Rotational thromboelastometry ROTEM is available as point-of-care coagulation monitoring in an increasing number of European operating theatres and emergency rooms. The Platelet Mapping Assay has been described as a platelet aggregation assay for thromboelastography TEG. The aim of this experimental trial was to evaluate feasibility of the Platelet Mapping Assay on the ROTEM test system. Whole blood was drawn from 22 adult volunteers and patients with and without antiplatelet medication. Platelet aggregability was determined in three whole blood assays: the Platelet Mapping Assay using both activators arachidonic acid (AA) and adenosine diphosphate (ADP) on TEG, its adapted version on ROTEM, and the multiple electrode impedance aggregometer Multiplate. Percent aggregation inhibition results were plotted in a linear regression analysis and correlation was estimated. Sensitivity and specificity for detecting antiplatelet medication were determined. Overall correlations were statistically significant with an r(2) = 0.83 in AA-activated and an r(2) = 0.82 in ADP-activated Platelet Mapping Assay. AA-activated tests and the Multiplate analysis identified aspirin-inhibition in 86% and 100%, respectively. ADP-activated tests and the Multiplate analysis identified clopidogrel-inhibition in 67% and 89%, respectively. Specificity was low both in ROTEM and TEG. Differences in frequency distribution between the results obtained in ROTEM and TEG were not statistically significant. The Platelet Mapping Assay can be performed on the ROTEM. For the perioperative scenario, however, longer test duration and higher costs have to be considered compared to Multiplate analyses.
"As methods for sample fixation are improved, this method will gain wider application in the clinical setting when LTA testing alone is inadequate to assess overall platelet function. Thromboelastography (TEG; ROTEM, TEM Innovations, Munich, Germany) is used to assess clot formation, including the kinetics of clotting, clot strength, and lysis that involves globally platelet function and coagulation [Scharbert et al., 2009; Stafford and Weitzel, 2013]. This test has been traditionally used in the surgical setting as a screen for bleeding risk. "
[Show abstract][Hide abstract] ABSTRACT: Strategy, Management and Health PolicyEnabling Technology, Genomics, ProteomicsPreclinical ResearchPreclinical Development Toxicology, Formulation Drug Delivery, PharmacokineticsClinical Development Phases I-III Regulatory, Quality, ManufacturingPostmarketing Phase IV
There is an increasing need for the standardization of platelet function and coagulation testing for the assessment of antithrombotic therapies. Investigators continue to strive to identify ideal laboratory testing and monitoring procedures for acquired and inherited platelet function defects as well as for evaluating patient status when treated with existing or emerging antithrombotics. These therapies are used primarily in the treatment of ischemic complications. In patients receiving antithrombotic therapy, the balance between hemostasis and thrombosis is a challenge as there is an ongoing risk for bleeding when patients are receiving antiplatelet agents or anticoagulants to lessen their risk for secondary thrombotic events. There are several diverse tests for monitoring anticoagulant therapy; however, as new agents are developed, more specific tests will be required to directly assess these agents in relationship to overall coagulation status. Research in the platelet biology field is ongoing to provide point-of-care methodologies for the assessment of platelet reactivity in terms of both bleeding and thrombosis risk. Currently there are no instruments that reliably assess the risk of bleeding. The challenges that routinely faced are the complexity of physiology, the need for standardization of platelet testing methodology, and the necessity for appropriate interpretation of the test results.
Drug Development Research 12/2013; 74(8):587-593. DOI:10.1002/ddr.21119 · 0.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The prognostic value of the vasodilator-stimulated phosphoprotein (VASP) phosphorylation assay and multiple electrode aggregometry (MEA) for thrombotic adverse events has been shown in independent studies. As no direct comparison between the two methods has been made so far, we investigated which laboratory approach has a better predictive value for stent thrombosis.
The VASP phosphorylation assay and MEA were performed in 416 patients with coronary artery disease undergoing percutaneous coronary intervention. The rate of stent thrombosis was recorded during a 6-month follow-up.
Definite stent thrombosis occurred in three patients (0.7%) and probable stent thrombosis in four (1%). Receiver operating characteristic (ROC) analysis demonstrated that MEA distinguishes between patients with or without subsequent stent thrombosis better than the VASP phosphorylation assay: the area under the ROC curve was higher for MEA (0.92; P=0.012) than for the VASP phosphorylation assay (0.60; P=0.55). At equal levels of sensitivity (100%), the specificity was greater for MEA than for the VASP phosphorylation assay (86% vs. 37%). Stent thrombosis occurred in 9% of patients with platelet hyperreactivity in MEA, who were simultaneously clopidogrel non-responders in the VASP phosphorylation assay. Interestingly, clopidogrel non-responders in the VASP phosphorylation assay without platelet hyperreactivity in MEA did not suffer from stent thrombosis.
Platelet hyperreactivity in MEA might be a better risk predictor for stent thrombosis than the assessment of the specific clopidogrel effect with the VASP phosphorylation assay.
Journal of Thrombosis and Haemostasis 11/2009; 8(2):351-9. DOI:10.1111/j.1538-7836.2009.03699.x · 5.72 Impact Factor
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