A pilot study evaluating the Calibrated Automated Thrombogram assay and application of plasma-thromboelastography for detection of hemostatic aberrations in horses with gastrointestinal disease

Background Critically ill horses, such as horses with gastrointestinal (GI) disease, often suffer from hemostatic aberrations. Global hemostatic tests examining the initiation of coagulation, clot strength and fibrinolysis, such as the Calibrated Automated Thrombogram (CAT) and plasma-thromboelastography (TEG) have not been evaluated in horses. This study aimed to evaluate CAT and apply plasma-TEG in horses. Test performance of CAT was evaluated on equine platelet poor plasma with intra- and inter-assay variability (CV) and a heparin dilution curve. To examine clinical performance of both tests, group comparisons were assessed comparing healthy horses, horses with mild and severe GI disease with both CAT and plasma-TEG. Results For CAT, intra- and inter-assay CVs were established for lag-time (1.7, 4.7%), endogenous thrombin potential (1.6, 4.6%), peak (2.6, 3.9%) and time to peak (ttPeak) (1.9, 3.4%). Increasing heparin concentrations led to the expected decrease in thrombin generation. In the group comparison analysis, CAT showed significant higher peak (p = 0.04) and ttPeak (p = 0.008) in the severe GI disease group compared to horses with mild GI disease and healthy horses, respectively. Plasma-TEG showed an increased angle (p = 0.032), maximum amplitude (p = 0.017) and shear elastic force (G) (p = 0.017) in the severe GI disease group compared to healthy horses. Conclusions CAT performed well in horses. Both CAT and plasma-TEG identified hemostatic aberrations in horses with severe GI disease compared to healthy horses. Further studies including more horses, are needed to fully appreciate the use of CAT and plasma-TEG in this species.

Investigating the Kinetics of Blood Coagulation Using High-Frequency Ultrasound

Blood circulation requires regulated clot formation and breakdown to prevent blood loss following an injury and to ensure that clots do not form and circulate within the vasculature. Known as hemostasis, this delicate balance between coagulant and anti-coagulant pathways can be disrupted by disease, medication, or trauma, and may lead to morbidity or mortality. Current in vitro hemostatic tests have shown promise as tools for diagnosis and risk assessment in certain disorders. However, these tests are limited in their ability to assess the complete hemostatic process or are restricted to studies of blood plasma. In this work, high frequency ultrasound is proposed as a method of assessing hemostasis in whole blood samples. A system was developed and experiments were performed by monitoring acoustic changes in mouse blood during coagulation. Blood cell motion and frequency dependant changes in ultrasound intensity were found to be sensitive to the kinetics of clot formation

Investigating the Kinetics of Blood Coagulation Using High-Frequency Ultrasound

Blood circulation requires regulated clot formation and breakdown to prevent blood loss following an injury and to ensure that clots do not form and circulate within the vasculature. Known as hemostasis, this delicate balance between coagulant and anti-coagulant pathways can be disrupted by disease, medication, or trauma, and may lead to morbidity or mortality. Current in vitro hemostatic tests have shown promise as tools for diagnosis and risk assessment in certain disorders. However, these tests are limited in their ability to assess the complete hemostatic process or are restricted to studies of blood plasma. In this work, high frequency ultrasound is proposed as a method of assessing hemostasis in whole blood samples. A system was developed and experiments were performed by monitoring acoustic changes in mouse blood during coagulation. Blood cell motion and frequency dependant changes in ultrasound intensity were found to be sensitive to the kinetics of clot formation

Longitudinal Dynamics of Coagulation and Angiogenesis Markers in Cancer Patients During and After Chemotherapy

Hemostatic parameters have been investigated as molecular determinants of tumor progression. To analyze the dynamics of microparticle-associated tissue factor activity (MPTF), tissue factor antigen (TF-Ag), and angiopоietin-2 (ANG-2) in cancer patients before, during, and after active treatment and to explore their potential as biomarkers for metastatic occurrence and death. Blood for the analysis of MPTF, TF-Ag, ANG-2, and conventional hemostatic tests was sampled in 111 patients with various cancers at 4 consecutive visits: before first chemotherapy cycle, after 3 courses, at the sixth course, and 3 months after chemotherapy cessation. Patients were followed up until metastatic progression/death or the end of the study. MPTF did not change during chemotherapy, but increased significantly after treatment cessation. Total TF-Ag and ANG-2 decreased throughout active treatment. Significant drop of their levels was observed 3 months post therapy cessation. Progressive disease was significantly associated with higher pre-chemotherapy TF-Ag and fibrinogen. Elevated baseline levels of fibrinogen were associated with increased risk of shortened progression free survival. Cessation of chemotherapy is associated with significant change of hemostatic parameters. Pre-chemotherapy levels of TF-Ag and fibrinogen may be informative of disease state and prognosis.

Coagulation Profiles of Pulmonary Arterial Hypertension Patients, Assessed by Non-Conventional Hemostatic Tests and Markers of Platelet Activation and Endothelial Dysfunction

Many pathophysiologic processes of pulmonary arterial hypertension (PAH), namely, excess vasoconstriction, vascular remodeling and in situ thrombosis, involve the coagulation cascade, and more specifically, platelets. The aim of this study was to globally assess coagulation processes in PAH, by using non-conventional hemostatic tests, along with markers of platelet activation and endothelial dysfunction. We studied 44 new PAH patients (22 with idiopathic PAH and 22 with connective tissue disease) and 25 healthy controls. The following tests were performed: platelet function analyzer-100 (PFA-100), light transmission aggregometry (LTA), rotational thromboelastometry (ROTEM), endogenous thrombin potential (ETP), serotonin, thromboxane A2 and p-selectin plasma levels, and von Willebrand antigen (VWF:Ag) and activity (VWF:Ac). Our results showed that PAH patients had diminished platelet aggregation, presence of disaggregation, defective initiation of the clotting process and clot propagation, and diminished thrombin formation capacity. Serotonin, thromboxane A2 and p-selectin levels were increased, and VWF:Ag and VWF:Ac decreased in the same population. The results of this study suggest that the platelets of PAH patients are activated and present functional abnormalities. The procoagulant activity, in general, appears to be impaired probably due to a sustained and prolonged activation of the procoagulant processes. Larger observational studies are warranted to confirm these laboratory findings.

Effect of transportation and freeze-thaw procedure on hemostatic tests

ObjectiveCoagulation tests are sensitive to pre-analytical variables. The aim of our study is to identify the effect of transportation and freeze-thaw status on for Factor VIII, Factor IX, Anti-thrombin III, Protein S, Protein C, Prothrombin time (PT) and Activated partial thromboplastin time (aPTT).Materials and methodsThe study was performed on 102 plasma samples obtained from 34 healthy volunteers. The samples were divided into three groups. Group A was analyzed whereas group B, C were frozen at −20°C. After 24 h, group B and C were transported for 2 h. Following the transfer, group B was analyzed and C was frozen at −20°C. After 24 h, group C was analyzed. Analyses of samples were performed in Thrombolyzer-XRM for PT, aPTT, Factor VIII, Factor IX, Anti-thrombin III, Protein C and Protein S.ResultsThere were significant variations for PT, aPTT, Protein S, Factor VIII and Factor IX for group A&B and A&C comparisons in different stability criteria approaches. In significant change limit and percentage change calculations Protein S, Factor VIII and IX showed significant differences. For acceptable change limit approach, aPTT and Factor IX showed significant changes.ConclusionLaboratories should take precautions for transportation and freeze-thaw cycles to prevent inaccurate results.

Modern aspects of the pathogenesis, diagnosis and therapy of hemostasis disorders in children with acute leukemias

Patients with oncohematological diseases, both children and adults, face high risks of thrombotic and hemorrhagic complications.About 40 % of pediatric patients with acute lymphoblastic leukemia develop bleedings, and the incidence of thrombosis in this disease ranges from 1 to 36 %. Most thromboses are associated with the use of central venous catheters and the use of L-asparaginase, which leads to a significant reduction in the synthesis of coagulation proteins.Massive hemorrhages account for two-thirds of all causes of early death in pediatric patients with acute myelogenous leukemia (AML). Absolute risks of death due to bleeding and leukostasis range from 1.8 % in the total population of children with AML to 14.3 % in a population with hyperleukocytosis more than 200 × 109 /l. The risk of thrombotic complications in children with AML varies between 3.4–11 %. In patients with AML, complex systemic coagulopathies may occur, such as disseminated intravascular coagulation (DIC), excessive fibrinolysis, or nonspecific proteolysis. This scale is not yet applicable due to the lack of research on its effectiveness in the pediatric population. The laboratory diagnostics of hemostasis is difficult due to the combined nature of thrombotic and hemorrhagic complications: bleeding, thrombosis and even DIC syndrome (combining both hyper- and hypocoagulation phases) can be expected in each specific patient with hemoblastosis. Because of the long-term nature of the treatment and the varying intensity of the various treatment units, the patient’s hemostasis during disease manifestation does not allow one to predict with any certainty the complications on induction or consolidation therapy. Involving all the components of the hemostasis system – vascular, platelet and plasma – into the pathological process makes prediction and diagnosis of thrombohemorrhagic complications impossible with the help of standard hemostatic tests and a general blood test, since these tests are designed to assess the concentrations of individual proteins and the functioning of individual components of the hemostatic system, and does not assess the balance between its procoagulant and anticoagulant components. Global hemostatic tests such as thromboelastography, thrombodynamics and thrombin generation test adequately reflect hypercoagulable conditions and can serve as a basis for the development of a new set of laboratory hemostasis tests.Conflict of interest. F.I. Ataullakhanov is co-founder of HemaCore LLC, which holds several patents and patent applications that are related to the diagnostic use of Thrombodynamics® (Ataullakhanov F.I., international patent applications: PCT/CH2007/000543 filing date 02.11.2007 and РСТ/RU2012/000570 filing date 16.07.2012). None of the other authors has any competing interests to declare.

CHANGES OF HEMOSTATIC PARAMETERS IN PRENATAL AND POSTNATAL PERIODS AT WOMAN WITH CESAREAN DELIVERY

Введение. Выделение группы риска венозных тромбоэмболических осложнений (ВТЭО) является непростой задачей. На сегодняшний день врачи пользуются балльными шкалами риска, которые учитывают только анамнестические данные и никак не показатели лабораторных тестов гемостаза. Цель исследования. Провести сравнительную оценку показателей плазменного звена гемостаза в дородовом и послеродовом периодах у женщин, родоразрешенных путем операции кесарева сечения, в группах высокого, среднего и низкого риска ВТЭО. Материалы и методы. Обследовано 235 беременных в возрасте 21–45 лет. Отбор проб крови проводили в 4 точках: точка 1 — непосредственно до кесарева сечения; точка 2 — через 3–5 часов после окончания операции; точка 3 — через 2 суток после окончания операции; точка 4 — через 4 суток после окончания операции. Измеряли содержание фибриногена и Д-димера, протромбина по Квику и активированное частичное тромбопластиновое время. Риск ВТЭО оценивали согласно шкале RCOG Green-top Guidelines №{37a; cтепень риска развития ВТЭО определяли по сумме баллов. Результаты. Выявлено, что степени риска развития ВТЭО у женщин в послеродовом периоде, определенные из анализа анамнестических данных и лабораторных показателей системы гемостаза, дают различную картину состояния пациенток, что может нести дополнительную информацию о состоянии системы свертывания конкретной пациентки. Заключение. Д-димер может быть использован как маркер тромботической готовности у женщин после операции кесарева сечения, так как все остальные проанализированные параметры изменялись в пределах референтных диапазонов, характерных для послеродового периода. Introduction. To select a risk group of venous thromboembolic complications (VTE) is not a simple task. Today doctors use scales of risk scores that take into account only anamnestic data, and do not take into account hemostatic laboratory tests. The aim of study: comparative assessment of plasma hemostatic parameters in prenatal and postnatal periods in women delivered by Cesarean section with high, medium and low VTE risks. Materials and methods. We examined 235 pregnant women aged 21–45 years. Blood hemostatic parameters analyzed at 4 points: point 1 — before Cesarean section; point 2–3–5 hours after the end of operation; point 3–2 days after operation; point 4–4 days after operation. We measured fi brinogen and D-dimer levels, prothrombin (Quick’s value) and activated partial thromboplastin time. VTE risk assessed according to RCOG scale Green-top Guidelines №{37a; degree of VTE risk development determined by the sum of scores. Results. It was revealed that VTE risk at women in postnatal period obtained from the analysis of anamnestic data and hemostatic tests gave a diff erent picture of patients’ state which can provide additional information about hemostasis of a particular patient. Conclusion. D-dimer can be used as a marker of thrombotic readiness in women after Cesarean section, since all other analyzed parameters varied within reference ranges typical for postpartum.