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

Early vs Delayed Bypass Surgery in Patients With Acute Coronary Syndrome Receiving Ticagrelor: The RAPID CABG Randomized Open-Label Noninferiority Trial

Importance

Perioperative bleeding is a major concern in patients receiving ticagrelor for acute coronary syndromes (ACS) when coronary artery bypass graft (CABG) surgery is required.

Objective

To evaluate whether early CABG surgery at 2 to 3 days after ticagrelor cessation is noninferior to waiting 5 to 7 days.

Design, Setting, and Participants

RAPID CABG was a noninferiority, open-label randomized trial with 6 months of follow-up. Participants were patients with ACS who had received ticagrelor and required CABG. Patients were enrolled in tertiary centers in Canada between January 2016 and March 2021. Data were analyzed from March 2021 to December 2023.

Intervention

Early or delayed CABG.

Main Outcomes and Measures

The primary outcome was based on noninferiority comparison of class 3 or 4 universal definition of perioperative bleeding (UDPB). Noninferiority was prespecified as 8% between groups. Twelve-hour chest tube drainage was reported as a noninferiority comparison. Other bleeding, ischemic, and length-of-stay outcomes were assessed for superiority.

Results

Among 143 randomized patients, the median (IQR) age was 65 (58-72) years; there were 117 male patients (82%) and 26 female (18%). Of these, 123 patients (86.0%) underwent surgery in the allocated time frame (per protocol). The median (IQR) time to surgery was 3 (2-3) days in the early group and 6 (5-7) days in the delayed group (P < .001). In a per-protocol analysis, severe or massive UDPB occurred in 3 of 65 early-group patients (4.6%) and 3 of 58 patients (5.2%) in the delayed group (between-group difference, -0.6%; 95% CI, -8.3% to 7.1%; P = .03 for noninferiority). Median (IQR) chest tube drainage was 470 (330-650) mL vs 495 (380-610) mL (between-group difference -25 mL; 95% CI, -111.25 to 35; P = .01 for noninferiority). Median (IQR) hospital stay was 9 (7-13) days and 12 (10-15) days for the early and delayed groups (P < .001).

Conclusion and Relevance

This study found that an early surgical strategy, 2 to 3 days after ticagrelor cessation, was noninferior in incurring perioperative bleeding. The data support a reduction in the delay between ticagrelor cessation and CABG surgery and may decrease hospital length of stay.

Trial Registration

ClinicalTrials.gov Identifier: NCT02668562.

Accurate prediction of bleeding risk after coronary artery bypass grafting with dual antiplatelet therapy: A machine learning model vs. the PRECISE-DAPT score

BACKGROUND

Dual antiplatelet therapy (DAPT) after coronary artery bypass grafting (CABG), although might be protective for ischemic events, can lead to varying degrees of bleeding, resulting in serious clinical events, including death. This study aims to develop accurate and scalable predictive tools for early identification of bleeding risks during the DAPT period post-CABG, comparing them with the PRECISE-DAPT score.

METHODS

Clinical data were collected from patients who underwent isolated CABG at Nanjing Drum Tower Hospital between June 2021 and December 2023. The dataset was split into derivation and validation cohorts at a 7:3 ratio. Machine learning models were developed to predict bleeding within six months post-CABG in DAPT patients and tested in a temporal external validation cohort. The SHapley Additive exPlanations method visualized variable importance regarding outcomes. The performance of the PRECISE-DAPT score was also validated in this cohort.

RESULTS

Among 561 enrolled patients, 165 (29.4 %) experienced bleeding events, with 49 (8.7 %) cases being significant. In the validation cohort, eXtreme gradient boosting (XGB) achieved the highest area under the receiver operating characteristic curve (0.915) and precision-recall curve (0.692). Compared to PRECISE-DAPT, XGB showed no difference in AUROC (p = 0.808) but had a higher AUPRC (p = 0.009). In the temporal external validation cohort, the XGB model has an AUROC of 0.926 and an AUPRC of 0.703. We developed a dynamic high-accuracy bleeding risk calculator based on the XGB model and created a mobile-friendly QR code for easy access to this tool.

CONCLUSION

Bleeding risk during DAPT in post-CABG patients can be reliably predicted using selected baseline features. The XGB model outperforms the Precise-Dapt model, showing better precision and recall.

Temporal Effect of CYP3A4/5 Induction on Ticagrelor's Pharmacodynamic Effects: A Case Series

Ticagrelor is contraindicated in combination with cytochrome P450 3A4 and 3A5 enzyme (CYP3A4/5) inducers due to increased clearance, causing diminished antiplatelet effects. The emergent nature of acute coronary syndromes (ACS) may preclude scrutinization of home medications before P2Y12 inhibitor administration. The purpose of this case series is to establish the temporal impact of CYP3A4/5 enzyme induction on ticagrelor's pharmacodynamic effect by utilizing VerifyNow platelet aggregation studies. This was a retrospective case series of three patients who were taking a CYP3A4/5-inducing medication and loaded with ticagrelor for ACS. The duration of ticagrelor's antiplatelet effect was dramatically shortened in the presence of background CYP3A4/5 induction. The offset of antiplatelet effect, defined by platelet reactivity units (PRU), was 10-24 hours in the presence of CYP3A4/5 enzyme induction compared to the anticipated 36-48 hours. This was consistent across CYP3A4/5-inducing medications including carbamazepine, phenobarbital, and phenytoin. This study demonstrates rapid return of platelet function after a ticagrelor loading dose in the presence of CYP3A4/5-inducing medications. Monitoring of PRU every 6-12 hours with subsequent loading with clopidogrel or prasugrel should be considered. Larger scale studies are warranted to confirm these results.

Dynamics of Thrombogenicity and Platelet Function and Correlation with Bleeding Risk in Patients Undergoing M-TEER Using the PASCAL System

BACKGROUND

 Transcatheter mitral valve repair is performed in a patient population at risk for thrombotic and bleeding events. The effects on platelet function and reactivity and their association with bleeding events after mitral transcatheter edge-to-edge therapy (M-TEER) have not been systematically examined.

OBJECTIVES

 We sought to investigate the association of different parameters of platelet function and thrombogenicity with bleeding events post M-TEER.

METHODS

 In this single-center study, 100 consecutive patients with mitral regurgitation receiving TEER were analyzed. Blood was taken directly from the guide-catheter in the left atrium before and after placing the device. Blood samples were analyzed using impedance aggregometry (Multiplate) and TEG6s. The results were compared pre- and postprocedural. The primary outcome was any bleeding complication according to the Bleeding Academic Research Consortium classification within 6 months.

RESULTS

 A total of 41 patients experienced bleeding events. TEG analysis showed a significant decrease in ADP aggregation and increase in ADP inhibition. In ROC-analysis, TEG ADP aggregation and inhibition and Multiplate ADP aggregation showed moderate predictive values for bleeding events. The delta-ADP-Test (Multiplate) showed the strongest prediction of bleeding (area under the curve: 0.69). Adding platelet function and TEG markers to a model of clinical bleeding risk factors improved the prediction for bleeding events.

CONCLUSION

 This study indicates that thrombogenicity might be affected immediately after M-TEER probably due to changes in flow conditions. In particular, platelet aggregation involving the ADP receptor pathway significantly correlated with postprocedural bleeding events. Whether these results could guide peri-interventional antithrombotic therapy and improve peri- and postprocedural outcome requires further investigation.

Relevance of High Bleeding Risk and Postdischarge Bleeding in Patients Undergoing Percutaneous Coronary Intervention

Bleeding avoidance strategies are critical in the modern era of percutaneous coronary intervention; however, most efforts are geared toward reducing access-related complications. Improvements in procedural techniques (radial access, improved procedural anticoagulation regimens, etc) and modifications in postdischarge pharmacotherapy (shortened dual antiplatelet therapy, genotype-guided P2Y12 inhibition, etc) that led to a decline in bleeding related to percutaneous procedures were largely offset by increases in complexity and performance of percutaneous coronary intervention in high-risk patients. Among patients presenting with acute coronary syndrome, aggressive antiplatelet regimens with potent P2Y12 inhibitors are typically prescribed for a longer duration, prioritizing reduction in ischemic events over bleeding risk. Because postdischarge bleeding connotes an adverse prognosis similar to an ischemic event, postprocedure freedom from adverse outcomes can be best tailored by individualizing and recognizing the patient's bleeding and ischemic risks. This review of the contemporary and historical literature (PubMed, EMBASE, Cochrane Library) summarizes the available data, provides strategies to navigate these complex decisions, and helps individualize antithrombotic therapy.

A Microflow Chip Technique for Monitoring Platelets in Late Pregnancy: A Possible Risk Factor for Thrombosis

Purpose

To study the platelet adhesion and aggregation behaviour of late pregnancy women under arterial shear rate using microfluidic chip technology and evaluate the risk of thrombosis in late pregnancy.

Methods

We included pregnant women who were registered in the obstetrics department of our hospital between January 2021 and October 2022 and underwent regular prenatal examinations. Blood samples were collected at 32-35 weeks of gestation for routine blood tests and progesterone, oestradiol, and platelet aggregation function. A microfluidic chip was used to construct an in vitro stenosis vascular model to explore the platelet reactivity at shear rates of 1000s-1, 1500s-1 and 4000s-1. Flow cytometry was used to analyse the effect of shear rate induction on the expression of platelet membrane surface fibrin receptor (PAC-1) and P-selectin (CD62P) in pregnant women.

Results

Compared to the non-pregnant healthy control group, the white blood cell count increased and platelet count decreased significantly in late pregnant women (P < 0.05), and platelet reactivity to agonists increased under non-flow conditions (adhesion and aggregation rates, P < 0.05). Microfluidic chip technology showed that platelet aggregation in late pregnant women increased significantly (P < 0.05) in the shear-rate environment and was positively correlated with the shear rate. The degree of aggregation at 4000s-1 was more evident, but the stability of platelet aggregates was low. Shear rate increased PAC-1 and CD62P expression.

Conclusion

Microfluidic chip technology was used to analyse the platelet aggregation function under arterial shear rate combined with flow cytometry to detect platelet activation, which was consistent with the traditional non-flow conditions used to evaluate platelet function. However, microfluidic technology can simulate a more realistic in vivo shear rate environment, providing more effective clinical application data and a theoretical basis for the diagnosis and prevention of platelet dysfunction and thrombotic diseases during pregnancy.

Intra-operative and post-operative management of conduits for coronary artery bypass grafting: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Surgery and the European Association for Cardio-Thoracic Surgery Coronary Task Force

The structural and functional integrity of conduits used for coronary artery bypass grafting is critical for graft patency. Disruption of endothelial integrity and endothelial dysfunction are incurred during conduit harvesting subsequent to mechanical or thermal injury and during conduit storage prior to grafting, leading to acute thrombosis and early graft failure. Late graft failure, in particular that of vein grafts, is precipitated by progressive atherogenesis. Intra-operative management includes appropriate selection of conduit-specific harvesting techniques and storage solutions. Arterial grafts are prone to vasospasm subsequent to surgical manipulation, and application of intra-operative vasodilatory protocols is critical. Post-operative management includes continuation of oral vasodilator therapy and selection of antithrombotic and lipid-lowering agents to attenuate atherosclerotic disease progression in conduits. In this review, the scientific evidence underlying the key aspects of intra- and post-operative management of conduits for coronary artery bypass grafting is examined. Clinical consensus statements for best clinical practice are provided, and areas requiring further research are highlighted.

Demographic diversity in platelet function and response to antiplatelet therapy

Recent studies have highlighted the complexity of platelet biology, revealing their diverse roles beyond hemostasis. Pathological platelet activation is now recognized as a key contributor to thrombosis and inflammation that are both central to cardiovascular disease (CVD). Emerging research emphasizes the significant impact of demographic factors - such as age, sex, race, and ethnicity - on CVD risk and responses to antiplatelet therapies. These population-based differences, shaped by genetic and non-genetic factors, highlight the need for reevaluation of antiplatelet strategies. We address current knowledge and emphasize the pressing need for further research into platelet biology and cardiovascular outcomes across diverse populations. In this review we advocate for tailored therapeutic approaches in CVD based on the recent demographic-focused findings.

Interindividual variability in platelet reactivity among individuals with or without antiplatelet therapy: results from a large tertiary care hospital

Antiplatelet therapy is crucial for reducing thrombotic events in patients with atherosclerotic disease, but the response vary widely among individuals. The identification of patients at high (HPR), optimal (OPR) or low platelet reactivity (LPR) is dependent on high interlaboratory variability. We report results of a large dataset of patients to assess the gold standard light transmission aggregometry (LTA). A total of 11,913 patients who sequentially underwent LTA assessment using several stimuli (ADP-2µM, collagen-2 µg/ml, arachidonic acid 0.5 mM, epinephrine 10µM) with a standardized methodology between 2004 and 2022 were screened. After application of inclusion-exclusion criteria, 5,901 patients were included and divided into five groups: healthy-volunteers (HV; N = 534); controls (CTR; N = 1073); aspirin-treated patients (ASA; 75-150 mg/die; N = 3280); clopidogrel-treated patients (CLOP; 75 mg/die; N = 495) and patients treated with dual antiplatelet therapy, ASA plus CLOP (DAPT; N = 519). The mean PA% in response to ADP 2 μm was 72.4 ± 33.3 in the CTR population, 40.6 ± 29.9 in the ASA group, 25.1 ± 35.1 in the CLOP group and 10.2 ± 18.5 in the DAPT group. The mean PA% in response to collagen 2 ug/ml was 90.7 ± 10.5 in the CTR population, 40.8 ± 26.3 in the ASA group, 79.4 ± 21.8 in the CLOP group and 17.9 ± 19.9 in the DAPT group. The percentage of patients at OPR following ADP stimuli was 66%, 25%, and 26%, in the ASA, CLOP, and DAPT group, respectively. The percentage of patients at OPR following collagen stimuli was 56%, 22%, and 41%, in the ASA, CLOP, and DAPT group, respectively. LTA was significantly increased in response to ADP (72.4 ± 33.3vs62.7 ± 37.1; p < 0.001) and AA (90.7 ± 15.6vs87.6 ± 20.5; p < 0.001) in CTR compared to HV. Our findings support the concept that a significant proportion of individuals present a hyper- or hypo-reactive platelet phenotype potentially affecting the safety and efficacy of antiplatelet therapy. The variability in response to antiplatelet therapy was particularly evident in patients undergoing single as opposed to dual antiplatelet therapy regimens. These data support ongoing strategies of guided selection of antiplatelet therapy in patients with cardiovascular disease.

Therapeutic strategies aiming at the reduction of the antiplatelet intensity should not overlook the ischemic risk in patients with coronary syndromes

De-escalation of dual antiplatelet therapy (DAPT) is gaining traction as a strategy to reduce bleeding risks while ensuring ischemic outcomes. Undiscriminating de-escalation, notably in patients with high ischemic risk, might expose them to major adverse cardiac events. Platelet function and genetic tests are emerging tools to guide de-escalation, but both present specific drawbacks. Recent meta-analyses have aimed to consolidate the findings of individual trials to provide clearer insights. Yet, limitations remain for patients with concomitant high bleeding and ischemic risks. These high-risk patients are frequently underrepresented in clinical trials, and, therefore, currently available guidelines lack evidence-based recommendations for this subset. While DAPT de-escalation strategies hold promise, the choice of approach, whether clinically or assay-guided, remains complex and should be individualized.

Unprotected distal left main percutaneous intervention

Revascularization has been demonstrated to be clearly superior to medical therapy for significant unprotected left main coronary artery (LMCA) disease. Coronary artery bypass graft surgery (CABG) has a class 1 indication in both the American and European society guidelines for the treatment of LMCA disease. However, for the population of patients who are declined CABG after a heart team evaluation, percutaneous coronary interventional (PCI) may be an efficacious alternative. This review summarizes the data on percutaneous coronary intervention of distal left main coronary artery disease including the various contemporary techniques and associated challenges.

Changes in platelet maturity and reactivity following acute ST-segment elevation myocardial infarction

Background

Reduced effect of antiplatelet therapy has been reported in patients with ST-segment elevation myocardial infarction (STEMI). This could partly be explained by an increase of highly reactive immature platelets.

Objectives

To investigate changes in platelet maturity and reactivity after acute STEMI.

Methods

Patients diagnosed with STEMI, admitted for primary percutaneous coronary intervention, and treated according to international guidelines, were included. Blood samples were obtained within 24 hours after admission and at 2- to 3-months follow-up. Platelet maturity and reactivity using multicolor flow cytometry with SYTO-13 to categorize platelet maturity, whole blood platelet aggregation, serum thromboxane B2 levels, and standard immature platelet markers (eg, immature platelet count and fraction, and mean platelet volume) were measured.

Results

A total of 44 STEMI patients were included. The reactivity of immature platelets was consistently higher at baseline and at follow-up when compared to the entire platelet population and the mature platelet population (all P values < .05). The expression of CD63 (a dense granule marker) in immature platelets was consistently high compared to the entire platelet population and the mature platelet population and did not change from baseline to follow-up (P values > .24). Additionally, a positive significant correlation was found between standard immature platelet markers and the expression of CD63 on platelets both at baseline and follow-up (rho ranging from 0.32 to 0.62, all P values < .05).

Conclusion

Immature platelets represent a highly reactive platelet subpopulation crucial for the overall platelet reactivity, partly due to a high expression of dense granules. Despite treatment with loading and maintenance doses of antiplatelet therapy, the reactivity of immature platelets remained high in STEMI patients.

Aspirin vs. clopidogrel monotherapy after percutaneous coronary intervention: 1-year follow-up of the STOPDAPT-3 trial

BACKGROUND AND AIMS

There was no previous trial comparing aspirin monotherapy with a P2Y12 inhibitor monotherapy following short dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stents.

METHODS

In the STOPDAPT-3, patients with acute coronary syndrome or high bleeding risk (HBR) were randomly assigned to either 1-month dual antiplatelet therapy with aspirin and prasugrel followed by aspirin monotherapy (aspirin group) or 1-month prasugrel monotherapy followed by clopidogrel monotherapy (clopidogrel group). This secondary analysis compared aspirin monotherapy with clopidogrel monotherapy by the 30-day landmark analysis. The co-primary endpoints were the cardiovascular endpoint defined as a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, or ischaemic stroke and the bleeding endpoint defined as Bleeding Academic Research Consortium 3 or 5.

RESULTS

Of the 6002 assigned patients, 5833 patients (aspirin group: N = 2920 and clopidogrel group: N = 2913) were included in the 30-day landmark analysis. Median age was 73 (interquartile range 64-80) years, women 23.4%, acute coronary syndrome 74.6%, and high bleeding risk 54.1%. The assigned monotherapy was continued at 1 year in 87.5% and 87.2% in the aspirin and clopidogrel groups, respectively. The incidence rates beyond 30 days and up to 1 year were similar between the aspirin and clopidogrel groups for both cardiovascular endpoint [4.5 and 4.5 per 100 person-year, hazard ratio 1.00 (95% confidence interval .77-1.30), P = .97], and bleeding endpoint [2.0 and 1.9, hazard ratio 1.02 (95% confidence interval .69-1.52), P = .92].

CONCLUSIONS

Aspirin monotherapy compared with clopidogrel monotherapy was associated with similar cardiovascular and bleeding outcomes beyond 1 month and up to 1 year after percutaneous coronary intervention with drug-eluting stents (STOPDAPT-3 ClinicalTrials.gov number, NCT04609111).

Efficacy and safety of ticagrelor monotherapy following a brief DAPT vs. prolonged 12-month DAPT in ACS patients post-PCI: a meta-analysis of RCTs

BACKGROUND

As per current guidelines, acute coronary syndrome (ACS) patients who undergo percutaneous coronary intervention (PCI) should be started on dual antiplatelet therapy (DAPT) for a period of 12 months.

OBJECTIVE

To assess the efficacy and safety of brief DAPT (up to 3 months) succeeded by ticagrelor monotherapy compared with a 12-month DAPT in ACS patients following PCI.

METHODS

We systematically searched Cochrane, Embase, and PubMed to find relevant randomized clinical trials. Examined outcomes included the incidence of major adverse cerebrovascular and cardiovascular events (MACCE), bleeding events, and the composite incidence of net adverse clinical events (NACE).

RESULTS

Our primary analysis included 21,927 ACS patients from six RCTs. Our pooled results indicate that following PCI in individuals with ACS, brief DAPT followed by ticagrelor did not increase the risk of MACCE (OR 0.92, 95% CI 0.79-1.07) but significantly reduced the risk of minor or major bleeding (OR 0.52, 95% CI 0.44-0.62) and NACE (OR 0.71, 95% CI 0.59-0.86) compared with a long-term DAPT within a follow-up of 12 months.

CONCLUSION

Brief DAPT followed by ticagrelor monotherapy is superior to a 12-month DAPT in offering a net clinical advantage in ACS patients following PCI.

Intra-operative and post-operative management of conduits for coronary artery bypass grafting: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Surgery and the European Association for Cardio-Thoracic Surgery Coronary Task Force

The structural and functional integrity of conduits used for coronary artery bypass grafting is critical for graft patency. Disruption of endothelial integrity and endothelial dysfunction are incurred during conduit harvesting subsequent to mechanical or thermal injury and during conduit storage prior to grafting, leading to acute thrombosis and early graft failure. Late graft failure, in particular that of vein grafts, is precipitated by progressive atherogenesis. Intra-operative management includes appropriate selection of conduit-specific harvesting techniques and storage solutions. Arterial grafts are prone to vasospasm subsequent to surgical manipulation, and application of intra-operative vasodilatory protocols is critical. Post-operative management includes continuation of oral vasodilator therapy and selection of antithrombotic and lipid-lowering agents to attenuate atherosclerotic disease progression in conduits. In this review, the scientific evidence underlying the key aspects of intra- and post-operative management of conduits for coronary artery bypass grafting is examined. Clinical consensus statements for best clinical practice are provided, and areas requiring further research are highlighted.

International Consensus Statement on Platelet Function and Genetic Testing in Percutaneous Coronary Intervention: 2024 Update

Current evidence indicates that dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor is essential for the prevention of thrombotic events after percutaneous coronary interventions. However, dual antiplatelet therapy is associated with increased bleeding which may outweigh the benefits. This has set the foundations for customizing antiplatelet treatments to the individual patient. However, bleeding and ischemic risks are often present in the same patient, making it difficult to achieve this balance. The fact that oral P2Y12 inhibitors (clopidogrel, prasugrel, and ticagrelor) have diverse pharmacodynamic profiles that affect clinical outcomes supports the rationale for using platelet function and genetic testing to individualize antiplatelet treatment regimens. Indeed, up to one-third of patients treated with clopidogrel, but a minority of those treated with prasugrel or ticagrelor, exhibit high residual platelet reactivity resulting in an increased thrombotic risk. On the other hand, prasugrel and ticagrelor are frequently associated with low platelet reactivity and increased bleeding risk compared with clopidogrel without providing any additional reduction in ischemic events compared with patients who adequately respond to clopidogrel. The use of platelet function and genetic testing may allow for a guided selection of oral P2Y12 inhibitors. However, the nonuniform results of randomized controlled trials have led guidelines to provide limited recommendations on the implementation of these tests in patients undergoing percutaneous coronary intervention. In light of recent advancements in the field, this consensus document by a panel of international experts fills in the guideline gap by providing updates on the latest evidence in the field as well as recommendations for clinical practice.

P2Y12 inhibitor monotherapy after short DAPT in acute coronary syndrome: a systematic review and meta-analysis

BACKGROUND

P2Y12 inhibitor monotherapy after a short course of dual antiplatelet therapy (DAPT) may balance ischaemic and bleeding risks in patients with acute coronary syndrome (ACS). However, it remains uncertain how different P2Y12 inhibitors used as monotherapy affect outcomes.

METHODS AND RESULTS

Randomized controlled trials comparing P2Y12 inhibitor monotherapy after a short course of DAPT (≤3 months) vs. 12-month DAPT in ACS were included. The primary endpoint was major adverse cardiovascular events (MACE). All analyses included an interaction term for the P2Y12 inhibitor used as monotherapy. Trial sequential analyses were run to explore whether the effect estimate of each outcome may be affected by further studies. Seven trials encompassing 27 284 ACS patients were included. Compared with 12-month DAPT, P2Y12 inhibitor monotherapy after a short course of DAPT was associated with no difference in MACE [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.76-1.12] and a significant reduction in net adverse clinical events (NACE) (OR 0.75; 95% CI 0.60-0.94), any bleeding (OR 0.54, 95% CI 0.43-0.66), and major bleeding (OR 0.47, 95% CI 0.37-0.60). Significant interactions for subgroup difference between ticagrelor and clopidogrel monotherapy were found for MACE (Pint = 0.016), all-cause death (Pint = 0.042), NACE (Pint = 0.018), and myocardial infarction (Pint = 0.028). Trial sequential analysis showed conclusive evidence of improved NACE with ticagrelor, but not with clopidogrel monotherapy, compared with standard DAPT.

CONCLUSIONS

In patients with ACS, P2Y12 inhibitor monotherapy after short DAPT halves bleeding without increasing ischaemic events compared with standard DAPT. Ticagrelor, but not clopidogrel monotherapy, reduced MACE, NACE, and mortality compared with standard DAPT, supporting its use after aspirin discontinuation.

Ticagrelor 60 vs. 90 mg in elderly ACS patients undergoing PCI: a randomized, crossover trial

AIMS

Although dual antiplatelet therapy with aspirin and a potent P2Y12 receptor inhibitor is currently recommended in patients with acute coronary syndrome (ACS), its use in elderly patients remains challenging. The aim of this trial is to evaluate the pharmacodynamic and pharmacokinetic profile of ticagrelor 60 vs. 90 mg twice daily among elderly patients (≥75 years) with ACS undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

PLINY The ELDER (NCT04739384) was a randomized, crossover trial testing the non-inferiority of a lower vs. standard dose of ticagrelor with respect to the primary endpoint of P2Y12 inhibition as determined by pre-dose P2Y12 reaction units (PRU) using the VerifyNow-P2Y12 (Accumetrics, San Diego, CA, USA). Other pharmacodynamic tests included light transmittance aggregometry, multiple electrode aggregometry, and response to aspirin. Plasma levels of ticagrelor and its active metabolite AR-C124910XX were also evaluated. A total of 50 patients (mean age 79.6 ± 4.0 years, females 44%) were included in the trial. Ticagrelor 60 mg was non-inferior to ticagrelor 90 mg according to VerifyNow-P2Y12 results (PRU 26.4 ± 32.1 vs. 30.4 ± 39.0; least squares mean difference: -4; 95% confidence interval: -16.27 to 8.06; P for non-inferiority = 0.002). Other pharmacodynamic parameters were similar between the two ticagrelor doses and there were no differences in response to aspirin. Plasma levels of ticagrelor (398.29 ± 312.36 ng/mL vs. 579.57 ± 351.73 ng/mL, P = 0.006) and its active metabolite were significantly lower during treatment with ticagrelor 60 mg.

CONCLUSION

Although plasma concentrations were lower, ticagrelor 60 mg twice daily provided a similar magnitude of platelet inhibition compared with ticagrelor 90 mg twice daily among elderly patients undergoing PCI.

Aspirin Hypersensitivity in Patients With Atherosclerotic Cardiovascular Disease

Low-dose aspirin remains the most commonly used antiplatelet agent among patients with atherosclerotic cardiovascular disease. Aspirin hypersensitivity occurs in 1% to 5% of patients and is among the most frequent causes for prohibiting the use of aspirin, posing a significant dilemma on how to manage these patients in clinical practice. Aspirin hypersensitivity is often misinterpreted and confused with aspirin intolerance, with treatment approaches being often unclear and lacking specific recommendations. Aspirin desensitization and low-dose aspirin challenge have emerged as pragmatic, effective, and safe approaches in patients with suspected or confirmed aspirin hypersensitivity who require aspirin therapy, but they are underused systematically in clinical practice. Furthermore, there is confusion over alternative antiplatelet agents to be used in these patients. The pathophysiological mechanisms and classification of aspirin hypersensitivity, as well as alternative strategies and practical algorithms to overcome the need for aspirin use in patients with atherosclerotic cardiovascular disease with suspected aspirin hypersensitivity, are discussed.

Comparative effects of different antiplatelet strategies in carriers of CYP2C19 loss-of-function alleles: a network meta-analysis

BACKGROUND

Carriers of cytochrome 2C19 (CYP2C19) loss-of-function (LoF) alleles treated with clopidogrel have impaired drug metabolism, resulting in reduced active metabolite levels, high platelet reactivity (HPR), and an increased risk of thrombotic events. Several alternative antiplatelet therapies have been proposed to overcome HPR in these patients, but their comparative effects remain poorly explored.

METHODS

Randomized controlled trials (RCTs) comparing different oral antiplatelet therapies in carriers of CYP2C19 LoF alleles undergoing percutaneous coronary interventions (PCI) were included. A frequentist network meta-analysis was conducted to estimate mean difference (MD) or odds ratios and 95% confidence intervals (CI). The primary outcome was platelet reactivity assessed by VerifyNow and reported as P2Y12 reaction unit (PRU). The secondary outcome was the rate of HPR. Standard dose of clopidogrel (75 mg daily) was used as a reference treatment.

RESULTS

A total of 12 RCTs testing 6 alternative strategies (i.e. clopidogrel 150 mg, prasugrel 3.75 mg, 5 mg, and 10 mg, ticagrelor 90 mg bid, and adjunctive cilostazol 100 mg bid) were included in the network. Compared with standard-dose clopidogrel, the greatest reduction in PRU was observed with prasugrel 10 mg (MD -127.91; 95% CI -141.04; -114.78) and ticagrelor 90 mg bid (MD -124.91; 95% CI -161.78; -88.04), followed by prasugrel 5 mg (MD -76.33; 95% CI -98.01; -54.65) and prasugrel 3.75 mg (MD -73.00; 95% CI -100.28; -45.72). Among other strategies, adjunctive cilostazol (MD -42.64; 95% CI -64.72; -20.57) and high-dose clopidogrel (MD -32.11; 95% CI -51.33; -12.90) were associated with a modest reduction in PRU compared with standard-dose clopidogrel.

CONCLUSION

Among carriers of CYP2C19 LoF alleles undergoing PCI, standard-dose prasugrel or ticagrelor are most effective in reducing platelet reactivity, while double-dose clopidogrel and additional cilostazol showed modest effects. Reduced-dose of prasugrel may represent a balanced strategy to overcome HPR without a significant increase in bleeding. The clinical implications of these pharmacodynamic findings warrant further investigation.

Genetic Determinants of Response to P2Y12 Inhibitors and Clinical Implications

The CYP2C19 enzyme metabolizes clopidogrel, a prodrug, to its active form. Approximately 30% of individuals inherit a loss-of-function (LoF) polymorphism in the CYP2C19 gene, leading to reduced formation of the active clopidogrel metabolite. Reduced clopidogrel effectiveness has been well documented in patients with an LoF allele following an acute coronary syndrome or percutaneous coronary intervention. Prasugrel or ticagrelor is recommended in those with an LoF allele as neither is affected by CYP2C19 genotype. Although data demonstrate improved outcomes with a CYP2C19-guided approach to P2Y12 inhibitor selection, genotyping has not yet been widely adopted in clinical practice.

Considerations in Antiplatelet Therapy in Women Undergoing Treatment of Acute Coronary Syndrome or Percutaneous Coronary Intervention

Antiplatelet therapy is integral to reduce the risk of future ischemic events following acute coronary syndrome (ACS) or percutaneous coronary intervention (PCI); this aim must be balanced by limiting the risk of bleeding. Women with ACS or undergoing PCI have distinct platelet physiology, vascular anatomy, and clinical profiles that can influence the selection of an appropriate regimen. There are procedural techniques that can enhance safety in women. The poor inclusion of women in ACS and PCI trials limits our understanding of the ideal antiplatelet regimen in women, and future studies must find ways to increase the participation of female patients.

Antithrombotic Therapy in Acute Coronary Syndrome

Early mechanical reperfusion, primarily via percutaneous coronary intervention, combined with timely antithrombotic drug administration, constitutes the main approach for managing acute coronary syndrome (ACS). Clinicians have access to a variety of antithrombotic agents, necessitating careful selection to balance reducing thrombotic events against increased bleeding risks. This review offers a comprehensive update on current antithrombotic therapy in ACS, emphasizing the need for individualized treatment strategies.

Effect of lipid-lowering therapy on platelet reactivity in patients treated with and without antiplatelet therapy

Circulating lipoproteins may interact with platelets, increasing platelet sensitivity to aggregating agonists and their tendency towards activation and thrombus formation. In particular, patients with hypercholesterolemia exhibit a higher degree of platelet reactivity compared to normolipidemic. Moreover, accruing evidence report that lipid-lowering therapies can reduce thrombus formation, particularly in the absence of concomitant antiplatelet therapy. However, the underlying biological mechanism(s) explaining these clinical observations are not completely understood. Baseline platelet reactivity and high on-treatment platelet reactivity while on antiplatelet therapy (e.g., aspirin and clopidogrel) are associated with poor clinical outcomes. Therefore, strategies to reduce baseline platelet reactivity or improve the pharmacodynamic profile of antiplatelet therapies are an unmet clinical need. The potential use of lipid-lowering therapies for optimizing platelet reactivity provides several advantages as there is strong evidence that reducing circulating lipoproteins can improve clinical outcomes, and they may avoid the need for potent antiplatelet therapies that, although more effective, are associated with increased bleeding risk. This review will provide a systematic overview of the effects of lipid-lowering therapy on platelet reactivity in patients treated with and without antiplatelet therapy. We will focus on the potential biological mechanism(s) of action and the effect of statins, ezetimibe, proprotein convertase subtilisin/kexin 9 inhibitors, omega-3 fatty acids, and recombinant high-density lipoprotein on platelet reactivity. Ultimately, we will assess the current gaps in the literature and future perspective in the field.

Impact of CYP2C19 Genotype Status on Clinical Outcomes in Patients with Symptomatic Coronary Artery Disease, Stroke, and Peripheral Arterial Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Clopidogrel is widely used for the secondary prevention of atherothrombotic events in patients with coronary artery disease (CAD), ischemic stroke, and peripheral arterial disease (PAD). CYP2C19 plays a pivotal role in the conversion of clopidogrel to its active metabolite. Clopidogrel-treated carriers of a CYP2C19 loss-of-function allele (LOF) may have a higher risk of new atherothrombotic events. Previous studies on genotype-guided treatment were mainly performed in CAD and showed mixed results.

PURPOSE

To simultaneously investigate the impact of CYP2C19 genotype status on the rate of atherothrombotic events in the most common types of atherosclerotic disease (CAD, stroke, PAD).

METHODS

A comprehensive search in Pubmed, EMBASE, and MEDLINE from their inception to July 23rd 2023 was performed. Randomized controlled trials (RCTs) comparing genotype-guided and standard antithrombotic treatment, and cohort studies and post hoc analyses of RCTs concerning the association between CYP2C19 genotype status and clinical outcomes in clopidogrel-treated patients were included. The primary efficacy endpoint was major adverse cardiovascular events (MACE) and the safety end point major bleeding. Secondary endpoints were myocardial infarction, stent thrombosis, and ischemic stroke.

RESULTS

Forty-four studies were identified: 11 studies on CAD, 29 studies on stroke, and 4 studies on PAD. In CAD, genotype-guided therapy significantly reduced the risk of MACE [risk ratio (RR) 0.60, 95% confidence interval (CI) 0.43-0.83], myocardial infarction (RR 0.53, 95% CI 0.42-0.68), and stent thrombosis (RR 0.64, 95% CI 0.43-0.94), compared with standard antithrombotic treatment. The rate of major bleeding did not differ significantly (RR 0.93, 95% CI 0.70-1.23). Most RCTs were performed in patients after percutaneous coronary intervention (9/11). In stroke, LOF carriers had a significantly higher risk of MACE (RR 1.61, 95% CI 1.25-2.08) and recurrent ischemic stroke (RR 1.89, 95% CI 1.48-2.40) compared with non-carriers. No significant differences were found in major bleeding (RR 0.90, 95% CI 0.43-1.89). In the 6955 patients with symptomatic PAD treated with clopidogrel in the EUCLID trial, no differences in MACE or major bleeding were found between LOF carriers and non-carriers. In three smaller studies on patients with PAD treated with clopidogrel after endovascular therapy, CYP2C19 genotype status was significantly associated with atherothrombotic events.

CONCLUSIONS

Genotype-guided treatment significantly decreased the rate of atherothrombotic events in patients with CAD, especially after PCI. In patients with history of stroke, LOF carriers treated with clopidogrel had a higher risk of MACE and recurrent stroke. The available evidence in PAD with regard to major adverse limb events is too limited to draw meaningful conclusions.

REGISTRATION

PROSPERO identifier no. CRD42020220284.

Switching Platelet P2Y12 Receptor Inhibiting Therapies

Antiplatelet therapy involving aspirin and a P2Y12 receptor inhibitor is fundamental in managing patients with atherothrombotic disease. Switching between P2Y12 inhibitors is frequently observed in clinical settings for various reasons, such as safety, efficacy, patient adherence, or cost concerns. Although it occurs often, the optimal method for switching remains a concern owing to potential drug interactions, which can result in either inadequate platelet inhibition and subsequent thrombotic events or low platelet reactivity and increased bleeding risks due to therapy overlap. This review offers practical guidance on switching P2Y12 inhibitors, drawing from pharmacodynamic and clinical data.

Implementing a pharmacogenomic-driven algorithm to guide antiplatelet therapy among Caribbean Hispanics: a non-randomised clinical trial

OBJECTIVES

To assess whether genotype-guided selection of oral antiplatelet drugs using a clinical decision support (CDS) algorithm reduces the rate of major adverse cardiovascular and cerebrovascular events (MACCEs) among Caribbean Hispanic patients, after 6 months.

DESIGN

An open-label, multicentre, non-randomised clinical trial.

SETTING

Eight secondary and tertiary care hospitals (public and private) in Puerto Rico.

PARTICIPANTS

300 Caribbean Hispanic patients on clopidogrel, both genders, underwent percutaneous coronary intervention (PCI) for acute coronary syndromes, stable ischaemic heart disease and documented extracardiac vascular diseases.

INTERVENTIONS

Patients were separated into standard-of-care (SoC) and genotype-guided (pharmacogenetic (PGx)-CDS) groups (150 each) and stratified by risk scores. Risk scores were calculated based on a previously developed CDS risk prediction algorithm designed to make actionable treatment recommendations for each patient. Individual platelet function, genotypes, clinical and demographic data were included. Ticagrelor was recommended for patients with a high-risk score ≥2 in the PGx-CDS group only, the rest were kept or de-escalated to clopidogrel. The intervention took place within 3-5 days after PCI. Adherence medication score was also measured.

PRIMARY AND SECONDARY OUTCOMES

The occurrence rate of MACCEs (primary) and bleeding episodes (secondary). Statistical associations between patient time free of events and predictor variables (ie, treatment groups, risk scores) were tested using Kaplan-Meier survival analyses and Cox proportional-hazards regression models.

RESULTS

The genotype-guided group had a clinically lower but not significantly different risk of MACCEs compared with the SoC group (8.7% vs 10.7%, p=0.56; HR=0.56). Among high-risk score patients, genotype-driven guidance of antiplatelet therapy showed superiority over SoC in reducing MACCE incidence 6 months postcoronary stenting (adjusted HR=0.104; p< 0.0001).

CONCLUSIONS

The potential benefit of implementing our PGx-CDS algorithm to significantly reduce the incidence rate of MACCEs in post-PCI Caribbean Hispanic patients on clopidogrel was observed exclusively among high-risk patients, with apparently no evident effect in other patient groups.

TRIAL REGISTRATION NUMBER

NCT03419325.

Outcomes of Ticagrelor Versus High-dose Clopidogrel in CYP2C19 Intermediate Metabolizer Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndromes

ABSTRACT

Guidelines on antiplatelet recommendation for CYP2C19 intermediate metabolizer (IM) have not come to an agreement. This study aimed to evaluate the clinical benefit of ticagrelor when compared with high-dose clopidogrel in CYP2C19 IM after percutaneous coronary intervention for acute coronary syndromes. Patients were enrolled according to CYP2C19 genotype and individual antiplatelet therapy. Patient characteristics and clinical outcomes were collected through electronic medical record system. The primary outcome was major adverse cardiac and cerebrovascular event (MACCE), namely a composite of death from cardiovascular causes, myocardial infarction, stroke, and stent thrombosis within 12 months. The secondary outcome was Bleeding Academic Research Consortium scale bleeding events within 12 months. The Cox proportional hazards regression model was performed, with inverse probability treatment weighting (IPTW) adjusting for potential confounders. A total of 532 CYP2C19 IM were enrolled in this retrospective single-center study. No statistically significant difference in incidence rate of MACCE was found between patients receiving ticagrelor versus clopidogrel (7.01 vs. 9.52 per 100 patient-years; IPTW-adjusted hazard ratio 0.71; 95% confidence interval: 0.32-1.58; adjusted log-rank P = 0.396), but the incidence rate of Bleeding Academic Research Consortium type 2, 3, or 5 bleeding events was statistically higher in the loss of function-ticagrelor group than in the loss of function-clopidogrel group (13.53 vs. 6.16 per 100 patient-years; IPTW-adjusted hazard ratio: 2.29; 95% confidence interval: 1.10-4.78; adjusted log-rank P = 0.027). Ticagrelor treatment in CYP2C19 IM resulted in a statistically higher risk of bleeding compared with high-dose clopidogrel, whereas a clear association between treatments and MACCE warrants further investigations.

Cost-effectiveness of platelet function testing in dual antiplatelet therapy decision-making after intracranial aneurysm treatment with flow diversion

Dual antiplatelet therapy (DAPT) use is the standard of practice after flow diversion (FD) for intracranial aneurysms (IAs). Yet, no consensus exists in the literature regarding the optimal regimen. Certain institutions utilize various platelet function testing (PFT) to assess patient responsiveness to DAPT. Clopidogrel is the most commonly prescribed drug during DAPT; however, up to 52% of patients can be non-responders, justifying PFT use. Additionally, prices vary significantly among antiplatelet drugs, often further complicated by insurance restrictions. We aimed to determine the most cost-effective strategy for deciding DAPT regimens for patients after IA treatment. A decision tree with Monte Carlo simulations was performed to simulate patients undergoing various three-month postoperative DAPT regimens. Patients were either universally administered aspirin alongside clopidogrel, ticagrelor, or prasugrel without PFT, or administered one of the former thienopyridine medications based on platelet reactivity unit (PRU) results after clopidogrel. Input data for the model were extracted from the current literature, and the willingness-to-pay threshold (WTP) was defined as $100,000 per QALY as per standard practice in the US. The baseline comparison was with universal clopidogrel DAPT without any PFT. Probabilistic and deterministic sensitivity analyses were performed to evaluate the robustness of the model. Utilizing PFT and switching clopidogrel to prasugrel if resistance is documented was the most cost-effective regimen compared to universal clopidogrel, with a base-case incremental cost-effectiveness ratio (ICER) of $-35,255 (cost $2,336.67, effectiveness 0.85). Performing PFT and switching clopidogrel to ticagrelor (ICER $-4,671; cost $2,995.06, effectiveness 0.84), universal prasugrel (ICER $5,553; cost $3,097.30, effectiveness 0.84), or universal ticagrelor (ICER $75,969; cost $3,801.36, effectiveness 0.84) were all more cost-effective than treating patients with universal clopidogrel (cost $3,041.77, effectiveness 0.83). These conclusions remain robust in probabilistic and deterministic sensitivity analyses. The most cost-effective strategy guiding DAPT after FD for IAs is to perform PFTs and switch clopidogrel to prasugrel if resistance is documented, alongside aspirin. The cost of PFT is strongly justified and recommended when deciding patient-specific DAPT regimens.

Impact of proton pump inhibitor use on clinical outcomes in East Asian patients receiving clopidogrel following drug-eluting stent implantation

BACKGROUND

Concomitant use of clopidogrel and proton pump inhibitor (PPI) is common, but PPI may reduce the antiplatelet effects of clopidogrel in patients undergoing percutaneous coronary intervention (PCI). We evaluated the impact of PPI use on clinical outcomes in post-PCI patients, by incorporating P2Y12 reaction unit (PRU) and CYP2C19 genotyping results.

METHODS

From a multicenter registry of patients who underwent PCI with drug-eluting stent implantation and received clopidogrel-based dual antiplatelet therapy (DAPT), patients who were prescribed a PPI at the time of PCI (PPI users) were compared to those who were not (non-users). The primary outcome included all-cause death, myocardial infarction, stent thrombosis, or cerebrovascular accident at 12 months. Major bleeding (Bleeding Academic Research Consortium [BARC] types 3-5) and gastrointestinal (GI) bleeding (BARC types 3-5) were important secondary outcomes. The adjusted outcomes were compared using a 1:1 propensity-score (PS) matching and competing risk analysis.

RESULTS

Of 13,160 patients, 2,235 (17.0%) were prescribed PPI, with an average age of 65.4 years. PPI users had higher on-treatment PRU levels than non-users. After PS matching, the primary outcome occurred in 51 patients who were PPI users (cumulative incidence, 4.7%) and 41 patients who were non-users (cumulative incidence, 3.7%; log-rank p = 0.27). In carriers of both CYP2C19 loss-of-function alleles, PPI use was linked to an increased risk of the primary outcome (hazard ratio, 3.22; 95% confidence interval, 1.18-8.78). The incidence of major bleeding and GI bleeding (BARC types 3-5) was comparable between PPI users and non-users in the PS-matched cohort.

CONCLUSIONS

In post-PCI patients receiving clopidogrel-based DAPT, PPI use was not linked to an increased risk of adverse cardiac and cerebrovascular events, but there was a small but significant increase in on-treatment PRU. Future research using a more individualized approach would further elucidate these interactions and guide evidence-based clinical practices.

Recommendations for pharmacogenetic testing in clinical practice guidelines in the US

PURPOSE

Pharmacogenetic testing can identify patients who may benefit from personalized drug treatment. However, clinical uptake of pharmacogenetic testing has been limited. Clinical practice guidelines recommend biomarker tests that the guideline authors deem to have demonstrated clinical utility, meaning that testing improves treatment outcomes. The objective of this narrative review is to describe the current status of pharmacogenetic testing recommendations within clinical practice guidelines in the US.

SUMMARY

Guidelines were reviewed for pharmacogenetic testing recommendations for 21 gene-drug pairs that have well-established drug response associations and all of which are categorized as clinically actionable by the Clinical Pharmacogenetics Implementation Consortium. The degree of consistency within and between organizations in pharmacogenetic testing recommendations was assessed. Relatively few clinical practice guidelines that provide a pharmacogenetic testing recommendation were identified. Testing recommendations for HLA-B*57:01 before initiation of abacavir and G6PD before initiation of rasburicase, both of which are included in drug labeling, were mostly consistent across guidelines. Gene-drug pairs with at least one clinical practice guideline recommending testing or stating that testing could be considered included CYP2C19-clopidogrel, CYP2D6-codeine, CYP2D6-tramadol, CYP2B6-efavirenz, TPMT-thiopurines, and NUDT15-thiopurines. Testing recommendations for the same gene-drug pair were often inconsistent between organizations and sometimes inconsistent between different guidelines from the same organization.

CONCLUSION

A standardized approach to evaluating the evidence of clinical utility for pharmacogenetic testing may increase the inclusion and consistency of pharmacogenetic testing recommendations in clinical practice guidelines, which could benefit patients and society by increasing clinical use of pharmacogenetic testing.

CYP2C19 Genetic Testing for Oral P2Y12 Inhibitor Therapy: A Scientific Statement From the American Heart Association

There is significant variability in the efficacy and safety of oral P2Y12 inhibitors, which are used to prevent ischemic outcomes in common diseases such as coronary and peripheral arterial disease and stroke. Clopidogrel, a prodrug, is the most used oral P2Y12 inhibitor and is activated primarily after being metabolized by a highly polymorphic hepatic cytochrome CYP2C219 enzyme. Loss-of-function genetic variants in CYP2C219 are common, can result in decreased active metabolite levels and increased on-treatment platelet aggregation, and are associated with increased ischemic events on clopidogrel therapy. Such patients can be identified by CYP2C19 genetic testing and can be treated with alternative therapy. Conversely, universal use of potent oral P2Y12 inhibitors such as ticagrelor or prasugrel, which are not dependent on CYP2C19 for activation, has been recommended but can result in increased bleeding. Recent clinical trials and meta-analyses have demonstrated that a precision medicine approach in which loss-of-function carriers are prescribed ticagrelor or prasugrel and noncarriers are prescribed clopidogrel results in reducing ischemic events without increasing bleeding risk. The evidence to date supports CYP2C19 genetic testing before oral P2Y12 inhibitors are prescribed in patients with acute coronary syndromes or percutaneous coronary intervention. Clinical implementation of such genetic testing will depend on among multiple factors: rapid availability of results or adoption of the concept of performing preemptive genetic testing, provision of easy-to-understand results with therapeutic recommendations, and seamless integration in the electronic health record.

Precision Medicine in Acute Coronary Syndromes

Nowadays, current guidelines on acute coronary syndrome (ACS) provide recommendations mainly based on the clinical presentation. However, greater attention is being directed to the specific pathophysiology underlying ACS, considering that plaque destabilization and rupture leading to luminal thrombotic obstruction is not the only pathway involved, albeit the most recognized. In this review, we discuss how intracoronary imaging and biomarkers allow the identification of specific ACS endotypes, leading to the recognition of different prognostic implications, tailored management strategies, and new potential therapeutic targets. Furthermore, different strategies can be applied on a personalized basis regarding antithrombotic therapy, non-culprit lesion revascularization, and microvascular obstruction (MVO). With respect to myocardial infarction with non-obstructive coronary arteries (MINOCA), we will present a precision medicine approach, suggested by current guidelines as the mainstay of the diagnostic process and with relevant therapeutic implications. Moreover, we aim at illustrating the clinical implications of targeted strategies for ACS secondary prevention, which may lower residual risk in selected patients.

Does one size really fit all? The case for personalized antiplatelet therapy in interventional cardiology

Cardiovascular disease is the leading cause of death worldwide. Dual antiplatelet therapy (DAPT), with aspirin plus a P2Y12 inhibitor, is currently recommended as a default for patients after acute coronary syndrome (ACS) and following percutaneous coronary intervention (PCI). However, controversies arise over the role of aspirin, the optimal duration of DAPT after drug-eluting stent (DES) implantation, the choice of P2Y12 inhibitor and the variability in individual responses to antiplatelet agents. Recent data indicate that monotherapy with a P2Y12 inhibitor may have adequate anti-ischemic effects with lower bleeding risk. Additionally, discrepancies in DAPT duration recommendations and the optimal P2Y12 inhibitor, provides more uncertainty. We ask the question "does one size really fits all?" or should a more personalized strategy should be implemented.

Precision Antiplatelet Therapy after Percutaneous Coronary Intervention (Precision PCI) Registry - Informing optimal antiplatelet strategies

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor (clopidogrel, prasugrel, or ticagrelor) is indicated after percutaneous coronary intervention (PCI) to reduce the risk of atherothrombotic events. Approximately 30% of the US population has a CYP2C19 no-function allele that reduces the effectiveness of clopidogrel, but not prasugrel or ticagrelor, after PCI. We have shown improved outcomes with the integration of CYP2C19 genotyping into clinical care to guide the selection of prasugrel or ticagrelor in CYP2C19 no-function allele carriers. However, the influence of patient-specific demographic, clinical, and other genetic factors on outcomes with genotype-guided DAPT has not been defined. In addition, the impact of genotype-guided de-escalation from prasugrel or ticagrelor to clopidogrel in patients without a CYP2C19 no-function allele has not been investigated in a diverse, real-world clinical setting. The Precision Antiplatelet Therapy after Percutaneous Coronary Intervention (Precision PCI) Registry is a multicenter US registry of patients who underwent PCI and clinical CYP2C19 testing. The registry is enrolling a diverse population, assessing atherothrombotic and bleeding events over 12 months, collecting DNA samples, and conducting platelet function testing in a subset of patients. The registry aims to define the influence of African ancestry and other patient-specific factors on clinical outcomes with CYP2C19-guided DAPT, evaluate the safety and effectiveness of CYP2C19-guided DAPT de-escalation following PCI in a real-world setting, and identify additional genetic influences of clopidogrel response after PCI, with the ultimate goal of establishing optimal strategies for individualized antiplatelet therapy that improves outcomes in a diverse, real-world population.

P2Y12 Receptor Inhibitor for Antiaggregant Therapies: From Molecular Pathway to Clinical Application

Platelets play a significant role in hemostasis, forming plugs at sites of vascular injury to limit blood loss. However, if platelet activation is not controlled, it can lead to thrombotic events, such as myocardial infarction and stroke. To prevent this, antiplatelet agents are used in clinical settings to limit platelet activation in patients at risk of arterial thrombotic events. However, their use can be associated with a significant risk of bleeding. An enhanced comprehension of platelet signaling mechanisms should facilitate the identification of safer targets for antiplatelet therapy. Over the past decade, our comprehension of the breadth and intricacy of signaling pathways that orchestrate platelet activation has expanded exponentially. Several recent studies have provided further insight into the regulation of platelet signaling events and identified novel targets against which to develop novel antiplatelet agents. Antiplatelet drugs are essential in managing atherothrombotic vascular disease. The current antiplatelet therapy in clinical practice is limited in terms of safety and efficacy. Novel compounds have been developed in response to patient variability and resistance to aspirin and/or clopidogrel. Recent studies based on randomized controlled trials and systematic reviews have definitively demonstrated the role of antiplatelet therapy in reducing the risk of cardiovascular events. Antiplatelet therapy is the recommended course of action for patients with established atherosclerosis. These studies compared monotherapy with a P2Y12 inhibitor versus aspirin for secondary prevention. However, in patients undergoing percutaneous coronary intervention, it is still unclear whether the efficacy of P2Y12 inhibitor monotherapy after a short course of dual antiplatelet therapy depends on the type of P2Y12 inhibitor. This paper focuses on the advanced-stage evaluation of several promising antiplatelet drugs.

Platelet-fibrin clot strength and platelet reactivity predicting cardiovascular events after percutaneous coronary interventions

BACKGROUND AND AIMS

Platelet-fibrin clot strength (PFCS) is linked to major adverse cardiovascular event (MACE) risk. However, the association between PFCS and platelet reactivity and their prognostic implication remains uncertain in patients undergoing percutaneous coronary intervention (PCI).

METHODS

In PCI-treated patients (n = 2512) from registry data from January 2010 to November 2018 in South Korea, PFCS using thromboelastography and platelet reactivity using VerifyNow were measured. High PFCS (PFCSHigh) was defined as thromboelastography maximal amplitude ≥ 68 mm, and high platelet reactivity (HPR) was defined as >208 P2Y12 reaction units. Patients were stratified into four groups according to maximal amplitude and P2Y12 reaction unit levels: (i) normal platelet reactivity (NPR)-PFCSNormal (31.8%), (ii) HPR-PFCSNormal (29.0%), (iii) NPR-PFCSHigh (18.1%), and (iv) HPR-PFCSHigh (21.1%). Major adverse cardiovascular event (all-cause death, myocardial infarction, or stroke) and major bleeding were followed up to 4 years.

RESULTS

High platelet reactivity and PFCSHigh showed an additive effect for clinical outcomes (log-rank test, P < .001). Individuals with NPR-PFCSNormal, NPR-PFCSHigh, HPR-PFCSNormal, and HPR-PFCSHigh demonstrated MACE incidences of 7.5%, 12.6%, 13.4%, and 19.3%, respectively. The HPR-PFCSHigh group showed significantly higher risks of MACE compared with the NPR-PFCSNormal group [adjusted hazard ratio (HRadj) 1.89; 95% confidence interval (CI) 1.23-2.91; P = .004] and the HPR-PFCSNormal group (HRadj 1.60; 95% CI 1.12-2.27; P = .009). Similar results were observed for all-cause death. Compared with HPR-PFCSNormal phenotype, NPR-PFCSNormal phenotype was associated with a higher risk of major bleeding (HRadj 3.12; 95% CI 1.30-7.69; P = .010).

CONCLUSIONS

In PCI patients, PFCS and platelet reactivity demonstrated important relationships in predicting clinical prognosis. Their combined assessment may enhance post-PCI risk stratification for personalized antithrombotic therapy.

The influence of P2Y12 gene polymorphisms on clopidogrel therapy in patients after percutaneous coronary intervention

Aim: We aimed to define the influence of P2Y12 polymorphisms (rs6801273, rs2046934, and rs6809699), diabetes, hypertension, obesity, hypercholesterolemia, statins intake, and smoking habit on clopidogrel therapy in patients undergoing percutaneous coronary intervention.Materials & methods: We used PCR-RFLP and PCR-ASO for P2Y12 genotype analysis. The effectiveness of the therapy was measured with the VerifyNow method and defined in platelet reactivity units.Results: Studied polymorphisms had no statistically significant influence on PRU before (PRU0) and 6 months (PRU6) after the procedure. H1/H1 diabetic carriers had significantly higher PRU6 values than patients without diabetes. Obese H1/H2 subjects had significantly lower PRU6 values than H1/H2 non-obese carriers.Conclusion: We found that obesity and diabetes may influence the long-term outcome of antiplatelet therapy.

Clopidogrel-Mediated P2Y12 Inhibition According to Renal Function in Patients With Diabetes Mellitus and CAD

This prospective ex vivo and in vitro pharmacodynamic (PD)/pharmacokinetic investigation was conducted in patients with diabetes mellitus with (n = 31) and without chronic kidney disease (n = 30). PD assessments included platelet reactivity index, maximum platelet aggregation, and P2Y12 reaction units. Ex vivo pharmacokinetic assessments included plasma levels of clopidogrel and its active metabolite. In vitro PD assessments were conducted on baseline samples incubated with escalating concentrations of clopidogrel and its active metabolite. Among patients with diabetes mellitus treated with clopidogrel, impaired renal function was associated with increased maximum platelet aggregation. This finding could be attributed partially to upregulation of the P2Y12 activity without differences in drug absorption or metabolism. (Impact of Chronic Kidney Disease on Clopidogrel Effects in Diabetes Mellitus; NCT03774394).

Stratified medicine for acute and chronic coronary syndromes: A patient-tailored approach

The traditional approach to management of cardiovascular disease relies on grouping clinical presentations with common signs and symptoms into pre-specified disease pathways, all uniformly treated according to evidence-based guidelines ("one-size-fits-all"). The goal of precision medicine is to provide the right treatment to the right patients at the right time, combining data from time honoured sources (e.g., history, physical examination, imaging, laboratory) and those provided by multi-omics technologies. In patients with ischemic heart disease, biomarkers and intravascular assessment can be used to identify endotypes with different pathophysiology who may benefit from distinct treatments. This review discusses strategies for the application of stratified management to patients with acute and chronic coronary syndromes.

Huanglian Jiedu decoction inhibits vascular smooth muscle cell-derived foam cell formation by activating autophagy via suppressing P2RY12

ETHNOPHARMACOLOGICAL RELEVANCE

Huanglian Jiedu Decoction (HLJDD) is a Chinese medicine with a long history of therapeutic application. It is widely used in treating atherosclerosis (AS) in Chinese medicine theory and clinical practice. However, the mechanism of HLJDD in treating AS remains unclear.

AIM OF THE STUDY

To investigate the efficacy and mechanism of HLJDD in treating AS.

MATERIALS AND METHODS

AS was induced on high-fat diet-fed ApoE-/- mice, with the aorta pathological changes evaluated with lipid content and plaque progression. In vitro, foam cells were induced by subjecting primary mouse aortic vascular smooth muscle cells (VSMCs) to oxLDL incubation. After HLJDD intervention, VSMCs were assessed with lipid stack, apoptosis, oxidative stress, and the expression of foam cell markers. The effects of P2RY12 were tested by adopting clopidogrel hydrogen sulfate (CDL) in vivo and transfecting P2RY12 over-expressive plasmid in vitro. Autophagy was inhibited by Chloroquine or transfecting siRNA targeting ATG7 (siATG7). The mechanism of HLJDD treating atherosclerosis was explored using network pharmacology and validated with molecular docking and co-immunoprecipitation.

RESULTS

HLJDD exhibited a dose-dependent reduction in lipid deposition, collagen loss, and necrosis within plaques. It also reversed lipid accumulation and down-regulated the expression of foam cell markers. P2RY12 inhibition alleviated AS, while P2RY12 overexpression enhanced foam cell formation and blocked the therapeutic effects of HLJDD. Network pharmacological analysis suggested that HLJDD might mediate PI3K/AKT signaling pathway-induced autophagy. P2RY12 overexpression also impaired autophagy. Similarly, inhibiting autophagy counteracted the effect of CDL, exacerbated AS in vivo, and promoted foam cell formation in vitro. However, HLJDD treatment mitigated these detrimental effects by suppressing the PI3K/AKT signaling pathway. Immunofluorescence and molecular docking revealed a high affinity between P2RY12 and PIK3CB, while co-immunoprecipitation assays illustrated their interaction.

CONCLUSIONS

HLJDD inhibited AS in vivo and foam cell formation in vitro by restoring P2RY12/PI3K/AKT signaling pathway-suppressed autophagy. This study is the first to reveal an interaction between P2RY12 and PI3K3CB.

Variability patterns in dual antiplatelet therapy following endovascular repair of intracranial aneurysms: Insight into regimen heterogeneity and the need for a consensus

This comprehensive review delves into the evolving field of neurointervention for intracranial aneurysms, exploring the critical adjunct of Dual Antiplatelet Therapy (DAPT) to endovascular coiling, stent-assisted coiling (SAC), flow-diversion stents, and flow-disruption (intrasaccular) devices. Despite growing evidence supporting the success of DAPT in reducing thromboembolic events, the lack of consensus on optimal regimens, doses, and duration is evident. Factors contributing to this variability include genetic polymorphisms affecting treatment response and ongoing debates regarding the clinical significance of hemorrhagic complications associated with DAPT. This review analyzes pre- and post-procedural antiplatelet usage across various interventions. The imperative lies in ongoing research to define optimal DAPT durations, ensuring a nuanced approach to the delicate balance between thrombosis and hemorrhage in intracranial aneurysm management.

Genotype-guided prescribing predictors in CYP2C19 intermediate metabolizers receiving percutaneous coronary intervention

Background: Previous differences in guideline recommendation strength for CYP2C19 intermediate metabolizers may have limited genotype (PGx)-optimal post-percutaneous coronary intervention antiplatelet prescribing.Results: In this single-center retrospective observational cohort study of CYP2C19 intermediate metabolizers, patients prescribed PGx-optimal therapy were younger and less likely on anticoagulation (2 vs 12%; p = 0.006). More patients prescribed PGx-optimal therapy possessed commercial insurance (36 vs 7%; p < 0.001), which was a predictor for PGx-optimal selection (OR: 6.464; 95% CI: 2.386-17.516; p < 0.001).Conclusion: Anticoagulation use was significantly associated with clopidogrel use (OR: 0.138; 95% CI: 0.026-0.730; p = 0.020). No statistical difference in composite major adverse cardiovascular events (5 vs 14%; p = 0.173) or bleeding (8 vs 6%; Not significant) was observed between PGx-optimal and PGx-suboptimal therapy.

Individualized antiplatelet therapy for non-cardiogenic ischemic stroke

OBJECTIVE

This research aims to investigate the impact of individualized antiplatelet therapy guided by thromboelastography with platelet mapping (TEG-PM) on the clinical outcomes of patients with non-cardiogenic ischemic stroke.

METHODS

Among a total of 1264 patients, 684 individuals diagnosed with non-cardiogenic ischemic stroke underwent TEG-PM testing. Based on the adjustment of antiplatelet medication, these patients were divided into individual and control groups. Within the individual group, in accordance with the TEG-PM test results, a Maximum amplitude (MA) value greater than 47mm was defined as high residual platelet reactivity (HRPR), while an MA value less than 31mm was defined as low residual platelet reactivity (LRPR). Patients with arachidonic acid (AA) less than 50% and adenosine diphosphate (ADP) less than 30% were classified as aspirin-resistant or clopidogrel-resistant. Treatment strategies for antiplatelet medication were subsequently adjusted accordingly, encompassing increment, decrement, or replacement of drugs. Meanwhile, the control group maintained their original medication regimen without alterations.

RESULTS

The individual group included 487 patients, while the control group had 197. In the individual group, approximately 175 patients (35.9%) were treated with increased medication dosages, 89 patients (18.3%) with reduced dosages, and 223 patients (45.8%) switched medications. The results showed that the incidence rate of ischemic events in the individual group was lower than that of the control group (5.54% vs. 12.6%, P = 0.001), but no significant difference was observed in bleeding events. Cox regression analysis revealed age (hazard ratio, 1.043; 95% CI, 1.01-1.078; P = 0.011) and coronary heart disease (hazard ratio, 1.902; 95% CI, 1.147-3.153; P = 0.013) as significant risk factors for adverse events.

CONCLUSION

Individualized antiplatelet therapy based on TEG-PM results can reduce the risk of ischemic events in patients with non-cardiogenic ischemic stroke without increasing the risk of bleeding events or mortality. Advanced age and coronary heart disease were identified as risk factors affecting the outcomes of individualized antiplatelet therapy.

Clopidogrel resistance and its relevance: Current concepts

Clopidogrel is the most widely used P2Y12 receptor inhibitor (P2Y12i) as a part of dual antiplatelet therapy along with aspirin. Clopidogrel is a pro-drug and is metabolized to its active metabolite by the hepatic enzyme cytochrome P4502C19 (CYP2C19). This active metabolite is responsible for the antiplatelet action of clopidogrel. Recent studies have demonstrated that single nucleotide polymorphisms in the CYP2C19 gene, including CYP2C19*2,*3,*4, and *5 alleles, result in reduced production of the active metabolite of clopidogrel, and hence reduced inhibition of platelet aggregation. This in turn enhances the incidence of stent thrombosis and recurrent cardiovascular (CV) events. We report a case of coronary stent thrombosis due to clopidogrel resistance proven by CYP2C19 genotyping. We then review the literature on clopidogrel resistance and its impact on CV outcomes. Subsequently, we discuss the methods of diagnosis of resistance, evidence from clinical trials for tailoring clopidogrel therapy, the role of potent P2Y12 inhibitors, the current guidelines, and future directions.

Prognostic Impact of CYP2C19 Genotypes on Long-Term Clinical Outcomes in Older Patients After Percutaneous Coronary Intervention

BACKGROUND

Carriers of CYP2C19 loss-of-function alleles have increased adverse events after percutaneous coronary intervention, but limited data are available for older patients. We aimed to evaluate the prognostic impact of CYP2C19 genotypes on clinical outcomes in older patients after percutaneous coronary intervention.

METHODS AND RESULTS

The study included 1201 older patients (aged ≥75 years) who underwent percutaneous coronary intervention and received clopidogrel-based dual antiplatelet therapy in South Korea. Patients were grouped on the basis of CYP2C19 genotypes. The primary outcome was 3-year major adverse cardiac events, defined as a composite of cardiac death, myocardial infarction, and stent thrombosis. Older patients were grouped into 3 groups: normal metabolizer (36.6%), intermediate metabolizer (48.1%), and poor metabolizer (15.2%). The occurrence of the primary outcome was significantly different among the groups (3.1, 7.0, and 6.2% in the normal metabolizer, intermediate metabolizer, and poor metabolizer groups, respectively; P=0.02). The incidence rate of all-cause death at 3 years was greater in the intermediate metabolizer and poor metabolizer groups (8.1% and 9.2%, respectively) compared with that in the normal metabolizer group (3.5%, P=0.03) without significant differences in major bleeding. In the multivariable analysis, the intermediate metabolizer and poor metabolizer groups were independent predictors of 3-year clinical outcomes.

CONCLUSIONS

In older patients, the presence of any CYP2C19 loss-of-function allele was found to be predictive of a higher incidence of major adverse cardiac events within 3 years following percutaneous coronary intervention. This finding suggests a need for further investigation into an optimal antiplatelet strategy for older patients.

REGISTRATION

URL: https://clinicaltrials.gov. Identifier: NCT04734028.