Whole Blood Impedance Aggregometry: A New Tool for Severe Inherited Platelet Disorder Diagnosis?

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 5266-5266 ◽  
Author(s):  
Celine Desconclois ◽  
Vincent Valarche ◽  
Tewfik Boutekedjiret ◽  
Martine Raphael ◽  
Marie Dreyfus ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Von Willebrand Disease ◽  
Fast Method ◽  
Normal Ranges ◽  
Platelet Function Disorders ◽  
Platelet Disorder ◽  
Platelet Disorders ◽  
Von Willebrand

Abstract Abstract 5266 Diagnosis and characterization of platelet function disorders may be challenging. It requires multiple laboratory data including the assessment of platelet functions. Platelet function analysis is most commonly performed using light transmission aggregometry (LTA). LTA is a time-consuming method requiring centrifugation steps and large blood volumes. It is difficult to perform in children and in cases of thrombocytopenia. In contrast, platelet aggregation in whole blood using impedancemetry (WBI) is a fast method, allows omission of centrifugation steps and performance of platelet function studies under more physiological conditions with small samples size. It is based on the change of resistance proportional to the amount of platelets sticking to two electrodes where an alternating current is applied. Multiplate® (for “multiple electrode aggregometry”, Dynabite Medical) is a new generation of WBI aggregometer using diluted blood and single-use test cells containing twin electrodes that reduce the variation of results. We have already showed the good Multiplate® performance concerning ristocetin-induced platelet aggregation in a population of 30 patients with characterized von Willebrand disease (Valarche et al, 2011). Our aim in this ongoing study was to assess the performance of WBI in patients with inherited platelet function disorders. We tested 8 patients including 2 unrelated patients with Glanzmann Thrombasthenia (GT), 2 unrelated patients with Bernard-Soulier Syndrome (BSS), 1 patient with Gray Platelet Syndrome (GPS) and 3 patients from the same family with a platelet type von Willebrand disease (PTVWD). GT, BSS, and PTVWD diagnosis were confirmed using genotyping. BSS and GPS patients had chronic thrombocytopenia. GT, BSS, GPS and 1/3 PTVWD had platelet function tests with LTA in parallel. WBI was performed on heparinized whole blood diluted at ½ in NaCl at 37°C and triggered using high (0.77 mg/mL, WBI RH) and low (0.5 mg/mL, WBI RL) final ristocetin concentrations, ADP (6.5 Âμ Mol, WBI ADP) and collagen (3.2 Âμg/mL, WBI Coll). Results were expressed in arbitrary unit (AU) corresponding to the area under the aggregation curve observed during 6 min. Normal ranges indicated in brackets were based on the mean +/− 2 SD of 30 healthy volunteers' results. Results highlighted in grey are those out of the normal ranges (Table 1).Table 1:Results of the 8 patients with inherited platelet disorders.PatientsPlatelet count (109/L)WBI RH (AU) [>500]WBI RL (AU) [<150]WBI ADP (AU) [>550]WBI Coll (AU) [>500]GT 116923441443GT 224955417ND7BSS 134371119129BSS 230254733582GPS7916217ND42PTVWD22099493ND338PTVWD231116560ND1092PTVWD2341174168ND852 All patients except those with PTVWD had decreased results with WBI. However, as expected, patients with GT had flat traces using WBI ADP and WBI Coll but normal or only decreased curves (234 – 554 AU) using WBI RH. On the opposite, BSS patients had flat traces using WBI RH but detectable curves using WBI ADP (191 – 335 AU) despite decreased platelet count. The thrombocytopenic GPS patient has a flat trace using WBI Coll and decreased WBI RH (162 AU). Members of the PTVWD family had normal results except a slightly increased result with WBI RH in 1/3 patients. Finally, LTA results performed in 6/8 patients were all in accordance with those of the WBI. In conclusion, in 8 patients with well characterized inherited platelet disorders, WBI was able to detect all abnormalities except PTVWD. In such cases, different ristocetin concentrations use might be critical to increase sensitivity. In our hands, WBI was able to discriminate disorders involving platelet glycoprotein (GP) IIb-IIIa from GP Ib-IX-V: GT patients exhibited flat traces using WBI ADP and WBI Coll, whereas patients with BSS exhibited flat traces with ristocetin. These preliminary results need to be confirmed on a larger population of patients with various characterized platelet function disorders. They suggest that WBI using the Multiplate® analyzer, which is a fast, easy and blood-preserving test, could be a valuable extra step before or in addition to the classic LTA for the diagnosis of severe inherited platelet disorders. Disclosures: No relevant conflicts of interest to declare.

Platelet Disorders

2015 ◽  
Author(s):  
Lawrence L K Leung ◽  
James L. Zehnder
Keyword(s):  
Platelet Function ◽  
Clinical Manifestations ◽  
Von Willebrand Disease ◽  
Drug Induced ◽  
Excessive Bleeding ◽  
Vascular Integrity ◽  
Patient Reports ◽  
Platelet Function Disorders ◽  
Hemorrhagic Disorders ◽  
Von Willebrand

A bleeding disorder may be suspected when a patient reports spontaneous or excessive bleeding or bruising, often secondary to trauma. Possible causes can vary between abnormal platelet number or function, abnormal vascular integrity, coagulation defects, fibrinolysis, or a combination thereof. This review addresses hemorrhagic disorders associated with quantitative or qualitative platelet abnormalities, such as thrombocytopenia, platelet function disorders, thrombocytosis and thrombocythemia, and vascular purpuras. Hemorrhagic dis­orders associated with abnormalities in coagulation (e.g., von Willebrand disease and hemophilia) are not covered. An algorithm shows evidence-based practice guidelines for the management of immune thrombocytopenic purpura. Tables list questions regarding bleeding and bruising to ask patients, clinical manifestations of hemorrhagic disorders, typical results of tests for hemostatic function in bleeding disorders, causes of thrombocytopenia, other forms of drug-induced thrombocytopenia, classification of platelet function disorders, and selected platelet-modifying agents. This review contains ­1 highly rendered figure, 7 tables, and 82 references. 

Rapid Assessment of Platelet Function Using Thromboelastography and Small Volumes of Citrated Whole Blood.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3995-3995 ◽  
Author(s):  
Fred G. Pluthero ◽  
Margaret L. Rand ◽  
Victor S. Blanchette ◽  
Walter H. Kahr
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Function Analysis ◽  
Maximum Amplitude ◽  
Ease Of Use ◽  
Platelet Response ◽  
Platelet Function Disorders ◽  
Wide Range

Abstract Platelet function disorders are a key cause of abnormal bleeding, and diagnosis is challenging because: platelet abnormalities are diverse, affecting many aspects of function; variability in platelet function testing in clinical laboratories makes it difficult to compare results; large blood volumes required for platelet function analysis make it difficult to perform in neonatal patients; manipulation of platelet rich plasma used for platelet aggregation can lead to test variability; platelet aggregation curves are difficult to interpret in thrombocytopenic patients. We describe a method of testing platelet function using citrated whole blood and thromboelastography (TEG) that overcomes some of these limitations. Commercially-available platelet mapping kits allow the effects of the platelet agonists adenosine diphosphate (ADP) and arachidonic acid (AA) to be assessed via a TEG assay where reptilase and activated factor XIII produce fibrin clots independent of thrombin in heparinized whole blood. The activation and aggregation of platelets is quantified by measuring the difference in maximum amplitude (MA) between unstimulated samples, which form weak fibrin-only clots, and samples with agonists added, which form stronger clots containing fibrin and activated/aggregated platelets. Platelet mapping was used as the basis for a TEG assay which can be used to assess platelet responses to a wide range of stimuli - including ADP, AA, epinephrine, collagen, U46619 (thromboxane-A2 receptor agonist), SFLLRN (PAR-1 thrombin receptor activating peptide) and AYPGKF (PAR-4 activating peptide) - in small samples (330μL) of citrated native (CN) blood or plasma to which heparin is added to a concentration of 20U/mL. Samples were recalcified by adding calcium chloride to 10mM (necessary for the function of reptilase and FXIIIa), and other reagent volumes were the same as in platelet mapping assays, with fibrin activator prepared at 1/2 regular strength. The concentrations of platelet agonists were: collagen 51μg/ml, epinephrine 0.27μM, ADP 5.4μM, arachidonic acid 135μg/mL, U46619 2.6μM, SFLLRN 6.76μM and AYPGKF 34μM. These concentrations produced TEG MA values in heparinated fibrin-activated CN blood from a panel of normal individuals comparable to those obtained from recalcified CN blood in the absence of heparin (the fibrin/platelet response control). The platelet response was rapid with maximum amplitudes reached within 10 minutes for all agonists except collagen, which required &gt;30 minutes to produce maximum amplitude. We have found this TEG platelet-response assay to be useful in detecting platelet function abnormalities, producing results which correlate with and extend those of other platelet function tests. For example in one patient a weak response to epinephrine corresponded to similar platelet aggregation results, and in another the TEG assay detected a weak PAR-1 response not specifically detected in other tests. The assay has also proven useful in assessing platelet function in blood and plasma having low platelet concentrations (&lt;50 x 10E9/L) from experimental or pathological causes (e.g. thrombocytopenia), in titrating platelet responses to agonists and in assessing the effects of antiplatelet agents in vivo and in vitro. Thus this TEG platelet function assay has the advantages of speed, ease of use, flexibility, adaptability to low platelet concentrations and sample economy, requiring small volumes of citrated blood which can be used for other coagulation assays and platelet response tests.

Simultaneous measurement of adenosine triphosphate release and aggregation potentiates human platelet aggregation responses for some subjects, including persons with Quebec platelet disorder

2012 ◽  
Vol 107 (04) ◽  
pp. 726-734 ◽  
Author(s):  
Catherine P. M. Hayward ◽  
Karen A. Moffat ◽  
Jean-Francois Castilloux ◽  
Yang Liu ◽  
Jodi Seecharan ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Adenosine Triphosphate ◽  
Whole Blood ◽  
Human Platelet ◽  
Atp Release ◽  
Firefly Luciferase ◽  
Dense Granule ◽  
Human Platelet Aggregation ◽  
Platelet Disorder ◽  
Platelet Disorders

SummaryPlatelet aggregometry and dense granule adenosine triphosphate (ATP) release assays are helpful to diagnose platelet disorders. Some laboratories simultaneously measure aggregation and ATP release using Chronolume®, a commercial reagent containing D-luciferin, firefly luciferase and magnesium. Chronolume® can potentiate sub-maximal aggregation responses, normalising canine platelet disorder findings. We investigated if Chronolume® potentiates human platelet aggregation responses after observing discrepancies suspicious of potentiation. Among patients simultaneously tested by light transmission aggregometry (LTA) on two instruments, 18/43 (42%), including 14/24 (58%) with platelet disorders, showed full secondary aggregation with one or more agonists only in tests with Chronolume®. As subjects with Quebec platelet disorder (QPD) did not show the expected absent secondary aggregation responses to epinephrine in tests with Chronolu-me®, the reason for the discrepancy was investigated using samples from 10 QPD subjects. Like sub-threshold ADP (0.75 μM), Chronolume® significantly increased QPD LTA responses to epinephrine (p<0.0001) and it increased both initial and secondary aggregation responses, leading to dense granule release. This potentiation was not restricted to QPD and it was mimicked adding 1–2 mM magnesium, but not D-luciferin or firefly luciferase, to LTA assays. Chronolume® potentiated the ADP aggregation responses of QPD subjects with a reduced response. Furthermore, it increased whole blood aggregation responses of healthy control samples to multiple agonists, tested at concentrations used for the diagnosis of platelet disorders (p values <0.05). Laboratories should be aware that measuring ATP release with Chronolume® can potentiate LTA and whole blood aggregation responses, which alters findings for some human platelet disorders, including QPD.

Acquired Disorders of Platelet Function

Hematology ◽  
2005 ◽  
Vol 2005 (1) ◽  
pp. 403-408 ◽  
Author(s):  
Amy A. Hassan ◽  
Michael H. Kroll
Keyword(s):  
Platelet Function ◽  
Hepatic Cirrhosis ◽  
Treatment Options ◽  
Underlying Disease ◽  
Von Willebrand Disease ◽  
Platelet Aggregometry ◽  
Platelet Disorder ◽  
Function Analyzer ◽  
Platelet Function Analyzer ◽  
Von Willebrand

Abstract A qualitative abnormality of platelet function should be considered in patients with mucocutaneous bleeding in the absence of thrombocytopenia or von Willebrand disease. Antiplatelet drugs are the most common cause of acquired platelet disorders leading to bleeding. Uremia, hepatic cirrhosis, myeloma and related disorders, polycythemia vera, essential thrombocythemia, and cardiopulmonary bypass have long been recognized as clinical situations in which platelet dysfunction may contribute to bleeding. When an acquired platelet disorder is suspected, it is useful to examine platelet function by measuring the bleeding time, examining platelet-dependent closure time in a platelet function analyzer and performing platelet aggregometry. When a specific acquired platelet disorder is diagnosed, many treatment options are available including controlling the underlying disease, giving platelet transfusions and administering a hemostatic drug.

Risk and Management of Intracerebral Hemorrhage in Patients with Bleeding Disorders

2022 ◽  
Author(s):  
Akbar Dorgalaleh ◽  
Yadolah Farshi ◽  
Kamand Haeri ◽  
Omid Baradarian Ghanbari ◽  
Abbas Ahmadi
Keyword(s):  
Risk Factors ◽  
Intracerebral Hemorrhage ◽  
Platelet Function ◽  
Hemophilia A ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Vacuum Extraction ◽  
Bleeding Disorders ◽  
Platelet Function Disorders ◽  
Von Willebrand

AbstractIntracerebral hemorrhage (ICH) is the most dreaded complication, and the main cause of death, in patients with congenital bleeding disorders. ICH can occur in all congenital bleeding disorders, ranging from mild, like some platelet function disorders, to severe disorders such as hemophilia A, which can cause catastrophic hemorrhage. While extremely rare in mild bleeding disorders, ICH is common in severe coagulation factor (F) XIII deficiency. ICH can be spontaneous or trauma-related. Spontaneous ICH occurs more often in adults, while trauma-related ICH is more prevalent in children. Risk factors that can affect the occurrence of ICH include the type of bleeding disorder and its severity, genotype and genetic polymorphisms, type of delivery, and sports and other activities. Patients with hemophilia A; afibrinogenemia; FXIII, FX, and FVII deficiencies; and type 3 von Willebrand disease are more susceptible than those with mild platelet function disorders, FV, FXI, combined FV–FVIII deficiencies, and type 1 von Willebrand disease. Generally, the more severe the disorder, the more likely the occurrence of ICH. Contact sports and activities can provoke ICH, while safe and noncontact sports present more benefit than danger. An important risk factor is stressful delivery, whether it is prolonged or by vacuum extraction. These should be avoided in patients with congenital bleeding disorders. Familiarity with all risk factors of ICH can help prevent occurrence of this diathesis and reduce related morbidity and mortality.

Platelet Aggregation in Whole Blood - Studies with a Platelet Counting Technique - Methodological Aspects and Some Applications

1989 ◽  
Vol 61 (03) ◽  
pp. 423-428 ◽  
Author(s):  
C Falcon ◽  
J Arnout ◽  
J Vermylen
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
High Sensitivity ◽  
Optimal Concentration ◽  
Counting Technique ◽  
Platelet Function Disorders ◽  
Methodological Aspects ◽  
Storage Times

SummaryWe describe a method for measuring platelet aggregation in whole blood by single platelet counting. The importance of a low stirring speed (100 rpm) to obtain agonist-specific aggregation is stressed. Despite this low stirring speed, the sensitivity to agonists equals that of the turbidometric technique in platelet-rich plasma. The optimal concentration of formaldehyde for fixing the aggregates, the effects of storage times and anticoagulant are studied. Applicability to the study of platelet function inhibitors or of inherited platelet function disorders is illustrated. It is concluded that this technique, used under the appropriate conditions, combines the advantage of measuring platelet aggregation in a more physiologtc environment with the advantages of the turbidometric technique such as high sensitivity.

scholarly journals Evaluation of Pediatric Bleeding Questionnaire in Turkish Children With Von Willebrand Disease and Platelet Function Disorders

2014 ◽  
Vol 21 (6) ◽  
pp. 565-569 ◽  
Author(s):  
Burcu Belen ◽  
Ulker Kocak ◽  
Melek Isik ◽  
Ebru Yilmaz Keskin ◽  
Nergiz Oner ◽  
...  
Keyword(s):  
Platelet Function ◽  
Von Willebrand Disease ◽  
Turkish Children ◽  
Platelet Function Disorders ◽  
Von Willebrand

Flow Devices to Assess Platelet Function: Historical Evolution and Current Choices

2019 ◽  
Vol 45 (03) ◽  
pp. 297-301 ◽  
Author(s):  
Raisa Silva ◽  
Eric Grabowski
Keyword(s):  
Blood Flow ◽  
Platelet Function ◽  
Von Willebrand Disease ◽  
Cell Monolayers ◽  
Shear Rates ◽  
Platelet Disorders ◽  
Adhesive Proteins ◽  
Von Willebrand ◽  
Flow Devices

AbstractPlatelet function testing, which began more than a hundred years ago, is a time-consuming and uncertain process. Simulating hemostasis and the blood vessel microenvironment in vitro is challenging, which poses a difficulty for diagnosing platelet dysfunction and mild von Willebrand disease (VWD). In an effort to simulate the rheological microenvironment within blood vessels, several blood flow devices have been introduced since the 1980s. These devices are capable of reproducing the shear rates found in arterioles and venules, and of incorporating endothelial cell monolayers and surfaces with adsorbed platelet-adhesive proteins. The authors will describe and review here the presently most well-known blood flow devices. The technologies inherent in these devices offer a combination of physiologic accuracy and small blood volume requirements in the evaluation of platelet disorders and mild VWD (or “symptomatic low von Willebrand factor”) in flowing whole blood, with the potential to individualize therapeutic options for and to achieve greater diagnostic accuracy in mild platelet disorders and VWD.

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