Hyperaggregation of Platelets Detected by Whole Blood Platelet Aggregometry in Newly Diagnosed Noninsulin-dependent Diabetes Mellitus

SummarySeveral methods are used to analyse platelet function in whole blood. A new device to measure whole blood platelet aggregation has been developed, called multiple electrode platelet aggregometry (MEA). Our aim was to evaluate MEA in comparison with the single platelet counting (SPC) method for the measurement of platelet aggregation and platelet inhibition by aspirin or apyrase in diluted whole blood. Platelet aggregation induced by different concentrations of ADP, collagen and TRAP-6 and platelet inhibition by apyrase or aspirin were determined in citrateor hirudin-anticoagulated blood by MEA and SPC. MEA indicated that spontaneous platelet aggregation was lower, and stimulated platelet aggregation was higher in hirudin- than citrate-anticoagulated blood. In hirudin-anticoagulated, but not citrate-anticoagulated blood, spontaneous platelet aggregation measured by MEA was inhibited by apyrase. For MEA compared with SPC the dose response-curves of agonist-induced platelet aggregation in citrate- and hirudin-blood showed similar EC50 values for TRAP, and higher EC50 values for ADP (non-significant) and collagen (p<0.05). MEA and the SPC method gave similar results concerning platelet-inhibition by apyrase and aspirin. MEA was more sensitive than SPC to the inhibitory effect of aspirin in collagen-induced aggregation. In conclusion, MEA is an easy, reproducible and sensitive method for measuring spontaneous and stimulated platelet aggregation, and evaluating antiplatelet drugs in diluted whole blood. The use of hirudin as an anticoagulant is preferable to the use of citrate. MEA is a promising technique for experimental and clinical applications.

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Determination of Clopidogrel Resistance by Whole Blood Platelet Aggregometry and Inhibitors of the P2Y12 Receptor

Clinical Chemistry ◽

10.1373/clinchem.2005.059535 ◽

2006 ◽

Vol 52 (3) ◽

pp. 383-388 ◽

Cited By ~ 57

Author(s):

Boris T Ivandic ◽

Philipp Schlick ◽

Peter Staritz ◽

Kerstin Kurz ◽

Hugo A Katus ◽

...

Keyword(s):

Whole Blood ◽

Adenosine Monophosphate ◽

Blood Platelet ◽

P2y12 Receptor ◽

Fisher Exact Test ◽

Exact Test ◽

Clopidogrel Resistance ◽

Impedance Aggregometry ◽

Platelet Aggregometry ◽

Increased Risk

Abstract Background: Inhibition of platelet aggregation by clopidogrel may be insufficient in up to 30% of users. These nonresponders carry an increased risk of cardiovascular events. We reported here a simple assay to study clopidogrel responsiveness. Methods: Electrical impedance aggregometry was performed in diluted whole blood in the presence of 5 and 20 μmol/L ADP. Some samples were incubated with 0.1 mmol/L methyl-S-adenosine monophosphate (MeSAMP), a P2Y12 receptor blocker, to maximize inhibition of aggregation before aggregometry. To validate the assay, we analyzed 6-min impedance in 21 healthy probands and 244 patients with coronary artery disease (CAD). Results: At 5 μmol/L ADP, the imprecision of the assay was 11%. Mean (SD) impedance of the healthy cohort was 12.2 (2.2) Ω. The mean − 3 SD was used to define the cutoff for clopidogrel responsiveness: responders and nonresponders exhibited a 6-min impedance ≤5 Ω and >5 Ω, respectively. Samples from nonresponders were incubated with MeSAMP and analyzed again to distinguish pharmacokinetic and pharmacodynamic types of resistance. Sixteen percent of CAD patients were classified as nonresponders (38 and 2 cases of pharmacokinetic and pharmacodynamic resistance, respectively). Female sex was strongly associated with clopidogrel resistance (P = 0.0002, Fisher exact test). A higher clopidogrel loading dose (P = 0.0353, Mann–Whitney U-test) was given to responders (median, 450 mg) than nonresponders (median, 300 mg). Age and cardiovascular diagnosis showed no significant associations. Conclusions: Impedance aggregometry using 5 μmol/L ADP is a useful tool for studying clopidogrel responsiveness. MeSAMP allows characterization of responsiveness “on treatment” and may be useful for optimizing clopidogrel dosing.

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COST ANALYSIS OF INPATIENT (INPT) VERSUS OUTPATIENT (OPT) MANAGEMENT (RX) OF CHILDREN WITH NEWLY DIAGNOSED (DX) INSULIN-DEPENDENT DIABETES MELLITUS (IDDM).499

Pediatric Research ◽

10.1203/00006450-199604001-00519 ◽

1996 ◽

Vol 39 ◽

pp. 86-86

Author(s):

José F Cara ◽

Karen Basha ◽

Donna Marvicsin ◽

Patti Williams ◽

David Nerenz

Keyword(s):

Diabetes Mellitus ◽

Cost Analysis ◽

Insulin Dependent Diabetes Mellitus ◽

Insulin Dependent Diabetes ◽

Dependent Diabetes Mellitus ◽

Newly Diagnosed ◽

Insulin Dependent

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An introduction to point-of-care testing in extracorporeal circulation and LVADs

Hematology ◽

10.1182/asheducation-2018.1.516 ◽

2018 ◽

Vol 2018 (1) ◽

pp. 516-521 ◽

Cited By ~ 2

Author(s):

Rachel Sara Bercovitz

Keyword(s):

Whole Blood ◽

Point Of Care ◽

Blood Platelet ◽

Ventricular Assist Devices ◽

Bleeding Complications ◽

Future Research ◽

Ventricular Assist ◽

Assist Devices ◽

Platelet Aggregometry ◽

Coagulation Tests

Abstract There is a delicate balance between bleeding and clotting in patients on circuits such as ventricular assist devices or extracorporeal membrane oxygenation. Traditional coagulation tests, prothrombin time, activated partial thromboplastin time, and anti-factor Xa levels, are used to monitor patients on these devices. However, turnaround times and inability to assess global hemostasis, including platelets and fibrinogen have contributed to a recognition that faster, accurate, and more informative coagulation tests are needed. Activated clotting time is used to monitor heparin in patients on circuits and has the advantages of being a near-patient point-of-care test. However, its utility is limited to heparin monitoring. Viscoelastic tests (thromboelastometry and thromboelastography) are global, whole-blood coagulation tests, and whole-blood platelet aggregometry evaluates platelet function. Ideally, these tests can ensure that patients are within the therapeutic range of their antithrombotic medications, identify patients at risk for hemorrhagic or thrombotic complications, and guide management of acute bleeding complications. This ideal is currently hampered by a lack of studies that delineate clear ranges that are clinically relevant. Future research is needed to better understand the optimal use of point-of-care coagulation testing in patients on extracorporeal circuits and ventricular assist devices.

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