Thrombin generation assays: Accruing clinical relevance

Synapse BV, Cardiovascular Research Institute, 6200 MD Maastricht, The Netherlands.
Current Opinion in Hematology (Impact Factor: 3.97). 06/2004; 11(3):170-5. DOI: 10.1097/01.moh.0000130314.33410.d7
Source: PubMed


After decades of near oblivion, thrombin generation is being revived as an overall function test of the plasmatic coagulation system in platelet-poor plasma (PPP). In platelet-rich plasma (PRP) it assesses platelet procoagulant functions as well.
The recently developed use of special fluorogenic thrombin substrates allows monitoring of thrombin concentration in clotting PPP and PRP on line in up to 24 parallel samples. Studies in model systems stress the importance of cell-bound thrombin generation such as measured in PRP.
The method can be profitably applied to various hitherto unyielding problems such as the control of (low-molecular-weight) heparin therapy, the detection of lupus anticoagulant, and various forms of thrombomodulin and activated protein C resistance (including the use of oral contraceptives) as well as monitoring the treatment of hemophiliacs by factor VIII bypassing therapy. In PRP it reflects the abnormalities encountered in von Willebrand disease and Glanzmann and Bernard-Soulier thrombopathy as well as the action of antiplatelet drugs.

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Available from: H. Coenraad Hemker,
    • "Reconstituted systems are as realistic as our insight into the clotting mechanism allows: extrapolation to physiology should therefore be regarded with due suspicion. Hemker et al. 58 (2004, p. 171). "
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    ABSTRACT: Traumatic-induced coagulopathy (TIC) is a hemostatic disorder that is associated with significant bleeding, transfusion requirements, morbidity and mortality. A disorder similar or analogous to TIC was reported around 70 years ago in patients with shock, hemorrhage, burns, cardiac arrest or undergoing major surgery, and the condition was referred to as a "severe bleeding tendency," "defibrination syndrome," "consumptive disorder," and later by surgeons treating US Vietnam combat casualties as a "diffuse oozing coagulopathy." In 1982, Moore's group termed it the "bloody vicious cycle," others "the lethal triad," and in 2003 Brohi and colleagues introduced "acute traumatic coagulopathy" (ATC). Since that time, early TIC has been cloaked in many names and acronyms, including a "fibrinolytic form of disseminated intravascular coagulopathy (DIC)." A global consensus on naming is urgently required to avoid confusion. In our view, TIC is a dynamic entity that evolves over time and no single hypothesis adequately explains the different manifestations of the coagulopathy. However, early TIC is not DIC because an increased thrombin-generating potential in vitro does not imply a clinically relevant thrombotic state in vivo as early TIC is characterized by excessive bleeding, not thrombosis. DIC with its diffuse anatomopathologic fibrin deposition appears to be a latter phase progression of TIC associated with unchecked inflammation and multiple organ dysfunction.
    08/2015; 79(2):301-309. DOI:10.1097/TA.0000000000000729
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    • "Thrombin also activates platelets, and furthermore, besides procoagulant effects it has also anticoagulant effects following its binding to thrombomodulin. Ex vivo TG tests, like CAT, measure the haemostatic function of the blood, determined by simultaneous prothrombin activation and thrombin inactivation [9]: it measures the remaining capacity of blood to generate a thrombin burst indicating an increased risk of thrombosis or bleeding [11]. In contrast, in vivo TG, revealed by products like prothrombin fragment F1+2, thrombin antithrombin complex, and d-dimers, provides indications of TG that has already occurred [12] at the moment of blood collection. "
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    ABSTRACT: Background In this study the value of thrombin generation parameters measured by the Calibrated Automated Thrombography for prediction of blood loss after cardiac surgery with cardiopulmonary bypass was investigated. Methods Thirty male patients undergoing first-time coronary artery bypass grafting were enrolled. Blood samples were taken pre-bypass before heparinisation (T1) and 5 min after protamine administration (T2). Thrombin generation was measured both in platelet-rich plasma and in platelet-poor plasma. Besides thrombin generation measurements, activated clotting time, haematocrit, haemoglobin, platelet number, fibrinogen, antithrombin, D-dimers, prothrombin time and activated partial thromboplastin time were determined. Blood loss was measured and the amount of transfusion products was recorded postoperatively until 20 hours after surgery. Patients were divided into two groups based on the median volume of postoperative blood loss (group 1: patients with median blood loss <930 ml; group 2: patients with median blood loss ≥930 ml). Results On T1, patients of group 2 had a significantly lower endogenous thrombin potential and peak thrombin (p<0.001 and p=0.004 respectively) in platelet-rich plasma, a significantly lower endogenous thrombin potential (p=0.004) and peak thrombin (p=0.014) in platelet-poor plasma, and a lower platelet count (p=0.002). On T2 both endogenous thrombin potential and peak thrombin remain significantly lower (p=0.011 and p=0.010) in group 2, measured in platelet-rich plasma but not in platelet-poor plasma. In addition, platelet number remains lower in group 2 after protamine administration (p=0.002). Conclusions The key finding is that the Calibrated Automated Thrombography assay, performed preoperatively, provides information predictive for blood loss after cardiac surgery.
    Journal of Cardiothoracic Surgery 06/2013; 8(1):154. DOI:10.1186/1749-8090-8-154 · 1.03 Impact Factor
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    • "Activated recombinant FVII was added to the plasma (1.26 µg/ml, approximately equivalent to a 90 µg/kg clinical dose [14]. Thrombin generation was studied according to the assay of Hemker et al. [25] [27] [28]. Briefly, thrombin generation was triggered by adding a solution containing Tissue Factor (TF), phosphatidyl choline/phosphatidyl serine (PCPS;Hemotologic Technologies), CaCl2 and Fluorogenic thrombin substrate Z-Gly-Gly-Arg- AMC HCl (Bachem) to 80µL platelet poor plasma. "
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    ABSTRACT: Coagulopathy can occur after hemorrhage, trauma and resuscitation, and has been associated with dilution of coagulation factors and hypothermia. Recombinant activated Factor VII (rFVIIa) has been used, often as a last resort, to improve hemostasis in trauma/hemorrhage patients with coagulopathy. The aim of this study was to further characterize the effects of rFVIIa on various coagulation parameters and the influence of temperature and hemodilution. WHOLE BLOOD FROM HEALTHY HUMAN VOLUNTEERS WAS INCUBATED IN A COMBINATION OF THREE CONDITIONS: undiluted or diluted 40% with either lactated Ringer's solution or Hextend, at 37°C or 34°C, and with and without rFVIIa (1.26 μg/ml, final concentration). Blood or plasma, as appropriate, was measured for coagulation by thrombin generation, thromboelastography (TEG), prothrombin Time (PT) and activated partial thromboplastin (aPTT). Incubation of plasma at 34°C significantly elevated thrombin generation, and prolonged PT and aPTT. Dilution of blood or plasma with 40% Hextend, but not lactated Ringer's, had a significant effect on TEG parameters, and prolonged PT and aPTT. In control conditions (37°C, 0 dilution), the addition of rFVIIa to human plasma or whole blood led to a significant change in all TEG parameters, and Lagtime for thrombin generation, but not to PT or aPTT. Theses data show that thrombin generation is affected by hypothermia, but not 40% dilution. TEG is affected by 40% dilution with Hextend, but not by hypothermia. PT and aPTT are significantly affected by both hypothermia and dilution. Recombinant FVIIa caused a greater change in thrombin generation at 34°C as compared to 37°C, and a greater change in PT at 40% dilution, suggesting that the effect of rFVIIa on coagulation is both temperature and dilution dependant.
    International Journal of Burns and Trauma 08/2012; 2(1):42-50.
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