Unguided de-escalation from ticagrelor to clopidogrel in stabilised patients with acute myocardial infarction undergoing percutaneous coronary intervention (TALOS-AMI): an investigator-initiated, open-label, multicentre, non-inferiority, randomised trial

Balancing Benefits and Risks of Oral Antiplatelet Strategies in patients With Coronary Artery Diseases: An Evolving Issue

Identifying the most appropriate antiplatelet therapy for each patient to prevent ischemic events while minimizing the risk of bleeding is an integral part of the short- and long-term management of patients with coronary artery disease (CAD). This review aims to summarize the available evidence on the contemporary use of P2Y12 inhibitors in CAD patients, focusing on strategies aimed at providing adequate ischemic protection while preventing bleeding risk through dual antiplatelet therapy (DAPT) modulation. Randomized trials and observational studies have been reviewed to determine the most appropriate antiplatelet treatment for CAD patients with different risk profiles. Both ischemic and bleeding events have a significant prognostic impact and should be carefully considered in clinical decision-making. Current guidelines recommend the use of third-generation PY2Y12 inhibitors (prasugrel or ticagrelor) over clopidogrel, as a part of DAPT, in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention. Newer P2Y12 inhibitors have a more rapid onset of action and less interindividual variability in platelet inhibition than clopidogrel but are associated with an increased risk of bleeding that may limit their benefit. Importantly, the anti-ischemic benefit of ticagrelor and prasugrel is mainly observed in the first weeks after ACS, whereas clopidogrel seems to provide the best balance between ischemic protection and bleeding as long-term maintenance therapy. These concepts support DAPT modulation after the acute phase, by de-escalating from full-dose to low-dose newer P2Y12 inhibitors, by switching to clopidogrel, or by early withdrawing aspirin to maximize both the efficacy and safety of antiplatelet therapy in patients with CAD.

Thrombus remodelling by reversible and irreversible P2Y12 inhibitors

Pharmacological inhibition of the platelet ADP-receptor P2Y₁₂ is a cornerstone in the prevention of atherothrombotic events in adult patients with acute coronary syndrome (ACS). Thienopyridines such as clopidogrel and prasugrel exert their antithrombotic effect by means of active metabolites that irreversibly inhibit P2Y₁₂. Due to the short half-life of these metabolites, a subpopulation of ADP-responsive platelets will form in between dosing. With increased platelet turnover rate or poor patient compliance, the fraction of ADP-responsive platelets will increase, potentially increasing the risk for new thrombotic events. In contrast, the reversible P2Y₁₂ inhibition produced by direct-acting ADP blockers such as ticagrelor and cangrelor inhibit the entire platelet population. In this study, we evaluated the impact of these pharmacological differences on thrombus formation in an ex vivo flow chamber model. A customized image analysis pipeline was used for automatized, large-scale identification and tracking of single platelets incorporated into the thrombus, enabling quantitative analysis of the relative contribution of inhibited and uninhibited platelets to thrombus growth and consolidation. Comparative experiments were conducted using the irreversible and reversible P2Y₁₂ inhibitors prasugrel active metabolite (PAM) and ticagrelor, respectively. Our results show that PAM inhibited thrombus platelet recruitment more gradually than ticagrelor, with a slower onset of inhibition. Further, we show that the presence of a small fraction (<10%) of uninhibited platelets did not abrogate the antithrombotic effect of PAM to any significant extent. Finally, we demonstrate a gradual enrichment of inhibited platelets in the thrombus shell due to selective recruitment of inhibited platelets to the thrombus periphery.

De-escalation or abbreviation of dual antiplatelet therapy in acute coronary syndromes and percutaneous coronary intervention: a Consensus Statement from an international expert panel on coronary thrombosis

Conventional dual antiplatelet therapy (DAPT) for patients with acute coronary syndromes undergoing percutaneous coronary intervention comprises aspirin with a potent P2Y purinoceptor 12 (P2Y12) inhibitor (prasugrel or ticagrelor) for 12 months. Although this approach reduces ischaemic risk, patients are exposed to a substantial risk of bleeding. Strategies to reduce bleeding include de-escalation of DAPT intensity (downgrading from potent P2Y12 inhibitor at conventional doses to either clopidogrel or reduced-dose prasugrel) or abbreviation of DAPT duration. Either strategy requires assessment of the ischaemic and bleeding risks of each individual. De-escalation of DAPT intensity can reduce bleeding without increasing ischaemic events and can be guided by platelet function testing or genotyping. Abbreviation of DAPT duration after 1-6 months, followed by monotherapy with aspirin or a P2Y12 inhibitor, reduces bleeding without an increase in ischaemic events in patients at high bleeding risk, particularly those without high ischaemic risk. However, these two strategies have not yet been compared in a head-to-head clinical trial. In this Consensus Statement, we summarize the evidence base for these treatment approaches, provide guidance on the assessment of ischaemic and bleeding risks, and provide consensus statements from an international panel of experts to help clinicians to optimize these DAPT approaches for individual patients to improve outcomes.

Net clinical benefit of dual antiplatelet therapy in elderly patients with acute coronary syndrome: A systematic review and meta-analysis

BACKGROUND

Contemporary dual antiplatelet therapy (DAPT) strategies, such as short-term DAPT or de-escalation of DAPT, have emerged as attractive strategies to treat patients with acute coronary syndrome (ACS). However, it remains uncertain whether they are suitable for elderly patients.

METHODS

PubMed, Embase, and Cochrane CENTRAL databases were searched in September 2022. Randomized controlled trials (RCTs) investigating DAPT strategies, including standard (12 months), short-term, uniform de-escalation, and guided-selection strategies for elderly patients with ACS (age ≥ 65 years) were identified, and a network meta-analysis was conducted. The primary endpoint was the net clinical benefit outcome, a composite of major adverse cardiovascular events (MACEs: cardiovascular death, myocardial infarction, or stroke) and clinically relevant bleeding (equivalent to bleeding of at least type 2 according to the Bleeding Academic Research Consortium). The secondary outcomes were MACE and major bleeding.

RESULTS

Sixteen RCTs with a combined total of 47,911 patients were included. The uniform de-escalation strategy was associated with an improved net clinical benefit compared with DAPT using potent P2Y12 inhibitors. The short-term DAPT strategy was associated with reduced risks of the primary outcome and major bleeding compared with DAPT using potent P2Y12 inhibitors, however, it was ranked as the least effective strategy for MACE compared with other DAPT strategies.

CONCLUSIONS

Uniform de-escalation and short-term DAPT strategies may be advantageous for elderly patients, but need to be tailored based on individual bleeding and ischemic risks. Further RCTs of contemporary DAPT strategies specifically designed for elderly patients are warranted to confirm the findings of the present study.

Strategy of dual antiplatelet therapy for patients with ST-elevation myocardial infarction and non-ST-elevation acute coronary syndromes: A systematic review and network meta-analysis

BACKGROUND

Various durations and de-escalation strategies of dual antiplatelet therapy (DAPT) after ST-elevation myocardial infarction (STEMI) or non-ST-elevation acute coronary syndromes (NSTE-ACS) have been tested in randomized controlled trials (RCT)s. However, evidence by specific ACS subtype is unknown.

METHODS

PubMed, EMBASE, and Cochrane CENTRAL were searched in February 2023. RCTs on DAPT strategies included STEMI or NSTE-ACS patients with standard DAPT (12 months) with clopidogrel or potent P2Y12 inhibitors, short-term DAPT (≤6 months) followed by potent P2Y12 inhibitors or aspirin, unguided de-escalation from potent P2Y12 inhibitors to low-dose potent P2Y12 inhibitors or clopidogrel at one month, and guided selection with genotype or platelet function tests were identified. The primary outcome was the net adverse clinical events (NACE) defined as a composite of major adverse cardiovascular events (MACE) and clinically relevant bleeding events.

RESULTS

Twenty RCTs with a combined total population of 24,745 STEMI and 37,891 NSTE-ACS patients were included. In STEMI patients, unguided de-escalation strategy was associated with a lower rate of NACE compared with standard DAPT using potent P2Y12 inhibitors (HR:0.57; 95% CI:0.34-0.96) without increased risk of MACE. In NSTE-ACS patients, unguided de-escalation strategy was associated with a lower rate of NACE compared with the guided selection strategy (HR:0.65; 95% CI:0.47-0.90), standard DAPT using potent P2Y12 inhibitors (HR:0.62; 95% CI:0.50-0.78) and standard DAPT using clopidogrel (HR:0.73; 95% CI:0.55-0.98) without increased risk of MACE.

CONCLUSION

Unguided de-escalation strategy was associated with a reduced risk of NACE and may be the most effective DAPT strategy for STEMI and NSTE-ACS.

Current concepts and novel targets for antiplatelet therapy

Platelets have a crucial role in haemostasis and atherothrombosis. Pharmacological control of platelet hyper-reactivity has become a cornerstone in the prevention of thrombo-ischaemic complications in atherosclerotic diseases. Current antiplatelet therapies substantially improve clinical outcomes in patients with coronary artery disease, but at the cost of increased risk of bleeding. Beyond their role in thrombosis, platelets are known to regulate inflammatory (thrombo-inflammatory) and microcirculatory pathways. Therefore, controlling platelet hyper-reactivity might have implications for both tissue inflammation (myocardial ischaemia) and vascular inflammation (vulnerable plaque formation) to prevent atherosclerosis. In this Review, we summarize the pathophysiological role of platelets in acute myocardial ischaemia, vascular inflammation and atherosclerotic progression. Furthermore, we highlight current clinical concepts of antiplatelet therapy that have contributed to improving patient care and have facilitated more individualized therapy. Finally, we discuss novel therapeutic targets and compounds for antiplatelet therapy that are currently in preclinical development, some of which have a more favourable safety profile than currently approved drugs with regard to bleeding risk. These novel antiplatelet targets might offer new strategies to treat cardiovascular disease.

Short-Term DAPT and DAPT De-Escalation Strategies for Patients With Acute Coronary Syndromes: A Systematic Review and Network Meta-Analysis

BACKGROUND

Short-term (≤6 months) dual antiplatelet therapy (DAPT) and DAPT de-escalation become attractive for patients with acute coronary syndrome.

METHODS

A systemic search identified randomized controlled trials that included patients with acute coronary syndrome treated using (1) standard DAPT (12 months) with clopidogrel, prasugrel (standard/low dose), or ticagrelor; (2) extended DAPT (≥18 months); (3) short-term DAPT (≤6 months) followed by P2Y12 inhibitor or aspirin; (4) 12-month DAPT with unguided de-escalation from potent P2Y12 inhibitors to low-dose potent P2Y12 inhibitor or clopidogrel at 1 month; and (5) guided selection DAPT with genotype or platelet function tests. The primary efficacy outcome (major adverse cardiovascular events) was a composite of cardiovascular death, myocardial infarction, or stroke. The primary safety outcome was major or minor bleeding.

RESULTS

This meta-analysis included 32 randomized controlled trials with 103 497 patients. While there were no differences in efficacy between short, unguided de-escalation and guided selection strategies, unguided de-escalation was associated with reduced risk of major adverse cardiovascular events compared with standard DAPT with clopidogrel or ticagrelor (hazard ratio [95% CI], 0.67 [0.49-0.93] and 0.68 [0.50-0.93]). Both short DAPT followed by P2Y12 inhibitor and unguided de-escalation were associated with reduced risks in safety compared with other strategies, including guided selection (hazard ratio [95% CI], 0.66 [0.47-0.93] and 0.48 [0.33-0.71]). Short DAPT followed by a P2Y12 inhibitor was associated with reduced risk of major bleeding and all-cause death compared with standard, extended DAPT (eg, versus DAPT with clopidogrel; hazard ratio [95% CI], 0.64 [0.42-0.97] and 0.60 [0.44-0.82]). By rankogram, unguided de-escalation strategy was the safest and most effective strategy in reducing major adverse cardiovascular events and major or minor bleeding while short DAPT followed by P2Y12 inhibitor was ranked the best for major bleeding and all-cause death.

CONCLUSIONS

In patients with acute coronary syndrome, unguided de-escalation was associated with the lowest risk of major adverse cardiovascular events and major or minor bleeding outcomes, while short DAPT followed by P2Y12 inhibitor was associated with the lowest risk of major bleeding and all-cause death.

Short dual antiplatelet therapy duration after percutaneous coronary intervention in high bleeding risk patients: Systematic review and meta-analysis

INTRODUCTION

Dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI) reduces major adverse cardiovascular events (MACE) and stent thrombosis. However, DAPT duration is a concern in high bleeding risk (HBR) patients. We evaluated the effect of short DAPT (1-3 months) compared to standard DAPT (6-12 months) on bleeding and ischemic events in HBR PCI.

METHODS

We searched MEDLINE, Embase and CENTRAL up to August 18, 2022. Randomized controlled trials (RCTs) comparing short DAPT (1-3 months) versus standard DAPT in HBR PCI were included. We assessed risk of bias (RoB) using the Cochrane RoB2 tool, and certainty of evidence using GRADE criteria. Outcomes included MACE, all-cause death, stent thrombosis, major bleeding, and the composite of major or clinically-relevant non-major bleeding. We estimated risk ratios (RR) and 95% confidence intervals (CI) using a random-effects model.

RESULTS

From 503 articles, we included five RCTs (n = 7,242) at overall low risk of bias with median follow-up of 12-months. Compared to standard DAPT, short DAPT did not increase MACE (RR 1.02, 95% CI 0.84-1.23), all-cause death (RR 0.92, 95% CI 0.71-1.20) or stent thrombosis (RR 1.47, 95% CI 0.73-2.93). Short DAPT reduced major bleeding (RR 0.34, 95% CI 0.13-0.90) and the composite of major or clinically-relevant non-major bleeding (RR 0.60, 95% CI 0.44-0.81), translating to 21 and 34 fewer events, respectively, per 1000 patients.

CONCLUSIONS

In HBR PCI, DAPT for 1-3 months compared to 6-12 months reduced clinically-relevant bleeding events without jeopardizing ischemic risk. Short DAPT should be considered in HBR patients receiving PCI.

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

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

A novel de-escalation antiplatelet therapy for patients with acute coronary syndrome undergoing percutaneous coronary intervention

To investigate the effect of different DAPTs in patients with ACS undergoing PCI, and to identify the most efficient DAPT to reduce the risk of ischemia and bleeding after PCI. Between March 2017 and December 2021, 1598 patients with ACS who underwent PCI were included in the study. The DAPT protocol included the clopidogrel group (aspirin 100 mg + clopidogrel 75 mg), ticagrelor group (aspirin 100 mg + ticagrelor 90 mg), de-escalation Group 1 (reduced dose of ticagrelor [from 90 mg to 60 mg]) after 3 months of oral DAPT [aspirin 100 mg + ticagrelor 90 mg]), and de-escalation Group 2 (switched from ticagrelor to clopidogrel after 3 months of oral DAPT [aspirin 100 mg + ticagrelor 90 mg]). All patients received a 12-month follow-up. The primary endpoint was net adverse clinical events (NACEs) that included the composite endpoints of cardiac death, myocardial infarction, ischemia-driven revascularization, stroke, and bleeding events. There were 2 secondary endpoints, major adverse cardiovascular and cerebrovascular events (MACCEs) and bleeding. No statistically significant difference was found in the incidence of NACEs between the 4 groups at the average 12-month follow-up (15.7% vs 19.2% vs 16.7% vs 20.4%). Cox regression analysis revealed that DAPT ticagrelor group regimen (hazard ratio [HR] 0.547; 95% confidence interval [CI]: 0.334-0.896; P  = .017) were associated with a lower risk of MACCEs. Age (HR 1.024; 95% CI: 1.003-1.046; P  = .022). DAPT de-escalation Group 2 regimen (HR 1.665; 95% CI: 1.001-2.767; P  = .049) were marginally associated with a higher risk of MACCEs. Ticagrelor group regimen (HR 1.856; 95% CI: 1.376-2.504; P  < .001) was associated with higher risk of bleeding events. Ticagrelor group regimen (HR 1.606; 95% CI: 1.179-2.187; P  = .003) were associated with a higher risk of minor bleeding events. For patients with ACS underwent PCI, there were no significant difference in the incidence of NACEs between 3 and 12 months after PCI between de-escalation and non-de-escalation therapies. Compared with ticagrelor-based 12-month DAPT, there was no significant difference in MACCEs and bleeding events in patients receiving de-escalation treatment (ticagrelor reduction from 90 to 60 mg, 3 months after PCI).

Personalized Dual Antiplatelet Therapy in Acute Coronary Syndromes: Striking a Balance Between Bleeding and Thrombosis

PURPOSE OF REVIEW

Dual antiplatelet therapy (DAPT)-aspirin in conjunction with a P2Y12 inhibitor-is the cornerstone of managing patients with acute coronary syndromes post-revascularization, but the clinical response is highly variable, with potentially devastating consequences. Herein, we review the mechanisms underpinning said variability and explore emerging approaches to normalizing therapeutic benefit.

RECENT FINDINGS

The potent P2Y12 inhibitors, prasugrel and ticagrelor, exhibit minimal inter-individual variability, replacing clopidogrel in DAPT and achieving greater rates of therapeutic response. However, these benefits decline in later phases when bleeding risk begins to supersede that of ischemia. Guided de-escalation of P2Y12 inhibition as well as shortening DAPT duration have emerged as strategies that retain antithrombotic efficacy while reducing bleeding risk. Aspirin is the other component of DAPT but is also used in isolation for secondary prevention of thrombotic disease. In contrast to the P2Y12 inhibitors, genetic influences on aspirin non-response appear to be outweighed by a triad of clinical factors: non-adherence, enteric aspirin use, and inappropriate dosing according to bodyweight and BMI. Multiple de-escalation strategies for DAPT have been shown to mitigate bleeding risk, but it remains unclear which approach is ideal, necessitating head-to-head investigations to determine which exhibits the most favorable cost-to-benefit ratio. However, there is likely a role for more than one approach in clinical practice, depending on patient risk profile. Our approach to aspirin use is also in need of reassessment: strategies to improve adherence, avoidance of enteric aspirin in cardiac patients, and dose adjustment according to bodyweight and/or BMI are all likely to improve rates of therapeutic response. Moreover, platelet function testing may have a role in identifying patients expected to benefit from primary prophylactic aspirin.

Bleeding in acute coronary syndrome: from definitions, incidence, and prognosis to prevention and management

INTRODUCTION

In patients with acute coronary syndrome (ACS), the ischemic benefit of antithrombotic treatment is counterbalanced by the risk of bleeding. The recognition that bleeding events have prognostic implications (i.e. mortality) similar to recurrent ischemic events led to the development of treatment regimens aimed at balancing both ischemic and bleeding risks.

AREAS COVERED

This review aims at describing definitions, incidence, and prognosis related to bleeding events in ACS patients as well as bleeding-avoidance strategies for their prevention and management of bleeding complications.

EXPERT OPINION

Management of ACS patients has witnessed remarkable progress after the shift in focusing on the trade-off between ischemia and bleeding. Efforts in standardizing bleeding definitions will allow for better defining the prognostic impact of different types of bleeding events and enable to identify the high-bleeding risk patient. Such efforts will allow to balance the trade-off between the thrombotic and bleeding risk of the individual patient translating into better downward diagnostic and therapeutic decision-making. Novel strategies aiming at maximizing the safety and efficacy of antithrombotic regimens as well as the development of novel antithrombotic drugs and reversal agents and technological advances will allow for optimization of bleeding-avoidance strategies and management of bleeding complications.

Defining Strategies of Modulation of Antiplatelet Therapy in Patients With Coronary Artery Disease: A Consensus Document from the Academic Research Consortium

Antiplatelet therapy is the mainstay of pharmacologic treatment to prevent thrombotic or ischemic events in patients with coronary artery disease treated with percutaneous coronary intervention and those treated medically for an acute coronary syndrome. The use of antiplatelet therapy comes at the expense of an increased risk of bleeding complications. Defining the optimal intensity of platelet inhibition according to the clinical presentation of atherosclerotic cardiovascular disease and individual patient factors is a clinical challenge. Modulation of antiplatelet therapy is a medical action that is frequently performed to balance the risk of thrombotic or ischemic events and the risk of bleeding. This aim may be achieved by reducing (ie, de-escalation) or increasing (ie, escalation) the intensity of platelet inhibition by changing the type, dose, or number of antiplatelet drugs. Because de-escalation or escalation can be achieved in different ways, with a number of emerging approaches, confusion arises with terminologies that are often used interchangeably. To address this issue, this Academic Research Consortium collaboration provides an overview and definitions of different strategies of antiplatelet therapy modulation for patients with coronary artery disease, including but not limited to those undergoing percutaneous coronary intervention, and consensus statements on standardized definitions.

De-escalation strategies in patients with acute coronary syndrome: a step towards precision medicine

INTRODUCTION

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y₁₂ inhibitor is a cornerstone in the treatment of patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Current international guidelines recommend the use of 12 months of DAPT with newer P2Y₁₂ inhibitors (i.e. ticagrelor or prasugrel) as first-line therapy in this setting. However, intense and prolonged DAPT regimens are associated with an increased risk of bleeding, with relevant prognostic implications. Recently, a strategy of de-escalation of P2Y₁₂ inhibitors has been proposed as an alternative to conventional DAPT to mitigate the risk of bleeding while preserving ischemic protection after ACS.

AREAS COVERED

In this review, we summarize the available evidence on guided and unguided strategies for P2Y₁₂ inhibitor de-escalation in patients with ACS undergoing PCI.

EXPERT OPINION

Among patients with ACS, guided and unguided de-escalation strategies are safe and effective for secondary cardiovascular prevention. Although the implementation of genetic and platelet function tests is of interest for treatment personalization, the routine use of guided de-escalation strategies seems impractical. In this context, unguided de-escalation approaches appear more attractive, convenient, and suitable for contemporary practice.

The association between higher FFAs and high residual platelet reactivity among CAD patients receiving clopidogrel therapy

Background

Metabolic abnormalities are associated with the occurrence, severity, and poor prognosis of coronary artery disease (CAD), some of which affect the antiplatelet efficacy of clopidogrel. Free fatty acids (FFAs) is a biomarker for metabolic abnormalities, and elevated FFAs is observed among CAD patients. Whether FFAs enhances residual platelet reactivity induced by adenosine diphosphate (ADP) while using clopidogrel was unknown. The purpose of our study is exploring the issue.

Method

Current study included 1,277 CAD patients using clopidogrel and used logistic regression to detect whether the higher level of FFAs is associated with high residual platelet reactivity (HRPR). We additionally performed subgroup and sensitivity analyses to evaluate the stability of the results. We defined HRPR as ADP-induced platelet inhibition rate (ADP_i) < 50% plus ADP-induced maximum amplitude (MA_ADP) > 47 mm.

Results

486 patients (38.1%) showed HRPR. The proportion of HRPR among patients with higher FFAs (>0.445 mmol/L) is greater than among patients with lower FFAs (46.4% vs. 32.6%, P < 0.001). Multivariate logistic regression demonstrated that higher FFAs (>0.445 mmol/L) is independently associated with HRPR (adjusted OR = 1.745, 95% CI, 1.352-2.254). After subgroup and sensitivity analyses, the results remained robust.

Conclusion

The higher level of FFAs enhances residual platelet reactivity induced by ADP and is independently associated with clopidogrel HRPR.

Curcumin analogue C66 ameliorates mouse cardiac dysfunction and structural disorders after acute myocardial infarction via suppressing JNK activation

Myocardial infarction contributes to the development of cardiovascular disease, and leads to severe inflammation and health hazards. Our previous studies identified C66, a novel curcumin analogue, had pharmacological benefits in suppressing tissue inflammation. Therefore, the present study hypothesized C66 might improve cardiac function and attenuate structural remodeling after acute myocardial infarction. Administration of 5 mg/kg C66 for 4-week significantly improved cardiac function and decreased infarct size after myocardial infarction. C66 also effectively reduced cardiac pathological hypertrophy and fibrosis in non-infarct area. In vitro H9C2 cardiomyocytes, C66 also exerted the pharmacological benefits of anti-inflammatory and anti-apoptosis under hypoxic conditions Mechanistically, C66 inhibited cardiac inflammation and cardiomyocyte apoptosis by targeting on JNK phosphorylation, whereas replenishment of JNK activation abolished the cardioprotective benefits of C66 treatment. Taken together, curcumin analogue C66 inhibited the activation of JNK signaling, and possessed pharmacological benefits in alleviating myocardial infarction-induced cardiac dysfunction and pathological tissue injuries.

Antiplatelet Strategies Following PCI: A Review of Trials Informing Current and Future Therapies

Dual antiplatelet therapy (DAPT) has been paramount in preventing thrombosis following percutaneous coronary intervention for nearly 3 decades. However, over the years, DAPT has seen significant changes in the agents utilized and duration of therapy as trials have raced to keep up with advancements made in stent technology and our understanding of bleeding and ischemic risk. Recently, there have been a number of trials demonstrating significant reductions in bleeding events with shorter DAPT durations, which are not yet reflected in practice guidelines. Further, there has been a shift toward more individualized antiplatelet regimens to meet patient-specific risk profiles. This review provides a comprehensive summary of the major trials that have informed current DAPT strategies, puts into context recent trials driving a shift toward more tailored antiplatelet regimens, and highlights gaps in knowledge that remain and the ongoing trials designed to address them.

Assessment of Nonfatal Bleeding Events as a Surrogate for Mortality in Coronary Artery Disease

Background

Bleeding events are frequently applied as safety end points for randomized controlled trials (RCTs) investigating the effect of antithrombotic agents in patients with coronary artery disease. However, whether a bleeding event is a valid surrogate for death remain uncertain.

Objectives

This study aimed to assess the correlation between the treatment effect on bleeding events and mortality.

Methods

Multiple databases were searched to identify RCTs studying antithrombotic agents for patients with coronary artery disease through August 2022. Major and minor bleeding events were defined in included trials, mostly defined with BARC (Bleeding Academic Research Consortium) or TIMI (Thrombolysis In Myocardial Infarction) criteria. Trial-level correlations between nonfatal bleeding events and mortality were assessed. We performed subgroup analyses by the definitions of bleeding (BARC vs TIMI criteria), study year, and follow-up duration. We used a cutoff with a lower limit of 95% confidence interval of R2 >0.72 as a strong correlation and with an upper limit of 95% confidence interval of R2 <0.50 as a weak correlation.

Results

A total of 48 RCTs with 181,951 participants were analyzed. Overall, trial-level R2 for major and minor bleeding were 0.09 (95% CI: 0.00-0.26) and 0.09 (95% CI: 0.00-0.27) for all-cause or cardiovascular death, respectively. When confined to major bleeding, R2 were 0.03 (95% CI: 0.00-0.13) and 0.01 (95% CI: 0.00-0.05), respectively. All of the subgroup analyses did not show any significant correlations.

Conclusions

We demonstrated a trial-defined bleeding event may not be a valid surrogate for mortality in RCTs investigating the effect of antithrombotic agents for coronary artery disease.

Comparison of De-escalation of DAPT Intensity or Duration in East Asian and Western Patients with ACS Undergoing PCI: A Systematic Review and Meta-analysis

BACKGROUND

 Guideline-recommended dual antiplatelet therapy (DAPT; aspirin plus prasugrel/ticagrelor) for 12 months in acute coronary syndrome (ACS) patients increases bleeding, with East Asians (EAs) exhibiting higher bleeding and lower ischemic risk, compared with non-East Asians (nEAs). We sought to compare DAPT "de-escalation" strategies in EA and nEA populations.

METHODS

 A systematic review and meta-analysis of randomized controlled trials assessing reduction of DAPT intensity or duration in ACS patients undergoing percutaneous coronary intervention, in EA and nEA, was performed using a random-effects model.

RESULTS

 Twenty-three trials assessed reduction of DAPT intensity (n = 12) or duration (n = 11). Overall, reduced DAPT intensity attenuated major bleeding (odds ratio [OR]: 0.78, 95% confidence interval [CI]: 0.65-0.94, p = 0.009), without impacting net adverse cardiovascular events (NACE) or major adverse cardiovascular events (MACE). In nEA, this increased MACE (OR: 1.20, 95% CI: 1.09-1.31, p < 0.0001) without impacting NACE or bleeding; while in EA, it reduced major bleeding (OR: 0.71, 95% CI: 0.53-0.95, p = 0.02) without affecting NACE or MACE. Overall, abbreviation of DAPT duration reduced NACE (OR: 0.90, 95% CI: 0.82-0.99, p = 0.03) due to major bleeding (OR: 0.69, 95% CI: 0.53-0.99, p = 0.006), without impacting MACE. In nEA, this strategy did not impact NACE, MACE, or major bleeding; while in EA, it reduced major bleeding (OR: 0.60, 95% CI: 0.4-0.91, p = 0.02) without impacting NACE or MACE.

CONCLUSION

 In EA, reduction of DAPT intensity or duration can minimize bleeding, without safety concerns. In nEA, reduction of DAPT intensity may incur an ischemic penalty, while DAPT abbreviation has no overall benefit.

Efficacy and Safety of Ticagrelor versus Aspirin and Clopidogrel for Stroke Prevention in Patients with Vascular Disease: A Systematic Review and Meta-Analysis

INTRODUCTION

Currently, it is still controversial to treat stroke with ticagrelor alone. The purpose of our study was to systematically review and analyze the efficacy and safety of ticagrelor on cerebrovascular outcomes in patients with vascular risk factors.

METHODS

The PubMed, Cochrane Library, and Embase databases were systematically searched using the keywords stroke, ticagrelor, clopidogrel, and aspirin to identify randomized controlled trials (RCTs). Primary outcomes included reported stroke, ischemic stroke, and complex events; the secondary outcome was hemorrhagic stroke. The safety outcomes included major bleeding events, major or minor bleeding, and intracranial bleeding. The pooled odds ratio (OR), hazard ratios (HRs), and 95% confidence interval (CI) were calculated. We used I2 statistics to assess statistical heterogeneity.

RESULTS

This meta-analysis included 15 RCTs involving 63,865 patients. Compared to the control group, ticagrelor reduced the risk of stroke (OR: 0.90; 95% CI: 0.81-0.99, p = 0.03; I2 = 3%), ischemic stroke (OR: 0.81; 95% CI: 0.74-0.90, p < 0.0001; I2 = 0%). Ticagrelor was not associated with an increased risk of all-cause mortality (OR: 0.94; 95% CI: 0.84-1.06, p = 0.31; I2 = 62%), major bleeding (OR: 1.06; 95% CI: 0.97-1.15, p = 0.20; I2 = 17%), hemorrhagic strokes (OR: 1.22, 95% CI: 0.76-1.96, p = 0.41; I2 = 0%), and intracranial hemorrhage (OR: 1.06; 95% CI: 0.78-1.43, p = 0.71; I2 = 12%). There was an increased risk of major or minor bleeding with ticagrelor compared to the control group (OR: 1.40; 95% CI: 1.19-1.66, p < 0.0001; I2 = 56%). Additional analyses demonstrated that ticagrelor reduced the risk of incident recurrent stroke (HR: 0.83; 95% CI: 0.75-0.93, p = 0.0009; I2 = 0%), recurrent ischemic stroke (HR: 0.79; 95% CI: 0.71-0.89, p < 0.0001; I2 = 0%) among patients with a history of acute ischemic stroke (AIS) or transient ischemic attack (TIA). There were no significant differences in safety outcomes.

CONCLUSION

Ticagrelor is slightly better than clopidogrel and aspirin in preventing stroke, especially ischemic stroke, with significant safety risks. For patients with a history of AIS/TIA, the use of ticagrelor was superior to the use of clopidogrel or aspirin in reducing the risk of subsequent stroke. We believe that ticagrelor is a potential alternative to aspirin or clopidogrel in some cases, especially for patients with CYP2C19 deficiency.

Antiplatelet Therapy in Coronary Artery Disease: Now and Then

Cardiovascular disease, particularly coronary artery disease (CAD), remains the leading cause of mortality and morbidity in industrialized countries. Platelet activation and aggregation at the site of endothelial injury play a key role in the processes ultimately resulting in thrombus formation with vessel occlusion and subsequent end-organ damage. Consequently, antiplatelet therapy has become a mainstay in the pharmacological treatment of CAD. Several drug classes have been developed over the last decades and a broad armamentarium of antiplatelet agents is currently available. This review portrays the evolution of antiplatelet therapy, and provides an overview on previous and current antiplatelet drugs and strategies.

Clinical Impact of CYP2C19 Genotype on Clopidogrel-Based Antiplatelet Therapy After Percutaneous Coronary Intervention

BACKGROUND

Although there is a growing body of evidence that CYP2C19 genotyping can be beneficial when considering treatment with clopidogrel after percutaneous coronary intervention (PCI), whether a genotype-guided strategy can be generally adopted in routine practice remains unclear among East Asians.

OBJECTIVES

This study sought to investigate long-term outcomes of patients undergoing clopidogrel-based antiplatelet therapy after drug-eluting stent (DES) implantation according to CYP2C19 genotypes.

METHODS

From the nationwide multicenter PTRG-DES (Platelet function and genoType-Related long-term proGnosis in DES-treated patients) consortium, patients who underwent CYP2C19 genotyping were selected and classified according to CYP2C19 loss-of-function allele: rapid metabolizers (RMs) or normal metabolizers (NMs) vs intermediate metabolizers (IMs) or poor metabolizers (PMs). The primary outcome was a composite of cardiac death, myocardial infarction, and stent thrombosis at 5 years after the index procedure.

RESULTS

Of 8,163 patients with CYP2C19 genotyping, 56.7% presented with acute coronary syndrome. There were 3,098 (37.9%) in the RM or NM group, 3,906 (47.9%) in the IM group, and 1,159 (14.2%) in the PM group. IMs or PMs were associated with an increased risk of 5-year primary outcome compared with RMs or NMs (HR_adj: 1.42; 95% CI: 1.01-1.98; P = 0.041), and the effect was more pronounced in the first year (HR_adj: 1.67; 95% CI: 1.10-2.55; P = 0.016). The prognostic implication of being an IM and PM was significant in acute coronary syndrome patients (HR_adj: 1.88; 95% CI: 1.20-2.93; P = 0.005) but not in those with stable angina (HR_adj: 0.92; 95% CI: 0.54-1.55; P = 0.751) (interaction P = 0.028).

CONCLUSIONS

Among East Asians with clopidogrel-based antiplatelet therapy after DES implantation, CYP2C19 genotyping could stratify patients who were likely to have an increased risk of atherothrombotic events. (Platelet Function and genoType-Related Long-term progGosis in DES-treated Patients: A Consortium From Multi-centered Registries [PTRG-DES]; NCT04734028).

Feasibility of Community Pharmacist-Initiated and Point-of-Care CYP2C19 Genotype-Guided De-Escalation of Oral P2Y12 Inhibitors

Tailoring antiplatelet therapy based on CYP2C19 pharmacogenetic (PGx) testing can improve cardiovascular outcomes and potentially reduce healthcare costs in patients on a P2Y12-inhibitor regime with prasugrel or ticagrelor. However, ubiquitous adoption—particularly in an outpatient setting—remains limited. We conducted a proof-of-concept study to evaluate the feasibility of CYP2C19-guided de-escalation of prasugrel/ticagrelor to clopidogrel through point-of-care (POC) PGx testing in the community pharmacy. Multiple feasibility outcomes were assessed. Overall, 144 patients underwent CYP2C19 PGx testing in 27 community pharmacies. Successful test results were obtained in 142 patients (98.6%). De-escalation to clopidogrel occurred in 19 patients (20%) out of 95 (67%) eligible for therapy de-escalation, which was mainly due to PGx testing not being included in cardiology guidelines. Out of the 119 patients (84%) and 14 pharmacists (100%) surveyed, 109 patients (92%) found the community pharmacy a suitable location for PGx testing, and the majority of pharmacists (86%) thought it has added value. Net costs due to PGx testing were estimated at €43 per patient, which could be reduced by earlier testing and could turn into savings if de-escalation would double to 40%. Although the observed de-escalation rate was low, POC CYP2C19-guided de-escalation to clopidogrel appears feasible in a community pharmacy setting.

Tailoring oral antiplatelet therapy in acute coronary syndromes: from guidelines to clinical practice

The assessment of bleeding and ischemic risk is a crucial step in establishing appropriate composition and duration of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome (ACS) treated with percutaneous coronary angioplasty. Evidence from recent randomized clinical trials led to some paradigm shifts in current guidelines recommendations. Options alternative to the standard 12-month DAPT duration include shorter periods of DAPT followed by single antiplatelet treatment with either aspirin or P2Y12 monotherapy, guided or unguided de-escalation DAPT, prolonged DAPT beyond the 12-month treatment period. Although DAPT composition and duration should be selected for each ACS patient on an individual basis weighing clinical and procedural variables, data from latest trials and meta-analyses may permit suggesting the most appropriate DAPT strategy according to the ischemic and bleeding risk assessed using validated tools and scores.

Platelet P2Y12 Inhibitor Monotherapy after Percutaneous Coronary Intervention: An Emerging Option for Antiplatelet Therapy De-escalation

Antiplatelet therapy is considered essential for secondary prevention of ischemic heart disease. After percutaneous coronary intervention (PCI), temporary dual antiplatelet therapy (DAPT), a combination consisting of aspirin and an oral P2Y12 receptor blocker, is recommended. In the long term, this strategy results in more bleeding than antiplatelet therapy with aspirin alone. Therefore, to reduce bleeding, an increasing trend has been to keep DAPT as short as clinically acceptable, after which aspirin monotherapy is continued. Another option to diminish bleeding is to discontinue aspirin at the moment of DAPT cessation after PCI, and to continue on P2Y12 blocker monotherapy. This survey reviews the evidence on P2Y12 blocker monotherapy. Some clinical guidance will be provided on when and in whom P2Y12 inhibitor monotherapy may be applied after DAPT cessation following PCI.

Acute, periprocedural and longterm antithrombotic therapy in older adults: 2022 Update by the ESC Working Group on Thrombosis

The first international guidance on antithrombotic therapy in the elderly came from the European Society of Cardiology Working Group on Thrombosis in 2015. This same group has updated its previous report on antiplatelet and anticoagulant drugs for older patients with acute or chronic coronary syndromes, atrial fibrillation, or undergoing surgery or procedures typical of the elderly (transcatheter aortic valve implantation and left atrial appendage closure). The aim is to provide a succinct but comprehensive tool for readers to understand the bases of antithrombotic therapy in older patients, despite the complexities of comorbidities, comedications and uncertain ischaemic- vs. bleeding-risk balance. Fourteen updated consensus statements integrate recent trial data and other evidence, with a focus on high bleeding risk. Guideline recommendations, when present, are highlighted, as well as gaps in evidence. Key consensus points include efforts to improve medical adherence through deprescribing and polypill use; adoption of universal risk definitions for bleeding, myocardial infarction, stroke and cause-specific death; multiple bleeding-avoidance strategies, ranging from gastroprotection with aspirin use to selection of antithrombotic-drug composition, dosing and duration tailored to multiple variables (setting, history, overall risk, age, weight, renal function, comedications, procedures) that need special consideration when managing older adults.

Timing, Selection, Modulation, and Duration of P2Y12 Inhibitors for Patients With Acute Coronary Syndromes Undergoing PCI

Dual antiplatelet therapy with aspirin and the oral P2Y₁₂ inhibitor clopidogrel as the cornerstone of treatment for patients with an acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) was firstly established in 2001. Soon thereafter, the newer-generation P2Y₁₂ inhibitors prasugrel and ticagrelor became commercially available. The clinical management of ACS patients undergoing PCI has evolved significantly in the last 2 decades, with a shift toward more rapid invasive management, broader use of drug-eluting stents, and the increasing recognition that major bleeding due to antiplatelet therapy is detrimental. In this ever-changing scenario, numerous studies have addressed 4 main questions regarding P2Y₁₂ inhibition in ACS patients undergoing PCI: timing, selection, modulation, and duration. This paper reviews the latest evidence surrounding these topical questions, with a focus on efficacy and safety data, practice guidelines, and residual areas of uncertainty.

Antiplatelet Therapy Aims and Strategies in Asian Patients with Acute Coronary Syndrome or Stable Coronary Artery Disease

Dual antiplatelet therapy (DAPT) has been the mainstay treatment to reduce ischemic events, such as myocardial infarction or stroke, in patients with coronary artery disease (CAD). The development of potent P2Y12 inhibitors (ticagrelor and prasugrel) has helped to further reduce ischemic events, particularly among high-risk patients. Meanwhile, the evolution of newer generations of drug-eluting stents are also improving outcomes of percutaneous coronary intervention. Research studies on antiplatelet therapy in recent years have focused on balancing ischemic and bleeding risks through different strategies, which include P2Y12 inhibitor monotherapy, escalation and de-escalation, and extended DAPT. Because results from the large number of clinical studies may sometimes appear conflicting, this review aims to summarize recent advances, and demonstrate that they are aligned by a general principle, namely, strategies may be adopted based on treatment aims for specific patients at several time points. Another aim of this review is to outline the important considerations for using antiplatelet therapy in Asian patients, in whom there is a greater prevalence of CYP2C19 loss-of-function mutations, and a common increased risk of bleeding, despite high platelet reactivity (the so-called "East Asian Paradox").

Prevalence of adverse events during ticagrelor versus clopidogrel treatment and its association with premature discontinuation of dual antiplatelet therapy in East Asian patients with acute coronary syndrome

BACKGROUND

Clinical evidence raises the issues regarding the high risk of adverse events and serious bleeding in East Asian patients receiving standard-dose ticagrelor treatment. We sought to evaluate the association between adverse events and their associations with premature discontinuation of dual antiplatelet therapy (DAPT).

METHODS

We enrolled East Asian patients presented with acute coronary syndrome who took DAPT with 90-mg ticagrelor (n = 270) or 75-mg clopidogrel (n = 674). During 1-month treatment, antiplatelet effect was evaluated with the VerifyNow P2Y12 assay, and the occurrence of Bleeding Academic Research Consortium (BARC) bleeding and modified Medical Research Council (mMRC) dyspnea was assessed with the dedicated questionnaire.

RESULTS

During 1-month follow-up, patients on ticagrelor showed the higher risks of bleeding (any BARC type: 45.6% vs. 23.6%; odds ratio [OR], 2.71 and BARC 1 or 2 type: 45.2% vs. 22.1%; OR, 2.90, respectively) and dyspnea (26.3% vs. 13.6%; OR, 2.25) compared with those on clopidogrel. In a receiver-operating characteristics curve analysis to predict bleeding risk, ticagrelor showed a lower cutoff of low platelet reactivity (LPR) (P2Y12 reaction unit [PRU] ≤ 20) than clopidogrel (PRU ≤ 110). Early occurrence of bleeding episode was significantly associated with LPR phenotype (OR, 2.68), not type of P2Y12 inhibitor. In multivariate analysis, type of P2Y12 inhibitor (ticagrelor vs. clopidogrel: OR, 2.19) and bleeding episode (OR, 2.94) were independent predictors for dyspnea occurrence. During 1-year follow-up, DAPT with ticagrelor showed a higher risk of premature discontinuation compared to DAPT with clopidogrel (27.8% vs. 4.7%; adjusted HR, 8.84), which risk appeared frequent during the first month (14.4%) during DAPT with ticagrelor. Early occurrence of bleeding and dyspnea synergistically increased a risk of DAPT non-adherence, irrespective of type of P2Y12 inhibitor.

CONCLUSION

This analysis is the first evidence to show the different cutoff of low platelet reactivity during the reversible (ticagrelor) versus irreversible P2Y12 inhibitor (clopidogrel). Early occurrence of bleeding and dyspnea is very common during standard-dose ticagrelor treatment in East Asian patients, which show a close association with premature DAPT discontinuation.

CLINICAL TRIAL REGISTRATION

[https://www.clinicaltrials.gov], identifier[NCT046 50529].

Prognosis and the Effect of De-Escalation of Antiplatelet Therapy After Nuisance Bleeding in Patients With Myocardial Infarction

BACKGROUND

Data regarding prognosis and management after nuisance bleeding (NB) is limited. The purpose was to examine the prognostic significance of NB in patients receiving potent dual antiplatelet treatment (DAPT) after acute myocardial infarction and the impact of de-escalation of DAPT on clinical outcomes thereafter.

METHODS

From the TALOS-AMI trial (Ticagrelor Versus Clopidogrel in Stabilized Patients With Acute Myocardial Infarction)' 2583 patients were used to investigate the clinical impact of NB (defined as Bleeding Academic Research Consortium [BARC] 1 bleeding) during 1-month treatment with ticagrelor-based DAPT after acute myocardial infarction. We assessed the associations between NB within 1 month and BARC 2, 3, or 5 bleeding and major adverse cardiovascular event (a composite of cardiovascular death, myocardial infarction, stroke) from 1 to 12 months. We also evaluated the effect of de-escalation to clopidogrel in patients with or without NB.

RESULTS

NB occurred in 416 patients (16.7%) after 1 month of ticagrelor-based DAPT. At 1 year, NB was not associated with increase in BARC 2, 3, or 5 bleeding (hazard ratio [HR]' 1.29 [95% CI' 0.7-2.14]) and major adverse cardiovascular event (HR' 1.72 [95% CI' 0.87-3.39]). However, patients with NB had an increased risk of BARC 2, 3, or 5 bleeding at 6 months (HR, 1.94 [95% CI, 1.08-3.48]; P=0.026), which diminished over the next 6 months. De-escalation from ticagrelor to clopidogrel reduced the incidence of BARC 2, 3, or 5 bleeding compared with ticagrelor plus aspirin in NB (HR' 0.31 [95% CI' 0.10-0.92]) and non-NB patients (HR' 0.58 [95% CI' 0.37-0.90]) without heterogeneity (P interaction=0.291). There was no increase in major adverse cardiovascular event after DAPT de-escalation, irrespective of NB.

CONCLUSIONS

NB was frequent in patients with acute myocardial infarction on 1-month ticagrelor-based DAPT and was associated with an early increase of bleeding. DAPT de-escalation after NB may reduce bleeding without increasing ischemic events.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02018055.

The developmental journey of therapies targeting purine receptors: from basic science to clinical trials

Since the discovery of ATP as an extracellular signalling molecule in 1972, purinergic signalling, mediated by extracellular purines and pyrimidines has been identified in virtually all mammalian tissues and is implicated in regulating fundamental cellular processes. In recent years, there has been an increasing focus on the pathophysiology and potential therapeutic interventions based on purinergic signalling. A vast range of compounds targeting purine receptors are in clinical development, and many more are in preclinical studies, which highlights the fast growth in this research field. As a tribute to Professor Geoffrey Burnstock's legacy in purinergic signalling, we present here a brief review of compounds targeting purine receptors that are in different stages of clinical trials. The review highlights the 50-year journey from basic research on purinergic receptors to clinical applications of therapies targeting purine receptors.

Antiplatelet efficacy of ticagrelor versus clopidogrel in Mediterranean patients with diabetes mellitus and chronic coronary syndromes: A crossover pharmacodynamic investigation

Introduction

Patients with diabetes mellitus (DM) have augmented platelet reactivity and diminished responsiveness to clopidogrel. Ticagrelor, a more potent P2Y12 inhibitor, is clinically superior to clopidogrel in acute coronary syndromes, although its role in chronic coronary syndromes (CCS) is still the subject of debate. The aim of this investigation was to compare the pharmacodynamic effectiveness of ticagrelor and clopidogrel in Mediterranean DM patients with CCS.

Materials and methods

In this prospective, randomized, crossover study, patients (n = 20) were randomized (1:1) to receive, on top of aspirin therapy, either ticagrelor 180 mg loading dose (LD)/90 mg maintenance dose (MD) b.i.d. or clopidogrel 600 mg LD/75 mg MD o.d. for 1 week in a crossover fashion with a 2-4 week washout period between regimens. Platelet function measurements were performed at 4 timepoints in each period (baseline, 2 h and 24 h after LD, and 1 week), including light transmission aggregometry (LTA, primary endpoint), VASP assay, Multiplate and VerifyNow P2Y12.

Results

The ticagrelor LD achieved greater platelet inhibitory effect than clopidogrel LD, assessed with LTA (20 μM ADP as agonist), at 2 h (34.9 ± 3.9% vs. 63.6 ± 3.9%; p < 0.001) and 24 h (39.4 ± 3.5% vs. 52.3 ± 3.8%; p = 0.014). After 1 week of therapy, platelet reactivity was again significantly inferior with ticagrelor compared to clopidogrel (30.7 ± 3.0% vs. 54.3 ± 3.0%; p < 0.001). The results were consistent with the other platelet function assays employed.

Conclusion

In Mediterranean patients with DM and CCS, ticagrelor provides a more potent antiplatelet effect than clopidogrel after the LD and during the maintenance phase of therapy.

Clinical trial registration

[ClinicalTrials.gov], identifier [NCT02457130].

Clinical benefit of long-term use of dual antiplatelet therapy for acute myocardial infarction patients with the PEGASUS-TIMI 54 criteria

Background

We evaluated the effectiveness of extended dual antiplatelet therapy (DAPT) usage after 2nd-generation drug elution stent implantation in acute myocardial infarction (AMI) survivors with high ischemic risk characteristics who had no major bleeding for 24 months under at least 1 year of DAPT maintenance.

Materials and methods

The primary ischemic and bleeding endpoints were the risk of mortality and the risk of BARC 3 or 5 (major) bleeding. We investigated the event rates for 2–5 years after the index procedure.

Results

Of 3382 post-AMI survivors who met the PEGASUS-TIMI 54 (PEGASUS) criteria and without major bleeding until 2 years, 2281 (67.4%) maintained DAPT over 24 months, and 1101 (32.5%) switched DAPT to a single antiplatelet agent. The &gt;24 M DAPT group showed a lower risk of mortality than the 12–24 M DAPT group (7.2 vs. 9.2%; adjusted hazard ratio: 0.648; 95% confidence interval: 0.595–0.976; p &lt; 0.001). The mortality risk was significantly greater as the number of PEGASUS criteria increased (p &lt; 0.001). DAPT &gt; 24 months was not significantly associated with a decreased risk for major bleeding in the population meeting the PEGASUS criteria (2.0 vs. 1.1%; p = 0.093). The results were consistent after propensity-score matching and inverse probability weighting to adjust for baseline differences.

Conclusion

Extended DAPT over 24 months was associated with a lower risk of mortality without increasing the risk of major bleeding among 2 years survivors after AMI who met the PEGASUS criteria and had no major bleeding events before 24 months.

Reduced Mortality With Antiplatelet Therapy Deescalation After Percutaneous Coronary Intervention in Acute Coronary Syndromes: A Meta-Analysis

BACKGROUND

Antiplatelet therapy deescalation has been suggested as an alternative to standard treatment with potent dual antiplatelet therapy (DAPT) for 1 year in low bleeding risk patients with acute coronary syndromes undergoing percutaneous coronary intervention to mitigate the increased risk of bleeding. Whether this strategy preserves the ischemic and survival benefits of potent DAPT is uncertain.

METHODS

We performed a pairwise meta-analysis in patients with acute coronary syndrome undergoing percutaneous coronary intervention treated with either 1-year standard potent DAPT versus deescalation therapy (potent DAPT for 1-3 months followed by either reduced potency DAPT or ticagrelor monotherapy for up to 1 year). Randomized trials comparing standard DAPT versus deescalation therapy in patients with acute coronary syndrome undergoing percutaneous coronary intervention were searched through MEDLINE, EMBASE, Cochrane databases, and proceedings of international meetings. The primary end point was 1-year all-cause mortality.

RESULTS

The meta-analysis included 6 trials in which 20 837 patients were randomized to potent DAPT for 1 to 3 months followed by deescalation therapy for up to 1 year (n=10 392) or standard potent DAPT for 1 year (n=10 445). Deescalation therapy was associated with lower 1-year rates of all-cause mortality compared with standard therapy (odds ratio, 0.75 [95% CI, 0.59-0.95]; P=0.02). Deescalation therapy was also associated with lower rates of major bleeding (odds ratio, 0.59 [95% CI, 0.48-0.72]; P<0.0001), with no significant difference in major adverse cardiac events (major adverse cardiovascular events; odds ratio, 0.89 [95% CI, 0.77-1.04]; P=0.14).

CONCLUSIONS

In low bleeding risk patients with acute coronary syndrome undergoing percutaneous coronary intervention, compared with 1-year of potent DAPT, antiplatelet therapy deescalation therapy after 1 to 3 months was associated with decreased mortality and major bleeding with similar rates of major adverse cardiovascular events.

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

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

Reduction or de-escalation of dual antiplatelet therapy intensity or duration in patients with acute coronary syndromes undergoing percutaneous coronary intervention: A mini-review

Current guidelines for patients with acute coronary syndrome (ACS) recommend dual antiplatelet therapy (DAPT) for 12 months. Since bleeding is the main Achilles' heel of DAPT, in recent years several randomized controlled trials have evaluated the safety and efficacy of de-escalation of DAPT with respect to ischaemic and bleeding endpoints. These trials can be broadly divided into studies evaluating a shorter duration of DAPT, and those studies in which DAPT that includes a potent P2Y₁₂ inhibitor, such as prasugrel or ticagrelor, is compared to less intense DAPT, mainly clopidogrel or reduced-dose prasugrel. We sought to evaluate the studies assessing de-escalation of DAPT in patients with ACS undergoing PCI. We review the studies evaluating the strategies of de-escalation of DAPT intensity and those evaluating a strategy of de-escalation of DAPT duration in ACS patients undergoing PCI. We summarize the limitations of studies to date, gaps in evidence and make recommendations for future studies.

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.

Extended, standard, or De-escalation antiplatelet therapy for patients with coronary artery disease undergoing percutaneous coronary intervention? A trial-sequential, bivariate, influential, and network meta-analysis

AIMS

The relative safety and efficacy of de-escalation, extended duration (ED) (>12-months), and standard dual antiplatelet therapy for 12-months (DAPT-12) in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) remains controversial.

METHODS AND RESULTS

Online databases were queried to identify relevant randomized control trials (RCTs). ED-DAPT, high-potency (HP) DAPT, shorter duration (SD) DAPT, and low-dose (LD) DAPT were compared with DAPT-12. A trial sequential, bivariate, influential, and frequentist network meta-analysis (NMA) was performed to determine the pooled estimates. A total of 30 RCTs comprising 81 208 (40 839 experimental, 40 369 control arm) patients with CAD were included in the quantitative analysis. On NMA, compared with DAPT-12, all types of de-escalation, HP-DAPT-12, and ED-DAPT strategies had a statistically non-significant difference in the incidence of MACE at a median follow-up of 1-year. Similarly, there was no significant difference in the incidence of stroke, stent thrombosis, target lesion revascularization (TLR), target vessel revascularization (TVR), and all-cause mortality between DAPT-12 and all other strategies. The network estimates showed a significantly lower incidence of major bleeding with DAPT for 3-months followed by P2Y12-inhibitor monotherapy (RR 0.62, 95% CI 0.45-0.84), while a higher risk of bleeding with HP-DAPT for 12 months (RR 1.55, 95% CI 1.16-2.06). The net clinical benefit and rankograms also favoured DAPT-3 (P2Y12) and discouraged the use of HP-DAPT-12 and ED-DAPT. A subgroup analysis of 19 RCTs restricted to patients who presented with acute coronary syndrome (ACS) mirrored the findings of pooled analysis. A sensitivity analysis revealed no influence of any individual study or individual strategy on net ischemic estimates. The trial sequential analysis (TSA) illustrated a consistently non-significant difference at the interim analysis of trials, reaching the futility area for MACE, while the cumulative Z-values line surpassed the monitoring boundary as well as the required information size for major bleeding favouring de-escalation strategy.

CONCLUSION

DAPT for three months followed by ticagrelor-only and use of aspirin + clopidogrel after a short period of high potency DAPT appears to be a safe strategy for treating post-PCI patients. However, given the methodological limitations and inclusion of a small number of trials in novel de-escalation strategies, these findings need validation by future large scale RCTs.

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.

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

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

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

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

Comparison of Unguided De-Escalation Versus Guided Selection of Dual Antiplatelet Therapy After Acute Coronary Syndrome: A Systematic Review and Network Meta-Analysis

BACKGROUND

The benefit of dual antiplatelet therapy (DAPT) for reducing ischemic events is greatest in the early period of acute coronary syndrome, and recent randomized controlled trials have investigated the unguided de-escalation strategy of changing potent P2Y₁₂ inhibitors to less potent or reduced-dose P2Y₁₂ inhibitors 1 month after acute coronary syndrome. However, it remains unclear which strategy is more effective and safer: the uniform unguided de-escalation strategy versus the personalized guided selection of DAPT with genotype or platelet function tests.

METHODS

PubMed, EMBASE, and Cochrane Central were searched for articles published from database inception to September 10, 2021. Randomized controlled trials investigating DAPT using clopidogrel, low-dose prasugrel, standard-dose prasugrel, ticagrelor, unguided de-escalation strategy, and guided selection strategy for patients with acute coronary syndrome were included. Hazard ratios and relative risk estimates were extracted from each study. The estimates were pooled using a random-effects network meta-analysis. The primary efficacy outcome was major adverse cardiovascular events, defined as a composite of cardiovascular death, myocardial infarction, or stroke. The primary safety outcome was major or minor bleeding. Secondary outcomes were all-cause death, cardiovascular death, myocardial infarction, stroke, stent thrombosis, and major bleeding.

RESULTS

This study included 19 randomized controlled trials with 69 746 patients. Compared with guided selection of DAPT, unguided de-escalation of DAPT was associated with a decreased risk of the primary safety outcome (hazard ratio, 0.48 [95% CI, 0.33-0.72]) without increased risks of major adverse cardiovascular events (hazard ratio, 0.82 [95% CI, 0.53-1.28]) or any secondary outcomes. The results were similar when the guided selection strategy was divided into platelet function-guided and genotype-guided strategies.

CONCLUSIONS

Compared with guided selection of DAPT, unguided de-escalation of DAPT decreased bleeding without increasing ischemic events in patients after acute coronary syndrome. If a strategy of de-escalation is chosen, these findings do not support the routine use of personalized guiding tests.

REGISTRATION

URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42021273082.

Clopidogrel Monotherapy After 1-Month Dual Antiplatelet Therapy in Percutaneous Coronary Intervention: From the STOPDAPT-2 Total Cohort

BACKGROUND

The benefit of clopidogrel monotherapy after 1-month dual antiplatelet therapy (DAPT) compared with 12-month DAPT with aspirin and clopidogrel was demonstrated in the STOPDAPT-2 (Short and Optimal Duration of Dual Antiplatelet Therapy After Everolimus-Eluting Cobalt-Chromium Stent-2), but not in the STOPDAPT-2 acute coronary syndrome (ACS); however, both trials were underpowered based on the actual event rates.

METHODS

We obtained the prespecified pooled population of 5997 patients as the STOPDAPT-2 total cohort (STOPDAPT-2: N=3009/STOPDAPT-2 ACS: N=2988; ACS: N=4136/chronic coronary syndrome [CCS]: N=1861), comprising 2993 patients assigned to 1-month DAPT followed by clopidogrel monotherapy, and 3004 patients assigned to 12-month DAPT with aspirin and clopidogrel after percutaneous coronary intervention. The primary end point was the composite of cardiovascular (cardiovascular death, myocardial infarction, definite stent thrombosis, or any stroke) or bleeding (Thrombolysis in Myocardial Infarction major/minor) end points at 1 year.

RESULTS

One-month DAPT was noninferior to 12-month DAPT for the primary end point (2.84% versus 3.04%; hazard ratio [HR], 0.94 [95% CI, 0.70-1.27]; Pnoninferiority=0.001; Psuperiority=0.68). There was no significant risk-difference for the cardiovascular end point between the 1- and 12-month DAPT groups (2.40% versus 1.97%; HR, 1.24 [95% CI, 0.88-1.75]; Pnoninferiority=0.14; Psuperiority=0.23). There was a lower risk of the bleeding end point with 1-month DAPT relative to 12-month DAPT (0.50% versus 1.31%; HR, 0.38 [95% CI, 0.21-0.70]; Psuperiority=0.002). One-month DAPT relative to 12-month DAPT was associated with a lower risk for major bleeding regardless of ACS or CCS (ACS: HR, 0.46 [95% CI, 0.23-0.94]; P=0.03, and CCS: HR, 0.26 [95% CI, 0.09-0.79]; P=0.02; Pinteraction=0.40), while it was associated with a numerical increase in cardiovascular events in ACS patients, but not in CCS patients, although not statistically significant and without interaction (ACS: HR, 1.50 [95% CI, 0.99-2.27]; P=0.053, and CCS: HR, 0.74 [95% CI, 0.38-1.45]; P=0.39; Pinteraction=0.08).

CONCLUSIONS

Clopidogrel monotherapy after 1-month DAPT compared with 12-month DAPT with aspirin and clopidogrel had a benefit in reducing major bleeding events without being associated with increase in cardiovascular events.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifiers: NCT02619760, NCT03462498.

Advances in Clinical Cardiology 2021: A Summary of Key Clinical Trials

INTRODUCTION

Over the course of 2021, numerous key clinical trials with valuable contributions to clinical cardiology were published or presented at major international conferences. This review seeks to summarise these trials and reflect on their clinical context.

METHODS

The authors reviewed clinical trials presented at major cardiology conferences during 2021 including the American College of Cardiology (ACC), European Association for Percutaneous Cardiovascular Interventions (EuroPCR), European Society of Cardiology (ESC), Transcatheter Cardiovascular Therapeutics (TCT), American Heart Association (AHA), European Heart Rhythm Association (EHRA), Society for Cardiovascular Angiography and Interventions (SCAI), TVT-The Heart Summit (TVT) and Cardiovascular Research Technologies (CRT). Trials with a broad relevance to the cardiology community and those with potential to change current practice were included.

RESULTS

A total of 150 key cardiology clinical trials were identified for inclusion. Interventional cardiology data included trials evaluating the use of new generation novel stent technology and new intravascular physiology strategies such as quantitative flow ratio (QFR) to guide revascularisation in stable and unstable coronary artery disease. New trials in acute coronary syndromes focused on shock, out of hospital cardiac arrest (OOHCA), the impact of COVID-19 on ST-elevation myocardial infarction (STEMI) networks and optimal duration/type of antiplatelet treatment. Structural intervention trials included latest data on transcatheter aortic valve replacement (TAVR) and mitral, tricuspid and pulmonary valve interventions. Heart failure data included trials with sodium-glucose cotransporter 2 (SGLT2) inhibitors, sacubitril/valsartan and novel drugs such as mavacamten for hypertrophic cardiomyopathy (HCM). Prevention trials included new data on proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. In electrophysiology, new data regarding atrial fibrillation (AF) screening and new evidence for rhythm vs. rate control strategies were evaluated.

CONCLUSION

This article presents a summary of key clinical cardiology trials published and presented during the past year and should be of interest to both practising clinicians and researchers.

De-escalation of Dual Antiplatelet Therapy After Percutaneous Coronary Intervention in Patients With Acute Coronary Syndrome: An Updated Meta-analysis and Trial Sequential Analysis of 21 Studies and 38,741 Patients

ABSTRACT

Dual antiplatelet therapy (DAPT) is recommended among patients with established acute coronary syndrome. In this meta-analysis, we sought to compare the clinical outcomes between de-escalation versus unchanged DAPT based on both randomized controlled trials (RCTs) and observational studies. The primary outcomes were major adverse cardiovascular events for observational studies and net clinical events for RCTs. Four RCTs and 17 observational studies with a total of 38,741 patients were included. Net clinical events were more common with unchanged DAPT than with de-escalation in RCTs [odd ratio (OR): 1.71; 95% confidence interval (CI), 1.21-2.43; I2 = 69.4%], which was mainly due to higher risks of any bleeding (OR: 1.81; 95% CI, 1.14-2.88; I2 = 75.5%) and major bleeding (OR: 1.58; 95% CI, 1.02-2.46; I2 = 0), without significant differences in ischaemic events. However, trial sequential analysis revealed that sufficient information was obtained just for net clinical events, not for respective ischaemic or bleeding events in RCTs. In the analysis based on real-world observational studies, the risks of myocardial infarction (OR: 0.77; 95% CI, 0.61-0.98; I2 = 0) and stroke (OR: 0.42; 95% CI, 0.22-0.81; I2 = 0) were lower with the unchanged DAPT group. Therefore, de-escalation of DAPT led to a marked reduction in net clinical events compared with unchanged DAPT in RCTs, which was mainly due to reduced bleeding events. However, sufficient information for ischaemic events was not obtained. In the analysis based on real-world observational studies, myocardial infarction and stroke were more common with de-escalation, which should arise our attention.

Antiplatelet Therapy in Atherothrombotic Diseases: Similarities and Differences Across Guidelines

Antiplatelet therapy, mainly consisting of aspirin and P2Y₁₂ receptor antagonists, is the cornerstone of the pharmacological treatment and prevention of atherothrombotic diseases. Its use, especially in secondary cardiovascular prevention, has significantly improved patient clinical outcomes in the last decades. Primary safety endpoint (i.e., bleeding complications) remain a major drawback of antiplatelet drugs. National and international societies have published and regularly updated guidelines for antiplatelet therapy aiming to provide clinicians with practical recommendations for a better handling of these drugs in various clinical settings. Many recommendations find common ground between international guidelines, but certain strategies vary across the countries, particularly with regard to the choice of molecules, dosage, and treatment duration. In this review, we detail and discuss the main antiplatelet therapy indications in the light of the different published guidelines and the significant number of recently published clinical trials and meta-analyses and highlight the areas that deserve further investigation in order to improve antiplatelet therapy in patients with atherothrombotic diseases.

De-escalation strategies of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention for acute coronary syndrome

Antiplatelet therapy is important for reducing systemic and local thrombotic events in patients undergoing percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). Antiplatelet treatment regimens, along with dual antiplatelet therapy consisting of aspirin and a P2Y12 inhibitor for patients receiving PCI, have frequently changed over the years. With improvements in the understanding of the prognostic relevance of bleeding events in patients with PCI, as well as the safety and efficacy of drug-eluting stents, several randomized controlled trials (RCTs) have been conducted on antiplatelet treatment strategies associated with a more favorable balance between ischemic and bleeding risks. Several key RCTs for appropriate antiplatelet therapy in patients receiving PCI for ACS have been reported, and practical guidelines have been updated. This manuscript presents the results of major RCTs on de-escalation strategies of dual antiplatelet treatment in patients receiving PCI for ACS.