Advances In Antiplatelet Therapy Research Articles

456-P: Ongoing Knowledge Gaps in Antiplatelet Therapy for High-Risk Diabetes Patients with CAD

Patients with diabetes and coronary artery disease (CAD) are at increased risk for atherothrombotic events compared to CAD patients without diabetes. Current antiplatelet therapy may not be adequate in these high-risk patients, and several recent clinical trials have evaluated the use of more potent agents in this setting. Therefore, it is crucial to educate clinicians about their results and clinical practical implications. CMHC organized a CME virtual symposium to educate multi-disciplinary clinicians and assessed the changes in knowledge and competence using pre-/post assessment questions. A Chi-Square test was used to analyze the percentage of correct responses and determine statistical significance (p <0.05). The activity took place on Oct. 23, 2020, with participation of 263 healthcare professionals (MD/DO, PAs, RNs, NPs, PharmDs) representing specialties that treat high-risk diabetes patients with CAD (including 48% PCPs, 24% cardiologists, 23% endocrinologists). A slight increase in knowledge about recent clinical trial results was observed, though not statistically significant (9.2% relative increase in knowledge compared to baseline, p = 0.5). Conversely, a significant increase in competency in selecting correct treatment regimens to prevent adverse CVD events in high-risk diabetes patients with CAD was demonstrated (58% relative increased to baseline, p=.0002); however, only ~60% of participants opted for the correct option. According to post-activity evaluation (n=208), 29% identified insurance and financial issues, 28% identified formulary restriction, and 9% not knowing treatment-related adverse events as the primary barriers to implementing change in their practices. It is evident from the outcomes of this educational activity that there was a noticeable gap in attendee’s knowledge about advances in antiplatelet therapy in patients with diabetes and CAD. A series of educational activities is imperative to increase awareness and improve patient outcomes. Disclosure S. Karandrea: None. N. Agarwal: None. A. Jamrogiewicz: None. Funding AstraZeneca (62051961)

Pre-Hospital Antiplatelet Therapy for STEMI Patients Undergoing Primary Percutaneous Coronary Intervention: What We Know and What Lies Ahead.

Early recanalization of the infarct-related artery to achieve myocardial reperfusion is the primary therapeutic goal in patients with ST-elevation myocardial infarction (STEMI). To decrease the duration of ischaemia, continuous efforts have been made to improve pre-hospital treatment and to target the early period after symptom onset. In this period the platelet content of the fresh coronary thrombus is maximal and the thrombi are dynamic, and thus more susceptible to powerful antiplatelet agents. There have been substantial advances in antiplatelet therapy in the last three decades with several classes of oral and intravenous antiplatelet agents with different therapeutic targets, pharmacokinetics, and pharmacodynamic properties. New parenteral drugs achieve immediate inhibition of platelet aggregation, and fast and easy methods of administration may create the opportunity to bridge the initial gap in platelet inhibition observed with oral P2Y12 inhibitors. Moreover, potential future management of STEMI could directly involve patients in the process of care with self-administered antiplatelet agents designed to achieve rapid reperfusion. However, the potential anti-ischaemic benefits of potent antiplatelet agents will need to be balanced against their risk of increased bleeding. This study presents a comprehensive and updated review of pre-hospital antiplatelet therapy among STEMI patients undergoing primary percutaneous intervention and explores new therapies under development.

Dual-pathway inhibition for secondary and tertiary antithrombotic prevention in cardiovascular disease.

Advances in antiplatelet therapies for patients with cardiovascular disease have improved patient outcomes over time, but the challenge of balancing the risks of ischaemia and bleeding remains substantial. Moreover, many patients with cardiovascular disease have a residual risk of ischaemic events despite receiving antiplatelet therapy. Therefore, novel strategies are needed to prevent clinical events through mechanisms beyond platelet inhibition and with an acceptable associated risk of bleeding. The advent of non-vitamin K antagonist oral anticoagulants, which attenuate fibrin formation by selective inhibition of factor Xa or thrombin, has renewed the interest in dual-pathway inhibition strategies that combine an antiplatelet agent with an anticoagulant drug. In this Review, we highlight the emerging pharmacological rationale and clinical development of dual-pathway inhibition strategies for the prevention of atherothrombotic events in patients with different manifestations of cardiovascular disease, such as coronary artery disease, cerebrovascular disease and peripheral artery disease.

Advances in Antiplatelet Therapy for Dentofacial Surgery Patients: Focus on Past and Present Strategies.

Background: Nowadays, patients involved in antiplatelet therapy required special attention during oral surgery procedures, due to the antiplatelet drugs assumption. The motivations of the assumption may be different and related to the patient’s different systemic condition. For this reason, accordingly to the current international guidelines, different protocols can be followed. The aim of this work is to analyze how the dentist’s approach to these patients has changed from the past to the present, evaluating the risk exposure for the patients. Methods: This review paper considered different published papers in literature through quoted scientific channels, going in search of “ancient” works in such a way as to highlight the differences in the protocols undertaken. The analyzed manuscripts are in the English language, taking into consideration reviews, case reports, and case series in such a way as to extrapolate a sufficient amount of data and for evaluating the past therapeutic approaches compared to those of today. Results: Colleagues in the past preferred to subject patients to substitution therapy with low molecular weight anticoagulants, by suspending antiplatelet agents to treatment patients, often for an arbitrary number of days. The new guidelines clarify everything, without highlighting an increased risk of bleeding during simple oral surgery in patients undergoing antiplatelet therapy. Conclusion: Either patients take these medications for different reasons, because of cardiovascular pathologies, recent cardiovascular events, or even for simple prevention, although the latest research shows that there is no decrease of cardiovascular accidents in patients who carry out preventive therapy. Surely, it will be at the expense of the doctor to assess the patient’s situation and risk according to the guidelines. For simple oral surgery, it is not necessary to stop therapy with antiplatelet agents because the risk of bleeding has not increased, and is localized to a post-extraction alveolus or to an implant preparation, compared to patients who do not carry out this therapy. From an analysis of the results it emerges that the substitutive therapy should no longer be performed and that it is possible to perform oral surgery safely in patients who take antiplatelet drugs, after a thorough medical history. Furthermore, by suspending therapy, we expose our patients to more serious risks, concerning their main pathology, where present.

Cangrelor for the management and prevention of arterial thrombosis

ABSTRACTIntroduction: Despite advances in antiplatelet therapy, the optimum antithrombotic regimen during percutaneous coronary intervention (PCI) remains to be determined. Cangrelor is an intravenous, reversibly-binding platelet P2Y12 receptor antagonist with ultra-rapid onset and offset of action that is approved in Europe and United States for use in patients undergoing PCI. This article describes the background for the development of cangrelor, the biology, pharmacology and clinical evidence supporting its use, and its likely position in the future.Areas covered: The role of the platelet P2Y12 receptor in platelet biology and the implications of this for atherothrombotic disease are described. Currently unmet needs in antithrombotic management during and after PCI are discussed followed by a description of the chemistry, pharmacokinetics and pharmacodynamics of cangrelor, including its interactions with oral thienopyridines. Subsequently, the clinical trial evidence supporting its adoption into clinical practice is reviewed, including the evidence indicating its superiority over a strategy based on clopidogrel treatment alone.Expert commentary: The current status and future potential of cangrelor is discussed, including a view of its place in current clinical practice.

Use of novel antiplatelet agents in acute coronary syndromes.

Acute coronary syndromes (ACS) encompass a broad spectrum of clinical presentations based on underlying pathology that results in myocardial ischemia and/or infarction. Despite advancements in invasive management and secondary preventive therapies, recurrent atherothrombotic coronary events remain a prevalent cause of death and recurrent cardiac events after ACS and, in those who survive, the root of long-standing cardiac comorbidities. Antiplatelet drug therapy has proven beneficial in the reduction of these events, and novel antiplatelet agents have resulted in significant improvement in clinical outcomes over the last decade. However, the balance of optimal platelet inhibition with minimal bleeding complications remains a clinical challenge. This review focuses on more recent advances in antiplatelet therapies used in the treatment of ACS.

Ticagrelor-Associated Bleeding in a Patient Undergoing Surgery for Acute Type A Aortic Dissection

The recent review by Patel et al highlights the advances in antiplatelet therapy.1 In the dawn of the era of more potent antiplatelet therapy in the treatment of acute coronary syndromes (ACS), the impact of these novel drugs in patients in need of urgent surgery deserves further mention.

Novel Antiplatelet Therapies

Advances in antiplatelet therapy have significantly improved outcomes in patients with ischemic heart disease. Thienopyridines remain a cornerstone of therapy along with aspirin. Recently, concerns have been raised about the use of clopidogrel due to its pharmacokinetic and pharmacogenetic interpatient variability. A third-generation thienopyridine, prasugrel, overcomes some of these problems by improving inhibition of platelet aggregation, but increasing the risk of peri-procedural bleeding. Other novel antiplatelet agents, such as ticagrelor, have shown improved efficacy in recent trials and require further investigations. The field of pharmacotherapy continues to rapidly evolve as newer agents, such as thrombin receptor antagonists, along with older agents, such as cilostazol and glycoprotein IIb/IIIa inhibitors, are being explored.

Vascular PAR-1: Activity and Antagonism

Despite major advances in antiplatelet therapies, recurrent cardiovascular events remain high after acute coronary syndrome. Furthermore, incremental benefits achieved in the reduction of atherothrombotic events have almost always been at the expense of hemorrhagic side effects. Thrombin is the most potent platelet activating factor known and it makes important interactions with the endothelium and vascular smooth muscle with proinflammatory, proatherogenic effects. Distinct from its activity within the coagulation cascade, thrombin mediates these effects via protease-activated receptor type 1 (PAR-1) in man. This review discusses the role of PAR-1 in the vasculature and the development of novel PAR-1 antagonists. These drugs may provide important antiatherothrombotic effects without attendant bleeding complications and could represent a major breakthrough for the treatment of cardiovascular diseases.

In-stent restenosis associated with stent malapposition: Seven year optical coherence tomography findings

Stent thrombosis and in-stent restenosis remain significant issues in post-coronary angioplasty care despite advances in anti-platelet therapy and stent technology. Angiographic predictors of stent failure have been proposed, but its precise mechanism has been difficult to elucidate on conventional coronary angiography and intravascular ultrasound due to the low resolution of either approach. Optical coherence tomography (OCT) as a high-resolution intracoronary imaging modality has enabled more detailed insight into the interaction between implanted stent and underlying endothelium, the evolution of unstable plaque, and the pathogenesis of late lumen loss, affirming its place as an essential tool in the modern-day cardiac catheterisation laboratory. We present a case of in-stent restenosis seven years after bare-metal stent insertion, the mechanism of which was gross stent malapposition as clearly demonstrated on OCT examination.

Advances in Antiplatelet Therapy for Stroke Prevention: the New P2Y12 antagonists

Thrombus formation at a site of arterial injury (eg, rupture of an atherosclerotic plaque in a carotid artery), a crucial step in the pathogenesis of cerebral ischemia, is initiated by the adhesion of platelets to the arterial wall. In vivo, activated platelets release adenosine diphosphate (ADP), whose binding to the platelet P2Y12 receptor elicits progressive and sustained platelet aggregation. As a result, this receptor has been a target for the development of clinically effective antiplatelet agents, such as the thienopyridines ticlopidine and, more recently, clopidogrel, the only two currently FDA-approved P2Y12 antagonists. Clopidogrel has a well-established role as an antithrombotic agent in the setting of ischemic stroke. However, several challenges remain, including the relatively slow onset of action of this drug and the phenomenon of clopidogrel response variability or "resistance". A number of novel P2Y12 antagonists are therefore under investigation to determine whether they can result in better or more rapid antithrombotic effects than clopidogrel, without an unacceptable increase in hemorrhagic (or other) side effects. These include 1) prasugrel, an orally-administered thienopyridine prodrug, 2) ticagrelor (AZD6140), an ATP analog reversible P2Y12 antagonist, 3) cangrelor, an intravenously-administered reversible P2Y12 antagonist, and 4) PRT060128. Whether the promising pharmacological profile of these drugs will be translated into clinical benefit for stroke patients will be determined by the results of clinical trials.

Advances in Antiplatelet Therapy: Agents in Clinical Development

Antiplatelet agents are the cornerstone of treatment for patients with acute coronary syndromes and patients undergoing percutaneous coronary intervention. The current "gold standard" consists of a combination of aspirin and clopidogrel administered orally shortly before invasive procedures and then continued in the form of maintenance doses. Not all patients respond optimally to standard therapy. Resistance to the antiplatelet activity of both drugs when used either singly or in combination has been observed and may lead to treatment failure, including further atherothrombotic events. Potential limitations associated with the combined use of aspirin and clopidogrel have inspired clinical investigation into several promising new antiplatelet agents as potential additions or alternatives to standard therapy. The candidates include prasugrel, which has a mechanism similar to that of clopidogrel but with superior pharmacokinetics; ticagrelor, a nonthienopyridine that binds reversibly to the platelet P2Y(12) receptor; cangrelor, an intravenously administered analogue of ticagrelor; and various thrombin receptor antagonists.

Advances in Antiplatelet Therapy for ACS and PCI

Platelet activation and thrombin formation play significant roles in the pathophysiology of acute coronary syndrome. To overcome this pathophysiology, antiplatelet agents are utilized to decrease platelet aggregation and anticoagulants to decrease thrombin formation. Current antiplatelet agents are designed to inhibit various mediators of platelet activation, such as thromboxane A2 and adenosine diphosphate, and platelet-surface receptors (e.g., glycoprotein IIb/IIIa receptors). The rationale for upstream versus deferred administration of antiplatelet therapy in patients scheduled for percutaneous intervention and the current ACC/AHA guidelines for the management of patients with unstable angina/non-ST-segment myocardial infarction are discussed. The next-generation antiplatelet drugs are in various stages of clinical development, with unique differentiating mechanistic and pharmacokinetic properties. The newer P2Y12 thienopyridine receptor antagonists and protease receptor inhibitor are also examined, in addition to the rationale of various outcome studies evaluating the efficacy and safety of the different agents.

Advances in antiplatelet therapy: overview of new P2Y12 receptor antagonists in development

Platelets play an important role in thrombus formation. A number of new antiplatelet agents currently in development are anticipated to improve clinical outcomes and safety benefits in patients with acute coronary syndrome (ACS). This manuscript reviews the pharmacology and clinical development of three of these agents: prasugrel, cangrelor, and AZD6140. Prasugrel, a third-generation, oral thienopyridine, has been shown to be superior to clopidogrel, the current gold standard, in preventing ischaemic events in patients with ACS undergoing percutaneous coronary intervention (PCI), although the bleeding rate was higher. Cangrelor, a chemical analogue of adenosine triphosphate, is a potent direct platelet P2Y12 antagonist. In development as an intravenous agent, cangrelor is currently being evaluated in two phase III studies in patients requiring PCI. AZD6140 is the first of a novel new class of antiplatelet agents that inhibits adenosine diphosphate-induced platelet aggregation at the level of the P2Y12 receptor. AZD6140 was shown to have a good safety profile in phase II studies and is currently being studied in a phase III trial in patients with ACS.

Coronary stenting and abciximab in primary angioplasty for ST-segment-elevation myocardial infarction

Advances in anti-platelet therapy and improvement of stent deployment techniques have improved the safety and efficacy of stenting in the setting of ST-segment-elevation myocardial infarction (STEMI). However, in randomized trials, routine coronary stenting does not reduce mortality and re-infarction, compared to balloon angioplasty. Further, the benefits in target vessel revascularization seem to be reduced when applied to unselected patients with STEMI. Direct stenting represents an attractive strategy with potential benefits in terms of myocardial perfusion. Future large randomized trials are needed to evaluate whether this strategy has a significant impact on outcome, and to provide a cost-benefit analysis of the unrestricted use of drug-eluting stents in this high-risk subset of patients. The additional use of abciximab reduces mortality in primary angioplasty. Since the feasibility of long-distance transportation has been shown in several randomized trials, early pharmacological pre-treatment may confer further advantages by early recanalization and shorter ischaemic time, particularly in high-risk patients. Further randomized trials are needed to clarify the potential benefits from early abciximab administration and the potential role of small molecules in primary angioplasty for STEMI.

Scientific and therapeutic advances in antiplatelet therapy.

Over the past decade, the platelet has emerged as a pivotal entity in cardiovascular diseases. Indeed, the 'preeminence of the platelet' has spawned a variety of drugs that have been shown in large-scale randomized trials to improve patient outcomes in acute coronary syndromes and percutaneous revascularization procedures. Although the platelet was initially viewed only as a bystander in haemostasis, it is now evident that the platelet is in fact a key mediator of thrombosis as well as of inflammation. New insights at the cellular and genomic levels will probably generate novel drugs to inhibit platelet function more effectively and safely than previously possible.

Advances in antiplatelet therapy

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in the western world. These disorders share a common pathophysiology – atherosclerosis, which affects various arterial beds, leading to protean manifestations (coronary artery disease [CAD], stroke, peripheral arterial disease [PAD]). The platelet plays a pivotal role in the perpetuation and clinical expression of these disorders. The platelet, once believed to have a role confined to modulation of thrombosis and haemostasis, also plays an active role in vascular inflammation. Antiplatelet agents have become first-line therapy for CVD, and their unequivocal benefits are demonstrated in various basic and experimental models and supported by overwhelming evidence from clinical trials. Search is underway for more effective and safer antiplatelet therapy. Novel therapies are emerging to target the redundant pathways of platelet adhesion, activation and aggregation. Efforts are also ongoing to enhance implementation of existent therapy, target therapy selectively to high-risk patients and to those likely to respond (pharmacogenomics), and study the incremental benefits and safety of various antiplatelet combinations and their interaction with other medications in patients with CVD treated with polypharmacy.

Atherosclerosis: a unifying disorder with diverse manifestations.

The epidemiology, costs, and comorbidities associated with atherosclerosis and the role of newer antiplatelet agents are reviewed. Cardiovascular disease is the leading cause of death in the United States. More than 60 million Americans have one or more types of cardiovascular disease. The total annual cost of coronary heart disease has been estimated at $95 billion. Patients with an existing atherosclerotic disease in one vascular bed are at high risk of having an ischemic vascular event in the same or another vascular bed. Peripheral arterial disease is a strong marker for underlying cerebrovascular and cardiovascular disease. The common link among these diseases is atherosclerosis leading to atherothrombosis. Platelets play an integral role in atherosclerosis and the formation of arterial thrombus as well as in subsequent acute events such as ischemic stroke, myocardial infarction, and vascular death. Arterial thrombosis can be mediated by shear-stress-induced platelet aggregation. Currently, only one third to one half of all eligible patients with stroke, myocardial infarction, or peripheral arterial disease receive antiplatelet therapy. Thienopyridines such as ticlopidine and clopidogrel are effective inhibitors of shear-stress-induced and endothelial-injury-induced platelet aggregation. Advances in antiplatelet therapy provide an opportunity to use newer antiplatelet agents in the prevention of atherosclerosis-related morbidity and mortality; therapeutic approaches should be directed toward recognizing atherosclerosis as a generalized disease process and preventing ischemic events in multiple vascular beds.

Advances in Antiplatelet Therapy in Coronary Artery Disease: Importance of the Platelet GPIIb/IIIa Receptor

It is now widely agreed that platelets are intimately involved in and contribute to the pathogenesis of acute coronary thrombosis. Aspirin, a relatively weak inhibitor of platelet activation, saves lives when administered early after acute myocardial infarction and should be routinely used as lifelong therapy in patients with coronary atherosclerosis. Ticlopidine has a mechanism of action distinct from and additive to that of aspirin; it inhibits activation of platelets mediated by the agonist, adenosine diphosphate (ADP). The reduction in subacute coronary thrombosis attained by the use of combination therapy with aspirin and ticlopidine (for 2–4 weeks) after intracoronary stenting is further evidence of the role of platelets in mediating acute arterial thrombosis. Potent platelet agonists (like thrombin) can override the effect of aspirin and ticlopidine; therefore these agents are of limited efficacy. In contrast, inhibitors of the platelet glycoprotein (GP) IIb/IIIa receptor are potentially more potent inhibitors of adhesive platelet interaction and may therefore be effective in blocking adhesive platelet interactions irrespective of the activating agonist. The GPIIb/IIIa receptor mediates the bridging of platelets (platelet aggregation) via fibrinogen, thus allowing platelet to bind other platelets at the injured vessel wall. Antagonists of this receptor are thus capable of blocking the “effector function” by acting at a step that is downstream to platelet activation. By abrogating the final common pathway of platelet aggregation, antagonists of GPIIb/IIIa also affect the most proximal step in thrombin generation (that most efficiently occurs on the membrane surface provided by platelets). Accordingly, these agents can profoundly inhibit arterial thrombosis. The clinical use of the antibody fragment directed against the GPIIb/IIIa receptor (c7E3 Fab) has truly revolutionized the practice of interventional cardiology and has the potential to effectively treat heparin‐resistant intracoronary thrombosis. Synthetic antagonists of fibrinogen binding to the GPIIb/IIIa receptor (the “fibans”) are currently under initial clinical testing.

Recent advances in antiplatelet therapy

Aspirin is a highly successful antiplatelet drug; however, increased understanding of platelet