Determinants of high on-treatment platelet reactivity and agreement between VerifyNow and Multiplate assays

Randomized, Double-Blind, Active Comparator Pharmacodynamic Study of Platelet Inhibition with Crushed and Integral Formulations of Clopidogrel and Ticagrelor in Acute Coronary Syndrome

BACKGROUND

Crushed formulations of specific antiplatelet agents produce earlier and stronger platelet inhibition. We studied the platelet inhibitory effect of crushed clopidogrel in patients with acute coronary syndrome (ACS) and its relative efficacy compared with integral clopidogrel, crushed and integral ticagrelor.

OBJECTIVES

We aimed to compare the platelet inhibitory effect of crushed and integral formulations of clopidogrel and ticagrelor in patients with acute coronary syndrome (ACS).

METHODS

Overall, 142 patients with suspected ACS were randomly assigned to receive crushed or integral formulations of clopidogrel or ticagrelor. Platelet inhibition at baseline and 1 and 8 h was assessed using the VerifyNow assay. High on-treatment platelet reactivity (HTPR) ≥ 235 P2Y₁₂ reaction units (PRUs) 1 h after the medication loading dose was also determined.

RESULTS

The PRU and percentage inhibition median (interquartile range) at 1 h for the different formulations were as follows: crushed clopidogrel: 196.50 (155.50, 246.50), 9.36 (- 1.79, 25.10); integral clopidogrel: 189.50 (159.00, 214.00), 2.32 (- 2.67, 19.89); crushed ticagrelor: 59.00 (10.00, 96.00), 75.53 (49.12, 95.18); and integral ticagrelor: 126.50 (50.00, 168.00), 40.56 (25.59, 78.69). There was no significant difference in PRU or percentage platelet inhibition between the crushed and integral formulations of clopidogrel (p = 0.990, p = 0.479); both formulations of ticagrelor were superior to the clopidogrel formulations (p < 0.05). On paired comparison, crushed ticagrelor showed robust early inhibition of platelets compared with the integral formulation (p = 0.03). Crushed clopidogrel exhibited the maximal HTPR of 34.3%, but was < 3% for both formulations of ticagrelor.

CONCLUSIONS

The platelet inhibitory effect of crushed clopidogrel is not superior to integral preparation in patients with ACS. Crushed ticagrelor produced maximal platelet inhibition acutely. HTPR rates in ACS are similar and very low with both formulations of ticagrelor, and maximal with crushed clopidogrel. Clinical Trials Registry of India identifier number CTRI/2020/06/025647.

Sex-stratified differences in early antithrombotic treatment response in patients presenting with ST-segment elevation myocardial infarction

BACKGROUND

The mechanisms underlying the increased risk of bleeding that female patients with ST-segment Elevation Myocardial Infarction (STEMI) exhibit, remains unclear. The present report assessed sex-related differences in response to pre-hospital dual antiplatelet therapy (DAPT) initiation in patients with STEMI.

METHODS

The COMPARE CRUSH trial randomized patients presenting with STEMI to receive a pre-hospital loading dose of crushed or integral prasugrel tablets in the ambulance. In this substudy, we compared platelet reactivity levels and the occurrence of high platelet reactivity (HPR; defined as platelet reactivity ≥208) between sexes at 4 prespecified time points after DAPT initiation, and evaluated post-PCI bleeding between groups.

RESULTS

Out of 633 STEMI patients, 147 (23%) were female. Females compared with males presented with significantly higher levels of platelet reactivity and higher HPR rates at baseline (232 [IQR, 209-256] vs 195 [IQR, 171-220], P < .01, and 76% vs 41%, OR 4.58 [95%CI, 2.52-8.32], P < .01, respectively). Moreover, female sex was identified as the sole independent predictor of HPR at baseline (OR 5.67 [95%CI, 2.56-12.53], P < .01). Following DAPT initiation, levels of platelet reactivity and the incidence of HPR were similar between sexes. Post-PCI bleeding occurred more frequently in females compared with males (10% vs 2%, OR 6.02 [95%CI, 2.61-11.87], P < .01). Female sex was an independent predictor of post-PCI bleeding (OR 3.25 [95%CI, 1.09-9.72], P = .04).

CONCLUSIONS

In this contemporary STEMI cohort, female STEMI patients remain at risk of bleeding complications after primary PCI. However, this is not explained by sex-specific differences in the pharmacodynamic response to pre-hospital DAPT initiation.

Ticagrelor and primidone interaction masquerading as dual antiplatelet therapy noncompliance

Ticagrelor and aspirin is a common dual antiplatelet therapy regimen for patients who undergo percutaneous coronary intervention. Despite its ability to significantly reduce cardiovascular complications, ticagrelor response may be altered by other medications causing subtherapeutic effects. Traditionally, ticagrelor is thought to have fewer drug-drug interactions compared to other thienopyridine antiplatelet medications such as clopidogrel. Primidone, metabolized into phenobarbital, is a strong CYP-3A inducer that can reduce serum concentrations of ticagrelor resulting in ineffective antiplatelet therapy. We present a 67-year-old male who suffered in-stent thrombosis after percutaneous intervention possibly due to the interaction between primidone and ticagrelor.

Long Noncoding RNA_Plasmacytoma Variant Translocation 1 (LncRNA_PVT1) Regulates the Biological Behaviors of Bone Marrow Mesenchymal Stem Cells (BMSC) to Promote Cervical Cancer Growth Through miR-266

To discuss the biological mechanism of lncRNA PVT1 on regulating BMSC and prompting the HPV growth through miR-266. The correlation between presentation of lncRNA PVT1 and HPV was analyzed. The HPV cells were transfected with lncRNA PVT1. The transfection efficiency was tested. These cells were detected through CCK8 test. The action of lncRNA PVT1 on the HPV cells’ cycle and apoptotic rate was tested with FCM. The correlation between lncRNA PVT1 and miR-266 was analyzed through Pearson correlation analysis. The presentation of mRNA was tested by RT-PCR. The presentation level of miR-266 in BMSC and HPV cells was analyzed through PCR. The presentation of lncRNA PVT1 in HPV tissue and cell was increased notably. The apoptotic rate was increased and proliferative rate was reduced through the transfection with lncRNA PVT1. The miR-266 was one kind of gene with differential presentation. It was reduced notably in HPV cells. There was negative correlation between lncRNA PVT1 and miR-266. The proliferation of HPV cells was related closely with the increasing of the presentation of lncRNA PVT1. The gene presentation could be affected through the targeted interaction with miR-266. It was conducive to BMSC growing into HPV. It could provide target spot for the prevention and control for HPV.

Comparison of three common whole blood platelet function tests for in vitro P2Y12 induced platelet inhibition

In the context of interventional cardiology, platelet function testing may identify patients treated with P2Y12-inhibitors at an increased risk of mortality, thrombosis and bleeding. Several whole blood point-of-care platelet function analyzers are available; however, inter-device differences have not been examined systematically. To compare three platelet function tests under standardized in vitro conditions. Healthy volunteer (n = 10) blood samples were spiked with increasing concentrations of ticagrelor (0–7500 ng/mL) and/or ASA (0–3280 ng/mL), measured on three platelet function analyzers (TEG^®6s, Multiplate^®, and VerifyNow^®) and respective Effective Concentration (EC) levels EC10, EC50 and EC90 were calculated. Repeatability was assessed in a separate group of pooled blood samples (n = 10) spiked with ticagrelor at EC10, EC50 and EC90. ASA had no impact on ADP-activated channels for all three devices. TEG^®6s was able to distinguish (p ≤ 0.05) between all ticagrelor EC zones; VerifyNow^® and Multiplate^® were able to distinguish between three and two zones, respectively. Multiplate^® showed the largest window between EC10 and EC90 (19–9153 ng/mL), followed by TEG^®6s (144–2589 ng/mL), and VerifyNow^® (191–1100 ng/mL). Drug effect models distribution of disagreements were identified for TEG^®6s (5.0%), VerifyNow^® (8.3%), and Multiplate^® (13.3%). TEG^®6s showed the smallest average coefficient of variation between EC conditions (5.1%), followed by Multiplate^® (14.1%), and VerifyNow^® (17.7%). Linear models could be generated between TEG^®6s and Multiplate^®, but not VerifyNow^®. Significant differences were found between whole blood point-of-care platelet function analyzers and the clinical impact of these differences needs to be further investigated.

Estimating short- and long-term reference change values and index of individuality for tests of platelet function

BACKGROUND

In order to manage risks of bleeding and thrombosis after some surgical procedures, platelet function is often measured repeatedly over days or weeks using laboratory tests of platelet function. To interpret test results in the perioperative period, it is necessary to understand analytical, biological and between-person variation.

METHODS

We collected three separate blood specimens from 16 healthy volunteers on the first study day, and one additional specimen from each volunteer 1, 2, and 3 months later. Arachidonic acid-induced and adenosine diphosphate (ADP)-induced platelet function were measured in duplicate by whole blood impedance aggregometry using Multiplate (ASPI/ADP tests) and VerifyNow (Aspirin Reaction Units [ARU] and P2Y12 Reaction Units [PRU]). The analytical variation (CV_A), within-subject variation (CV_I), between-subject variation (CV_G), index of individuality (II), and reference change values (RCV) were calculated.

RESULTS

VerifyNow ARU demonstrated the smallest short-term and long-term variability (CV_A, CV_I, and CV_G ~1%), resulting in short- and long-term RCV values <5%. II was also higher (1.92) for VerifyNow ARU than other platelet function tests. Multiplate ASPI and ADP tests had the highest RCV both short-(19.0% and 25.2%, respectively) and long-term (32.1% and 39.6%, respectively) due to increased CV_A (>5%) and CV_I (3.9-13.1%). VerifyNow PRU had a lower RCV than Multiplate ADP; but was the only test with II <0.6.

CONCLUSIONS

VerifyNow ARU results can be interpreted relative to a fixed cut-off or population-based reference interval; or relative to small changes in an individual's previous values. VerifyNow PRU and Multiplate ASPI and ADP tests should only be interpreted based upon relative change; and can only distinguish relatively large (>23%) changes over several weeks.

High and low on-treatment platelet reactivity to P2Y12 inhibitors in a contemporary cohort of acute coronary syndrome patients undergoing percutaneous coronary intervention

INTRODUCTION

There is compelling evidence supporting the association between high on-treatment platelet reactivity (HPR) and low on-treatment platelet reactivity (LPR) to clopidogrel with atherothrombotic and bleeding events, respectively. However, it is uncertain if current cutoff values should be used in prasugrel- or ticagrelor-treated subjects. The objective of this analysis was to evaluate the pharmacodynamic (PD) efficacy of P2Y₁₂ antagonists in a contemporary real-world population.

MATERIALS AND METHODS

This PD study included 988 patients with acute coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI) and receiving dual therapy with aspirin and a P2Y₁₂ inhibitor (clopidogrel, prasugrel or ticagrelor). Platelet function was assessed at day 1 and day 30 post-PCI by VerifyNow P2Y12 assay, multiple electrode aggregometry and vasodilator-stimulated phosphoprotein (VASP) assay.

RESULTS

Clopidogrel-treated patients (n = 324) had greater platelet reactivity than those receiving ticagrelor (n = 469) or prasugrel (n = 195) at both time points (p < 0.001 for all comparisons). No difference between ticagrelor and prasugrel was observed at day 1 with the VerifyNow P2Y12 assay (51.5 ± 2.8 vs. 42.7 ± 3.5 PRUs; p = 0.298), whereas ticagrelor achieved greater platelet inhibition at day 30 (48.1 ± 2.5 vs. 89.2 ± 4.2 PRUs; p < 0.001). Similar results were obtained with the VASP assay. Both prasugrel and ticagrelor had markedly lower HPR rates than clopidogrel and very high rates of LPR at both time points.

CONCLUSIONS

Prasugrel and ticagrelor displayed more potent and consistent PD effects than clopidogrel in ACS patients undergoing PCI, with a trend towards greater platelet inhibition with ticagrelor during the maintenance phase of therapy compared to prasugrel.

On-treatment platelet reactivity in peripheral and coronary blood in patients undergoing primary PCI for ST-segment elevation myocardial infarction (STEMI)

Dual antiplatelet therapy is recommended in patients undergoing primary percutaneous coronary intervention (p-PCI) for ST-segment elevation myocardial infarction (STEMI). Pre-analytical variables may influence platelet function analysis results. Our aim was to evaluate the on-treatment platelet reactivity in peripheral artery vs coronary blood in patients with STEMI. We enrolled one hundred and nine patients who consecutively underwent p-PCI at Cardiology Unit of Padua University Hospital between June 2014 and June 2015. Before the procedure, all patients received intravenous aspirin 250 mg and either of the thienopyridines; clopidogrel 600 mg, prasugrel 60 mg or ticagrelor 180 mg. ASPI-test and ADP-test using multiple electrode aggregometry (MEA) were performed in samples collected from both a peripheral artery and the culprit coronary artery. 'Low responders' were patients with an ASPI-test or ADP-test value greater than or equal to a pre-established normal range. No significant differences were observed in ASPI-test values between peripheral (19 (median) [3-49 (10-90 percentiles)] U) vs coronary (12 [1-40] U, p = .06) blood and in ADP-test (40 [14-82] U vs 33 [7-79] U, p =.68) blood. In peripheral blood, fifteen (14%) patients were 'low aspirin' and forty-one (38%) 'low thienopyridines' responders. The prevalence of 'low clopidogrel' responders was higher (45%) than prasugrel (36%) and ticagrelor (33%). Similar results were observed in coronary blood. In patients undergoing p-PCI for STEMI, MEA platelet function observed in coronary arteries was consistent with peripheral artery blood's independently of the antiplatelet drug used. The clinical significance of peripheral and coronary on-aspirin/thienopyridines platelet reactivity needs further clarification.