Case Study: Ticagrelor in PLATO and Prasugrel in TRITON-TIMI 38 and TRILOGY-ACS Trials in Patients With Acute Coronary Syndromes

SCAI Expert Consensus Statement on Management of In-Stent Restenosis and Stent Thrombosis

Stent failure remains the major drawback to the use of coronary stents as a revascularization strategy. Recent advances in imaging have substantially improved our understanding of the mechanisms underlying these occurrences, which have in common numerous clinical risk factors and mechanical elements at the time of stent implantation. In-stent restenosis remains a common clinical problem despite numerous improvements in-stent design and polymer coatings over the past 2 decades. It generates significant health care cost and is associated with an increased risk of death and rehospitalization. Stent thrombosis causes abrupt closure of the stented artery and therefore carries a high risk of myocardial infarction and death. This Society for Cardiovascular Angiography & Interventions (SCAI) Expert Consensus Statement suggests updated practical algorithmic approaches to in-stent restenosis and stent thrombosis. A pragmatic outline of assessment and management of patients presenting with stent failure is presented. A new SCAI classification that is time-sensitive with mechanistic implications of in-stent restenosis is proposed. Emphasis is placed on frequent use of intracoronary imaging and assessment of timing to determine the precise etiology because that information is crucial to guide selection of the best treatment option. SCAI recommends image-guided coronary stenting at the time of initial implantation to minimize the occurrence of stent failure. When in-stent restenosis and stent thrombosis are encountered, imaging should be strongly considered to optimize the subsequent approach.

A Review of the Role of the Antiplatelet Drug Ticagrelor in the Management of Acute Coronary Syndrome, Acute Thrombotic Disease, and Other Diseases

P2Y12 inhibitors, including aspirin, are key components of dual-antiplatelet therapy (DAPT), which is the optimal therapeutic strategy for preventing arterial thrombosis in patients with acute coronary syndromes (ACS) who underwent stent implantation. Ticagrelor is a cyclopentyl-triazole pyrimidine antiplatelet drug that was the first reversible oral P2Y12 receptor antagonist. Compared with clopidogrel, ticagrelor exerts a faster onset and offset of function by reversible and selective inhibition of platelet aggregation in ACS patients, including those with coronary artery blood revascularization. Despite improvement in stent materials, stent thrombosis (ST) due to high on-treatment platelet reactivity (HPR) to clopidogrel continues to occur. In addition to antiplatelet aggregation, ticagrelor displays pleiotropic cardioprotective effects, including improving coronary blood flow, reducing myocardial necrosis after an ischemic event, and anti-inflammatory effects. The benefits of ticagrelor over clopidogrel were consistent in the PLATO results, with lower incidence of the primary endpoint. Also, in 2020, the findings from the phase 3 THALES trial (NCT03354429) showed that aspirin combined with 90 mg of ticagrelor significantly reduced the rates of stroke and death compared with aspirin alone in patients with AIS or TIA. Here, we review recent research on the superiority of ticagrelor over clopidogrel, discuss the pharmacological mechanism, and present future perspectives. This review aims to present the roles of ticagrelor in the management of acute coronary syndrome, acute thrombotic disease, and other diseases.

Ticagrelor Utilization in Patients With Non-ST Elevation Acute Coronary Syndromes in Romania

BACKGROUND

Dual antiplatelet therapy (DAPT) represents a major tool of non-ST elevation acute coronary syndrome (NSTE-ACS) management. The real-world usage of potent P2Y12 inhibitors within DAPT in middle-income countries is poorly described.

STUDY QUESTION

To assess the factors that influence P2Y12 inhibitor choice at discharge in invasively managed NSTE-ACS patients, without an indication for oral anticoagulation, treated across Romania.

STUDY DESIGN

The Romanian National NSTE-ACS Registry allows the consecutive enrollment of NSTE-ACS patients admitted in 11 (of 24) interventional centers reimbursed from public funds.

MEASURES AND OUTCOMES

NSTE-ACS patients that received DAPT at discharge were identified. Deceased patients, those with an indication for oral anticoagulation or not receiving DAPT at discharge, were excluded. P2Y12 inhibitor choice was analyzed based on demographic, clinical, and invasive management characteristics.

RESULTS

One thousand fifty (63 ± 10 years, 73% male) of 1418 patients enrolled between 2016 and 2019 were analyzed. The P2Y12 inhibitor pretreatment rate was 90%. Obstructive coronary artery disease was found in 95.3% of patients. 84.6% underwent percutaneous coronary interventions (PCIs). Single vessel PCI was reported in 84% of PCI patients. The clopidogrel usage rate was 49.6%, ticagrelor 50.0%, and prasugrel 0.4%. Overall, higher ticagrelor usage was associated with: non-ST elevation myocardial infarction (P 0.035), age below 65 (P < 0.001), prior treatment with ticagrelor (P < 0.001), PCI during admission (P < 0.001), and its full 12-month reimbursement (since November 2017). Reimbursement increased the use of ticagrelor from 23.7% in 2016-2017 to 56.9% in 2018-2019 (P < 0.001). In PCI patients, ticagrelor use was associated with PCI with stenting (P 0.016) and multivessel PCI (0.013).

CONCLUSIONS

DAPT, P2Y12 inhibitor pretreatment, and single vessel PCI are the standards of care in invasively managed NSTE-ACS patients in Romania. Besides the clinical and invasive characteristics that favor its use, the full reimbursement of ticagrelor introduced in November 2017 doubled its yearly usage.

Involvement of P2 receptors in hematopoiesis and hematopoietic disorders, and as pharmacological targets

Several reports have shown the presence of P2 receptors in hematopoietic stem cells (HSCs). These receptors are activated by extracellular nucleotides released from different sources. In the hematopoietic niche, the release of purines and pyrimidines in the milieu by lytic and nonlytic mechanisms has been described. The expression of P2 receptors from HSCs until maturity is still intriguing scientists. Several reports have shown the participation of P2 receptors in events associated with modulation of the immune system, but their participation in other physiological processes is under investigation. The presence of P2 receptors in HSCs and their ability to modulate this population have awakened interest in exploring the involvement of P2 receptors in hematopoiesis and their participation in hematopoietic disorders. Among the P2 receptors, the receptor P2X7 is of particular interest, because of its different roles in hematopoietic cells (e.g., infection, inflammation, cell death and survival, leukemias and lymphomas), making the P2X7 receptor a promising pharmacological target. Additionally, the role of P2Y12 receptor in platelet activation has been well-documented and is the main example of the importance of the pharmacological modulation of P2 receptor activity. In this review, we focus on the role of P2 receptors in the hematopoietic system, addressing these receptors as potential pharmacological targets.

Ticagrelor Use in Indian Patients Undergoing Neuroendovascular Procedures: A Single Center Experience

PURPOSE

A safe and efficacious antiplatelet drug is needed for patients with clopidogrel resistance who undergo neuroendovascular procedures. Ticagrelor is a new reversibly binding, oral, direct-acting P2Y receptor antagonist with no known resistance. We describe our clinical experience using ticagrelor for neuroendovascular procedures in Indian patients with clopidogrel resistance at the NH Institute of Neurosciences, Narayana Health City, Bangalore.

MATERIALS AND METHODS

We retrospectively reviewed our endovascular procedure database for all patients with predefined clopidogrel resistance. Clopidogrel resistance was defined as P2Y12 inhibition <40%. Patients were administered ticagrelor along with aspirin prior to the procedure.

RESULTS

Of 127 patients, 32 (25%) were non-responders to clopidogrel (22 [69%] males, 10 [31%] females; median age, 54 years [range, 20-75]). All patients were treated with a 180-mg loading dose of ticagrelor, followed by 90 mg twice daily. Twenty patients (63%) underwent endovascular intervention for intracranial aneurysm, two (6%) for dissecting aneurysms, nine (28%) for stenotic lesions, and one (3%) for carotico-cavernous fistula. No patient experienced any adverse effects related to the use of Ticagrelor in the postoperative period.

CONCLUSION

Ticagrelor is an effective alternative to clopidogrel for use in conjunction with aspirin in patients with clopidogrel resistance. None of our patients had adverse effects from ticagrelor. Drug cost, twice-daily dosing, and risk of faster platelet aggregation activation after discontinuation should be taken into consideration prior to its use in such patients.

Comparison of Ticagrelor and Clopidogrel for Patients Undergoing Emergency Percutaneous Coronary Intervention

BACKGROUND

We compared treatments with the antiplatelets ticagrelor and clopidogrel used in patients with acute myocardial infarction (AMI) during the perioperative period for emergency percutaneous coronary intervention (PCI).

METHODS

A total of 120 patients were selected and randomly divided into control and observation groups (60 patients in each) from 2014-2016 at The Affiliated Hospital of Qingdao University. The patients in the control group received 300 mg clopidogrel and 300 mg aspirin for oral administration, while those in the observation group were given 180 mg ticagrelor and 300 mg aspirin orally prior to the PCI. During the operation, heparinization and a tirofiban micro-pump were used continuously.

RESULTS

Coronary artery and peripheral venous blood were extracted from each patient to obtain various parameters of thrombelastogram (TEG), and the maximum platelet aggregation rates in order to compare antiplatelet effects. Major adverse cardiac events (MACE) were recorded during the following 6-month follow-up. Analysis of the data showed no differences in terms of the time span between medication intake and stent implantation, or the dosage of heparin and tirofiban used between the two groups. Before stent implantation, and 24 and 48 h after the procedure the average R and K values of TEG in coronary artery blood and peripheral venous blood samples in the observation group were longer than those in the control group, while the α angle, MA, CI, MARAA and MARADP values were lower (P<0.05).

CONCLUSION

Ticagrelor can improve antiplatelet treatment for patients with AMI during the perioperative period of emergency PCI.

Association of different antiplatelet therapies with mortality after primary percutaneous coronary intervention

OBJECTIVES

Prasugrel and ticagrelor both reduce ischaemic endpoints in high-risk acute coronary syndromes, compared with clopidogrel. However, comparative outcomes of these two newer drugs in the context of primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) remains unclear. We sought to examine this question using the British Cardiovascular Interventional Society national database in patients undergoing primary PCI for STEMI.

METHODS

Data from January 2007 to December 2014 were used to compare use of P2Y12 antiplatelet drugs in primary PCI in >89 000 patients. Statistical modelling, involving propensity matching, multivariate logistic regression (MLR) and proportional hazards modelling, was used to study the association of different antiplatelet drug use with all-cause mortality.

RESULTS

In our main MLR analysis, prasugrel was associated with significantly lower mortality than clopidogrel at both 30 days (OR 0.87, 95% CI 0.78 to 0.97, P=0.014) and 1 year (OR 0.89, 95% CI 0.82 to 0.97, P=0.011) post PCI. Ticagrelor was not associated with any significant differences in mortality compared with clopidogrel at either 30 days (OR 1.07, 95% CI 0.95 to 1.21, P=0.237) or 1 year (OR 1.058, 95% CI 0.96 to 1.16, P=0.247). Finally, ticagrelor was associated with significantly higher mortality than prasugrel at both time points (30 days OR 1.22, 95% CI 1.03 to 1.44, P=0.020; 1 year OR 1.19 95% CI 1.04 to 1.35, P=0.01).

CONCLUSIONS

In a cohort of over 89 000 patients undergoing primary PCI for STEMI in the UK, prasugrel is associated with a lower 30-day and 1-year mortality than clopidogrel and ticagrelor. Given that an adequately powered comparative randomised trial is unlikely to be performed, these data may have implications for routine care.

Adequate Platelet Function Inhibition Confirmed by Two Inductive Agents Predicts Lower Recurrence of Ischemic Stroke/Transient Ischemic Attack

Background

The correlation between platelet function and recurrent ischemic stroke or TIA remains uncertain.

Objective

To investigate two inductive agents to detect platelet functions and assess associations with recurrent ischemic stroke/TIA.

Method

The study included 738 ischemic stroke/TIA patients. On days 0, 3, and 9 after antiplatelet therapy, platelet function tests were determined by maximum aggregation rate (MAR) using a PL-11 platelet function analyzer and phase matching reagents. Two induction agents were used: arachidonic acid (AA) and adenosine diphosphate (ADP). At 3-month follow-up, recurrence of stroke/TIA was recorded.

Result

Cut-off values of adequate platelet function inhibition were MAR_ADP < 35% and MAR_AA < 35%. Data showed that antiplatelet therapy could reduce the maximum aggregation rate. More importantly, adequate platelet function inhibition of either MAR_ADP or MAR_AA was not associated with the recurrence of stroke/TIA, but adequate platelet function inhibition of not only MAR_ADP but also MAR_AA predicts lower recurrence (0/121 (0.00%) versus 18/459 (3.92%), P = 0.0188).

Conclusion

The platelet function tested by PL-11 demonstrated that adequate inhibition of both MAR_ADP and MAR_AA could predict lower risk of ischemic stroke/TIA recurrence.