Management of major trauma haemorrhage: treatment priorities and controversies

The severely injured trauma patient often arrives in the emergency department bleeding, coagulopathic and in need of a blood transfusion. The diagnosis and management of these patients has vastly improved with a better understanding of acute traumatic coagulopathy (ATC). In the emergency setting, traditional laboratory coagulation screens are of limited use in the diagnosis and management of life-threatening bleeding. Whole blood assays, such as thrombelastography (TEG) and rotational thrombelastometry (ROTEM) provide a rapid evaluation of clot formation, strength and lysis. Rapid diagnosis of ATC and aggressive haemostatic transfusion strategies utilizing early high doses of plasma are associated with improved outcomes in trauma. At present there is no accurate guide for transfusion in trauma, therefore blood and clotting products are administered on an empiric basis. Targeted transfusion therapy for major trauma haemorrhage based on comprehensive and rapid measures of coagulation e.g. TEG/ROTEM may lead to improved outcomes while optimizing blood utilization. Evidence for the clinical application of TEG and ROTEM in trauma is emerging with a number of studies evaluating their ability to diagnose coagulopathy early and facilitate goal-directed transfusion. This review explores current controversies and best practice in the diagnosis and management of major haemorrhage in trauma.     

Thromboelastography reflects global hemostatic variation among severe haemophilia A dogs at rest and following acute exercise

Summary.  The heterogeneity among severe haemophilia A patients reflects on variable tendencies for bleeding and also variable responses to FVIII therapy. This variability cannot be detected or predicted by routine coagulation tests. Thromboelastography (TEG) has recently been evaluated for assessing hemostatic patterns in haemophiliacs and proved valuable in monitoring therapy and/or prophylaxis, however, usually only in limited small case series. Exercise is an important component of overall haemophilia care, however, in severe haemophiliacs there is an increased risk of bleeding. The availability of a validated hemostatic test to evaluate the influence of exercise would be advantageous. This study has used TEG analysis to evaluate the global hemostatic status of a group of severe haemophilia A dogs at rest and after a standardized period of exercise. The study demonstrated significant inter and intra-individual variations based on TEG patterns at rest and following acute exercise as well as significant improvement of global hemostasis after exercise in the majority of tested dogs. The study supports the utilization of TEG in assessment of the hemostatic pattern in severe haemophilia A and provides a potential for utilizing TEG evaluation in managing exercise regimens for haemophilia care.     

Thromboelastography and recombinant factor VIIa—hemophilia and beyond

Thromboelastography (TEG), which records the continuous profiles of whole blood (WB) coagulation, can be used to evaluate the effects of hemostatic agents, such as recombinant factor VII (rFVIIa). Our group has developed a revised TEG model, involving activation with minute amounts of tissue factor and subsequent signal processing, and has used this method to evaluate the effects of rFVIIa both in patients with hemophilia and in those receiving vitamin K antagonist (VKA) thromboprophylaxis. We review the early results of our investigations, which suggest that, in clinical situations where rFVIIa has shown benefit, the changes in the profiles obtained by TEG recording appear to correlate with the clinical outcome.     

Thrombelastography does not predict clinical response to rtPA for acute ischemic stroke

Thrombelastography (TEG) measures coagulation in venous blood. We hypothesized that TEG, by reflecting clot subtype and ex vivo fibrinolysis, might predict fibrinolytic response to tPA as reflected by rapid clinical improvement or hemorrhagic transformation of the infarct. 171 acute ischemic stroke patients treated with tPA were prospectively enrolled. Venous blood for TEG was drawn before and 10 min after tPA bolus. We measured rapid clinical improvement (RCI = 8 point improvement on NIHSS or total NIHSS of 0, 1 at 36 h), Hemorrhagic transformation (HT = any blood on imaging within 36 h), and hyperdense middle cerebral artery sign (HDMCA = biomarker for erythrocyte-rich clot). Multivariable regression models compared TEG parameters after adjusting for potential confounders. No differences in pre- or post-tPA TEG were found between patients with or without RCI. Also, there was no correlation between TEG and HDMCA. Clotting was slightly prolonged in patients with HT (p = 0.046). We failed to find a robust association between TEG and clinical response to tPA. It is likely that arterial clot lysis is determined by factors unrelated to coagulation status as measured by TEG in the venous circulation. It is unlikely that TEG will be useful to predict clinical response to tPA, but may help predict bleeding.     

血栓弹力图在危重患者救治中的应用评价

目的:探讨血栓弹力图仪在监测重症患者凝血功能中的应用及对临床输血治疗的指导意义。方法:对4例术中及术后存在严重凝血功能障碍的患者,采用TEG 5000型弹力图仪监测其凝血过程,并根据检测结果提出合理化治疗建议。结果:例1患者普通杯检测R值过高且其他参数均无法测出,追加肝素酶杯监测,提示患者体内肝素存留过量且血小板水平低下;其余3例患者均处于DIC的不同时期,血小板水平低下,存在严重的出血症状;且检测结果还显示3例患者的凝血因子活性偏强,多与临床输注大量血浆有关。结论:运用血栓弹力图能够及时、全面地反映患者的凝血现状,具有较高的临床相关性。同时可以针对不同患者实现个体化输血治疗。     

Effects of recombinant activated factor VII on coagulation measured by thromboelastography in liver transplantation.

Besides the conventional laboratory tests, thromboelastography (TEG) is used to monitor hemostasis during liver transplantation. A previous pilot study suggested a beneficial effect of recombinant activated factor VII (rFVIIa) on transfusion requirements in liver transplantation. In the present study, we assess the effects of rFVIIa on coagulation variables and TEG. In six study patients, the prothrombin time (PT), the activated partial thromboplastin time (aPTT) and TEG variables [reaction time (r), kinetic time (k), or clot formation time, alpha angle (alpha), and maximal amplitude (MA)] were recorded before and after the administration of a bolus of 80 microg/kg rFVIIa. These patients were compared with six controls who did not receive rFVIIa. In contrast with the control group, a significant shortening of PT (P = 0.028) and aPTT (P = 0.028), r (P = 0.046) and k (P = 0.043) values, and a significant incline of the alpha angle (P = 0.028) were noticed after injection of rFVIIa, whereas MA increased not significantly (P = 0.075). rFVIIa rapidly improved coagulation variables in liver transplant patients including PT and aPTT. Of the TEG variables, r, k and alpha angle significantly improved, and MA showed a trend to increase. These data suggest that rFVIIa not only influences the speed of clot formation, but also the physical properties of the clot, which cannot be detected by routine coagulation tests.     

Thromboelastographic evaluation of coagulation in patients with extrahepatic portal vein thrombosis and non‐cirrhotic portal fibrosis: A pilot study

Background and Aims: Non‐cirrhotic portal hypertension due to extrahepatic portal vein thrombosis (EHO) and non‐cirrhotic portal fibrosis (NCPF) is a major cause of upper gastrointestinal hemorrhage in India. Hypercoagulability has been proposed to explain the thrombosis in the portal vein in EHO and intrahepatic portal vein radicals in NCPF. However, some authors have reported hypocoagulability in these patients. Thromboelastography (TEG), which gives a dynamic assessment of coagulation, has potential for evaluating coagulation in these patients but has not been used so far. It was the aim of this study to evaluate the coagulation status in patients of EHO and NCPF using TEG. Methods: Thirty patients with EHO and 19 patients with NCPF were studied. TEG was done in all patients. R (reaction time), K (constant), α (angle), MA (maximal amplitude), A 60 (width of tracing after 60 min) were recorded and TEG index calculated and compared to controls. Results: Seven patients (23.3%) in the EHO group and eight (42.1%) in the NCPF group had severe thrombocytopenia (platlets, < 50 000 cells/dL). TEG showed significantly shorter R, higher MA and larger A in both EHO and NCPF compared to controls (P < 0.01). Thrombocytopenia normalized A but R continued to be significantly shorter in EHO and NCPF. Overt hypercoagulability (TEG index, > +2.5) was seen in two patients with EHO and one patient with NCPF. Conclusion: A latent hypercoagulable state exists in patients with EHO and NCPF which is partially masked by the thrombocytopenia secondary to splenomegaly and hypersplenism.     

血栓弹力图在冠状动脉介入治疗患者抗血小板治疗中的应用研究

目的研究血栓弹力图（TEG）在评价抗血小板治疗疗效中的作用。方法纳入因冠心病接受PCI术后出现氯吡格雷抵抗患者50例,在接受氯吡格雷加量前后分别通过TEG检测血小板抑制率,对比两次TEG结果。结果强化抗血小板治疗后,所有患者TEG结果较前均显示血小板抑制率明显增加[（60.02±3.12）%vs.（21.26±3.68）%,P〈0.05],反应时间和凝固时间较前延长,凝血酶形成速度减慢,血凝块稳定性降低。结论 TEG能较准确地反映患者抗血小板状态,可作为抗血小板治疗评价指标。     

Evaluation of hemostatic balance in blood from patients with polycythemia vera by means of thromboelastography: the effect of isovolemic erythrocytapheresis

Polycythemia vera (PV) is associated with an increased frequency of thrombotic complications. This study was undertaken to evaluate the hemostatic balance in the blood of PV patients by means of thromboelastography (TEG). The effect of isovolemic erythrocytapheresis (ECP) on the hemostasis of PV patients was also studied. We assessed the coagulation status of 76 PV patients undergoing ECP and 50 of healthy controls. TEG measurements were performed immediately before and after the ECP procedure. Coagulation was triggered by recalcification in freshly collected citrated blood. We recorded clotting time (R), alpha angle, and maximum amplitude (MA) of the clot. The results presented here show that, compared with healthy controls, PV patients demonstrated an increase in alpha angle (p<0.005) and in MA (p=0.14). In the subgroup of PV patients with high (>440 × 10(9)l(-1)) platelet (PLT) count, differences in MA (p<0.01) and alpha angle (p<0.001) were more significant. Following ECP procedure, a significant (p ≤ 0.01) reduction of R time, a rise of alpha angle, and MA were observed, indicating augmentation of a hypercoagulable state. In PV patients, the rise in alpha angle positively correlated (r=0.549) with platelet count but not with the number of erythrocytes and leukocytes. Following ECP, this correlation was reduced (r=0.382). Dilution (with saline) of blood from PV patients and of healthy controls, to a degree similar to that used during the ECP procedure, resulted in reduction of R and rise of the alpha angle. In conclusion, TEG measurements show that the majority of PV patients demonstrate abnormal hemostasis in which a major role is played by platelets rather than plasma factors. The hypercoagulable state in PV patients is significantly augmented following the ECP and may be related to the hemodilution intrinsically included in this procedure. TEG may help to assess the thrombotic risk in individual PV patients.     

Global hemostasis in pregnancy: are we using thromboelastography to its full potential?

Pregnancy is a unique situation where significant physiological changes in all maternal organ systems take place. Most of these changes return to normal after delivery. During normal pregnancy the hemostatic balance changes in the direction of hypercoagulability, thus decreasing bleeding complications at time of delivery. The pregnancy-associated hypercoagulability sets a foundation for hemostatic abnormalities during pregnancy and may be associated with pregnancy complications. Assessment of the hemostatic status in pregnancy and its complications can be critical to diagnosis and management not only within the obstetric ward but in trauma, anesthesia, and other situations. Conventional global tests such as prothrombin time and activated partial thromboplastin time cannot define this status appropriately, and full assessment requires measurements of several parameters. Thromboelastography (TEG) is a global hemostatic test that can analyze both coagulation and fibrinolysis. The technique has been available since the 1940s, but only recently has it shown great impact within the clinical practice arena. TEG measures the interactive dynamic coagulation process from the initial fibrin formation to platelet interaction and clot strengthening to fibrinolysis, which makes it superior to other conventional tests. In addition, TEG can guide therapy by documenting changes in coagulation in vitro before a therapy is instituted and also by helping the clinician make critical decisions. Despite the clear value as a test for monitoring hemostatic status of pregnancy-related complications, TEG is still underused for reasons such as poor awareness regarding the technique and interpretations, lack of full standardization, and the unavailability of large clinical studies. However, the fact remains that TEG is undoubtedly attractive to both researchers and clinicians, particularly in a point-of-care setting. We hope that much more investment is directed to TEG studies in both experimental and clinical fields to improve applications and promote use, especially with respect to clinical decision making in pregnancy-related complications.     

First report of the point-of-care TEG: A technical validation study of the TEG-6S system

Thrombelastography (TEG) measured by the TEG5000 Hemostasis Analyzer is an established but the labor-intensive method for assessing global hemostasis. The first true point-of-care TEG, the TEG6s system, uses resonance-frequency viscoelasticity measurements and a disposable multi-channel microfluidic cartridge to assess hemostasis and response to antiplatelet therapy. TEG assays (n = 5,100) were performed on the blood of healthy volunteers (n = 157) and patients undergoing coronary revascularization at three hospitals (n = 300). The results from the TEG6s were compared with the conventional TEG5000 in accordance with Clinical and Laboratory Standards Institute (CLSI) and FDA recommendations. Precision testing was conducted using blood from healthy donors, all assays were run for 5 consecutive days in duplicate using multiple operators, lots, and instruments. Reference ranges were comparable between the TEG systems.

Deming regression analysis demonstrated a strong correlation between the two systems for the standard hemostasis tests (R r = 0.932, MA r = 0.972, LY30 r = 0.938). Method comparison analysis showed an acceptable agreement between PlateletMapping (PM) assays for measuring arachidonic acid (indicator of aspirin response)- and adenosine diphosphate (indicator of P2Y₁₂ inhibitor response)-induced platelet aggregation (total agreement = 90%, and 72%, respectively). TEG6s precision testing yielded low variability (CV 0–13%) in all measures. The new point-of-care TEG6s is associated with greater ease of use than the TEG5000 and provides precise results. The results correlated between methods for all variables. TEG6s is a promising device for near-patient hemostasis monitoring and future trials of personalized therapy designed to reduce bleeding and thrombosis.     

Viscoelastic tests in liver disease: where do we stand now?

Hemostasis is a complex physiological process based on the balance between pro-coagulant and anticoagulant systems to avoid pathological bleeding or thrombosis. The changes in standard coagulation tests in liver disease were assumed to reflect an acquired bleeding disorder, and cirrhotic patients were considered naturally anticoagulated. In the light of the new evidence, the theory of rebalanced hemostasis replaced the old concept. According to this model, the hemostatic alteration leads to a unique balance between pro-coagulant, anticoagulant, and fibrinolytic systems. But the balance is fragile and may prone to bleeding or thrombosis depending on various risk factors. The standard coagulation tests [INR (international normalized ratio), platelet count and fibrinogen] only explore parts of the hemostasis, not offering an entire image of the process. Rotational thromboelastometry (ROTEM) and thromboelastography (TEG) are both point of care viscoelastic tests (VET) that provide real-time and dynamic information about the entire hemostasis process, including clot initiation (thrombin generation), clot kinetics, clot strength, and clot stability (lysis). Despite prolonged PT/INR (international normalized ratio of prothrombin time) and low platelet counts, VET is within the normal range in many patients with both acute and chronic liver disease. However, bleeding remains the dominant clinical issue in patients with liver diseases, especially when invasive interventions are required. VET has been shown to asses more appropriately the risk of bleeding than conventional laboratory tests, leading to decrial use of blood products transfusion. Inappropriate clotting is common but often subtle and may be challenging to predict even with the help of VET. Although VET has shown its benefit, more studies are needed to establish cut-off values for TEG and ROTEM in these populations and standardization of transfusion guidelines before invasive interventions in cirrhotic patients/orthotopic liver transplantation.     

血栓弹力图在晚期肺癌初诊患者凝血功能状态评估中的应用

目的 探讨血栓弹力图（TEG）在晚期肺癌初诊患者凝血功能状态评估中的应用价值。方法回顾性分析90例晚期肺癌初诊患者的血栓弹力图和常规凝血功能检测结果,比较两种检测方法对凝血功能异常检出的差异。结果经TEG检测发现38例（42.2%）患者存在凝血功能异常,经常规凝血功能检测方法发现85例（94.4%）患者存在凝血功能异常,两种检测方法对晚期肺癌初诊患者凝血功能异常检出率的差异有显著统计学意义（P〈0.01）。结论晚期肺癌患者经TEG检测存在高凝状态的比例低于常规凝血功能检测结果。     

Clinical Validation of Global Coagulation Tests to Guide Blood Component Transfusions in Cirrhosis and ACLF

Background and AimsPatients with cirrhosis and acute-on-chronic liver failure (ACLF) may have bleeding complications and need for invasive procedures. Point-of-care (POC) coagulation tests like thromboelastography (TEG) and Sonoclot may be better for guiding patient management than the standard coagulation tests (SCTs), like prothrombin time, platelet count and international normalized ratio.MethodsWe prospectively compared and validated the POC tests and SCTs in 70 persons with ACLF and 72 persons with decompensated cirrhosis who had clinical bleeding and checked for episodes of re-bleeding and transfusion requirements. We assessed pre-procedure requirement of blood components when correction was done based on an SCT or POC strategy.ResultsEpisodes of bleeding were seen in 45% and 28% of ACLF and cirrhosis patient, respectively (p=0.036), with the major site of bleeding being gastrointestinal (31% and 16%, respectively). Platelet counts correlated with TEG-maximum amplitude in cirrhosis (p=0.045) and prothrombin time correlated positively with TEG-reaction (R) time (p=0.032), TEG-Clot kinetics (K) time (p=0.042), Son-activated clotting time (p=0.038) and negatively with clot rate (p=0.043) in ACLF, making these correctable target variables in POC transfusion algorithms. Of 223 procedures, transfusion of fresh frozen plasma and platelet concentrate was reduced by 25% (p=0.035) and 20.8% (p=0.045) by using a POC strategy in 76 patients. Correction of deranged Son-activated clotting time and TEG-reaction time was noted in 68% and 72% after 24 h of fresh frozen plasma transfusion in ACLF and 85% and 80% in cirrhosis, respectively.ConclusionsOur study clinically validates that POC tests can better detect coagulation defects and transfusion thresholds in ACLF and cirrhosis, whereas use of conventional tests appear to be less suitable in patients with clinical bleeding.Trial Registration{"type":"clinical-trial","attrs":{"text":"NCT04332484","term_id":"NCT04332484"}}NCT04332484.     

Hematological findings and complications of COVID-19

COVID-19 is a systemic infection with a significant impact on the hematopoietic system and hemostasis. Lymphopenia may be considered as a cardinal laboratory finding, with prognostic potential. Neutrophil/lymphocyte ratio and peak platelet/lymphocyte ratio may also have prognostic value in determining severe cases. During the disease course, longitudinal evaluation of lymphocyte count dynamics and inflammatory indices, including LDH, CRP and IL-6 may help to identify cases with dismal prognosis and prompt intervention in order to improve outcomes. Biomarkers, such high serum procalcitonin and ferritin have also emerged as poor prognostic factors. Furthermore, blood hypercoagulability is common among hospitalized COVID-19 patients. Elevated D-Dimer levels are consistently reported, whereas their gradual increase during disease course is particularly associated with disease worsening. Other coagulation abnormalities such as PT and aPTT prolongation, fibrin degradation products increase, with severe thrombocytopenia lead to life-threatening disseminated intravascular coagulation (DIC), which necessitates continuous vigilance and prompt intervention. So, COVID-19 infected patients, whether hospitalized or ambulatory, are at high risk for venous thromboembolism, and an early and prolonged pharmacological thromboprophylaxis with low molecular weight heparin is highly recommended. Last but not least, the need for assuring blood donations during the pandemic is also highlighted.     

TEG and ROTEM: Technology and clinical applications

Initially described in 1948 by Hertert thromboelastography (TEG) provides a real‐time assessment of viscoelastic clot strength in whole blood. Rotational thromboelastometry (ROTEM) evolved from TEG technology and both devices generate output by transducing changes in the viscoelastic strength of a small sample of clotting blood (300 µl) to which a constant rotational force is applied. These point of care devices allow visual assessment of blood coagulation from clot formation, through propagation, and stabilization, until clot dissolution. Computer analysis of the output allows sophisticated clot formation/dissolution kinetics and clot strength data to be generated. Activation of clot formation can be initiated with both intrinsic (kaolin, ellagic acid) and extrinsic (tissue factor) activators. In addition, the independent contributions of platelets and fibrinogen to final clot strength can be assessed using added platelet inhibitors (abciximab and cytochalasin D). Increasingly, ROTEM and TEG analysis is being incorporated in vertical algorithms to diagnose and treat bleeding in high‐risk populations such as those undergoing cardiac surgery or suffering from blunt trauma. Some evidence suggests these algorithms might reduce transfusions, but further study is needed to assess patient outcomes. Am. J. Hematol. 89:228–232, 2014. © 2013 Wiley Periodicals, Inc.     

不同阶段肝病患者血栓弹力图与常规凝血检测的一致性研究

目的对不同阶段肝病患者的血栓弹力图(thrombelastograph,TEG)参数R值和常规凝血功能指标PT和APTT进行对比研究。方法将2016年2月—2017年1月解放军第三〇二医院住院患者232例作为研究对象,其中慢性肝炎患者41例,肝硬化代偿期患者69例,肝硬化失代偿期患者79例,慢性肝衰竭患者43例。检测上述各类患者TEG参数R值和常规凝血指标PT、APTT,并对2种检测方法的检测结果进行对比研究。结果慢性肝炎患者R值与PT、APTT进行一致性分析后,kappa值分别为-0.135(P0.05)、0.105(P0.05),一致率分别为34.15%和60.98%。肝硬化代偿期患者R值与PT、APTT一致性分析后,kappa值分别为0.175(P0.05)、0.038(P0.05),一致率均为60.90%。肝硬化失代偿期患者R值与PT、APTT一致性分析后,kappa值分别为0.023(P0.05)、0.038(P0.05),一致率分别为43.04%和49.37%。慢性肝衰竭患者R值与PT、APTT一致性分析,kappa值均为-0.049(P0.05),一致率均为13.95%。结论因TEG是从不同角度检测凝血功能,TEG检测结果可为评估不同阶段肝病患者凝血因子状态提供更加全面的依据。     

Thrombelastography.

Thrombelastography is a 'near patient' test of coagulation. It is easy to perform and can provide information on a patient's coagulation status within 30 min. Despite more than 25 years of clinical experience, however, several basic questions relating thromboelastograph (TEG) parameters to standard coagulation tests remain unanswered, and the value of the TEG is established only in the setting of orthotopic liver transplantation and cardiopulmonary bypass surgery. This review will focus on the principles and practise of the TEG(R), and data supporting the current accepted uses. Potential future uses will also be discussed including evaluation of hypercoagulable states, and investigating the mechanism of coagulopathies due to drugs or disease that standard tests have failed to unravel.     

Use of recombinant activated factor VII for bleeding following operations requiring cardiopulmonary bypass

Postoperative bleeding is a common complication following cardiothoracic surgical procedures requiring cardiopulmonary bypass (CPB). Serious bleeding complications requiring the administration of blood products, hemostatic drugs, and even repeat surgery are associated with considerable morbidity, mortality, and resource consumption. Therapy with recombinant activated factor VII (rFVIIa) may be an effective treatment strategy for patients with refractory bleeding. We report the successful use of rFVIIa for the treatment of intractable postoperative bleeding following aortic aneurysm repair in two patients with Marfan syndrome. In both patients, surgical reexploration was avoided, and the patients' clinical status was stabilized after the administration of rFVIIa. In one patient, hemostasis was rapidly achieved within minutes, whereas hemostasis occurred gradually over several hours in the second patient. Including our personal experience with the two cases, the use of rFVIIa has been reported in 20 patients who required CPB for cardiothoracic surgical procedures. Hemostasis was achieved in all patients. In 14 patients (70%), rapid hemostasis was achieved following a single dose of rFVIIa (mean dose, 57 microg/kg). In the remaining six patients, gradual hemostasis was achieved after a mean of 3.4 doses (mean cumulative dose, 225 microg/kg). Two patients (10%) were believed to have experienced thromboembolic complications after the administration of rFVIIa (one was fatal), and, in another patient, intracoronary thrombosis was suspected but was not confirmed. In patients experiencing postoperative bleeding complications that are refractory to treatment with blood products, hemostatic agents, and/or repeat surgery, the use of rFVIIa may be considered.     

The impact of schistosomes and schistosomiasis on murine blood coagulation and fibrinolysis as determined by thromboelastography (TEG)

Schistosomes are parasitic platyhelminths that currently infect over 200 million people and cause the chronic debilitating disease schistosomiasis. While these large intravascular parasites can disturb blood flow, surprisingly they do not appear to provoke thrombus formation around them in vivo. In order to determine if the worms can alter their local environment to impede coagulation, we incubated adult worms (50 pairs) in murine blood (500 µl) for 1 h at 37 °C and, using thromboelastography (TEG), we compared the coagulation profile of the blood with control blood that never contained worms. Substantial differences were apparent between the two profiles. Blood that had been exposed to schistosomes clotted more slowly and yielded relatively poor, though stable, thrombi; all TEG measures of blood coagulation (R, K, α-angle, MA, G and TMA) differed significantly between conditions. No fibrinolysis (as determined by LY30 and LY60 values) was detected in either case. The observed TEG profile suggests that the worms are acting as local anti-coagulants. Blood recovered from schistosome-infected mice, however, does not behave in this way. At an early time point post infection (4-weeks), the TEG profile of infected murine blood is essentially the same as that of control blood. However at a later time point (7-weeks) infected murine blood clots significantly faster than control blood but these clots also break down faster. The R, K, α-angle, and TMA measures of coagulation are all significantly different between the control versus infected mice as are the LY30 and LY60 values. This profile is indicative of a hypercoagulable state with fibrinolysis and is akin to that seen in human patients with advanced schistosomiasis.