scholarly journals The correlation and consistency of light transmission aggregometry and thrombelastography in identifying high clopidogrel on-treatment platelet reactivity in patients with acute coronary syndrome

2016 ◽  
Vol 25 (11) ◽  
Author(s):  
Nie Xiaoyan
Keyword(s):  
Acute Coronary Syndrome ◽  
Light Transmission ◽  
Platelet Reactivity ◽  
Coronary Syndrome ◽  
Light Transmission Aggregometry

High on-treatment platelet reactivity by more than one agonist predicts 12-month follow-up cardiovascular death and non-fatal myocardial infarction in acute coronary syndrome patients receiving coronary stenting

2010 ◽  
Vol 104 (08) ◽  
pp. 279-286 ◽  
Author(s):  
Anna Gori ◽  
Rita Paniccia ◽  
Betti Giusti ◽  
Serafina Valente ◽  
Cristina Giglioli ◽  
...  
Keyword(s):  
Acute Coronary Syndrome ◽  
Arachidonic Acid ◽  
Stent Implantation ◽  
Predictive Value ◽  
Light Transmission ◽  
Platelet Reactivity ◽  
Area Under The Curve ◽  
Cardiovascular Death ◽  
Coronary Syndrome

SummaryThere is some data available on the role of high on-treatment platelet reactivity by ADP whereas, as regards arachidonic acid or other agonists, there is no proof of the best cut-off for identifying populations with a different cardiovascular outcome by the construction of appropriate receiver-operator characteristics (ROC) curves. We enrolled 1,108 acute coronary syndrome patients undergoing percutaneous coronary intervention (PCI) with stent implantation and followed them up for 12 months. Platelet reactivity was assessed by light transmission aggregometry (LTA) using 10 μM ADP, 1 mM arachidonic acid (AA) and 2 μg/ml collagen. At a 12-month follow-up, we found 37 cardiovascular deaths (3.3%), 54 non-fatal myocardial infarctions (MI) (4.8%) and 154 target vessel revascularisations (TVR) (13.8%). ROC analysis demonstrated that 10 μM ADP LTA, 1 mM AA and 2 μg/ml collagen LTA were able to distinguish between patients with and without subsequent cardiovascular death and non-fatal MI (area under the curve for 10 μM ADP 0.63 (0.55–0.71), p<0.001; for 1 mM AA 0.68 (0.61–0.76), p<0.0001; for 2 μg/ml collagen 0.62 (0.52–0.73), p<0.0111), whereas no association was demonstrated with the occurrence of TVR. Ten μM ADP LTA ≥55%, 1 mM AA LTA ≥15% and 2 μg/ml collagen LTA ≥31% were identified as the optimal cut-off to predict cardiovascular death and non-fatal MI at 12-month follow-up. The contemporary platelet hyperreactivity to more than one agonist was associated with a higher risk of 12-month cardiovascular death and MI, whereas isolated platelet hyperreactivity to only one agonist had not a predictive value [10 μM ADP LTA ≥55% + 1 mM AA LTA ≥15%: odds ratio [OR]=3.6(2.4–6.1), p<0.0001; ADP LTA ≥55% + 1 mM AA LTA ≥15% + 2 μg/ml collagen LTA ≥31%: OR=4.7(2.9–7.7), p<0.0001]. In this prospective study on a large number of acute coronary syndrome patients undergoing stent implantation, we have found that high on-treatment platelet reactivity measured by LTA induced by more than one agonist – AA, ADP, collagen – is an independent risk factor for 12-month cardiovascular death and non-fatal MI. Isolated platelet hyperreactivity to only one agonist has not a predictive value for clinical recurrences.

scholarly journals Comparison of Light Transmission Aggregometry With Impedance Aggregometry in Patients on Potent P2Y12 Inhibitors

2020 ◽  
pp. 107424842096870
Author(s):  
Patricia P. Wadowski ◽  
Joseph Pultar ◽  
Constantin Weikert ◽  
Beate Eichelberger ◽  
Irene M. Lang ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Light Transmission ◽  
Platelet Reactivity ◽  
Adenosine Diphosphate ◽  
P2y12 Inhibitors ◽  
Coronary Syndrome ◽  
Multiple Electrode Aggregometry ◽  
Impedance Aggregometry ◽  
Light Transmission Aggregometry ◽  
Sensitivity Specificity

Since data on the agreement between light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA) in patients on the more potent P2Y12 inhibitors are missing so far, we investigated if the evaluation of the responsiveness to therapy by LTA can be replaced by MEA in 160 acute coronary syndrome (ACS) patients on dual antiplatelet therapy with aspirin and prasugrel or ticagrelor (n = 80 each). Cut-off values for high on-treatment residual platelet reactivity (HRPR) in response to adenosine diphosphate (ADP) or arachidonic acid (AA) were defined according to previous studies showing an association of HRPR with the occurrence of adverse ischemic outcomes. ADP- inducible platelet aggregation was 33% and 37% (p = 0.07) by LTA and 19 AU and 20 AU (p = 0.38) by MEA in prasugrel- and ticagrelor-treated patients, respectively. AA- inducible platelet aggregation was 2% and 3% by LTA and 15 AU and 16 AU by MEA, (all p ≥ 0.3) in patients on prasugrel and ticagrelor, respectively. By LTA, HRPR ADP and HRPR AA were seen in 5%/5% and in 4%/ 13% of patients receiving prasugrel- and ticagrelor, respectively. By MEA, HRPR ADP and HRPR AA were seen in 3%/ 25% and 0%/24% of prasugrel- and ticagrelor-treated patients, respectively. ADP-inducible platelet reactivity by MEA correlated significantly with LTA ADP in prasugrel-treated patients (r = 0.4, p < 0.001), but not in those receiving ticagrelor (r = 0.09, p = 0.45). AA-inducible platelet aggregation by LTA and MEA did not correlate in prasugrel- and ticagrelor-treated patients. Sensitivity/specificity of HRPR by MEA to detect HRPR by LTA were 25%/99% for MEA ADP and 100%/79% for MEA AA in prasugrel-treated patients, and 0%/100% for MEA ADP and 70%/83% for MEA AA in ticagrelor-treated patients. In conclusion, on-treatment residual ADP-inducible platelet reactivity by LTA and MEA shows a significant correlation in prasugrel- but not ticagrelor-treated patients. However, in both groups LTA and MEA revealed heterogeneous results regarding the classification of patients as responders or non-responders to P2Y12 inhibition.

Malondialdehyde Assay in the Evaluation of Aspirin Antiplatelet Effects

Pharmacology ◽  
2018 ◽  
Vol 103 (1-2) ◽  
pp. 23-29 ◽  
Author(s):  
Amin Polzin ◽  
Lisa Dannenberg ◽  
Theresa Schneider ◽  
Betül Knoop ◽  
David Naguib ◽  
...  
Keyword(s):  
Cardiovascular Events ◽  
Operating Characteristic ◽  
Light Transmission ◽  
Platelet Reactivity ◽  
Area Under The Curve ◽  
Healthy Individuals ◽  
Antibody Assay ◽  
Light Transmission Aggregometry ◽  
Artery Disease

Aspirin is essential in secondary prevention of patients after myocardial infarction and with coronary artery disease. However, impaired pharmacodynamic response to aspirin is frequent (high on-treatment platelet reactivity [HTPR]). This leads to an enhanced prevalence of cardiovascular events and to an impaired clinical outcome. The current specific assays to evaluate aspirin antiplatelet effects are complex, time-consuming and demand for a high laboratory expertise. Therefore, we developed a potentially bedside assay based on the determination of malondialdehyde (MDA). MDA is a by-product of the thromboxane (TX) formation, which is synthesized in equimolar concentrations. In this study, we compared this MDA assay to the conventional assays in determination of pharmacodynamic aspirin response. For this, aspirin antiplatelet effects were measured in 22 healthy individuals and 63 aspirin treated patients using TX B2 formation enzyme-linked antibody assay, arachidonic acid induced light transmission aggregometry (LTA) and the new fluorometric MDA assay. In patients, MDA levels correlated well with TX formation (R = 0.81; 95% CI 0.69–0.88; p < 0.001) and LTA (R = 0.84; CI 0.74–0.91; p < 0.001). Receiver operating characteristic analyses revealed that the MDA assay does detect HTPR to aspirin sufficiently (area under the curve: 0.965; p < 0.001). The optimal cut-off was > 128 nmol/L (sensitivity of 100%, specificity of 91%). The new MDA assay is reliable in detecting HTPR. It is highly specific in the evaluation of antiplatelet effects by aspirin. This promising and potential bedside assay needs to be evaluated in clinical practice.

A Prospective, Randomized, Open-Label, Blinded, Endpoint Study Exploring Platelet Response to Half-Dose Prasugrel and Ticagrelor in Patients with the Acute Coronary Syndrome: HOPE-TAILOR Study

Cardiology ◽  
2017 ◽  
Vol 138 (4) ◽  
pp. 201-206 ◽  
Author(s):  
Cai De Jin ◽  
Moo Hyun Kim ◽  
Junghee Bang ◽  
Victor Serebruany
Keyword(s):  
Acute Coronary Syndrome ◽  
Platelet Reactivity ◽  
Academic Research ◽  
P2y12 Receptor ◽  
Drug Eluting Stent ◽  
Platelet Response ◽  
Open Label ◽  
Korean Patients ◽  
Coronary Syndrome ◽  
Half Dose

Background: The optimal dosing of novel oral P2Y12 receptor platelet inhibitors such as prasugrel or ticagrelor is unclear and especially challenging in East Asians. We hypothesize that half-dose prasugrel and ticagrelor may be sufficient for long-term maintenance management in Korean patients with the acute coronary syndrome (ACS) compared with conventional dosages. Design: HOPE-TAILOR (Half Dose of Prasugrel and Ticagrelor in Platelet Response after Acute Coronary Syndromes) is a prospective, randomized, open-label, blinded, endpoint (PROBE) single-center, clinical trial. A total of 100 patients with ACS undergoing drug-eluting stent implantation will be randomly assigned to prasugrel, ticagrelor, or clopidogrel, and the patients in each treatment group will receive 1-month therapy with 100 mg q.d. aspirin plus prasugrel 10 mg q.d., ticagrelor 90 mg b.i.d., or clopidogrel 75 mg q.d., followed by half-dose prasugrel 5 mg q.d. or ticagrelor 45 mg b.i.d. for maintenance treatment but without clopidogrel dose reduction. The primary endpoint will be optimal platelet reactivity 3 months after coronary intervention, defined by VerifyNow Analyzer (PRU: 85-208) and vasodilator-stimulated phosphoprotein P2Y12 flow cytometry assay (platelet reactivity indices: 16-50%). Clinical outcomes will also be assessed, including major efficacy (composite of cardiac death, nonfatal myocardial infarction, repeat revascularization, or stroke) and safety (bleeding ≥2 according to the Bleeding Academic Research Consortium). Conclusion: HOPE-TAILOR is a prospective, randomized, open-label, blinded, endpoint study to explore the efficacy and safety of novel P2Y12 receptor inhibitors administered orally at half the dose in Korean patients with ACS. The results will be available late in 2017.

Comparison of VASP-phosphorylation assay to light-transmission aggregometry in assessing inhibition of the platelet ADP P2Y12 receptor

2006 ◽  
Vol 96 (12) ◽  
pp. 767-773 ◽  
Author(s):  
Agnieszka Pampuch ◽  
Giovanni de Gaetano ◽  
Chiara Cerletti
Keyword(s):  
Light Transmission ◽  
Platelet Reactivity ◽  
Flow Cytometric Analysis ◽  
Individual Variability ◽  
P2y12 Receptor ◽  
Reactivity Index ◽  
Drug Induced ◽  
Light Transmission Aggregometry ◽  
Adp Receptor

SummaryThere is need to improve platelet function testing to monitor the response to antiplatelet drugs. We compared flow-cytometric analysis of intraplatelet vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) to light-transmission aggregometry for the detection of drug-induced in-vitro inhibition of the platelet P2Y12 ADP receptor on 22 healthy subjects (10 males, 12 females, 28.5 ± 6.6 years). The platelet reactivity index (PRI) of VASP was calculated both from mean fluorescence intensity (MFI) and percent of fluorescence-positive platelets in the presence of PGE1 with or without ADP (10 µM). Platelet aggregation was induced by ADP (1.25, 2.5 and 5 µM). Cangrelor, a competitive inhibitor of the P2Y12 receptor, preincubated 5 minutes, induced a concentration-dependent inhibition of platelet ADP-receptor function in both tests. Indeed PRI (%) based on either MFI or percent platelets gated were highly correlated with each other (r = 0.97, p<0.0001) and with aggregation in- duced by ADP. The IC50 of cangrelor against each of the three ADP concentrations used in aggregometry increased from 5.8 ± 3.4 nM to 23.1 ± 4.0 nM and to 98 ± 25 nM, respectively. The IC50 of cangrelor based on VASP-P was within the same range (25.5 ± 7.7 nM). No correlation was observed between IC50 values of cangrelor and ADP concentrations giving 50% effect (EC50) in the absence of the drug. However, at 10 nM cangrelor seven subjects could be identified by the VASP-P assay as “low responders” to the drug (PRI> 50%), and six of them also had an aggregation response to 5 µM ADP > 50%. These six subjects showed the lowest ADP EC50 values in the absence of the drug, possibly reflecting high sensitivity of their platelet P2Y12 receptors to ADP. In conclusion, both the VASP-P assay and light-transmission aggregometry detect in a comparable way in-vitro pharmacological inhibition of the platelet P2Y12 ADP receptor and its individual variability.

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