Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

Use of Glycoprotein IIb-IIIa Inhibitors in Patients Undergoing Carotid Artery Stenting in the Vascular Quality Initiative

BACKGROUND

Antiplatelet therapies with thromboxane inhibitors and adenosine 5'-diphosphate antagonists have been widely used following carotid artery stenting (CAS). However, these therapies may not apply to patients who are intolerant or present acutely. Glycoprotein IIb/IIIa inhibitors (GPI) are a proposed alternative therapy in these patients; however, their use has been limited due to concerns of increased risk for intracranial bleeding. Thus, this study aims to assess the safety profile of GPI in patients undergoing CAS.

METHODS

All patients undergoing CAS in the Society of Vascular Surgery - Vascular Quality Initiative database from 2012 to 2021 was included and grouped into GPI versus non-GPI therapy (control). The primary outcome was in-hospital stroke or death, and secondary outcomes included in-hospital stroke/transient ischemic attack (TIA), death, myocardial infarction, and intracranial hemorrhage (ICH)/seizure. Patients were stratified by surgical approach (Transcarotid artery revascularization using flow reversal (TCAR) and transfemoral carotid artery stenting), and stepwise backward logistic regression analysis was conducted to evaluate major primary and secondary outcomes.

RESULTS

A total of 50,628 patients underwent carotid revascularization. Of these, 4.4% of the patients received GPI. Mean age was similar between control versus GPI (71.35(9.67) vs. 71.36(10.20) years). Compared to the control group, patients who receive GPI are less likely to be on optimal medical therapy, including aspirin (83.0% vs. 88.1%), P2Y12 inhibitor (73.0% vs. 82.7%), and statin (82.3% vs. 86.0%) (All P < 0.05). In addition, patients in the GPI group were more likely to undergo TCAR for carotid revascularization (52.2% vs. 48.4%) for emergent/urgent (29.4% vs. 16.8%) and symptomatic indications (55.5% vs. 49.7%) (All P < 0.001). After stratifying by surgical approach, if patients underwent TFCAS and received a GPI, they were at increased odds of developing stroke/death (1.77(1.25-2.51)), death (odds ratio (OR) (95% CI): 1.67(1.07-2.61)), stroke/TIA (OR (95% confidence interval (CI)): 1.65(1.09-2.51)), and ICH/seizure (OR (95% CI): 2.13(1.23-3.68)) (All P < 0.05). No difference was seen in outcomes between the 2 groups if undergoing TCAR.

CONCLUSIONS

Patients who receive GPI were more likely to be symptomatic at presentation and less likely to be medically optimized before their carotid revascularization. Transfemoral access in patients receiving GPI was associated with increased odds of morbidity and mortality. However, this was not observed if undergoing TCAR. TCAR can be considered for its overall favorable results in high-risk patients who are not medically optimized.

Vascular thiol isomerases: Structures, regulatory mechanisms, and inhibitor development

Vascular thiol isomerases (VTIs), including PDI, ERp5, ERp57, ERp72, and thioredoxin-related transmembrane protein 1 (TMX1), have important roles in platelet aggregation and thrombosis. Research on VTIs, their substrates in thrombosis, their regulatory mechanisms, and inhibitor development is an emerging and rapidly evolving area in vascular biology. Here, we describe the structures and functions of VTIs, summarize the relationship between the vascular TIs and thrombosis, and focus on the development of VTI inhibitors for antithrombotic applications.

Biomechanical thrombosis: the dark side of force and dawn of mechano-medicine

Arterial thrombosis is in part contributed by excessive platelet aggregation, which can lead to blood clotting and subsequent heart attack and stroke. Platelets are sensitive to the haemodynamic environment. Rapid haemodynamcis and disturbed blood flow, which occur in vessels with growing thrombi and atherosclerotic plaques or is caused by medical device implantation and intervention, promotes platelet aggregation and thrombus formation. In such situations, conventional antiplatelet drugs often have suboptimal efficacy and a serious side effect of excessive bleeding. Investigating the mechanisms of platelet biomechanical activation provides insights distinct from the classic views of agonist-stimulated platelet thrombus formation. In this work, we review the recent discoveries underlying haemodynamic force-reinforced platelet binding and mechanosensing primarily mediated by three platelet receptors: glycoprotein Ib (GPIb), glycoprotein IIb/IIIa (GPIIb/IIIa) and glycoprotein VI (GPVI), and their implications for development of antithrombotic 'mechano-medicine' .

Novel Pure αVβ3 Integrin Antagonists That Do Not Induce Receptor Extension, Prime the Receptor, or Enhance Angiogenesis at Low Concentrations

The integrin αVβ3 receptor has been implicated in several important diseases, but no antagonists are approved for human therapy. One possible limitation of current small-molecule antagonists is their ability to induce a major conformational change in the receptor that induces it to adopt a high-affinity ligand-binding state. In response, we used structural inferences from a pure peptide antagonist to design the small-molecule pure antagonists TDI-4161 and TDI-3761. Both compounds inhibit αVβ3-mediated cell adhesion to αVβ3 ligands, but do not induce the conformational change as judged by antibody binding, electron microscopy, X-ray crystallography, and receptor priming studies. Both compounds demonstrated the favorable property of inhibiting bone resorption in vitro, supporting potential value in treating osteoporosis. Neither, however, had the unfavorable property of the αVβ3 antagonist cilengitide of paradoxically enhancing aortic sprout angiogenesis at concentrations below its IC50, which correlates with cilengitide's enhancement of tumor growth in vivo.

Platelets in cardiac ischaemia/reperfusion injury: a promising therapeutic target

Acute myocardial infarction (AMI) is the single leading cause of mortality and morbidity worldwide. A key component of AMI therapy is the timely reopening of occluded vessels to prevent further ischaemic damage to the myocardium. However, reperfusion of the ischaemic myocardium can itself trigger reperfusion injury causing up to 50% of the overall infarct size. In recent years, considerable research has been devoted to understanding the pathogenesis of ischaemia/reperfusion (I/R) injury and platelets have emerged as a major contributing factor. This review summarizes the role of platelets in the pathogenesis of I/R injury and highlights the potential of platelet-directed therapeutics to minimize cardiac I/R injury. Activated platelets infiltrate specifically into the ischaemic/reperfused myocardium and contribute to I/R injury by the formation of microthrombi, enhanced platelet-leucocyte aggregation, and the release of potent vasoconstrictor and pro-inflammatory molecules. This review demonstrates the benefits of platelet inhibition beyond their well-described anti-thrombotic effect and highlights the direct cardioprotective role of anti-platelet drugs. In particular, the inhibition of COX, the P2Y12 receptor and the GPIIb/IIIa receptor has demonstrated the potential to attenuate I/R injury. Moreover, targeting of drug candidates or regenerative cells to the activated platelets accumulated within the ischaemic/reperfused myocardium shows remarkable potential to protect the myocardium from I/R injury. Overall, activated platelets play a key role in the pathogenesis of I/R injury. Their direct inhibition as well as their use as epitopes for site-directed therapy is a unique and promising therapeutic approach for the prevention of I/R injury and ultimately the preservation of cardiac function.

The Transradial Approach and Antithrombotic Therapy: Rationale and Outcomes

This article reviews antithrombotic strategies for percutaneous coronary interventions according to the access site and the current evidence with the aim of limiting ischemic complications and preventing radial artery occlusion (RAO). Prevention of RAO should be part of the quality control of any radial program. The incidence of RAO postcatheterization and interventions should be determined initially using the echo-duplex and then frequently assessed using the more cost-effective pulse oximetry technique. Any evidence of higher risk of RAO should prompt internal analysis and multidisciplinary mechanisms to be put in place.