Article

Quantitative measurement of thromboelastography as a function of platelet count

Hiroshima University, Hirosima, Hiroshima, Japan
Anesthesia & Analgesia (Impact Factor: 3.42). 09/1999; 89(2):296-9. DOI: 10.1097/00000539-199908000-00006
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    • "however, that karyotype analysis of the products of conception of those pregnancies that miscarried is not available, and it is of course possible that a pregnancy with an abnormal chromosome complement can advance to the fetal stage of develop- ment Three key questions raised in this study are: (i) whether increases in MA during pregnancy precede pregnancy loss and later pregnancy complications, such as pre-eclampsia and intra-uterine growth restriction, which are thought in some cases to have a thrombotic basis; (ii) whether it is possible to lower the elevated MA seen amongst women with recurrent miscarriage; and (iii) whether lowering the MA leads to an improved live birth rate. As the MA primarily re¯ects platelet function and activity, we are exploring the effect of aspirin, a recognized anti-platelet agent, on the MA (Orlikowski et al., 1996; Oshita et al., 1999). Our preliminary results suggest that whilst 75 mg/day of aspirin has no effect, a dose of 150 mg/day does signi®cantly reduce the MA. "
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    ABSTRACT: Some cases of recurrent miscarriage have a thrombotic basis. Thromboelastography is a rapid, reproducible test of whole-blood haemostasis. Thromboelastography was performed in 494 consecutive, non-pregnant women (median age 35 years; range 21-48) with a history of miscarriages at <12 weeks gestation (median 4; range 3-12) and 55 parous women (median age 33 years; range 20-41) with no history of pregnancy loss. The prospective outcome of untreated pregnancies amongst 108 women with recurrent miscarriage was studied. The maximum clot amplitude (MA) (median 66.0 mm; range 48.0-76.0) was significantly higher and the rate of clot lysis (LY30) (median 2.5%; range 0.5-7.8) significantly lower amongst women with recurrent miscarriage compared with controls (MA 61.5 mm; range 50.0-67.0; P = 0.01; LY30 4.9%; range 2.9-9.7; P = 0.01). The pre-pregnancy MA was significantly higher amongst women who subsequently miscarried (median 66.0 mm; range 54.0-73.0) compared with those whose had a live birth (median 61.7 mm; 48.0-71.5; P < 0.01). A pre-pregnancy MA >or=64 mm has a sensitivity of 68% and specificity of 82% to predict miscarriage. Thromboelastography identifies a subgroup of women with recurrent miscarriage to be in a prothrombotic state outside of pregnancy. Women in such a state are at increased risk of miscarriage in future untreated pregnancies.
    Human Reproduction 12/2003; 18(12):2540-3. DOI:10.1093/humrep/deg494 · 4.59 Impact Factor
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    ABSTRACT: Durch das Rotationsthrombelastometrie System (ROTEM) erlebt die Thrombelastographie Methode (TEG) eine Renaissance als Point of Care Diagnostik zur Erkennung von Hämostasestörungen und Therapiesteuerung. In dieser Studie untersuchten wir einige Einflussgrößen und variabilitätsbestimmende Faktoren, sowie die Empfindlichkeit der Methode gegenüber einzelnen thrombozytären und plasmatischen Gerinnungsstörungen. Wir verwendeten dafür das ROTEM System mit den Tests INTEM (Aktivierung des intrinsischen Gerinnungsystems), EXTEM (Aktivierung des extrinsischen Gerinnungsystems) und NATEM (ohne Zugabe von gerinnungsaktivierende Substanzen). Die Ergebnisse wurden mit den Bestimmungen von Quick, aPTT, Fibrinogenkonzentration, Thrombozytenzahl, Hämoglobinkonzentration (Hb), Hämatokrit (Hkt) verglichen. Weiterhin wurden Methoden zur Messung der Thrombozytenfunktion zum Vergleich herangezogen. Im Einzelnen Untersuchten wir den Einfluss des Zeitintervalls zwischen Blutabnahme und Testbeginn bei Spenderblut und bei Proben von thrombozytopenischen Patienten; zwei unterschiedliche Pippetiermethoden; zwei unterschiedliche EXTEM Reagenzien; Blutverdünnung mit NaCl, Haes und PAP (plättchenarmes Plasma). Wir untersuchten auch die Sensibilität der Methode gegenüber Gerinnungsveränderungen, hervorgerufen durch Einnahme von ASS, Marcumar, Heparin, von Willebrand Syndrom, Thrombozytopenie u.a. Durch Weiterentwicklungen in Technik, Methodik und Reagenzien hat ROTEM wesentliche Fortschritte hinsichtlich einer Standardisierung des Testablaufes gemacht. Es erfüllt viele der Kriterien für eine Point-of-Care Methode. ROTEM kann allerdings die Labordiagnostik nicht ersetzen, sondern nur ergänzen, da die wichtigsten und häufigsten Hämostasestörungen damit nicht oder zumindest nicht ausreichend sicher erkannt werden können. Andererseits ist ROTEM gut geeignet, um perioperativ oder posttraumatisch entstehende Hämostasestörungen vor allem durch stärkere Blutverdünnung oder Hyperfibrinolyse (in der Arbeit nicht untersucht) schnell und ausreichend sensitiv zu erfassen, um gegebenfalls therapeutisch adäquat intervenieren zu können. Für den Einsatz von ROTEM sind aber Standards festzulegen und einzuhalten, da das Verfahren durch zahlreiche Variablen beeinflusst wird und im Einzelfall verfälschte Ergebnisse erbringen kann. The TEG (Thrombelastography) experiences a renaissance through the ROTEM System (Rotationthrombelastometry) as a point-of-care test for the diagnosis and management of different bleeding disorders. In this study we examined several influencing variables and the sensitivity of the method with respect to different bleeding disorders, caused by changes in the function or the count of thrombocytes or the plasmatic coagulation factors. We used the ROTEM system with the tests INTEM (additional aktivation of the intrinsic pathway), EXTEM (additional aktivation of the extrinsic pathway) and NATEM (without additional aktivation). The results were compared with those, additionally determined by other methods: the platelet count, haemoglobin concentration (Hb), haematocrit (Hct), prothrombin time (PT), aktivated partial thromboplastin time (aPTT), fibrinogen concentration, PFA-100® (Platelet Funktion Analyzer 100®, a modified in-vitro bleedung test), VCP (“Virtual Capillary Prototype”, another modified in-vitro bleeding test), aggregometry and coagulometry. Particularly we examined the time interval between blood draw and the beginning of the measurement; two different pipeting methods; two different EXTEM reagents; the influence of haemodilution. Furthermore we examined bloodsamples from people, threated with ASS, phenprocoumon, heparin or suffering from thrombocytopenia or von Willebrand Syndrom. Considerable progress has been achieved in the standardization of ROTEM by altering the technique, method and reagents. It fulfils many of the criteria for a point-of-care test. ROTEM cannot replace the laboratory tests. It can only be a complement to them because it can not reveal the most common haemostasis disorders with an adequate degree of certainty. However, ROTEM is a good and sensitive method for the examination of bleeding disorders, developing perioperativly or posttraumatically, like severe blood dilution or hyperfibrinolysis (not examined in this assay) . By means of ROTEM, quick and important decisions could be made concerning the therapy in these cases. Standards for working with ROTEM have to be established and followed, since there are many variables, influencing the method, which can lead to incorrect results.
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    ABSTRACT: Background: Thromboelastography (TEG) is relatively recent assay to analyze the coagulation state of a blood sample, providing a continuous visualization of physical changes occurring during blood coagulation. There is a paucity of published literature on assessment of coagulation status using TEG in Indian population. Aim: The primary aim of the following study is to establish normal reference values for TEG in North Indian healthy volunteers and secondary aim is to compare them with conventional plasma-based routine coagulation tests and the manufacturers reference range. Materials and Methods: A total of 200 healthy volunteers comprised of 100 males and 100 females of age groups between 20 and 50 years, were enrolled over a period of 1 year, i.e., 2011-2012. Thromboelastometry (TEM) was performed on TEM-A automated thromboelastometer (Framar Biomedica, Rome, Italy), using whole blood non-additive (360 µl). TEG parameters analyzed were r-time, k-time, α-angle, maximal amplitude (MA). Prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet count was performed for all volunteers. The 95% reference range was calculated as (mean-1.96 standard deviation [SD]) to (mean + 1.96 SD). Results: Our reference values for 95% of 200 volunteers were r-time: 1.8-14.2 min, k-time: 0.7-7.3 min, α-angle: 27.3-72.3° and MA: 32.1-87.9 mm. Maximum clot strength was higher in women compared with men, however statistically insignificant. Overall 14.5% (29/200) of the volunteers had at least one abnormal parameter while 74% (149/200) had deranged TEG values using the manufacturer's reference range. Statistically significant variation was seen in r-time for 84.8% (P < 0.001), for k-time, in 87.1% (P < 0.001), for α-angle in 83.7% (P < 0.001) and for MA in 84% (P < 0.001), between the manufacturer and our reference range. Conclusion: The efficacy of classical coagulation test has been well-established; on the contrary TEG is a fairly recent assay and its utility for patient management remains to be demonstrated. We observed TEG to be oversensitive in determining coagulopathy where there is no clinical presentation. The manufacturer's reference values may not be appropriate for different ethnicity. TEG may give an overall representation of hemostasis; however, it cannot replace the conventional coagulation tests. We recommend the determination of normal TEG values by each laboratory for their target population.
    Indian Journal of Pathology and Microbiology 01/2014; 57(1):43-50. DOI:10.4103/0377-4929.130896 · 0.64 Impact Factor
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