACS.

Clinical pharmacology of antiplatelet drugs

INTRODUCTION

Platelets play a key role in arterial thrombosis and antiplatelet therapy is pivotal in the treatment of cardiovascular disease. Current antiplatelet drugs target different pathways of platelet activation and show specific pharmacodynamic and pharmacokinetic characteristics, implicating clinically relevant drug-drug interactions.

AREAS COVERED

This article reviews the role of platelets in hemostasis and cardiovascular thrombosis, and discusses the key pharmacodynamics, drug-drug interactions and reversal strategies of clinically used antiplatelet drugs.

EXPERT OPINION

Antiplatelet therapies target distinct pathways of platelet activation: thromboxane A₂ synthesis, adenosine diphosphate-mediated signaling, integrin α_IIbβ₃ (GPIIb/IIIa), thrombin-mediated platelet activation via the PAR1 receptor and phosphodiesterases. Key clinical drug-drug interactions of antiplatelet agents involve acetylsalicylic acid - ibuprofen, clopidogrel - omeprazole, and morphine - oral P2Y₁₂ inhibitors, all of which lead to an attenuated antiplatelet effect. Platelet function and genetic testing and the use of scores (ARC-HBR, PRECISE-DAPT, ESC ischemic risk definition) may contribute to a more tailored antiplatelet therapy. High on-treatment platelet reactivity presents a key problem in the acute management of ST-elevation myocardial infarction (STEMI). A treatment strategy involving early initiation of an intravenous antiplatelet agent may be able to bridge the gap of insufficient platelet inhibition in high ischemic risk patients with STEMI.

Impact of diabetes mellitus on the pharmacodynamic effects of prasugrel and ticagrelor after switching from clopidogrel in patients with coronary artery disease

Switching P2Y₁₂ inhibitors is common in clinical practice. However, data on the pharmacodynamic (PD) effects of switching in clinical settings characterized by high platelet reactivity, such as diabetes mellitus (DM), are limited. This is a post-hoc analysis from a prospective, randomized, open-label study conducted in coronary artery disease patients comparing the PD effects of loading dose (LD) and maintenance dose regimens of prasugrel vs ticagrelor according to DM status. A total of 110 patients were enrolled: 42 (38%) with DM and 68 (62%) without DM. All patients were on maintenance dual antiplatelet therapy with aspirin and clopidogrel. PD assessments were performed using whole blood vasodilator-stimulated phosphoprotein (VASP), with results quantified by the platelet reactivity index (PRI), VerifyNow P2Y12 (VN-P2Y12) with results reported as P2Y12 reaction units (PRU), and light transmittance aggregometry (LTA) following 20 and 5 µM adenosine diphosphate stimuli with results reported as maximum platelet aggregation (MPA). PD assessments were performed at baseline (while on clopidogrel), 30 min after LD, 2 h after LD, and 1 week after LD. Overall, platelet reactivity was higher in DM than in non-DM patients while on clopidogrel therapy. After switching to either prasugrel or ticagrelor, platelet reactivity dropped but remained significantly higher among patients with DM at 30 min with all tests (VN-PRU p < 0.01, MPA 20 µM p < 0.01, VASP-PRI p = 0.02) and at 2 h with VN-PRU (p < 0.01) and LTA-MPA 20 µM (p < 0.01) but not with VASP-PRI (p = 0.19). There were no significant differences between prasugrel and ticagrelor both among patients with or without DM, except for lower LTA-MPA 20 at 30 min (p < 0.01) among non-DM patients treated with prasugrel. Patients with DM treated with clopidogrel have higher platelet reactivity compared to patients without DM. Although platelet reactivity markedly reduces to a similar extent after switching to prasugrel or ticagrelor, patients with DM persist with increased platelet reactivity compared to patients without DM.Study registration: ClinicalTrials.gov identifier: NCT01852175.

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.

Evaluation of race and ethnicity disparities in outcome studies of CYP2C19 genotype-guided antiplatelet therapy

Dual antiplatelet therapy with a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor) and aspirin remains the standard of care for all patients undergoing percutaneous coronary intervention (PCI). It is well-established that patients carrying CYP2C19 no function alleles have impaired capacity to convert clopidogrel into its active metabolite and thus, are at higher risk of major adverse cardiovascular events (MACE). The metabolism and clinical effectiveness of prasugrel and ticagrelor are not affected by CYP2C19 genotype, and accumulating evidence from multiple randomized and observational studies demonstrates that CYP2C19 genotype-guided antiplatelet therapy following PCI improves clinical outcomes. However, most antiplatelet pharmacogenomic outcome studies to date have lacked racial and ethnic diversity. In this review, we will (1) summarize current guideline recommendations and clinical outcome evidence related to CYP2C19 genotype-guided antiplatelet therapy, (2) evaluate the presence of potential racial and ethnic disparities in the major outcome studies supporting current genotype-guided antiplatelet therapy recommendations, and (3) identify remaining knowledge gaps and future research directions necessary to advance implementation of this precision medicine strategy for dual antiplatelet therapy in diverse, real-world clinical settings.

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.

P2Y12-inhibitor monotherapy after coronary stenting: are all P2Y12-inhibitors equal?

INTRODUCTION

P2Y₁₂-inhibitor monotherapy following 1-3 months of dual antiplatelet therapy (DAPT) reduces (major) bleeding without an apparent increase in ischemic events and has therefore emerged as an alternative to 6-12 months of DAPT following percutaneous coronary intervention (PCI). However, there are important differences between the available P2Y₁₂-inhibitors (clopidogrel, prasugrel, and ticagrelor) as agents of choice for P2Y₁₂-inhibitor monotherapy.

AREAS COVERED

This review critically appraises the evidence for P2Y₁₂-inhibitor monotherapy after PCI using either clopidogrel, prasugrel, or ticagrelor. Furthermore, we discuss ongoing trials and future directions for research.

EXPERT OPINION

P2Y₁₂-inhibitor monotherapy following 1-3 months of DAPT is an alternative to 6-12 months of DAPT following PCI. Ticagrelor may be considered the current preferred option due to its reliable effect on platelet reactivity and its predominant use in clinical trials. Prasugrel could serve as a useful substitute for those not tolerating ticagrelor, but more research into prasugrel monotherapy is warranted. Alternatively, clopidogrel can be used, although there are concerns of high platelet reactivity, especially when genotyping and/or platelet function testing are not used. Future research will need to address the minimal duration of DAPT before switching to P2Y₁₂-inhibitor monotherapy and what the optimal antithrombotic therapy beyond 12 months is.

Protease-activated receptor-mediated platelet aggregation in patients with type 2 diabetes on potent P2Y12 inhibitors

BACKGROUND

Antiplatelet therapy is a cornerstone in the secondary prevention of ischemic events following percutaneous coronary intervention (PCI). The new P2Y₁₂ receptor inhibitors prasugrel and ticagrelor have been shown to improve patients' outcomes. Whether or not these drugs have equal efficacy in individuals with or without diabetes is disputed. Furthermore, platelets can be activated by thrombin, which is, at least in part, independent of P2Y₁₂ -mediated platelet activation. Protease-activated receptor (PAR)-1 and -4 are thrombin receptors on human platelets. We sought to compare the in vitro efficacy of prasugrel (n = 121) and ticagrelor (n = 99) to inhibit PAR-mediated platelet aggregation in individuals with type 2 diabetes (prasugrel n = 26, ticagrelor n = 29).

MATERIALS AND METHODS

We compared P2Y₁₂ -, PAR-1- and PAR-4-mediated platelet aggregation as assessed by multiple electrode platelet aggregometry between prasugrel- and ticagrelor-treated patients without and with type 2 diabetes who underwent acute PCI.

RESULTS

Overall, there were no differences of P2Y₁₂ -, PAR-1- and PAR-4-mediated platelet aggregation between prasugrel- and ticagrelor-treated patients. However, both drugs inhibited P2Y₁₂ -mediated platelet aggregation stronger, and thereby to a similar extent in patients with type 2 diabetes than in those without diabetes. There was no correlation between either P2Y₁₂ -, or PAR-1- or PAR-4-mediated platelet aggregation and levels of HbA1c or the body mass index (BMI). However, we observed patients with high residual platelet reactivity in response to PAR-1 and PAR-4 stimulation in all cohorts.

CONCLUSION

Prasugrel and ticagrelor inhibit P2Y₁₂ - and PAR-mediated platelet aggregation in individuals with diabetes to a similar extent, irrespective of HbA_1c levels and BMI.

Thrombelastography Compared with Multiple Impedance Aggregometry to Assess High On-Clopidogrel Reactivity in Patients with Atrial Fibrillation Undergoing Percutaneous Coronary Intervention

Background: High on-clopidogrel platelet reactivity (HPR) following percutaneous coronary intervention (PCI) is associated with increased ischemic risk. It is unclear whether conventional definitions of HPR apply to patients with concomitant oral anticoagulation (OAC). This study aimed to compare the performance of multiple platelet aggregometry (MEA) and thrombelastography (TEG) to detect HPR in patients with atrial fibrillation (AF) and indication for an OAC. Methods: In this observational single-center cohort study, MEA and TEG were performed in patients with AF with an indication for OAC on day 1 to 3 after PCI. The primary outcome was HPR as assessed by MEA (ADP area under the curve ≥ 46 units [U]) or TEG (MAADP ≥ 47 mm), respectively. The secondary exploratory outcomes were a composite of all-cause death, myocardial infarction (MI) or stroke and bleeding, as defined by the International Society on Thrombosis and Hemostasis, at 6 months. Results: Platelet function of 39 patients was analyzed. The median age was 78 (interquartile range [IQR] was 72−82) years. 25 (64%) patients were male, and 19 (49%) presented with acute coronary syndrome. All patients received acetylsalicylic acid and clopidogrel prior to PCI. Median (IQR) ADP-induced aggregation, MAADP, TRAP-induced aggregation, and MAthrombin were 9 (6−15) U, 50 (43−60) mm, 54 (35−77) U and 65 (60−67) mm, respectively. The rate of HPR was significantly higher if assessed by TEG compared with MEA (25 [64%] vs. 1 [3%]; p < 0.001). Within 6 months, four (10%) deaths, one (3%) MI and nine (23%) bleeding events occurred. Conclusion: In patients with AF undergoing PCI, the rates of HPR detected by TEG were significantly higher compared with MEA. Conventional cut-off values for HPR as proposed by consensus documents may need to be re-evaluated for this population at high ischemic and bleeding risk. Further studies are needed to assess the association with outcomes.

Impact of body size on platelet function in patients with acute coronary syndrome on dual antiplatelet therapy

INTRODUCTION

Patients undergoing acute percutaneous coronary intervention receive dual antiplatelet therapy for secondary prevention. Recurrent myocardial infarction or bleedings are possibly due to under- or overdosing of antiplatelet therapy in relation to body size.

METHODS

We correlated residual platelet aggregation with body mass index, body surface area, lean body mass and blood volume in 220 patients on prasugrel (n = 121) or ticagrelor (n = 99).

RESULTS

Platelet aggregation outside the recommended window was recorded in 85 patients, but not correlated with any of the body indices.

CONCLUSION

Body size does not affect platelet response to prasugrel or ticagrelor at the guideline-recommended fixed dosages.

Ticagrelor or prasugrel in patients with acute coronary syndrome with off-hour versus on-hour presentation: a subgroup analysis of the ISAR-REACT 5 trial

OBJECTIVES

To assess the efficacy and safety of ticagrelor versus prasugrel in patients with acute coronary syndrome (ACS) presenting during off- and on-hours.

BACKGROUND

The efficacy and safety of ticagrelor versus prasugrel in patients with ACS according to time of hospital presentation remain unknown.

METHODS

This post hoc analysis of the ISAR-REACT 5 trial included 1565 patients with ACS presenting off-hours and 2453 patients presenting on-hours, randomized to ticagrelor or prasugrel. The primary endpoint was a composite of death, myocardial infarction, or stroke; the safety endpoint was Bleeding Academic Research Consortium (BARC) type 3-5 bleeding, both at 12 months.

RESULTS

The primary endpoint occurred in 80 patients (10.4%) in the ticagrelor group and 57 patients (7.3%) in the prasugrel group in patients presenting off-hours (hazard ratio [HR] = 1.45; 95% confidence interval [CI] 1.03-2.03; P = 0.033), and 104 patients (8.5%) in the ticagrelor group and 80 patients (6.7%) in the prasugrel group in patients presenting on-hours (HR = 1.29 [0.97-1.73]; P = 0.085), without significant treatment arm-by-presentation time interaction (P_int = 0.62). BARC type 3 to 5 bleeding occurred in 35 patients (5.1%) in the ticagrelor group and 37 patients (5.3%) in the prasugrel group (P = 0.84) in patients presenting off-hours, and 60 patients (5.9%) in the ticagrelor group and 43 patients (4.6%) in the prasugrel group in patients presenting on-hours (P = 0.17).

CONCLUSIONS

In patients with ACS planned to undergo an invasive treatment strategy, time of presentation (off-hours vs. on-hours) does not interact significantly with the relative efficacy and safety of ticagrelor vs. prasugrel.

CLINICAL TRIAL REGISTRATION

NCT01944800.

Impact of the ABCD-GENE Score on Clopidogrel Clinical Effectiveness after PCI: A Multi-Site, Real-World Investigation

The Age, Body mass index, Chronic kidney disease, Diabetes mellitus, and CYP2C19 GENEtic variants (ABCD-GENE) score was developed to identify patients at risk for diminished antiplatelet effects with clopidogrel after percutaneous coronary intervention (PCI). The objective of this study was to validate the ability of the ABCD-GENE score to predict the risk for atherothrombotic events in a diverse, real-world population of clopidogrel-treated patients who underwent PCI and received clinical CYP2C19 genotyping to guide antiplatelet therapy. A total of 2,341 adult patients who underwent PCI, were genotyped for CYP2C19, and received treatment with clopidogrel across four institutions were included (mean age 64 ± 12 years, 35% women, and 20% Black). The primary outcome was major atherothrombotic events, defined as the composite of all-cause death, myocardial infarction, ischemic stroke, stent thrombosis, or revascularization for unstable angina within 12 months following PCI. Major adverse cardiovascular events (MACE), defined as the composite of cardiovascular death, myocardial infarction, ischemic stroke, or stent thrombosis, was assessed as the secondary outcome. Outcomes were compared between patients with an ABCD-GENE score ≥ 10 vs. < 10. The risk of major atherothrombotic events was higher in patients with an ABCD-GENE score ≥ 10 (n = 505) vs. < 10 (n = 1,836; 24.6 vs. 14.7 events per 100 patient-years, adjusted hazard ratio (HR) 1.66, 95% confidence interval (CI), 1.23-2.25, P < 0.001). The risk for MACE was also higher among patients with a score ≥ 10 vs. < 10 (16.7 vs. 10.1 events per 100 patient-years, adjusted HR 1.59, 95% CI 1.11-2.30, P = 0.013). Our diverse, real-world data demonstrate diminished clopidogrel effectiveness in post-PCI patients with an ABCD-GENE score ≥ 10.

A Sticky Situation: Variable Agreement Between Platelet Function Tests Used to Assess Anti-platelet Therapy Response

Background

Platelet function testing to monitor antiplatelet therapy is important for reducing thromboembolic complications, yet variability across testing methods remains challenging. Here we evaluated the agreement of four different testing platforms used to monitor antiplatelet effects of aspirin (ASA) or P2Y₁₂ inhibitors (P2Y12-I).

Methods

Blood and urine specimens from 20 patients receiving dual antiplatelet therapy were analyzed by light transmission aggregometry (LTA), whole blood aggregometry (WBA), VerifyNow PRUTest and AspirinWorks. Result interpretation based on pre-defined cutoff values was used to calculate raw agreement indices, and Pearson's correlation coefficient determined using individual units of measure.

Results

Agreement between LTA and WBA for P2Y12-I-response was 60% (r = 0.65, high-dose ADP; r = 0.75, low-dose ADP). VerifyNow agreed with LTA in 75% (r = 0.86, high-dose ADP; r = 0.75, low-dose ADP) and WBA in 55% (r = 0.57) of cases. Agreement between LTA and WBA for ASA-response was 45% (r = 0.09, high-dose collagen WBA; r = 0.19, low-dose collagen WBA). AspirinWorks agreed with LTA in 60% (r = 0.32) and WBA in 35% (r = 0.02, high-dose collagen WBA; r = 0.08, low-dose collagen WBA) of cases.

Conclusions

Overall agreement varied from 35 to 75%. LTA and VerifyNow demonstrated the highest agreement for P2Y12-I-response, followed by moderate agreement between LTA and WBA. LTA and AspirinWorks showed moderate agreement for aspirin response, while WBA showed the weakest agreement with both LTA and AspirinWorks. The results from this study support the continued use of LTA for monitoring dual antiplatelet therapy, with VerifyNow as an appropriate alternative for P2Y12-I-response. Integration of results obtained from these varied testing platforms with patient outcomes remains paramount for future studies.

Differential Impact of Clinical and Genetic Factors on High Platelet Reactivity in Patients with Coronary Artery Disease Treated with Clopidogrel and Prasugrel

AIM

High platelet reactivity (HPR) is associated with increased risks of thrombotic events in patients with coronary artery disease. The recently developed ABCD-GENE score identified five clinical and genetic factors (age, body mass index, chronic kidney disease, diabetes, and the CYP2C19 loss-of-function allele) for HPR, although the significance of various stages of each factor is unclear.

METHODS

Four prospective studies were pooled, in which platelet reactivity was measured using the VerifyNow assay with clopidogrel and prasugrel; genotyping of CYP2C19 was also performed. Each component of the ABCD-GENE score was divided into three subcategories. VerifyNow P2Y12 reactivity units ＞208 were defined as HPR.

RESULTS

A total of 184 patients were included, of which 111 (60%) and 51 (28%) had HPR with clopidogrel and prasugrel. Chronic kidney disease had an impact on HPR on both clopidogrel and prasugrel, whereas the impact of diabetes was more evident in patients treated with prasugrel. Although the number of CYP2C19 loss-of-function alleles was clearly associated with a likelihood of HPR with clopidogrel, P2Y12 reactivity units with prasugrel treatment were also significantly and progressively higher in patients with more CYP2C19 loss-of-function alleles.

CONCLUSIONS

Clinical and genetic factors had a differential effect on a P2Y12 inhibitor reactivity with clopidogrel and prasugrel in patients with coronary artery disease. The severity of the factors also had a different impact on HPR.

Does individualized guided selection of antiplatelet therapy improve outcomes after percutaneous coronary intervention? A systematic review and meta-analysis

Background

The potential benefits of individualized guided selection of antiplatelet therapy over standard antiplatelet therapy in improving outcomes in patients undergoing percutaneous coronary intervention (PCI) have not been established. Therefore, we pooled evidence from available clinical trials to assess the effectiveness by comparing the two regimens in patients undergoing PCI.

Methods

We queried two electronic databases, MEDLINE and Cochrane CENTRAL, from their inception to April 20, 2021 for published randomized controlled trials in any language that compared guided antiplatelet therapy, using either genetic testing or platelet function testing, versus standard antiplatelet therapy in patients undergoing PCI. The results from trials were presented as risk ratios (RRs) with 95% confidence intervals (CIs) and were pooled using a random-effects model.

Results

Eleven eligible studies consisting of 18,465 patients undergoing PCI were included. Pooled results indicated that guided antiplatelet therapy, compared to standard therapy, was associated with a significant reduction in the incidence of MACE [RR 0·78, 95% CI (0·62–0·99), P = 0·04], MI [RR 0·73, 95% CI (0·56–0.96), P = 0·03], ST [RR 0·66, 95% CI (0·47–0.94), P = 0·02], stroke [RR 0·71, 95% CI (0·50–1.00), P = 0·05], and minor bleeding [RR 0·78, 95% CI (0·66–0.91), P = 0·003].

Conclusions

Individualized guided selection of antiplatelet therapy significantly reduced the incidence of MACE, MI, ST, stroke, and minor bleeding in adult patients when compared with standard antiplatelet therapy. Our findings support the implementation of genetic and platelet function testing to select the most beneficial antiplatelet agent.

•

Benefits of individualized guided selection of antiplatelet therapy over standard antiplatelet therapy in improving outcomes in patients undergoing percutaneous coronary intervention (PCI) have not been established.

•

Guided therapy, consisting of either genetic testing or platelet function testing, can identify patients with this genetic variation allowing clinicians to provide modified and alternative treatment strategies and prescribe optimal antiplatelet agents.

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Individualized guided selection of antiplatelet therapy reduced the incidence of MACE, MI, ST, stroke, and minor bleeding in adult patients when compared with standard antiplatelet therapy.

•

Can be more cost-effective than medication cost for every stroke, in-stent thrombosis, or MI case that needs hospitalization requiring more imaging and tests which can increase the total cost of treatment.

The Use of Thromboelastography in Percutaneous Coronary Intervention and Acute Coronary Syndrome in East Asia: A Systematic Literature Review

Dual antiplatelet therapy (DAPT), alongside percutaneous coronary intervention (PCI), is central to the prevention of ischemic events following acute coronary syndrome (ACS). However, response to therapy can vary due to several factors including CYP2C19 gene variation, which shows increased prevalence in East Asian populations. DAPT responsiveness can be assessed using techniques such as light transmission aggregometry (LTA), VerifyNow^® and thromboelastography with the PlateletMapping^® assay, and there is increasing focus on the utility of platelet function testing to guide individualized treatment. This systematic literature review of one English and three Chinese language databases was conducted to evaluate the evidence for the utility of thromboelastography in ACS/PCI in East Asia. The search identified 42 articles from the English language and 71 articles from the Chinese language databases which fulfilled the pre-determined inclusion criteria, including 38 randomized controlled trials (RCTs). The identified studies explored the use of thromboelastography compared to LTA and VerifyNow in monitoring patient responsiveness to DAPT, as well as predicting ischemic risk, with some studies suggesting that thromboelastography is better able to detect low DAPT response than LTA. Other studies, including one large RCT, described the use of thromboelastography in guiding the escalation of DAPT, with some evidence suggesting that such protocols reduce ischemic events without increasing the risk of bleeding. There was also evidence suggesting that thromboelastography can be used to identify individuals with DAPT hyporesponsiveness genotypes and could potentially guide treatment by adjusting therapy in patients depending on responsiveness.

Sex-Specific Differences in Clinical Outcomes After Percutaneous Coronary Intervention: Insights from the TAILOR-PCI Trial

Background TAILOR-PCI (Tailored Antiplatelet Initiation to Lessen Outcomes due to decreased Clopidogrel Response After Percutaneous Coronary Intervention) studied genotype-guided selection of antiplatelet therapy after percutaneous coronary intervention versus conventional therapy with clopidogrel. The presence of CYP2C19 loss-of-function alleles in patients treated with clopidogrel may be associated with increased risk for ischemic events. We report a prespecified sex-specific analysis of genotyping and associated cardiovascular outcomes from this study. Methods and Results Associations between sex and major adverse cardiac events (MACE: cardiovascular death, myocardial infarction, stroke, stent thrombosis, and severe recurrent ischemia) and Bleeding Academic Research Consortium (BARC) bleeding at 12 months were analyzed using Cox proportional-hazards models. Among 5276 randomized patients, loss-of-function carriers were observed in ≈36% of both sexes, and >80% of carriers were heterozygotes. At 12 months, after adjustment for baseline differences, risks of MACE (HR , 1.28 [0.97 to 1.68]; P=0.088) and BARC bleeding (hazard ratio [HR], 1.36 [0.91 to 2.05]; P=0.14) were comparable among women and men. There were no significant interactions between sex and treatment strategy for MACE interaction P value (P_int=0.59) or BARC bleeding (P_int=0.47) nor for sex and genotype (MACE P_int=0.15, and BARC bleeding P_int=0.60). Conclusions CYP2C19 loss-of-function alleles were present in ≈1 in 3 women and men. Women had similar adjusted risks of MACE and bleeding as men following percutaneous coronary intervention. Genotype-guided therapy did not significantly reduce the risk of MACE or bleeding relative to conventional therapy for both sexes. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01742117.

Risk Scores of Bleeding Complications in Patients on Dual Antiplatelet Therapy: How to Optimize Identification of Patients at Risk of Bleeding after Percutaneous Coronary Intervention

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor in patients undergoing percutaneous coronary intervention (PCI) reduces the risk of ischemic events but reduces the risk of ischemic events but increases the risk of bleeding, which in turn is associated with increased morbidity and mortality. With the aim to offer personalized treatment regimens to patients undergoing PCI, much effort has been devoted in the last decade to improve the identification of patients at increased risk of bleeding complications. Several clinical scores have been developed and validated in large populations of patients with coronary artery disease (CAD) and are currently recommended by guidelines to evaluate bleeding risk and individualize the type and duration of antithrombotic therapy after PCI. In clinical practice, these risk scores are conventionally computed at the time of PCI using baseline features and risk factors. Yet, bleeding risk is dynamic and can change over time after PCI, since patients can worsen or improve their clinical status and accumulate comorbidities. Indeed, evidence now exists that the estimated risk of bleeding after PCI can change over time. This concept is relevant, as the inappropriate estimation of bleeding risk, either at the time of revascularization or subsequent follow-up visits, might lead to erroneous therapeutic management. Serial evaluation and recalculation of bleeding risk scores during follow-up can be important in clinical practice to improve the identification of patients at higher risk of bleeding while on DAPT after PCI.

Antithrombotic dilemmas in stroke medicine: new data, unsolved challenges

Antithrombotic therapy is a key element of secondary prevention in patients who have had an ischaemic stroke or transient ischaemic attack. However, its use in clinical practice is not always straightforward. This review provides an update on certain difficult scenarios in antithrombotic management, with a focus on recent clinical trials and large observational studies. We discuss the approach to patients with an indication for antithrombotic treatment who also have clinical or radiological evidence of previous intracranial bleeding, patients with indications for both anticoagulant and antiplatelet treatment, and patients in whom antithrombotic treatment fails to prevent stroke. We also review the timing of anticoagulation initiation after cardioembolic stroke, and the use of antithrombotics in patients with asymptomatic cerebrovascular disease. Despite a wealth of new evidence, numerous uncertainties remain and we highlight ongoing trials addressing these.

Intracranial haemorrhage in adult patients on venoarterial extracorporeal membrane oxygenation

AIMS

Intracranial haemorrhage (ICH) is one of the most serious complications of adult patients treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO) and is associated with increased morbidity and mortality. However, the prevalence and risk factors of ICH in this cohort are still insufficiently understood. We hypothesized that a considerable proportion of patients undergoing VA-ECMO support suffer from ICH and that specific risk factors are associated with the occurrence of ICH. Therefore, the purpose of this study was to further investigate the prevalence and associated mortality as well as to identify risk factors for ICH in VA-ECMO patients.

METHODS AND RESULTS

We conducted a retrospective multicentre study including adult patients (≥18 years) treated with VA-ECMO in cardiac intensive care units (ICUs) at five German clinical sites between January 2016 and March 2020, excluding patients with ICH upon admission. Differences in baseline characteristics and clinical outcome between VA-ECMO patients with and without ICH were analysed and risk factors for ICH were identified. Among the 598 patients included, 70/598 (12%) developed ICH during VA-ECMO treatment. In-hospital mortality in patients with ICH was 57/70 (81%) and 1-month mortality 60/70 (86%), compared to 332/528 (63%) (P = 0.002) and 340/528 (64%) (P < 0.001), respectively, in patients without ICH. Intracranial haemorrhage was positively associated with diabetes mellitus [odds ratio (OR) 2, 95% confidence interval (CI) 1.11-3.56; P = 0.020] and lactate (per mmol/L) (OR 1.06, 95% CI 1.01-1.11; P = 0.020), and negatively associated with platelet count (per 100 G/L) (OR 0.32, 95% CI 0.15-0.59; P = 0.001) and fibrinogen (per 100 mg/dL) (OR 0.64, 95% CI 0.49-0.83; P < 0.001).

CONCLUSION

Intracranial haemorrhage was associated with a significantly higher mortality rate. Diabetes mellitus and lactate were positively, platelet count, and fibrinogen level negatively associated with the occurrence of ICH. Thus, platelet count and fibrinogen level were revealed as potentially modifiable, independent risk factors for ICH. The findings address an area with limited data, provide information about risk factors and the epidemiology of ICH, and may be a starting point for further investigations to develop effective strategies to prevent and treat ICH.

Platelet Function and Genotype after DES Implantation in East Asian Patients: Rationale and Characteristics of the PTRG-DES Consortium

PURPOSE

Platelet function test (PFT) results and genotype hold unique prognostic implications in East Asian patients. The aim of the PTRG-DES (Platelet function and genoType-Related long-term proGnosis in Drug-Eluting Stent-treated Patients with coronary artery disease) consortium is to assess the clinical impact thereof on long-term clinical outcomes in Korean patients with coronary artery disease during dual antiplatelet therapy (DAPT) including clopidogrel.

MATERIALS AND METHODS

Searching publications on the PubMed, we reviewed clopidogrel treatment studies with PFT and/or genotype data for potential inclusion in this study. Lead investigators were invited to share PFT/genotype results, patient characteristics, and clinical outcomes to evaluate relationships among them.

RESULTS

Nine registries from 32 academic centers participated in the PTRG-DES consortium, contributing individual patient data from 13160 patients who underwent DES implantation between July 2003 and August 2018. The PTRG-PFT cohort was composed of 11714 patients with available VerifyNow assay results. Platelet reactivity levels reached 218±79 P2Y12 reaction units (PRU), and high on-clopidogrel platelet reactivity based on a consensus-recommended cutoff (PRU >208) was observed in 55.9%. The PTRG-Genotype cohort consisted of 8163 patients with candidate genotypes related with clopidogrel responsiveness. Of those with cytochrome P450 (CYP) 2C19 genotype, frequencies of carrying one and two loss-of-function allele (s) (^*2 or ^*3) were 47.9% (intermediate metabolizers) and 14.2% (poor metabolizers), respectively.

CONCLUSION

The PTRG-DES consortium highlights unique values for on-clopidogrel platelet reactivity and CYP2C19 phenotype that may be important to developing optimal antiplatelet regimens in East Asian patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04734028.

Effect of Genetic Polymorphism Including NUP153 and SVEP1 on the Pharmacokinetics and Pharmacodynamics of Ticagrelor in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVE

The search for potential gene loci that affect the pharmacodynamics and pharmacokinetics of ticagrelor is a matter of broad clinical interest. The objective of this study was to investigate the effect of genetic polymorphisms on the pharmacokinetics and pharmacodynamics of ticagrelor in healthy Chinese subjects.

METHODS

This is a multi-center study in China, including three hospitals from Beijing, Nanchang, and Changsha. Healthy Chinese subjects aged 18-45 years with unknown genotypes were included. All subjects received a single oral dose of 90 mg of ticagrelor. Platelet aggregation and the area under the concentration-time curve for ticagrelor and its major active metabolite in plasma samples were assessed. Genome-wide association studies and candidate gene association analysis related to ticagrelor were performed.

RESULTS

One hundred and seventy-five native Chinese subjects were enrolled and completed the study. According to the p value, the threshold of ticagrelor population was 6.57 × 10^-7 (0.05/76106), one single-nucleotide polymorphism chr6:17616513 of gene NUP153 (p = 2.03 × 10^-7) related to the area under the concentration-time curve for plasma concentration at time zero versus the last measurable timepoint, and one single nucleotide polymorphism rs17204533 of gene SVEP1 (p = 3.96 × 10^-7) related to P2Y12 reaction unit_12h of ticagrelor was identified. In addition, L1TD1, CETP, CLEC2A, CHSY1, PDZRN3, CTU2, PIEZO1, APOBEC1, SEMA6A, KAZN, and FASN polymorphisms might influence the pharmacokinetics of ticagrelor, while PARP10, TRIB1, CYP2C19, and UGT2B7 might affected its pharmacodynamics.

CONCLUSIONS

Genetic variation affects the pharmacokinetics and pharmacodynamics of ticagrelor in healthy individuals. The detection of NUP153, SVEP1 gene variation will be helpful for pharmacodynamic prediction and evaluation, and the regulation of these genes may be the target of new drug development. Further studies are required to confirm the results and explore whether these single-nucleotide polymorphisms are associated only with platelet activity or also with cardiovascular events and all-cause mortality.

CLINICAL TRIAL REGISTRATION

NCT03161002.

Circadian variations of platelet reactivity on clopidogrel in patients treated with elective percutaneous coronary intervention

Evidence assessing potential diurnal variations of platelet reactivity in patients on clopidogrel treated with elective percutaneous coronary intervention (PCI) for chronic coronary syndrome (CCS) are currently lacking. We prospectively enrolled 15 patients affected by stable coronary artery disease (CAD) previously treated with elective PCI and on clopidogrel for at least 8 days (administered at 8 a.m.). A significant heterogeneity in diurnal levels of ADP-dependent platelet aggregation was found (p = 0.0004), with a peak of platelet reactivity occurring at the 6 a.m. assessment, which resulted significantly increased compared to the afternoon (6 p.m.) evaluation (255 ± 66 vs 184 ± 67, p = 0.002). In addition, at the early-morning evaluation a considerably high proportion of patients with high platelet reactivity (53.3%) were observed. In conclusion, clopidogrel-induced platelet inhibition in patients with CCS after elective PCI follows a circadian rhythm, thus suggesting that a consistent and durable antiplatelet inhibition is often failed with standard clopidogrel administration at morning.

Growth Differentiation Factor-15 Correlates Inversely with Protease-Activated Receptor-1-Mediated Platelet Reactivity in Patients with Left Ventricular Assist Devices

Growth differentiation factor (GDF)-15 inhibits platelet activation, prevents thrombus formation, and has been linked to bleeding events. This was a prospective study including 51 left-ventricular assist device (LVAD) patients on aspirin and phenprocoumon. Platelet surface expression of activated glycoprotein (GP) IIb/IIIa was assessed by flow cytometry, and platelet aggregation was measured by multiple electrode aggregometry (MEA) in response to arachidonic acid (AA), adenosine diphosphate (ADP), and thrombin receptor-activating peptide (TRAP), a protease-activated-receptor-1 (PAR-1) agonist. GDF-15 was determined with a commercially-available assay. There was a trend towards an inverse correlation of GDF-15 with activated GPIIb/IIIa in response to TRAP (r = −0.275, p = 0.0532) but not in response to AA and ADP. Moreover, GDF-15 correlated with MEA TRAP (r = −0.326, p = 0.0194), whereas it did not correlate with MEA ADP and MEA AA. In a second step, GDF-15 levels in the fourth quartile were defined as high GDF-15. Patients with high GDF-15 showed significantly lower TRAP-inducible platelet aggregation by MEA compared to patients in the first quartile (63 AU vs. 113 AU, p = 0.0065). In conclusion, in LVAD patients receiving state-of-the-art antithrombotic therapy, GDF-15 correlates inversely with residual platelet reactivity via PAR-1.

Development and Validation of a Novel Tool for the Prediction of Clopidogrel Response in Chinese Acute Coronary Syndrome Patients: The GeneFA Score

Aim: Growing evidence indicated that CYP2C19 genotypes could only explain a fraction of the pharmacodynamic response to clopidogrel, while a number of clinical factors also have contributing roles. Our objective was to develop a new risk score to improve prognostication of ischemic events in Chinese patients treated with clopidogrel. Methods: A new risk score was developed and internally validated in 445 patients with acute coronary syndrome (ACS) undergoing coronary stenting. The final score was named the GeneFA score based on the inclusion of CYP2C19 genotype, fibrinogen, and age. External validation of the GeneFA score and comparison with the ABCD-GENE score were performed in an independent ACS cohort. Results: Based on the observed frequencies of high platelet reactivity (HRPR) in relation to the GeneFA risk score, a relatively higher clinical HRPR was observed in the upper quintile with a representative score of 3 (52.90%) and 4 (59.10%), whereas it was found less frequently in groups with scores 0 (6.70%), 1 (15.10%), and 2 (16.70%). Participants with a GeneFA score >2 had an increased risk of HRPR (54.3 vs. 14.7%, p < 0.001) and ischemic recurrence (20.7 vs. 5.4%, p < 0.001). The GeneFA score exhibited a better prediction for high HRPR patients as compared to the ABCD-GENE score (p < 0.001). In the validation population, GeneFA illustrated a similarly high prognostic value for HRPR incidence (C-statistic: 0.855 for GeneFA and 0.843 for ABCD-GENE) and ischemic recurrence (C-statistic: 0.726 for GeneFA and 0.724 for ABCD-GENE) on clopidogrel as compared to ABCD-GENE. Conclusion: The GeneFA risk score had a moderate predictive ability for HRPR on clopidogrel for CAD patients in Chinese populations. The predictive value of the GeneFA score was consistent with the ABCD-GENE score for HRPR identification.

Platelet reactivity testing in peripheral artery disease

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Oral antiplatelet therapy is routinely used to prevent adverse cardiovascular events in patients with peripheral artery disease (PAD). Several laboratory tests are available to quantify the degree of platelet inhibition following antiplatelet therapy. This article aims to provide a review of the literature surrounding platelet functional testing in patients with PAD receiving oral P2Y12 inhibitors and to offer guidance to clinicians for the use and interpretation of these tests.

SUMMARY

A literature search of PubMed and the Web of Science Core Collection database was conducted. All studies that performed platelet function testing and reported clinical outcomes in patients with PAD were included. Evaluation of the data suggests that, among the available testing strategies, the VerifyNow platelet reactivity unit (PRU) test is the most widely used. Despite numerous investigations attempting to define a laboratory threshold indicating suboptimal response to antiplatelet therapy, controversy exists about which PRU value best correlates with cardiovascular outcomes (ie, mortality, stent thrombosis, etc). In the PAD literature, the most commonly used PRU thresholds are 208 or higher and 235 or higher. Nonetheless, adjusting antiplatelet regimens based on suboptimal P2Y12 reactivity values has yet to be proven useful in reducing the incidence of adverse cardiovascular outcomes. This review examines platelet function testing in patients with PAD and discusses the interpretation and application of these tests when monitoring the safety and efficacy of P2Y12 inhibitors.

CONCLUSION

Although platelet functional tests may be simple to use, clinical trials thus far have failed to show benefit from therapy adjustments based on test results. Clinicians should be cautioned against relying on this test result alone and should instead consider a combination of laboratory, clinical, and patient-specific factors when adjusting P2Y12 inhibitor therapy in clinical practice.

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.

Platelet P2Y12 inhibiting therapy in adjunct to vascular dose of rivaroxaban or aspirin: A pharmacodynamic study of dual pathway inhibition versus dual antiplatelet therapy

AIM

Dual-pathway inhibition (DPI) by adding a vascular dose of rivaroxaban to a single antiplatelet agent has emerged as a promising antithrombotic strategy. However, in most studies the antiplatelet agent of choice used in adjunct to a vascular dose of rivaroxaban was aspirin, and data with a P2Y12 inhibitor and how this DPI regimen compares with standard dual antiplatelet therapy (DAPT) is limited.

METHODS AND RESULTS

This investigation was a sub-study analysis conducted in selected cohorts of patients with stable atherosclerotic disease enrolled from a larger prospective, open-label, parallel-group pharmacodynamics (PD) study. We analyzed data from 40 patients treated with either clopidogrel or ticagrelor-based DAPT first, and clopidogrel or ticagrelor-based DPI thereafter. PD measures explored key pathways involved in thrombus formation and included markers of: 1) P2Y12 reactivity, 2) platelet-mediated global thrombogenicity, 3) cyclooxygenase-1 activity, 3) TRAP-induced platelet aggregation; 4) tissue factor (TF)-induced platelet aggregation, and 5) thrombin generation. As compared to DAPT, on a background of the same P2Y12 inhibitor (clopidogrel or ticagrelor), DPI was associated with reduced thrombin generation, increased markers of cyclooxygenase-1 activity and TRAP-induced platelet aggregation and no differences in markers of P2Y12 signaling, platelet-mediated global thrombogenicity and TF-induced platelet aggregation. In an analysis according to P2Y12 inhibitor type, ticagrelor reduced markers of platelet-mediated global thrombogenicity, P2Y12 signaling and rates of high platelet reactivity compared to clopidogrel.

CONCLUSIONS

Compared to DAPT with aspirin and a P2Y12 inhibitor, the use of a P2Y12 inhibitor in adjunct to a vascular dose of rivaroxaban as part of a DPI strategy is associated with similar effects on platelet-mediated global thrombogenicity but reduced thrombin generation. A DPI strategy with ticagrelor is associated with enhanced antithrombotic efficacy, the clinical implications of which warrant larger scale investigations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03718429.

Genotype-Guided Use of P2Y12 Inhibitors: A Review of Current State of the Art

The pharmacodynamics of the purinergic receptor type Y, subtype 12 (P2Y12) inhibitors has evolved. Our understanding of the metabolism of P2Y12 inhibitors has revealed polymorphisms that impact drug metabolism and antiplatelet efficacy, leading to genetic testing guided therapy. In addition, assays of platelet function and biochemistry have provided insight into our understanding of the efficacy of "antiplatelet" therapy, identifying patients with high or low platelet reactivity on P2Y12 therapy. Despite the data, the implementation of these testing modalities has not gained mainstream adoption across hospital systems. Given differences in potency between the three clinically available P2Y12 inhibitors, the balance between thrombotic and bleeding complications must be carefully considered, especially for the large proportion of patients at higher risk for bleeding. Here we review the current data for genetic and functional testing, risk assessment strategies, and guidelines for P2Y12 inhibitors guided therapy.

Platelets, Thromboinflammation and Neurovascular Disease

The brain and spinal cord are immune-privileged organs, but in the disease state protection mechanisms such as the blood brain barrier (BBB) are ineffective or overcome by pathological processes. In neuroinflammatory diseases, microglia cells and other resident immune cells contribute to local vascular inflammation and potentially a systemic inflammatory response taking place in parallel. Microglia cells interact with other cells impacting on the integrity of the BBB and propagate the inflammatory response through the release of inflammatory signals. Here, we discuss the activation and response mechanisms of innate and adaptive immune processes in response to neuroinflammation. Furthermore, the clinical importance of neuroinflammatory mediators and a potential translational relevance of involved mechanisms are addressed also with focus on non-classical immune cells including microglia cells or platelets. As illustrative examples, novel agents such as Anfibatide or Revacept, which result in reduced recruitment and activation of platelets, a subsequently blunted activation of the coagulation cascade and further inflammatory process, demonstrating that mechanisms of neuroinflammation and thrombosis are interconnected and should be further subject to in depth clinical and basic research.

Signalling by extracellular nucleotides in health and disease

Nucleotides are released from all cells through regulated pathways or as a result of plasma membrane damage or cell death. Outside the cell, nucleotides act as signalling molecules triggering multiple responses via specific plasma membrane receptors of the P2 family. In the nervous system, purinergic signalling has a key function in neurotransmission. Outside the nervous system, purinergic signalling is one of the major modulators of basal tissue homeostasis, while its dysregulation contributes to the pathogenesis of various disease, including inflammation and cancer. Pre-clinical and clinical evidence shows that selective P2 agonists or antagonists are effective treatments for many pathologies, thus highlighting the relevance of extracellular nucleotides and P2 receptors as therapeutic targets.

CYP2C19 Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention in Diverse Clinical Settings

Background Studies have demonstrated increased risk of major atherothrombotic events in CYP2C19 loss-of-function (LOF) variant carriers versus non-carriers treated with clopidogrel after percutaneous coronary intervention (PCI). We sought to evaluate real-world outcomes with the clinical implementation of CYP2C19-guided antiplatelet therapy after PCI. Methods and Results Data from 9 medical centers where genotyping was performed in the setting of PCI were included. Alternative therapy with prasugrel or ticagrelor was recommended for patients with a CYP2C19 LOF variant. The primary outcome was the composite of major atherothrombotic events (all-cause death, myocardial infarction, ischemic stroke, stent thrombosis, or hospitalization for unstable angina) within 12 months following PCI. Moderate or severe/life-threatening bleeding within 12 months was a secondary outcome. Among 3342 patients, 1032 (31%) were LOF carriers, of whom 571/1032 (55%) were treated with alternative therapy. In LOF carriers, the rate of major atherothrombotic events was lower in patients treated with alternative therapy versus clopidogrel (adjusted HR, 0.56; 95% CI 0.39-0.82). In those without a LOF allele, no difference was observed (adjusted HR, 1.07; 95% CI 0.71-1.60). There was no difference in bleeding with alternative therapy versus clopidogrel in either LOF carriers or those without a LOF allele. Conclusions Real-world data demonstrate lower atherothrombotic risk in CYP2C19 LOF carriers treated with alternative therapy versus clopidogrel and similar risk in those without a LOF allele treated with clopidogrel or alternative therapy. These data suggest that PCI patients treated with clopidogrel should undergo genotyping so that CYP2C19 LOF carriers can be identified and treated with alternative therapy.

ABCD-GENE Score and Clinical Outcomes Following Percutaneous Coronary Intervention: Insights from the TAILOR-PCI Trial

Background In TAILOR-PCI, genotype-guided selection of P2Y₁₂ inhibitors after percutaneous coronary intervention did not significantly reduce the risk of ischemic events at 12 months. The Age, Body Mass Index, Chronic Kidney Disease, Diabetes, and Genotyping (ABCD-GENE) score identifies patients with high platelet reactivity on clopidogrel at increased risk of ischemic events. The aim of this study was to investigate the value of the ABCD-GENE score for tailoring P2Y₁₂ inhibitor selection after percutaneous coronary intervention. Methods and Results In a post hoc analysis of the TAILOR-PCI, outcomes were analyzed by ABCD-GENE score and allocation to genotype-guided or conventional P2Y₁₂ inhibitor selection. Primary (death, myocardial infarction, or stroke) and secondary (cardiovascular death, myocardial infarction, stroke, stent thrombosis, or severe recurrent ischemia) outcomes were assessed. Among 3883 patients discharged on clopidogrel in the genotype-guided and conventional therapy groups, 15.8% and 84.2% had high (≥10 points) or low (<10) ABCD-GENE scores, respectively. At 12 months, both the primary (5.2% versus 2.6%, P<0.001) and secondary outcomes (7.7% versus 4.6%, P=0.001) were significantly increased in patients with high ABCD-GENE score. Among 4714 patients allocated to genotype-guided or conventional therapy, the former did not significantly reduce the 12-month risk of the primary and secondary outcomes in both the high and low ABCD-GENE score groups (p_interaction=0.48 and 0.27, respectively). Conclusions Among patients with percutaneous coronary intervention on clopidogrel, the ABCD-GENE score was helpful in identifying those at higher risk. The ABCD-GENE score may potentially enhance the precision of tailored selection of P2Y₁₂ inhibitors, which needs to be confirmed in prospective investigations. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01742117.

Bleeding avoidance strategies in percutaneous coronary intervention

For many years, bleeding has been perceived as an unavoidable consequence of strategies aimed at reducing thrombotic complications in patients undergoing percutaneous coronary intervention (PCI). However, the paradigm has now shifted towards bleeding being recognized as a prognostically unfavourable event to the same extent as having a new or recurrent ischaemic or thrombotic complication. As such, in parallel with progress in device and drug development for PCI, there is clinical interest in developing strategies that maximize not only the efficacy but also the safety (for example, by minimizing bleeding) of any antithrombotic treatment or procedural aspect before, during or after PCI. In this Review, we discuss contemporary data and aspects of bleeding avoidance strategies in PCI, including risk stratification, timing of revascularization, pretreatment with antiplatelet agents, selection of vascular access, choice of coronary stents and antithrombotic treatment regimens.

Platelet reactivity and clinical outcomes following percutaneous coronary intervention in complex higher-risk patients

AIMS

To investigate the levels of platelet reactivity and the impact of high platelet reactivity (HPR) on long-term clinical outcomes of complex higher-risk and indicated patients (CHIP) with stable coronary artery disease (CAD) treated with elective percutaneous coronary intervention (PCI).

METHODS

We enrolled 500 patients undergoing elective PCI for stable CAD and treated with aspirin and clopidogrel. Patients were divided into four groups based on the presence of CHIP features and HPR. Primary endpoint was the occurrence of major adverse clinical events (MACE) at 5 years.

RESULTS

The prevalence of HPR was significantly greater in the CHIP population rather than non-CHIP patients (39.9% vs 29.8%, P = 0.021). Patients with both CHIP features and HPR showed the highest estimates of MACE (22.1%, log-rank P = 0.047). At Cox proportional hazard analysis, the combination of CHIP features and HPR was an independent predictor of MACE (hazard ratio 2.57, 95% confidence interval 1.30-5.05, P = 0.006).

CONCLUSION

Among patients with stable CAD undergoing elective PCI and treated with aspirin and clopidogrel, the combination of CHIP features and HPR identifies a cohort of patients with the highest risk of MACE at 5 years, who might benefit from more potent antiplatelet strategies.

Pharmacodynamic profiles of dual-pathway inhibition with or without clopidogrel vs dual antiplatelet therapy in patients with atherosclerotic disease

AIM

Inhibition of thrombin-mediated signaling processes using a vascular dose of rivaroxaban in adjunct to antiplatelet therapy, known as dual-pathway inhibition (DPI), reduces atherothrombotic events in patients with stable atherosclerotic disease. However, there are limited data on the pharmacodynamic (PD) effects of this strategy.

METHODS AND RESULTS

This investigation was conducted in selected cohorts of patients (n=40) with stable atherosclerotic disease enrolled within a larger prospective PD study who were treated with either aspirin plus clopidogrel (DAPT), aspirin plus rivaroxaban 2.5 mg/bid (DPI) or DAPT plus rivaroxaban 2.5 mg/bid. Multiple PD assays assessing of markers of thrombosis were used. PD endpoints included platelet-mediated global thrombogenicity measured by light transmittance aggregometry (LTA) following stimuli with CATF [collagen-related peptide +adenosine diphosphate (ADP) +tissue factor (TF)], markers of P2Y12 reactivity, markers of platelet aggregation using LTA following several stimuli (arachidonic acid, ADP, collagen, TF, and TRAP), thrombin generation and thrombus formation. There was no difference in platelet-mediated global thrombogenicity between groups. Rivaroxaban significantly reduced thrombin generation and was associated with a trend towards reduced TF-induced platelet aggregation. Clopidogrel-based treatments reduced markers of P2Y12 signaling and TRAP-induced platelet aggregation. There were no differences between groups on markers of cyclooxygenase-1 mediated activity.

CONCLUSIONS

Compared with DAPT, DPI does not result in any differences in platelet-mediated global thrombogenicity, but reduces thrombin generation. These PD observations support that modulating thrombin generation by means of factor Xa inhibition in adjunct to antiplatelet therapy provides effective antithrombotic effects, supporting the efficacy and safety findings of DPI observed in clinical.

Relationship between platelet aggregation and stroke risk after percutaneous coronary intervention: a PENDULUM analysis

In patients undergoing percutaneous coronary intervention (PCI) with a stent, high on-treatment platelet reactivity may be associated with an increased risk of stroke. This post hoc analysis of the PENDULUM registry compared the risk of post-PCI stroke according to on-treatment P2Y₁₂ reaction unit (PRU) values. Patients aged ≥ 20 years who underwent PCI were stratified by baseline PRU (at 12 and 48 h post-PCI) as either high (HPR, > 208), optimal (OPR, > 85 to ≤ 208), or low on-treatment platelet reactivity (LPR, ≤ 85). The incidences of non-fatal ischemic and non-ischemic stroke through to 12 months post-PCI were recorded. Almost all enrolled patients (6102/6267 [97.4%]) had a risk factor for ischemic stroke, and most were receiving dual antiplatelet therapy. Of the 5906 patients with PRU data (HPR, n = 2227; OPR, n = 3002; LPR, n = 677), 47 had a non-fatal stroke post-PCI (cumulative incidence: 0.68%, ischemic; 0.18%, non-ischemic stroke). Patients with a non-fatal ischemic stroke event had statistically significantly higher post-PCI PRU values versus those without an event (P = 0.037). The incidence of non-fatal non-ischemic stroke was not related to PRU value. When the patients were stratified by PRU ≤ 153 versus > 153 at 12–48 h post-PCI, a significant difference was observed in the cumulative incidence of non-fatal stroke at 12 months (P = 0.044). We found that patients with ischemic stroke tended to have higher PRU values at 12–48 h after PCI versus those without ischemic stroke.

Clinical trial registration: UMIN000020332.

Identification of Potential Biological Factors Affecting the Treatment of Ticagrelor After Percutaneous Coronary Intervention in the Chinese Population

Background

Generally, many individual factors can affect the clinical application of drugs, of which genetic factors contribute more than 20%. Ticagrelor is a new class of receptor inhibitors receptor antagonist of P2Y12 and is used as an antiplatelet agents. But it is not affected by the influence of CYP2C19 polymorphism. With lack of predicted biomarkers, especially the research data of Chinese, it has the important significance in studying individual differences of ticagrelor in the antiplatelet efficacy and safety, through pharmacogenomics research.

Methods

Whole-exome sequencing (WES) was performed in 100 patients after PCI with ticagrelor treatment. Clinical characteristics and WES of patients were used to performed genome-wide association analysis (GWAS), region-based tests of rare DNA variant to find the influencing factors of antiplatelet effect to ticagrelor and bleeding events. Co-expression, protein–protein interaction (PPI) network and pathway enrichment analysis were then used to find possible genetic mechanisms. Atlas of GWAS (https://atlas.ctglab.nl/) were used for external data validation.

Results

DNAH17, PGS1 and ABCA1 as the potential variant genes are associated with the expected antiplatelet effect to ticagrelor. The affected pathways may include the synthesis and metabolism of lipoprotein cholesterol and the catabolic process of pyrimidine-containing compound (GO:0072529). Age, sex and PLT were found may be potential factors for ticagrelor bleeding events.

Conclusion

We systematically identified new genetic variants and some risk factors for reduced efficacy of ticagrelor and highlighted related genes that may be involved in antiplatelet effects and bleeding event of ticagrelor. Our results enhance the understanding of the absorption and metabolic mechanisms that influence antiplatelet response to ticagrelor treatment.

Trial Registration

ClinicalTrials.gov Identifier: NCT03161002. First Posted: May 19, 2017. https://clinicaltrials.gov/ct2/show/study/NCT03161002.

Explaining the Variance in Cardiovascular Disease Risk Factors: A Comparison of Demographic, Socioeconomic, and Genetic Predictors

BACKGROUND

Efforts to explain the burden of cardiovascular disease (CVD) often focus on genetic factors or social determinants of health. There is little evidence on the comparative predictive value of each, which could guide clinical and public health investments in measuring genetic versus social information. We compared the variance in CVD-related outcomes explained by genetic versus socioeconomic predictors.

METHODS

Data were drawn from the Health and Retirement Study (N = 8,720). We examined self-reported diabetes, heart disease, depression, smoking, and body mass index, and objectively measured total and high-density lipoprotein cholesterol. For each outcome, we compared the variance explained by demographic characteristics, socioeconomic position (SEP), and genetic characteristics including a polygenic score for each outcome and principal components (PCs) for genetic ancestry. We used R-squared values derived from race-stratified multivariable linear regressions to evaluate the variance explained.

RESULTS

The variance explained by models including all predictors ranged from 3.7% to 14.3%. Demographic characteristics explained more than half this variance for most outcomes. SEP explained comparable or greater variance relative to the combination of the polygenic score and PCs for most conditions among both white and Black participants. The combination of SEP, polygenic score, and PCs performed substantially better, suggesting that each set of characteristics may independently contribute to the prediction of CVD-related outcomes. Philip R. Lee Institute for Health Policy Studies, Department of Family & Community Medicine, UCSF.

CONCLUSIONS

Focusing on genetic inputs into personalized medicine predictive models, without considering measures of social context that have clear predictive value, needlessly ignores relevant information that is more feasible and affordable to collect on patients in clinical settings. See video abstract at, http://links.lww.com/EDE/B879.