Effect of a high loading dose of clopidogrel on platelet function in patients undergoing coronary stent placement

Twenty Years of an Institutional Chest Pain Pathway: What's Come and What's Yet to Come

Acute coronary syndromes (ACS) remain one of the leading causes of cardiovascular morbidity and mortality in the United States and around the world. Because of the acute nature of ACS presentations, timely identification, risk stratification, and intervention are of the utmost importance. Twenty years ago, we published the first iteration of our institutional chest pain clinical pathway in this journal, which separated patients presenting with chest pain into one of the 4 levels of decreasing acuity, with associated actions and interventions for providers based on the level. This chest pain clinical pathway has undergone regular review and updates under a collaborative team of cardiologists, emergency department physicians, cardiac nurse practitioners, and other associated stakeholders in the treatment of patients presenting with chest pain. This review will discuss the key changes that our institutional chest pain algorithm has undergone over the last 2 decades and what the future holds for chest pain algorithms.

Antithrombotic Therapy in the Prevention of Stroke

OVERVIEW

Ischemic stroke is a leading cause of death and disability throughout the world. Antithrombotic therapy, which includes both antiplatelet and anticoagulant agents, is a primary medication of choice for the secondary prevention of stroke. However, the choices vary with the need to incorporate evolving, newer information into the clinical scenario. There is also the need to factor in co-morbid medical conditions as well as the cost ramifications for a particular patient as well as compliance with the regimen. Pertinent Updates: In the acute setting, dual antiplatelet therapy from three weeks to up to three months has become recognized as a reasonable approach for patients with either minor stroke or transient ischemic attack or those with symptoms associated with higher-grade intracranial stenosis. This approach is favored for non-cardioembolic stroke as a cardiogenic mechanism tends to be best managed with attention to the cardiac condition as well as anticoagulant therapy. Risk stratification for recurrent stroke is important in weighing potential risk versus benefits. For example, prolonged dual antiplatelet therapy, with a combination such as aspirin and clopidogrel or aspirin and ticagrelor, tends to have negation of the potential clinical benefit of stroke prevention, over time, by the enhanced bleeding risk. Anticoagulant choices are now impacted by newer agents, initially identified as novel oral anticoagulants (NOACs), which also became associated with "non-vitamin K" agents as they are no longer considered novel. Alternatively, they are now often identified as direct oral anticoagulants (DOACs). They tend to be viewed as superior or non-inferior to warfarin with the caveat that warfarin is still viewed as the agent of choice for stroke prevention in patients with mechanical heart valves.

CONCLUSION

Based upon cumulative information from multiple clinical trials of secondary prevention of stroke, there is an increasing array of approaches in an effort to provide optimal management. Antithrombotic therapy, including in combination with anticoagulant therapy, continues to evolve with the general caveat that "one size does not fit all". In view of this, we desire to provide an evidence-based approach for the prevention of stroke with antithrombotic agents.

Y-stent assisted coiling of ruptured wide neck intracranial aneurysm in the acute phase

BACKGROUND

The objective of the present study is to analyze the outcomes of patients with subarachnoid hemorrhage (SAH) in the acute phase after treatment with Y-stent-assisted coiling (YSAC) embolization.

METHODS

This retrospective study assessed of 30 patients with acutely ruptured wide-neck aneurysms following YSAC treatment between April 2013 and October 2019. The demographic data, aneurysm occlusion grade, procedural and periprocedural complications, and clinical outcomes were assessed.

RESULTS

The procedure was completed in 30 cases (90.1%) and technical failure occurred in 3 cases (9.1%). Immediate control angiography revealed that total occlusion Raymond-Ray Class 1 (RR1) was achieved in 21 (70%), neck filling (RR2) in eight (26.6%) and sac filling (RR1) in one (3.3%) aneurysm. Upon angiographic follow-up, RR1 occlusion was observed in 15 (71.4%) patients, RR2 in three (14.3%) patients and RR3 in three (14.3%) patients. In-stent thrombus developed in five (16.6%) patients; procedural ischemic events were observed in four (13.3%) patients; and two (6.6%) patients were symptomatic. A periprocedural asymptomatic intracranial hemorrhage was detected in two patients. At discharge, 17 (56.6%) patients were in good clinical condition, six (20%) were in a severe disability condition, and seven (23.3%) patients had died. At the final follow-up visit (mean: 18.9 months), 16 (76,2%) of 21 patients were in a good clinical condition and five (23.8%) had severe disabilities.

CONCLUSIONS

Y-stent assisted coiling in might be a feasible and promising option for treatment in acute phase in selected wide-necked ruptured intracranial aneurysms.

Safety and feasibility of low-dose ticagrelor in patients with ST-segment elevation myocardial infarction

Background

Previous studies have confirmed the safety and feasibility of half‐dose ticagrelor in Chinese patients with acute coronary syndrome, but currently there is no plan for the use of ticagrelor for Chinese ST‐segment elevation myocardial infarction (STEMI) patients.

Hypothesis

It is safe and feasible of low‐dose ticagrelor in patients with STEMI.

Methods

The STEMI patients who were undergoing emergency intervention and taking ticagrelor were enrolled. Patients whose level of platelet aggregation rate (PAR) less than 30% after 7‐day treatment with standard‐dose ticagrelor were randomly divided into low‐dose group (LD group, 45 mg twice daily) and standard‐dose group (SD group, 90 mg twice daily). The changes of levels of platelet parameters were compared between the two groups. The incidence of major adverse cardiac events (MACE), bleeding events were compared between the two groups within 6 months of follow‐up.

Results

The levels of PAR in the SD group decreased compared with baseline, and was lower than those of LD group at the same time point. The levels of platelet distribution width in both groups decreased from the baseline values (all p < .05) at 1, 3, and 6 months after grouping treatment, but there was no significant difference between the two groups. The incidence of MACE was similar between the two groups of patients. There were decreasing trends in the incidences of minimal bleeding event, minor bleeding event, dyspnea, and gout in the LD group.

Conclusion

It is safe and feasible of low‐dose ticagrelor for patients with STEMI based on the monitoring of PAR.

Increased risk of Ventriculostomy-Associated hemorrhage in patients treated with antiplatelet agents for stent-assisted coiling of ruptured intracranial aneurysms

PURPOSE

The aim of this study is to evaluate the impact of antiplatelet agents for stent-assisted coiling, including intravenous (IV) tirofiban as an antiplatelet premedication, on rates of external ventricular drain (EVD)-related hemorrhage in acutely ruptured intracranial aneurysms. The impact of IV tirofiban in particular was also evaluated.

METHODS

Rates of radiographically identified hemorrhage associated with EVD placement were compared between patients who received an antiplatelet agent for stent-assisted coil embolization (SACE), and patients who did not receive an antiplatelet agent between June 2013 and June 2019.

RESULTS

78 patients treated for a ruptured aneurysm which required an EVD were included. A total of 46 patients who underwent stent-assisted coiling and received IV tirofiban and oral asipirin and clopidogrel (DAPT) were included in the antiplatelet group, while 32 who underwent single coiling and received no antiplatelet therapy were included in the control group. Overall, EVD-related hemorrhage occurred in 13 patients (16.67%): 11 (23.91%) in the antiplatelet group and 2 (6.25%) in the control group (p = 0.040). Of 37 patients who underwent computed tomography after SACE, but before the use of DAPT, 8 (21.62%) exhibited EVD-related hemorrhage after IV tirofiban therapy (p = 0.070 vs. control group). EVD-related hemorrhage was not significantly different between patients with EVD placement after coil embolization versus before coil embolization (p = 0.124). In the subgroup analysis for the antiplatelet group, we did not observed increased EVD-related hemorrhage in patients receiving EVD placement after administration of antiplatelet agents (8/27 [29.63%]) versus before administration of antiplatelet agents (3/19 [15.79%]).

CONCLUSION

Patients with ruptured aneurysm who receive an antiplatelet agent for stent-assisted coiling are at a higher risk for EVD-related hemorrhage. The order of EVD placement and EVT, as well as the order of EVD placement and antiplatelet initiation do not appear to be significantly different regarding the outcome of EVD-related hemorrhage.HighlightsPatients with ruptured aneurysm who receive an antiplatelet agent for stent-assisted coiling are at a higher risk for EVD-related hemorrhage.There was a trend towards higher EVD related haemorrhage when tirofiban was used but it did not reach statisitical significance.The order of EVD-whether before vs after endovascular treatment, or before vs after antiplatelet therapy did not influence the EVD-related hemorrhage rates.

Association of ABCB1 Gene Polymorphisms and Clopidogrel Responsiveness in Iranian Patients undergoing Percutaneous Coronary Intervention

Clopidogrel is an antiplatelet agent currently used for preventing stent thrombosis. Despite certain clinical benefits of clopidogrel in patients undergoing percutaneous coronary intervention (PCI), adequate antiplatelet effect has not been obtained in some patients. The present study was designed to investigate the potential association of ABCB1 (ATP-Binding Cassette, Subfamily B, member1) gene polymorphism, and clopidogrel responsiveness in Iranian patients after PCI. Sixty-seven patients were included in the study. Blood samples were taken from patients at baseline, 2 h after administration of 600-mg loading dose of clopidogrel, 24 h and 30 days after PCI. Platelet aggregation was measured by light transmittance aggregometry (LTA) with two levels of adenosine diphosphate (ADP) concentrations (5 and 20 µM). ABCB1 genotyping was performed by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). The allelic frequencies of wild type, heterozygote, and homozygote genotypes of ABCB1 were 20.9%, 74.6%, and 4.5%, respectively. There was no significant association between polymorphism of ABCB1 and clopidogrel non-responsiveness (P > 0.05) in various situations. No significant difference was observed for demographic characteristics. Genetic and demographic factors had no significant effect on the platelet activity of clopidogrel in an Iranian population.

What Are Optimal P2Y12 Inhibitor and Schedule of Administration in Patients With Acute Coronary Syndrome?

Guidelines recommend treatment with a P2Y12 platelet adenosine diphosphate receptor inhibitor in patients undergoing elective or urgent percutaneous coronary intervention (PCI), but the optimal agent or timing of administration is still not clearly specified. The P2Y12 inhibitor was initially used for its platelet anti-aggregatory action to block thrombosis of the recanalized coronary artery or deployed stent. It is now recognized that these agents also offer potent cardioprotection against a reperfusion injury that occurs in the first minutes of reperfusion if platelet aggregation is blocked at the time of reperfusion. But this is difficult to achieve with oral agents which are slowly absorbed and often require time-consuming metabolic activation. Patients with ST-segment elevation myocardial infarction who usually have a large mass of myocardium at risk of infarction seldom have sufficient time for upstream-administered oral agents to achieve a therapeutic P2Y12 level of inhibition by the time of balloon inflation. However, optimal treatment could be assured by initiating an IV cangrelor infusion shortly prior to stenting followed by subsequent post-PCI transition to an oral agent, that is, ticagrelor, once success of the recanalization and absence of need for surgical intervention are confirmed. Not only should this sequence provide optimal protection against infarction, it should also negate bleeding if coronary artery bypass grafting should be required since stopping the cangrelor infusion at any time will quickly restore platelet reactivity. It is anticipated that cangrelor-induced myocardial salvage will help preserve myocardial function and significantly diminish postinfarction heart failure.

Evaluation of platelet activity by multiple electrode impedance aggregometry in acute coronary syndromes: pilot study in a Brazilian tertiary-care public hospital

There is no definite recommendation for testing platelet aggregation (PA) in acute coronary syndromes (ACS) due to inconclusive evidence on the usefulness of platelet function tests to guide therapy and improve clinical outcomes. The evaluation of PA with multiple electrode impedance platelet aggregometry (MEA) may be useful to manage antiplatelet therapy and possibly influence patient outcome. The primary aim of this study was to measure PA with MEA in Brazilian patients with ACS and evaluate the association between PA and adverse clinical outcomes. Forty-seven consecutive patients admitted with ACS to a Brazilian tertiary-care public hospital were studied and PA was evaluated using MEA. Patients were followed for six months for the occurrence of all-cause death, acute myocardial infarction, or stroke. Suboptimal inhibition of PA was found in 7 patients (14.9%); 5 (10.6%) in response to ASA (acetylsalicylic acid), 2 (5.0%) to clopidogrel, and none to ticagrelor. Inadequate PA inhibition in response to ASA was significantly associated with the composite end point, but there was no significant association for insufficient PA inhibition in response to clopidogrel. This study suggested that the evaluation of PA in ACS using MEA may identify non-responders to ASA. Larger studies are necessary to define, in a public health scenario, the value of MEA in the management of ACS.

Study on antiplatelet effect of a new thiophenopyridine platelets P2Y12 receptor antagonist DV-127

P2Y₁₂ receptor antagonists are a class of drugs that act on platelet P2Y₁₂ receptors and inhibit adenosine diphosphate-induced platelet aggregation. As a thienopyridine antiplatelet agent which is approved by the US Food and Drug Administration for the treatment of cardiovascular diseases, currently, clopidogrel was once considered to be the most safe and effective antiplatelet drug in the P2Y₁₂ receptor antagonists, however, it has become increasingly clear that clopidogrel does not satisfactorily inhibit the platelets of approximately one-third of patients. This is in part due to clopidogrel is a prodrug and reliance on multiple cytochrome P450 enzymes for conversion into its active metabolite. Prasugrel and ticagrelor reduces the risk of adverse cardiovascular events compared to clopidogrel in acute coronary syndromes patients, however, the cardiovascular benefit of both drugs is counter-balanced by increased rates of spontaneous bleeding. Unlike clopidogrel, which is a prodrug, cangrelor is an active drug not requiring metabolic conversion, despite fewer bleeding events during cardiac surgery, cangrelor carries the risk of potential autoimmune reactions manifesting as breathlessness. DV-127 was synthesized by using three generations of thienopyridine P2Y₁₂ receptor antagonists as research models, using high resolution mass spectrometry, selective deuteration, and 2,7-position replacement groups technologies in order to maximize cardiovascular benefit while minimizing adverse effects on hemostasis. Our results show that although the dose of DV-127 is greatly reduced, it can achieve similar anticoagulant and antiplatelet effects as clopidogrel, and DV-127 can more strongly inhibit the release of α-granules even though the inhibitory effect of dense granules is similar to clopidogrel.

Individualized antithrombotic therapy in high-risk cardiovascular patients

Recent guidelines suggest dual antiplatelet therapy (DAPT) after 'drug-eluting' stent (DES) implantation for 6 months in stable patients and for 12 months in patients after acute coronary syndrome. Serious complications after stent implantation include stent thrombosis, recurrent myocardial infarction, ischemic stroke, cardiovascular death and bleeding. These complications also occur beyond 1 year after coronary intervention. Thus, it is important to consider whether a prolonged DAPT (>12 months after percutaneous coronary intervention) is of benefit to lower thrombo-ischemic events in high-risk patients. This review addresses the results of recent randomized clinical studies (DAPT, ITALIC, OPTIDUAL and PEGASUS) and meta-analyses to support the author's view of which patient collectives might benefit from prolonged DAPT.

Platelet reactivity in patients with acute coronary syndrome treated with prasugrel or ticagrelor in comparison to clopidogrel: a retrospective pharmacodynamic analysis

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y₁₂ inhibitor is a mainstay of the prevention of stent thrombosis following percutaneous coronary intervention (PCI). In the 2015 European guidelines for the management of acute coronary syndrome (ACS), prasugrel (PRA) and ticagrelor (TICA) combined with aspirin are recommended as first-line therapy. Clopidogrel (CLO) is recommended as an alternative medication for patients with contradictions to these new drugs. This single-center study analyzed the platelet function of 809 ACS patients undergoing PCI and treatment with DAPT. The platelet response to ADP was determined using Multiplate® analyzer at a median of 3 days after PCI in 254 patients treated with PRA (loading dose [LD] 60 mg, 10 mg qd), 162 patients receiving TICA (LD 180 mg, D 90 mg bid), and 393 CLO-treated patients (LD 600 mg, 75 mg qd). An aggregation >468 arbitrary units (AU)*min was defined as "high on-treatment platelet reactivity" (HPR), <188 AU*min as "low on-treatment platelet reactivity" (LPR). Platelet response in PRA-treated patients was lower compared to CLO or TICA (median; interquartile range: PRA 220 [163-275] AU*min vs. CLO 268 [186-387] AU*min, p < 0.001 vs. TICA 245 [190-320] AU*min, p = 0.001). Only 1.6% of PRA patients were stratified as HPR and 34.6% as LPR, while in the TICA group 1.9% fulfilled the criteria of HPR and 24.1% criteria of LPR. Sixteen percent of CLO patients were stratified as HPR and 26.2% as LPR. In a real-world cohort of ACS patients following PCI, PRA results in more potent inhibition of platelet function compared to CLO and TICA. TICA achieves a consistent antiplatelet effect with reduced rates of HPR and LPR in relation to CLO.

P2Y12 receptor inhibitors: an evolution in drug design to prevent arterial thrombosis

INTRODUCTION

P2Y12 inhibitors are a critical component of dual antiplatelet therapy (DAPT), which is the superior strategy to prevent arterialthrombosis in patients with acute coronary syndromes (ACS) and undergoing stent implantation.. Areas covered: Basic science articles, clinical studies, and reviews from 1992-2017 were searched using Pubmed library to collet impactful literature. After an introduction to the purinergic receptor biology, this review summarizes current knowledge on P2Y12 receptor inhibitors. Furthermore, we describe the subsequent improvements of next-generation P2Y12 receptor inhibitors facing the ambivalent problem of bleeding events versus prevention of arterial thrombosis in a variety of clinical settings. Therefore, we summarize data from relevant preclinical and clinical trials of currently approved P2Y12 receptor inhibitors (clopidogrel, prasugrel, ticagrelor, cangrelor) and provide strategies of drug switching and management of bleeding events. Expert opinion: An enormous amount of pharmacologic and clinical data is available for the application of P2Y12 receptor inhibitors. Today prasugrel, ticagrelor and clopidogrel are the standard of care drugs during dual antiplatelet therapy for ACS patients, but have considerable rates of bleeding. Recent and future clinical trials will provide evidence for subsequent escalation and de-escalation strategies of P2Y12 receptor inhibition. These data may pave the way for an evidence-based, individualized P2Y12 receptor inhibitor therapy.

Potent P2Y12 receptor inhibitors in patients with acute coronary syndrome

Blood platelets are highly activated in the setting of an acute coronary syndrome (ACS). This fact mandates the need for potent platelet inhibition in ACS patients and especially in patients undergoing a percutaneous coronary intervention (PCI). The 2nd generation thienopyridine clopidogrel has been the standard of treatment in the past. Due to its pharmacological properties including a delayed onset of action, a large response variability and an insufficient antiplatelet action in some patients (low responsiveness or high on-treatment platelet reactivity), there was a need to develop, to study and to introduce more potent agents with a fast, reliable and potent antiplatelet action. With the 3rd generation thienopyridine prasugrel and with ticagrelor two potent agents for antiplatelet treatment of ACS patients are available now. Both drugs have demonstrated their superiority compared to clopidogrel in terms of thrombotic risk reduction in large-scale randomized trials. However, for these agents and in line with the expectations towards a more potent anti platelet treatment regimen, a higher risk for bleeding was observed for prasugrel and ticagrelor. Further on, the new anti platelet agents have their own and characteristic contraindications and numerous issues to be considered in clinical practice.

This review aims to provide an overview on the state of the art P2Y12 receptor directed inhibition in ACS patients with a focus on patients undergoing a coronary stenting procedure.

A randomised trial on platelet function-guided de-escalation of antiplatelet treatment in ACS patients undergoing PCI

Outcomes of acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) have been significantly improved with the use of potent P2Y12 receptor inhibitors like prasugrel. While most of the ischaemic risk reduction for prasugrel versus clopidogrel was demonstrated in the early treatment period, the risk of bleeding became particularly prominent during the chronic course of therapy. It may therefore be a valid approach to substitute prasugrel for clopidogrel in the early phase of chronic antiplatelet treatment after PCI. In the Testing Responsiveness To Platelet Inhibition On Chronic Antiplatelet Treatment For Acute Coronary Syndromes (TROPICAL-ACS) trial, we aim to compare standard prasugrel therapy with a de-escalating antiplatelet treatment approach guided by platelet function testing (PFT). The study is an investigator-initiated European multicentre, randomised clinical trial in biomarker-positive ACS patients after successful PCI. Two thousand six hundred patients will be randomised prior to hospital discharge in a 1:1 fashion to either receive standard prasugrel therapy (control group) or de-escalating therapy (one-week prasugrel followed by one-week clopidogrel and PFT-guided maintenance therapy from day 14 after hospital discharge, monitoring group). Patients of the monitoring group with high on-clopidogrel platelet reactivity (HPR) based on Multiplate analyzer testing (HPR: ≥ 46U per consensus definition) will be switched back to prasugrel, whereas those without HPR (<46 U) will continue clopidogrel treatment. The overall study treatment duration will be one year in both groups. The primary endpoint of the study is net clinical benefit (combined incidence of cardiovascular death, myocardial infarction, stroke and bleeding ≥ grade 2 according to BARC criteria) one-year after randomisation. TROPICAL-ACS is the first large-scale, randomised controlled trial assessing the clinical value of a PFT-guided de-escalation of antiplatelet treatment in biomarker positive ACS patients undergoing PCI.

ClinicalTrials.gov Identifier: NCT01959451

High platelet reactivity and clinical outcome – Fact and fiction

In patients suffering from acute coronary syndromes or undergoing percutaneous coronary intervention, oral antiplatelet treatment is routinely administered with the primary aim of inhibiting platelet-mediated thrombus formation and subsequent abrupt vessel occlusion. Simultaneous inhibition of blood platelet cyclooxygenase-1 by aspirin and of the P2Y12 receptor by clopidogrel or prasugrel is currently recommended in this setting. Inter-individual response variability to aspirin and especially to clopidogrel is the subject of much debate as evidence has grown over the years linking an attenuated response to treatment with the occurrence of ischaemic events. Consequently, the clinical entity of high (on-treatment) platelet reactivity (HPR) was born and subsequently characterised in numerous studies over the last decade. Until recently, alternative treatment options were limited in patients exhibiting HPR. At present the antiplatelet therapy landscape is changing with the advent of prasugrel and ticagrelor as alternative and more potent treatment options. Different tests for monitoring platelet function are available and are being increasingly employed in research projects and clinical routine. These tests may prove useful for achieving optimal platelet inhibition for the individual patient, and several centres now incorporate such testing in day-to-day practice. Widespread adoption of this practice and incorporation into clinical guidelines awaits the results of ongoing trials in which treatment is changed based on platelet function monitoring. This review aims to summarise available facts and fiction in relation to platelet function testing and reactivity with a particular focus on P2Y12 receptor inhibition in patients undergoing coronary stent placement.

Early ambulance initiation versus in-hospital initiation of high dose clopidogrel in ST-segment elevation myocardial infarction

Pre-hospital infarct diagnosis gives the opportunity to start anti-platelet and anti-thrombotic agents before arrival at the PCI centre. However, more evidence is necessary to demonstrate whether high dose (HD) clopidogrel (600 mg) administered in the ambulance is associated with improved initial patency of the infarct related vessel (IRV) and/or clinical outcome compared to in-hospital initiation of HD clopidogrel. From 2001 until 2009 all consecutive ST-Segment Elevation Myocardial Infarction (STEMI) patients who underwent pre-hospital diagnosis and therapy in the ambulance were prospectively included in our single-centre cohort study. We compared initial patency of the IRV and clinical outcome in patients treated from 2001 until June 2006 (in-hospital HD clopidogrel) with patients treated from July 2006 until 2009 (ambulance HD clopidogrel). A total of 2,475 patients with STEMI were registered; of these 1,110 (44.8%) received in-hospital HD clopidogrel and 1,365 (55.2%) received ambulance HD clopidogrel. Ambulance HD clopidogrel was not independently associated with initial patency (TIMI-2/3-flow pre-PCI (odds ratio: 1.18, 95% confidence interval [CI] 0.96–1.44); however, it was associated with fewer recurrent myocardial infarctions at 30 days (hazard ratio [HR]: 0.45, 95% CI 0.22–0.93) and at one year (HR: 0.45, 95% CI 0.25–0.80). No difference in TIMI 2/3 flow post-PCI, major bleeding, mortality, MACE – and the combination of mortality and recurrent myocardial infarction at 30-days and at one year was present between the two groups. In conclusion, early in-ambulance as compared to in-hospital initiation of HD clopidogrel in STEMI patients did not improve initial patency of the IRV or clinical outcome, except for a reduction of recurrent myocardial infarction. Therefore, early administration of HD clopidogrel seems to have net clinical benefit for these patients .

Prasugrel vs clopidogrel in cardiogenic shock patients undergoing primary PCI for acute myocardial infarction

There is limited clinical data comparing different P2Y12-receptor inhibitors in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock. The aim of the ISAR-SHOCK registry was to compare the clinical outcome of patients treated with clopidogrel vs prasugrel in this setting. Patients (n=145) with AMI complicated by cardiogenic shock and undergoing primary PCI in two centres (Deutsches Herzzentrum München and Klinikum rechts der Isar, Technical University Munich) between January 2009 and May 2012 were included in this registry. The use of prasugrel for patients within this registry reflected co-morbidities and platelet function testing results during the acute AMI phase. Early outcome at 30-days was reported with regard to all-cause mortality, myocardial infarction (MI), stent thrombosis (ST) and bleeding events. With regard to antiplatelet treatment in the 145 cardiogenic shock patients, 50 patients were initially treated or immediately switched to prasugrel while 95 patients were treated with clopidogrel. All-cause mortality was lower in prasugrelvs clopidogrel-treated patients (30 % vs 50.5%, HR: 0.51, 95% CI [0.29–0.92], p=0.025). No significant differences in prasugrel- vs clopidogrel-treated patients were observed for the occurrence of MI (p=0.233), ST (p=0.306) or TIMI major bleedings (p=0.571). Results of the ISAR-SHOCK registry suggest that the use of prasugrel in AMI patients complicated by cardiogenic shock might be associated with a lower mortality risk as compared to clopidogrel therapy without increasing the risk of bleeding. These findings, however, need confirmation from specifically designed randomised studies in this high-risk cohort of patients.

Sarpogrelate Based Triple Antiplatelet Therapy Improved Left Ventricular Systolic Function in Acute Myocardial Infarction: Retrospective Study

PURPOSE

The purpose of this study was to assess the potential benefit of a 5-hydroxytryptamine receptor antagonist, sarpogrelate-based triple antiplatelet therapy (TAPT) in comparison with dual antiplatelet therapy (DAPT) in patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

119 patients of STEMI were retrospectively assessed. All patients received aspirin and clopidogrel per standard of care. Among them, 53 patients received an additional loading dose of sarpogrelate and a maintenance dose for 6 months post-PCI (TAPT group), while others did not (DAPT group).

RESULTS

The rates of complete ST-segment resolution at 30 minutes post-PCI and post-procedural thrombolysis in myocardial infarction flow were not significantly different between the two groups (52.8% vs. 48.5%, p=0.200; 92.5% vs. 89.4%, p=0.080). In addition, no significant differences were observed between the two groups with regard to 30-day and 12-month clinical outcomes (cardiac death, myocardial infarction, stent thrombosis, target vessel revascularization, and severe bleeding). Meanwhile, improvement in left ventricular (LV) systolic function was observed in the TAPT group [ΔLV ejection fraction (LVEF)=17.1±9.4%, p<0.001; Δglobal longitudinal strain (GLS)=-9.4±4.2% , p<0.001] at 6 months, whereas it was not in the DAPT group (ΔLVEF= 8.8±6.5%, p=0.090; ΔGLS=-4.6±3.4%, p=0.106). In multivariate analyses, TAPT was an independent predictor for LV functional recovery (odds ratio, 2.61; 95% confidence interval, 1.16-5.87; p=0.003).

CONCLUSION

Sarpogrelate-based TAPT improved LV systolic function at 6 months in STEMI patients undergoing primary PCI.

Antithrombotic therapy for acute coronary syndrome: Past, present and future

Plaque erosions and ruptures are the histopathological hallmarks of arterial thrombus formation in the coronary arteries. The clinical condition associated with this process is usually referred to as acute coronary syndrome (ACS). Importantly, both blood platelets and the coagulation cascade are key players for initiation, amplification and perpetuation of ACS. There has been great progress in ACS treatment in recent decades, both at the technical level of (percutaneous) revascularisation and at the level of antithrombotic treatment. Numerous trials have led to significant advancements in the development of effective anticoagulant and antiplatelet drugs. The large number of randomised controlled clinical trials (RCTs) and the huge number of patients enrolled in these RCTs, with mega trials including >10,000 patients, is unique in the history of medical research and also reflects the exceptional efforts associated with these huge research activities. The crucial issue, however, with respect to optimising treatment, relates to finding the delicate balance between the reduction of thrombotic events by effective drug treatment and the induction of bleeding that is linked to the use of potent or multiple antithrombotic agents. Interestingly, there is a gap in modern days between current guideline recommendations favouring potent platelet inhibition in ACS and the utilization of the respective drugs in clinical practice. In this review, we will summarise and discuss the past, present and future antithrombotic treatment for ACS patients with a focus on the development of optimised antiplatelet treatment strategies and their utilisation in the real world.

Safety and efficacy of policosanol in patients with high on-treatment platelet reactivity after drug-eluting stent implantation: two-year follow-up results

OBJECTIVES

To investigate safety and efficacy of policosanol in patients with high on-treatment platelet reactivity after drug-eluting stent implantation.

BACKGROUND

Certain number of patients has high residual platelet reactivity on clopidogrel after coronary intervention, and their risk of thrombotic events is high.

METHOD

In this prospective, randomized trial conducted in four Chinese sites, 350 patients with high on-treatment platelet reactivity (HPR, defined as platelet aggregation >65%) were randomized by the ratio of 1:3:3 to: group A, clopidogrel 75 mg/d for 1 year (n=50); group B, clopidogrel 150 mg/d for 30 days followed by 75 mg/d until 1 year (n=150); or group C, policosanol 40 mg/d for 6 month and clopidogrel 75 mg/d for 1 year (n=150). All of them were treated with aspirin. The primary endpoint was the reversion rate of HPR at 1 month (reversion was defined as platelet aggregation <65%). The secondary endpoints were 6-month major adverse cardiac events (MACE), which included cardiac death, nonfatal myocardial infarction, or ischemic symptoms driven target vessel revascularization.

RESULTS

At 30 days, the reversion rate of HPR was 34.0%, 55.2%, and 48.7% in group A, group B, and group C, respectively (P=.029). Major adverse cardiac events occurred in 4 (8.0%), 6(4.0%), and 5(3.3%) patients (P=.342). There was 1 (0.7%) major bleeding and 1 (0.7%) minor bleeding event in high maintenance dose clopidogrel group, no major or moderate bleeding in the other two groups. The minimal bleeding in group B was significantly higher than group C (10.7% vs 2.7%, P=.022). At 2-year follow-up, the benefits of policosanol on bleedings persisted compared with group B.

CONCLUSIONS

Policosanol reduced platelet reactivity to a similar extent as high maintenance dose of clopidogrel without increasing bleeding rate.

Safety and Efficacy of Acute Clopidogrel Load in Patients with Moderate and Severe Ischemic Strokes

Objective. To study the safety and efficacy of a clopidogrel loading dose in patients with moderate and severe acute ischemic strokes. Background. The safety of clopidogrel loading has been extensively investigated in patients with minor strokes and transient ischemic attacks. Methods. Acute ischemic stroke patients presenting consecutively to our center from 07/01/08 to 07/31/13 were screened. Clopidogrel loading was defined as at least 300 mg dose (with or without aspirin) given within 6 hours of admission. We compared outcomes in patients with baseline NIHSS > 3 with and without clopidogrel loading. Results. Inclusion criteria were met for 1011 patients (43.6% females, 69.1% black, median age 63). Patients with clopidogrel loading had lower baseline NIHSS than patients who were not loaded (8 versus 9, p = 0.005). The two groups had similar risk for hemorrhagic transformation (p = 0.918) and symptomatic hemorrhage (p = 0.599). Patients who were loaded had a lower rate of neurological worsening (38.9% versus 48.3%, p = 0.031) and less in-hospital mortality (4.3% versus 13.4%, p = 0.001) compared to those who were not loaded. The likelihood of having a poor functional outcome did not differ between the two groups after adjusting for NIHSS on admission (OR = 0.71, 95% CI 0.4633–1.0906, p = 0.118). Conclusion. Clopidogrel loading dose was not associated with increased risk for hemorrhagic transformation or symptomatic intracranial hemorrhage in our retrospective study and was associated with reduced rates of neuroworsening following moderate and severe stroke.

Intravenous administration of tirofiban versus loading dose of oral clopidogrel for preventing thromboembolism in stent-assisted coiling of intracranial aneurysms

Background Thromboembolic complications after stenting of intracranial aneurysms may be affected by antiplatelet administration. Aims This retrospective study aimed to assess the safety of intravenous tirofiban versus loading dose of oral clopidogrel for preventing thromboembolism in stent-assisted coiling of intracranial aneurysms. Methods From January 2006 to December 2013, 281 patients with cerebral aneurysms were treated with stent-coiling using two antiplatelet strategies in comparison: the initial strategy (a loading dose of ≥300 mg clopidogrel followed by dual antiplatelet, clopidogrel group) and the modified strategy (intravenous administration of tirofiban 8 µg/kg over 3 min followed by a maintenance dose of 0.1 µg/kg/min for 24 h, tirofiban group). The end points were rates of perioperative thromboembolic events and intracranial hemorrhages. Results Thromboembolic events were observed more often in the clopidogrel group (13/120 aneurysms, 10.83%) than the tirofiban group (6/178 aneurysms, 3.37%; P = 0.010), with no increase in the rate of intracranial hemorrhages ( P = 0.164). In the ruptured subgroups, thromboembolic events were significantly fewer in the tirofiban subgroup (5/128, 3.91%) compared with the clopidogrel subgroup (7/53, 13.21%; P = 0.043) with no increase in the rate of hemorrhage ( P = 0.360). Conclusions Intravenous administration of tirofiban is safe in intracranial aneurysms treated with stent-assisted coiling.

Safety and Efficacy of Intravenous Tirofiban as Antiplatelet Premedication for Stent-Assisted Coiling in Acutely Ruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE

Stent-assisted coiling of intracranial aneurysms requires antiplatelet therapy, typically aspirin and clopidogrel to prevent thromboembolic complications. There is a substantial concern that tirofiban may increase the risk of hemorrhage when used as an antiplatelet premedication in ruptured intracranial aneurysms. Our aim was to evaluate the safety and efficacy of intravenous tirofiban administration, instead of oral dual antiplatelet agents, as an antiplatelet premedication for stent-assisted coiling in patients with acutely ruptured intracranial aneurysms.

MATERIALS AND METHODS

We conducted a retrospective review of a data base containing a consecutive series of patients who underwent stent-assisted coiling for acutely ruptured intracranial aneurysms between March 2010 and January 2015. Intravenous tirofiban was administered to all patients before stent-assisted coiling, instead of premedication with loading doses of aspirin or clopidogrel.

RESULTS

Forty patients with 41 aneurysms received intravenous tirofiban and underwent stent-assisted coiling. None of the patients had a newly developed intracerebral hemorrhage, subarachnoid hemorrhage, or intraventricular hemorrhage. Intraprocedural aneurysmal rupture occurred in 2 patients (5%). Cerebral infarction developed in 2 patients (5%). Ventriculostomy-related hemorrhage was seen in 2 of 10 patients in whom ventriculostomy was performed before or after coiling. Thirty-four (85%) patients had a good outcome (Glasgow Outcome Score of 4 or 5) at the time of discharge, but 1 patient died of cardiac arrest. None of the patients developed thrombocytopenia, retroperitoneal, gastrointestinal, or genitourinary bleeding related to tirofiban administration.

CONCLUSIONS

In our study, tirofiban showed a low risk of symptomatic hemorrhagic or thromboembolic complications. Tirofiban may offer a safe and effective alternative as an antiplatelet premedication during stent-assisted coiling of acutely ruptured intracranial aneurysms.

Upstream clopidogrel, prasugrel, or ticagrelor for patients treated with primary angioplasty: Results of an angiographic randomized pilot study

OBJETIVES

The main objective of the present randomized pilot study was to explore the effects of upstream prasugrel or ticagrelor or clopidogrel for patients with ST-segment-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

BACKGROUND

Administration of clopidogrel "as soon as possible" has been advocated for STEMI. Pretreatment with prasugrel and ticagrelor may improve reperfusion. Currently, the angiographic effects of upstream administration of these agents are poorly understood.

METHODS

A total of 132 patients with STEMI within the first 12 hr of chest pain referred to primary angioplasty were randomized to upstream clopidogrel (600 mg), prasugrel (60 mg), or ticagrelor (180 mg) while still in the emergency room. All patients underwent protocol-mandated thrombus aspiration.

RESULTS

Macroscopic thrombus material was retrieved in 79.5% of the clopidogrel group, 65.9% of the prasugrel group, and 54.3% of the ticagrelor group (P = 0.041). At baseline angiography, large thrombus burden was 97.7% vs. 87.8% vs. 80.4% in the clopidogrel, prasugrel, and ticagrelor groups, respectively (P = 0.036). Also, at baseline, 97.7% presented with an occluded target vessel in the clopidogrel group, 87.8% in the prasugrel group and 78.3% in the ticagrelor group (P = 0.019). At the end of the procedure, the percentages of patients with combined TIMI grade III flow and myocardial blush grade III were 52.3% for clopidogrel, 80.5% for prasugrel, and 67.4% for ticagrelor (P = 0.022).

CONCLUSIONS

In patients with STEMI undergoing primary PCI within 12 hr, upstream clopidogrel, prasugrel or ticagrelor have varying angiographic findings, with a trend toward better results for the latter two agents. © 2015 Wiley Periodicals, Inc.

Safety and efficacy of a new prophylactic tirofiban protocol without oral intraoperative antiplatelet therapy for endovascular treatment of ruptured intracranial aneurysms

BACKGROUND

Coil embolization of intracranial aneurysms is being increasingly used; however, thromboembolic events have become a major periprocedural complication.

OBJECTIVE

To determine the safety and efficacy of prophylactic tirofiban in patients with ruptured intracranial aneurysms.

METHODS

Tirofiban was administered as an intravenous bolus (8.0 μg/kg over 3 min) followed by a maintenance infusion (0.10 μg/kg/min) before stent deployment or after completion of single coiling. Dual oral antiplatelet therapy (loading doses) was overlapped with half the tirofiban dose 2 h before cessation of the tirofiban infusion. Cases of intracranial hemorrhage or thromboembolism were recorded.

RESULTS

Tirofiban was prophylactically used in 221 patients, including 175 (79.19%) who underwent stent-assisted coiling and 46 (20.81%) who underwent single coiling, all in the setting of aneurysmal subarachnoid hemorrhage. Six (2.71%) cases of intracranial hemorrhage occurred, including four (1.81%) tirofiban-related cases and two (0.90%) antiplatelet therapy-related cases. There were two (0.90%) cases of fatal hemorrhage, one related to tirofiban and the other related to dual antiplatelet therapy. Thromboembolic events occurred in seven (3.17%) patients (6 stent-assisted embolization, 1 single coiling), of which one (0.45%) event occurred during stenting and six (2.72%) occurred during intravenous tirofiban maintenance. No thromboembolic events related to dual antiplatelet therapy were found.

CONCLUSIONS

Tirofiban bolus over 3 min followed by maintenance infusion appears to be a safe and efficient prophylactic protocol for the endovascular treatment of ruptured intracranial aneurysms and may be an alternative to intraoperative oral antiplatelet therapy, especially in the case of stent-assisted embolization.

Serial clopidogrel dose adjustment after platelet function testing improves outcome of acute coronary syndrome patients undergoing percutaneous coronary intervention with high on-treatment platelet reactivity

High on-treatment platelet reactivity (HTPR) on clopidogrel correlates with adverse outcomes in patients treated with percutaneous coronary intervention (PCI). Whether HTPR is a modifiable risk factor for future events is not clear. We evaluated the effect of serial clopidogrel dose adjustment based on platelet function testing (PFT) during 12 months of dual antiplatelet therapy (DAPT) using Multiplate) analyzer in patients with HTPR after PCI in acute coronary syndrome on clinical outcome. Eighty-seven patients were randomized to interventional (n = 43) and control group (n = 44). Blood samples for PFT were drawn at day 1, 2, 3, 7, 30 and at month 2, 3, 6, 9 and 12. Clopidogrel dose was modified at each point of PFT in the interventional group with patients taking up to two additional 600 mg loading doses and a range of 75-300 mg maintenance dose to achieve and maintain optimal platelet reactivity (19-46 U). The incidence of the primary endpoint (composite of cardiovascular death, non-fatal myocardial infarction, target vessel revascularization and ischemic stroke) was significantly higher in the control group (36.3 vs. 16.2%; p = 0.034). There were no differences in total bleeding events (6.8 vs. 4.6%, p = ns). Patients in the interventional group maintained better P2Y12 inhibition during follow-up. We hypothesize that targeting the therapeutic window of platelet reactivity continuously throughout DAPT by dose adjustment of P2Y12 inhibitor may lead to better platelet reactivity control, and thus reduce the rate of ischemic complications in this high risk group of patients.

A Randomized Study of the Safety, Tolerability, Pharmacodynamics, and Pharmacokinetics of Clopidogrel in Three Different CYP2C19 Genotype Groups of Healthy Japanese Subjects

AIM

We investigated the safety of 600/150 mg regimen of clopidogrel and the pharmacodynamics and pharmacokinetics of both 300/75 mg regimen and 600/150 mg regimen of clopidogrel in 72 Japanese subjects.

METHODS

A randomized study was conducted in healthy Japanese male subjects. Eligible subjects were stratified by dose regimen (300 mg loading dose of clopidogrel on day 1 followed by a 75 mg maintenance dose from days 2 to 7 or a 600 mg loading dose of clopidogrel on day 1 followed by a 150 mg maintenance dose from days 2 to 7) and CYP2C19 metabolizer group [extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs)]. Platelet aggregation and platelet reactivity were evaluated by measuring the maximum platelet aggregation intensity (MAI) induced by 5 and 20 μM ADP, phosphorylation of vasodilator-stimulated phosphoprotein (VASP), and P2Y12 reaction units (PRU) using the VerifyNow system, respectively. We also measured the plasma concentrations of clopidogrel and its active metabolite H4.

RESULTS

No treatment emergent adverse events in the 300/75 mg and 600/150 mg regimen were observed in EMs, IMs, and PMs. All CYP metabolizer groups exhibited a lower MAI (%) induced by ADP in the 300/75 mg and 600/150 mg clopidogrel regimens, and MAI (%) in IM group was equipotent to EM irrespective of the clopidogrel dosage. The double dose regimen decreased MAI in the PM group as equipotent to the IM group receiving the standard dose regimen without the extension of bleeding time. No clear relationship of exposure to clopidogrel and CYP2C19 function was observed, whereas active metabolite H4 exposure was likely to be related to CYP2C19 function.

CONCLUSION

Clopidogrel in the 600/150 mg regimen was well tolerated. All CYP metabolizer groups exhibited a lower MAI (%) induced by ADP and anti-platelet activities analyzed by VASP and VerifyNow test in the 300/75 mg and 600/150 mg regimens in healthy Japanese subjects.

The impact of therapeutic hypothermia on on-treatment platelet reactivity and clinical outcome in cardiogenic shock patients undergoing primary PCI for acute myocardial infarction: Results from the ISAR-SHOCK registry

INTRODUCTION

Mild therapeutic hypothermia (TH) is standard of care after cardiac arrest of any cause. However, its impact on on-treatment platelet reactivity and clinical outcome in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock and undergoing PCI with P2Y12 receptor inhibitor treatment is less clear.

METHODS AND RESULTS

For the ISAR-SHOCK registry, 145 patients with AMI, cardiogenic shock and primary PCI in two centers (Deutsches Herzzentrum München and Klinikum rechts der Isar, Technical University Munich) between January 2009-May 2012 were analysed. Of these, 64 (44%) patients received TH treatment. The median [IQR] ADP-induced platelet aggregation following thienopyridine loading dose administration (clopidogrel in 95 and prasugrel in 50 patients) did not differ between the two groups (419 [283-684] for TH vs. 355 [207-710] AU x min for non-TH patients, P=0.22). After 30days follow-up, no significant differences were observed between both groups for mortality (42 vs. 44 %, HR: 0.93, 95% CI [0.56-1.53], p=0.77), MI (6 vs. 6%, HR: 0.99 95% CI [0.27-3.7], p=0.99) and TIMI minor bleedings (17 vs. 17%, HR 0.99 95% CI [0.45-2.18], p=0.98). TIMI major bleedings were numerically higher in the TH vs. non-TH cohort (25 % vs. 12 %, HR: 2.1 95% CI [0.95-4.63], p=0.07). Three definite stent thrombosis (ST) were observed in this registry and all STs occurred in the TH group of patients (p=0.09).

CONCLUSION

Results of this registry suggest that TH does not negatively impact on platelet reactivity in shock patients receiving either clopidogrel or prasugrel. The numerically higher rate of major bleedings and the clustering of STs in the TH cohort warrant further investigation.

Outcome comparison of 600 mg versus 300 mg loading dose of clopidogrel for patients with ST-elevation myocardial infarction: a meta-analysis

BACKGROUND

A 600-mg loading dose (LD) of clopidogrel has been shown to be superior to a 300-mg LD in inhibiting platelet function. However, data for clinical superiority are limited, and there is a paucity of adequately powered randomized trials investigating this issue. This meta-analysis was performed to determine the optimal LD of clopidogrel in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention.

METHODS

A meta-analysis of controlled trials and observational studies was performed comparing 600-mg with 300-mg LDs of clopidogrel. The primary efficacy end point was a major adverse cardiac event (MACE), and the primary safety end point was major bleeding. Data were extracted on an intention to treat basis. The X2 test was used to evaluate heterogeneity. A random effects model was used, and odds ratios (OR) were calculated using the Mantel-Haenszel method.

RESULTS

Nine studies involving 18 623 patients were included in the efficacy analysis. Mean duration of follow-up was 8 months. Four studies were eligible for the safety analysis. The MACE risk was lower with a 600-mg LD (7.0% [650/9231]) than with a 300-mg LD (9.2% [867/9392]; OR, 0.75; 95% CI, 0.63-0.91). On the other hand, there was no significant difference in the major bleeding events between the 2 groups (2.5% [89/3551] with 600 mg vs 2.3% [63/2796] with 300 mg; OR, 0.84; 95% CI, (0.60-1.16).

CONCLUSIONS

In ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention, administration of a 600-mg LD of clopidogrel is associated with a lower risk of MACE than is administration of a 300-mg LD, without increasing the risk of major bleeding.

Anti-platelet agents augment cisplatin nanoparticle cytotoxicity by enhancing tumor vasculature permeability and drug delivery

Tumor vasculature is critically dependent on platelet mediated hemostasis and disruption of the same can augment delivery of nano-formulation based chemotherapeutic agents which depend on enhanced permeability and retention for tumor penetration. Here, we evaluated the role of Clopidogrel, a well-known inhibitor of platelet aggregation, in potentiating the tumor cytotoxicity of cisplatin nano-formulation in a murine breast cancer model. In vivo studies in murine syngeneic 4T1 breast cancer model showed a significant greater penetration of macromolecular fluorescent nanoparticles after clopidogrel pretreatment. Compared to self-assembling cisplatin nanoparticles (SACNs), combination therapy with clopidogrel and SACN was associated with a 4 fold greater delivery of cisplatin to tumor tissue and a greater reduction in tumor growth as well as higher survival rate. Clopidogrel enhances therapeutic efficiency of novel cisplatin based nano-formulations agents by increasing tumor drug delivery and can be used as a potential targeting agent for novel nano-formulation based chemotherapeutics.

Early high-dose rosuvastatin and cardioprotection in the protective effect of rosuvastatin and antiplatelet therapy on contrast-induced acute kidney injury and myocardial damage in patients with acute coronary syndrome (PRATO-ACS) study

BACKGROUND

There is a strong correlation between adverse clinical events and peak values of myocardial necrosis markers in non-ST-elevation acute coronary syndrome patients. In this clinical setting, high-dose statin treatment exerts acute beneficial effects against renal and myocardial damage. The aim of this report was to evaluate if, on admission, high-dose rosuvastatin can exert cardioprotective effects when administered in addition to high-dose clopidogrel.

METHODS

In the PRATO-ACS trial, 504 consecutive statin-naïve non-ST-elevation acute coronary syndrome patients scheduled for early invasive strategy and pretreated with high-dose clopidogrel were randomly assigned to rosuvastatin (40 mg on admission followed by 20 mg/d; statin group, n = 252) or no statin treatment (control group, n = 252). Serial myocardial biomarker samples were collected before and after angiography and/or percutaneous coronary intervention. The primary end point was the peak level of cardiac troponin I (cTnI) during the index event.

RESULTS

Statin-treated patients presented median cTnI peak values similar to controls (3.9 [0.6-12.8] vs 3.5 [1.2-11.9] ng/mL, respectively; P = .60]; no differences were found between the 2 groups in cTnI and creatine kinase-MB values at any time point, in either preangiography and postangiography peak values or their cumulative release. In patients submitted to percutaneous coronary intervention, periprocedural myocardial infarction occurred in 8 (4.7%) of 171 statin-treated and 7 (4.3%) of 162 control patients (P = .87).

CONCLUSION

In the PRATO-ACS trial, early high-dose rosuvastatin did not show cardioprotective effects when administered in addition to high-dose clopidogrel.

SAR216471, an alternative to the use of currently available P2Y₁₂ receptor inhibitors?

P2Y12 antagonism is a key therapeutic strategy in the management and prevention of arterial thrombosis. The objective of this study was to characterize the pharmacodynamic (PD) and pharmacokinetic (PK) properties of SAR216471, a novel P2Y12 receptor antagonist. SAR216471 blocks the binding of 2MeSADP to P2Y12 receptors in vitro (IC50=17 nM). This inhibition was shown to be reversible. It potently antagonized ADP-induced platelet aggregation in human and rat platelet-rich plasma (IC50=108 and 62 nM, respectively). It also inhibited platelet aggregation when blood was exposed to collagen or thromboxane A2. Its high selectivity was demonstrated against a large panel of receptors, enzymes, and ion channels. Despite its moderate bioavailability in rats, oral administration of SAR216471 resulted in a fast, potent, and sustained inhibition of platelet aggregation where the extent and duration of platelet inhibition were directly proportional to its circulating plasma levels. Pre-clinical study of SAR216471 in a rat shunt thrombosis model demonstrated a dose-dependent antithrombotic activity after oral administration (ED50=6.7 mg/kg). By comparison, ED50 values for clopidogrel, prasugrel and ticagrelor were 6.3, 0.35 and 2.6 mg/kg, respectively. Finally, the anti-hemostatic effect of SAR216471 and its competitors was investigated in a rat tail bleeding model, revealing a favorable safety profile of SAR216471. Together, these findings have established a reliable antiplatelet profile of SAR216471, and support its potential use in clinical practice as an alternative to currently available P2Y12 receptor antagonists.

Comparison of prasugrel and bivalirudin vs clopidogrel and heparin in patients with ST-segment elevation myocardial infarction: Design and rationale of the Bavarian Reperfusion Alternatives Evaluation (BRAVE) 4 trial

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for patients with ST-segment elevation myocardial infarction (STEMI). Effective and safe adjunct antithrombotic therapy is a major determinant for short- and long-term outcomes after primary PCI. Two separate studies have shown significant benefits vs conventional therapy for 2 recently approved drugs. In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, bivalirudin after pretreatment with clopidogrel resulted in improved net clinical outcome compared with heparin plus glycoprotein IIb/IIIa inhibitors. However, during the first 24 hours after PCI, there was an increase in stent thrombosis rates with bivalirudin. In the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis In Myocardial Infarction (TRITON-TIMI) 38 trial, prasugrel was superior to clopidogrel in patients with acute coronary syndrome with and without ST-segment elevation. The synergic actions of prasugrel and bivalirudin may maximize the benefit of antithrombotic therapy for STEMI patients undergoing primary PCI. However, no specifically designed studies have so far compared the combination of prasugrel plus bivalirudin with that of clopidogrel plus unfractionated heparin in these patients. The Bavarian Reperfusion Alternatives Evaluation (BRAVE) 4 study is a randomized, open-label, multicenter trial aimed to test the hypothesis that a strategy based on prasugrel plus bivalirudin is superior to a strategy based on clopidogrel plus unfractionated heparin in terms of net clinical outcome in STEMI patients with planned primary PCI.

Development of glycoprotein IIb–IIIa antagonists: translation of pharmacodynamic effects into clinical benefit

This article will review the development of glycoprotein IIb-IIIa antagonists, with particular emphasis on the characteristics and pharmacodynamic studies of each agent that is available for clinical use. Abciximab is a Fab fragment of the 7E3 antibody that has high affinity and a slow rate of dissociation from glycoprotein IIb-IIIa. In contrast, the small molecules eptifibatide and tirofiban, have a much more rapid rate of dissociation, with an off time of 10 to 15 s. Accordingly, the circulating pool of abciximab is predominantly associated with platelets, whereas maintenance of a consistent concentration of tirofiban and eptifibatide in the blood is critical in order to achieve and sustain their inhibitory effects. The affinity of abciximab and tirofiban for glycoprotein IIb-IIIa are substantially greater than that of eptifibatide, necessitating maintenance of greater molar concentrations of eptifibatide in blood in order to achieve effective inhibition of the binding of fibrinogen to the activated conformer of glycoprotein IIb-IIIa.

Combination of high on-treatment platelet aggregation and low deaggregation better predicts long-term cardiovascular events in PCI patients under dual antiplatelet therapy

High on-treatment platelet reactivity is associated with short-term major cardiovascular (CV) events in patients undergoing percutaneous coronary intervention (PCI). Maximum and final aggregation assessed by light transmission aggregometry (LTA) have both been used to predict short-term outcome after PCI, however their long-term prognostic impact remains controversial. There is currently no information regarding the prognostic role of deaggregation and its added value in combination with established aggregation parameters. About 1279 patients with symptomatic coronary artery disease (CAD) undergoing PCI were enrolled in this monocentric study. On-treatment platelet aggregation under clopidogrel maintenance therapy, as well as deaggregation was determined by maximum and final aggregation (5 min after adding of the agonist). Deaggregation was defined as slope of the tangent between Aggmax +0.5 min. Primary endpoints were the composite of myocardial infarction, stroke, and CV death or stent thrombosis according to the ARC criteria. Low deaggregation, defined as values in the lowest tertile (<1.5), was more frequent in patients with acute coronary syndromes (ACS) compared to patients with stable angina pectoris (SAP), ACS: 29.6% vs. SAP: 22.0%, p = 0.001. The combination of high on-treatment platelet reactivity, defined by the upper tertile of Aggmax and low deaggregation, was associated with significantly increased risk for combined long-term CV events. The combination of low deaggregation and high on-treatment platelet reactivity is associated with higher risk for recurrent events in patients with CAD undergoing PCI. Thus, deaggregation might be a more sensitive parameter providing added value in terms of risk prediction for long-term recurrent CV events in relation with established aggregation parameters.

Strategies of clopidogrel load and atorvastatin reload to prevent ischemic cerebral events in patients undergoing protected carotid stenting. Results of the randomized ARMYDA-9 CAROTID (Clopidogrel and Atorvastatin Treatment During Carotid Artery Stenting) study

OBJECTIVES

This study sought to evaluate whether a strategy with a 600-mg clopidogrel load and a short-term, high-dose atorvastatin reload would improve outcomes in clopidogrel-naïve, statin-treated patients undergoing protected carotid stenting.

BACKGROUND

Optimal clopidogrel loading dose during carotid stenting has not been investigated; in addition, statin neuroprotection in this setting has not been described.

METHODS

A total of 156 patients were randomized using a 2 × 2 factorial design to receive either a 600-mg (n = 78) or 300-mg (n = 78) clopidogrel load given 6 h before intervention and either a atorvastatin reload (n = 76; 80 mg + 40 mg initiating 12 h before the procedure) or no statin reload (n = 80). The primary endpoint was the 30-day incidence of transient ischemic attack/stroke or new ischemic lesions on cerebral diffusion-weighted magnetic resonance imaging performed at 24 to 48 h.

RESULTS

Occurrence of the primary outcome measure was significantly lower in the 600-mg clopidogrel arm (18% vs. 35.9% in the 300-mg group; p = 0.019) and in the atorvastatin reload arm (18.4% vs. 35.0% in the no statin reload group; p = 0.031). High-dose clopidogrel also significantly reduced the transient ischemic attack/stroke rate at 30 days (0% vs. 9%, p = 0.02, secondary endpoint), without an increase in bleeding risk.

CONCLUSIONS

In patients undergoing carotid stenting, a strategy using both a 600-mg clopidogrel load and a short-term reload with high-dose atorvastatin protects against early ischemic cerebral events. These results, obtained along with routine mechanical neuroprotection, provide new evidence of the optimization of drug therapy before percutaneous carotid intervention. (Clopidogrel and Atorvastatin Treatment During Carotid Artery Stenting [ARMYDA-9 CAROTID]; NCT01572623).