Blood clotting studies with Thrombus stressography; a new Investigation procedure

Preoperative thromboelastography parameters in predicting the tumour stage of oral squamous cell carcinoma

BACKGROUND

A variety of solid tumours, including oral squamous cell carcinoma (OSCC), can cause coagulation abnormalities, and this phenomenon is known as tumour-associated hypercoagulation. We aimed to explore the preoperative thromboelastography (TEG) parameter profiles of OSCC patients, and to investigate their trends in relation to tumour stage progression, and to evaluate their value for predicting cervical lymph node metastasis.

METHODS

Data on thromboelastographic parameters and conventional coagulation indices were retrospectively collected, and comparisons were performed among preoperative primary OSCC patients (n = 311), recurrent/metastatic OSCC patients (n = 44) and a control group (n = 71). Among primary OSCC patients, the correlation with tumour stage and the predictive role of cervical lymph node metastasis were analyzed.

RESULTS

Hypercoagulability occurred in OSCC patients and tended to become more pronounced as the tumour progressed. The whole-time phase of coagulation increased with increasing T stage, while the early phase of coagulation increased with increasing N stage.

CONCLUSIONS

Preoperative TEG parameters are closely related to tumour stage and progression, suggesting that TEG can be used as an important indicator for predicting tumour stage and as a potential biomarker.

Development of a Methodology Based on Optical Interferometry for Measuring Fibrinolytic Activity

Fibrinolytic activity assay is particularly important for the detection, diagnosis, and treatment of cardiovascular disease and the development of fibrinolytic drugs. A novel efficacious strategy for real-time and label-free dynamic detection of fibrinolytic activity based on ordered porous layer interferometry (OPLI) was developed. Fibrin or a mixture of fibrin and plasminogen (Plg) was loaded into the highly ordered silica colloidal crystal (SCC) film scaffold to construct a fibrinolytic response interference layer to measure fibrinolytic activity with different mechanisms of action. Fibrinolytic enzyme-triggered fibrinolysis led to the migration of interference fringes in the interferogram, which could be represented by optical thickness changes (ΔOT) tracked in real time by the OPLI system. The morphology and optical property of the fibrinolytic response interference layer were characterized, and the Plg content in the fibrinolytic response interference layer and experimental parameters of the system were optimized. The method showed adequate sensitivity for the fibrinolytic activity of lumbrokinase and streptokinase, with wide linear ranges of 12-6000 and 10-2000 U/mL, respectively. Compared with the traditional fibrin plate method, it has a lower detection limit and higher linearity. The whole kinetic process of fibrinolysis by these two fibrinolytic drug models was recorded in real time, and the Michaelis constant and apparent kinetic parameters were calculated. Importantly, some other blood proteins were less interfering with this system, and it showed reliability in fibrin activity detection in real whole blood samples. This study established a better and more targeted research method of in vitro fibrinolysis and provided dynamic monitoring data for the analysis of fibrinolytic activity of whole blood.

Early Point-of-Care Thromboelastometry Reduces Mortality in Patients with Severe Trauma and Risk of Transfusion: An Analysis Based on the TraumaRegister DGU®

Background: Thromboelastometry like ROTEM® is a point-of-care method used to assess the coagulation status of patients in a rapid manner being particularly useful in critical care settings, such as trauma, where quick and accurate assessment of coagulation can guide timely and appropriate treatment. Currently, this method is not yet comprehensively available with sparse data on its effectiveness in resuscitation rooms. The aim of this study was to assess the effect of early thromboelastometry on the probability of mass transfusions and mortality of severely injured patients. Methods: The TraumaRegister DGU® was retrospectively analyzed for severely injured patients (2011 until 2020) with information available regarding blood transfusions and Trauma-Associated Severe Hemorrhage (TASH) score components. Patients with an estimated risk of mass transfusion >2% were included in a matched-pair analysis. Cases with and without use of ROTEM® diagnostic were matched based on risk categories for mass transfusion. A total of 1722 patients with ROTEM® diagnostics could be matched with a non-ROTEM® patient with an identical risk category. Adult patients (≥16) admitted to a trauma center in Germany, Austria, or Switzerland with Maximum Abbreviated Injury Scale severity ≥3 were included. Results: A total of 83,798 trauma victims were identified after applying the inclusion and exclusion criteria. For 7740 of these patients, the use of ROTEM® was documented. The mean Injury Severity Score (ISS) in patients with ROTEM® was 24.3 compared to 19.7 in the non-ROTEM® group. The number of mass transfusions showed no significant difference (14.9% ROTEM® group vs. 13.4% non-ROTEM® group, p = 0.45). Coagulation management agents were given significantly more often in the ROTEM® subgroup. Mortality in the ROTEM® group was 4.1% less than expected (estimated mortality based on RISC II 34.6% vs. observed mortality 30.5% (n = 525)). In the non-ROTEM® group, observed mortality was 1.6% less than expected. Therefore, by using ROTEM® analysis, the expected mortality could be reduced by 2.5% (number needed to treat (NNT) 40; SMR of ROTEM® group: 1:0.88; SMR of non-ROTEM® group: 1:0.96; p = 0.081). Conclusions: Hemorrhage is still one of the leading causes of death of severely injured patients in the first hours after trauma. Early thromboelastometry can lead to a more targeted coagulation management, but is not yet widely available. This study demonstrated that ROTEM® was used for the more severely injured patients and that its use was associated with a less than expected mortality as well as a higher utilization of hemostatic products.

In vitro evaluation of a new viscoelastometry-based point-of-care analyzer

INTRODUCTION

The VCM is a point-of-care analyzer using a new viscoelastometry technique for rapid assessment of hemostasis on fresh whole blood. Its characteristics would make it suitable for use in austere environments. The purpose of this study was to evaluate the VCM in terms of repeatability, reproducibility and interanalyzer correlation, reference values in our population, correlation with standard coagulation assays and platelet count, correlation with the TEG5000 analyzer and resistance to stress conditions mimicking an austere environment.

METHODS

Repeatability, reproducibility, and interanalyzer correlation were performed on quality control samples (n = 10). Reference values were determined from blood donor samples (n = 60). Correlations with standard biological assays were assessed from ICU patients (n = 30) and blood donors (n = 60) samples. Correlation with the TEG5000 was assessed from blood donor samples. Evaluation of vibration resistance was performed on blood donor (n = 5) and quality control (n = 5) samples.

RESULTS

The CVs for repeatability and reproducibility ranged from 0% to 11%. Interanalyzer correlation found correlation coefficients (r2) ranging from 0.927 to 0.997. Our reference values were consistent with those provided by the manufacturer. No robust correlation was found with conventional coagulation tests. The correlation with the TEG5000 was excellent with r2 ranging from 0.75 to 0.92. Resistance to stress conditions was excellent.

CONCLUSION

The VCM analyzer is a reliable, easy-to-use instrument that correlates well with the TEG5000. Despite some logistical constraints, the results suggest that it can be used in austere environments. Further studies are required before its implementation.

Early Goal-Directed Hemostatic Therapy for Severe Acute Bleeding Management in the Intensive Care Unit: A Narrative Review

This is a narrative review of the published evidence for bleeding management in critically ill patients in different clinical settings in the intensive care unit (ICU). We aimed to describe "The Ten Steps" approach to early goal-directed hemostatic therapy (EGDHT) using point-of-care testing (POCT), coagulation factor concentrates, and hemostatic drugs, according to the individual needs of each patient. We searched National Library of Medicine, MEDLINE for publications relevant to management of critical ill bleeding patients in different settings in the ICU. Bibliographies of included articles were also searched to identify additional relevant studies. English-language systematic reviews, meta-analyses, randomized trials, observational studies, and case reports were reviewed. Data related to study methodology, patient population, bleeding management strategy, and clinical outcomes were qualitatively evaluated. According to systematic reviews and meta-analyses, EGDHT guided by viscoelastic testing (VET) has been associated with a reduction in transfusion utilization, improved morbidity and outcome in patients with active bleeding. Furthermore, literature data showed an increased risk of severe adverse events and poor clinical outcomes with inappropriate prophylactic uses of blood components to correct altered conventional coagulation tests (CCTs). Finally, prospective, randomized, controlled trials point to the role of goal-directed fibrinogen substitution to reduce bleeding and the amount of red blood cell (RBC) transfusion with the potential to decrease mortality. In conclusion, severe acute bleeding management in the ICU is still a major challenge for intensive care physicians. The organized and sequential approach to the bleeding patient, guided by POCT allows for rapid and effective bleeding control, through the rational use of blood components and hemostatic drugs, since VET can identify specific coagulation disorders in real time, guiding hemostatic therapy with coagulation factor concentrates and hemostatic drugs with individual goals.

[Update on point-of-care-based coagulation treatment : Systems, reagents, device-specific treatment algorithms]

Viscoelastic test (VET) procedures suitable for point-of-care (POC) testing are in widespread clinical use. Due to the expanded range of available devices and in particular due to the development of new test approaches and methods, the authors believe that an update of the current treatment algorithms is necessary. The aim of this article is to provide an overview of the currently available VET devices and the associated reagents. In addition, two treatment algorithms for the VET devices most commonly used in German-speaking countries are presented.

Application of thromboelastography to predict the severity of bleeding after chimeric antigen receptor (CAR)-T cell therapy in patients with hematological malignancy

OBJECTIVES

We aim to analyze the predictive value of thromboelastography on bleeding severity of patients with chimeric antigen receptor (CAR)-T cell therapy.

METHODS

A total of 80 patients with refractory/relapsed hematological malignancy were enrolled and divided into two groups: the severe bleeding group and the non-severe bleeding group. The thromboelastography data was collected on the day of CAR-T infusion and the 3rd, 7th, 10th, 13th, 17th, and 20th day after CAR-T cell infusion.

RESULTS

The patients of the severe bleeding group had lower platelet (p < .007), maximum amplitude (p = .002), coagulation index (p = .005), and longer coagulation time (p = .019). Increasing trend in reaction time and coagulation time and decreasing trend in Alpha, maximum amplitude, and coagulation index on Days 0-10, opposite on Days 10-20. Univariate logistic regression analysis and multivariable logistic regression analysis showed maximum amplitude on the 3rd day after CAR-T cell infusion (MA3) (OR = 0.9; 95% CI = 0.84-0.95; p < .001) and cytokine release syndrome grade (OR = 2.57; 95% CI = 1.35-5.32; p = .006) were significantly associated with high bleeding severity.

CONCLUSIONS

Thromboelastography was considered to be a good predictor of bleeding severity.

Viscoelastic blood coagulation testing system enabled by a non-contact triboelectric angle sensor

Thromboelastography (TEG) remains a convenient and effective viscoelastic blood coagulation testing device for guiding blood component transfusion and assessing the risk of thrombosis. Here, a TEG enabled by a non-contact triboelectric angle sensor (NTAS) with a small size (∼7 cm3) is developed for assessing the blood coagulation system. With the assistance of a superelastic torsion wire structure, the NTAS-TEG realizes the detection of blood viscoelasticity. Benefiting from a grating and convex design, the NTAS holds a collection of compelling features, including accurate detection of rotation angles from -2.5° to 2.5°, high linearity (R 2 = 0.999), and a resolution of 0.01°. Besides, the NTAS exhibits merits of low cost and simplified fabrication. Based on the NTAS-TEG, a viscoelastic blood coagulation detection and analysis system is successfully constructed, which can provide a graph and parameters associated with clot initiation, formation, and stability for clinicians by using 0.36 mL of whole blood. The system not only validates the feasibility of the triboelectric coagulation testing sensor, but also further expands the application of triboelectric sensors in healthcare.

Characteristics of blood clotting on thromboelastography in patients with early burns

BACKGROUND

Thromboelastography (TEG) is a viscoelastic test that may be used to evaluate the hemostatic function of whole blood, and it may be useful for burn patients with multiple hemostatic defects.

METHODS

We retrospectively recruited patients with burns between January 2019 and July 2021. Blood samples were drawn on admission and subjected to coagulation parameter assessment, including conventional coagulation tests and TEG assessment. Receiver operating characteristic (ROC) analysis was performed to predict the occurrence of complications in patients with early burns.

RESULTS

Ninety-three patients with early burns met the inclusion criteria. Patients with minor, moderate, severe, and extremely severe burns accounted for 19.4 %, 36.6 %, 16.1 %, and 27.9 % of all patients, respectively. Compared with the healthy controls, patients with early burns showed significant reductions in the R and K values, and significant elevation in the maximum amplitude (MA), coagulation index (CI), and alpha angle. Compared with minor and moderate burn patients, patients with severe and extremely severe burns had lower K values and thrombin time and higher alpha angle, CI, prothrombin time, international normalized ratio, D-dimer, and fibrin degradation products. Patients with hypercoagulation had lower R and K values, longer MA, longer CI, and greater alpha angle. After ROC analysis, the areas under the ROC curve for acute lung injury, acute kidney injury, and bleeding were 0.789, 0.802, and 0.900, respectively.

CONCLUSION

TEG provides insight into the hemostatic state of patients with early burns, and can predict complications in early burn patients when combined with conventional coagulation tests.

Viscoelastic Testing Methods

Viscoelastic testing methods examine the real-time formation of a clot in a whole blood sample, and include thromboelastography (TEG), rotational thromboelastometry (ROTEM), and several other testing platforms. They allow for concurrent assessment of multiple aspects of clotting, including plasmatic coagulation factors, platelets, fibrinogen, and the fibrinolytic pathway. This testing is rapid and may be performed at the point-of-care, allowing for prompt identification of coagulopathies to guide focused and rational administration of blood products as well as the identification of anticoagulant effect. With recent industry progression towards user-friendly, cartridge-based, portable instruments, viscoelastic testing has emerged in the 21st century as a powerful tool to guide blood transfusions in the bleeding patient, and to identify and treat both bleeding and thrombotic conditions in many operative settings, including trauma surgery, liver transplant surgery, cardiac surgery, and obstetrics. In these settings, the use of transfusion algorithms guided by viscoelastic testing data has resulted in widespread improvements in patient blood management as well as modest improvements in select patient outcomes. To address the increasingly wide adoption of viscoelastic methods and the growing number of medical and laboratory personnel tasked with implementing, performing, and interpreting these methods, this chapter provides an overview of the history, physiology, and technology behind viscoelastic testing, as well as a practical review of its clinical utility and current evidence supporting its use. Also included is a review of testing limitations and the contextual role played by viscoelastic methods among all coagulation laboratory testing.

Native Whole Blood (TRUE-NATEM) and Recalcified Citrated Blood (NATEM) Reference Value Validation with ROTEM Delta

Background: Thromboelastography is a viscoelastic test of whole blood hemostasis. Currently, no reference value exists for native whole blood and recalcified citrated blood without activators. The aim of this study was to compare the results of ROTEM® tests using fresh native blood without decalcification "TRUE-NATEM" with those using decalcified citrated blood "NATEM" and provide reference values for each. Methods: Inclusion criteria were healthy adult volunteers (18-65 years). Exclusion criteria were any medical condition or medication affecting coagulation. Native whole blood testing was defined as "TRUE-NATEM-test." For recalcified citrated blood testing, the NATEM function was used on ROTEM®. Result: The reference value for TRUE-NATEM was CT: 872-1595s, A10: 14-34 mm, A20: 26-48 mm, CFT: 314-839s, MCF: 34-55 mm, and alpha angle: 17-40°. The reference value for NATEM was CT: 757-1327s, A10: 19-43 mm, A20: 33-55 mm, CFT: 219-615s, MCF: 37-61 mm, alpha angle: 24-51°, and ML: 0-3%. When comparing the reference value of NATEM to TRUE-NATEM, the CT and CFT values are decreased and the MCF and alpha angle are increased. The recalcification process of citrated blood in NATEM shows significant activation of coagulation. Female healthy volunteers had enhanced coagulation when activators were used. Age-related statistical difference was seen when activators were used. Ethnicity did not show any difference on the ROTEM values. Conclusion: We determined the reference value for native whole blood and recalcified whole blood using ROTEM®. A significant discrepancy in native whole blood and recalcified citrated blood coagulation was found. Our study underlines the importance of native whole blood as the gold standard reference value in coagulation.

The Effect of Sepsis and Septic Shock on the Viscoelastic Properties of Clot Quality and Mass Using Thromboelastometry: A Prospective Observational Study

Background

Sepsis is associated with wide variable coagulation abnormalities. Thromboelastography (TEG) effectively measures the viscoelastic properties of the clots. This study aims to illustrate the viscoelastic properties of clot quality and mass in sepsis and septic shock patients using TEG, as an effective tool over standard coagulation tests.

Materials and methods

A single-center, prospective observational study was conducted. 50 patients each meeting the criteria for sepsis and septic shock, and a healthy group of 30 patients was included in the study. Blood samples were obtained and analyzed for standard coagulation tests, platelet count, fibrinogen, and TEG study.

Results

A total of 130 patients were included. Septic shock patients had a higher sequential (sepsis-related) organ failure score. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were increased significantly as compared to the sepsis and control groups. TEG markers such as alpha angle, and maximum amplitude (MA) were significantly prolonged while reaction time (R time), was significantly shortened in the sepsis group as compared to the healthy group, suggestive of a hypercoagulable state in sepsis patients. While in septic shock patients, MA and Lysis Index 30 (LY 30) were significantly prolonged and, R time was significantly shortened compared to all other groups. Even though LY30 in sepsis patients was found to be within the normal range (p < 0.001), 18% of patients had prolonged LY30 indicating a hypercoagulable state with impaired fibrinolysis.

Conclusion

Thromboelastography, as a point-of-care test combined with conventional coagulation tests can provide additional, clinically relevant information on coagulopathy, and outcome, and thus help guide treatment modality in sepsis and septic shock-induced coagulopathy.

How to cite this article

Mohapatra P, Kumar A, Singh RK, Gupta R, Hussain M, Singh S, et al. The Effect of Sepsis and Septic Shock on the Viscoelastic Properties of Clot Quality and Mass Using Thromboelastometry: A Prospective Observational Study. Indian J Crit Care Med 2023;27(9):625-634.

Review of Thromboelastography (TEG): Medical and Surgical Applications

Thromboelastography (TEG) is a laboratory assay utilized to evaluate hemostatic properties of blood, identify coagulopathy, and guide blood product administration. While the clinical use of TEG started in the care of surgical patients, the assay has now been incorporated more routinely in the care of the medical patient as well. In this review, we explore the evolution of TEG from the historical perspective of its inception to the current state of the art of the assay. The TEG procedure and its measurements are illustrated along with a table that summarizes recommendations from across the medical and surgical literature. After each section, we review salient learning points to provide the busy clinician with information that can be immediately integrated at the bedside. We conclude with a series of summary questions to check for comprehension and direct the reader to additional resources to improve their knowledge of TEG.

Thromboelastography and Traditional Coagulation Testing in Non-ICU-Admitted Patients with Acute Kidney Injury: An Observational Cohort Study

INTRODUCTION

This study aimed to elucidate the coagulation disorders in non-ICU patients with acute kidney injury (AKI) and their contribution to clotting-related outcomes of intermittent kidney replacement therapy (KRT).

METHODS

We included non-ICU-admitted patients with AKI requiring intermittent KRT, clinically having a risk of bleeding and against systemic anticoagulant use during KRT between April and December 2018. The premature termination of treatment due to circuit clotting was considered a poor outcome. We analyzed the characteristics of thromboelastography (TEG)-derived and traditional coagulation parameters and explored the potential-affecting factors.

RESULTS

In total, 64 patients were enrolled. Hypocoagulability was detected in 4.7%-15.6% of patients by a combination of the traditional parameters, i.e., prothrombin time (PT)/international normalized ratio, activated partial PT, and fibrinogen. No patient had hypocoagulability observed on TEG-derived reaction time; only 2.1%, 3.1%, and 10.9% of patients had hypocoagulability on TEG-derived kinetic time (K-time), α-angle, and maximum amplitude (MA), respectively, which were also platelet-related coagulation parameters, despite 37.5% of the cohort having thrombocytopenia. In contrast, hypercoagulability was more prevalent, involving 12.5%, 43.8%, 21.9%, and 48.4% of patients on TEG K-time, α-angle, MA, and coagulation index (CI), respectively, although thrombocytosis was only in 1.5% of the cohort. Patients with thrombocytopenia showed lower fibrinogen level (2.6 vs. 4.0 g/L, p = 0.00), α-angle (63.5° vs. 73.3°, p = 0.00), MA (53.5 vs. 66.1 mm, p = 0.00), and CI (1.8 vs. 3.6, p = 0.00) but higher thrombin time (17.8 vs. 16.2 s, p = 0.00) and K-time (2.0 vs. 1.2 min, p = 0.00) than those with a platelet count over 100 × 109/L. 41 patients were treated with heparin-free protocol, and 23 were treated with regional citrate anticoagulation (RCA). The premature termination rate was 41.5% on heparin-free patients, while 8.7% of patients underwent an RCA protocol (p = 0.006). Heparin-free protocol was the strongest adverse factor to poor outcomes. A heparin-free subgroup analysis found that the circuit clotting risk was increased by 61.7% with a 10 × 109/L elevation in platelet count (odds ratio [OR] = 1.617, p = 0.049) and decreased by 67.5% following a second increase of PT (OR = 0.325, p = 0.041). No significant correlation was found between TEG parameters and premature circuit clotting.

CONCLUSIONS

Most non-ICU-admitted patients with AKI had normal-to-enhanced hemostasis and activated platelet function based on TEG results, as well as a high rate of premature circuit clotting when receiving heparin-free protocol despite thrombocytopenia. Further studies are needed to better determine the use of TEG in respect to management of anticoagulation and bleeding complications in AKI patients with KRT.

Elevated levels of soluble glycoprotein V - The plasma marker of platelet activation by thrombin in patients with early stage primary biliary cholangitis (PBC)

PURPOSE

There is a growing body of evidence for a prothrombotic tendency in patients with primary biliary cholangitis (PBC). The aim of the study was to evaluate coagulation disorders in patients with early stage PBC compared to healthy controls and evaluation of their relationship with clinical data, with particular emphasis on minimal hepatic encephalopathy (MHE).

PATIENTS AND METHODS

Fifty-one participants (PBC group - 38 patients, all patients but one Child-Pugh A; control group - 13 healthy controls) were included in our prospective, single center study. We assessed the plasma levels of sGPV, plasma procoagulant phospholipids (PPL) and rotational thromboelastometry (ROTEM) profiles in all study participants. Porto-systemic encephalopathy syndrome test was used to assess MHE.

RESULTS

The sGPV levels were higher in the PBC group compared to the controls: 36.07 ​± ​11.32 ​ng/mL vs 27.04 ​± ​11.72 ​ng/mL, p ​= ​0.031. The PPL level was lower in the PBC group compared to controls resulting in increased clotting time in a factor Xa-based coagulation assay: 54.65 (47.83-58.83) sec. vs 45.90 (43.3-50.5) sec., p ​= ​0.0065. PPL levels were correlated with platelet count (rho ​= ​-0.46, p ​= ​0.001). ROTEM parameters did not differ significantly between groups. Coagulation parameters did not differ significantly between patients with and without MHE.

CONCLUSIONS

We have showed increased levels of sGPV - a plasma marker of platelet activation by thrombin in patients with early stage PBC compared to healthy controls. We found no relationship between the coagulation disorders and the occurrence of MHE. The PPL level was lower in the PBC group.

Emerging technology for early detection and management of postpartum hemorrhage to prevent morbidity

Despite advances in hemorrhage detection and management, postpartum hemorrhage remains the single leading cause of maternal death worldwide. Within the United States, hemorrhage is the leading cause of maternal death on the day of delivery and within the first week after delivery. Blood transfusion after hemorrhage represents a large proportion of severe maternal morbidity during and after delivery. Blood loss during delivery has historically been assessed visually by inspecting soiled pads, linens, and laparotomy sponges. These methods underestimate the volume of blood loss by as much as 40%, becoming increasingly inaccurate as blood loss increases. Young, healthy obstetrical patients compensate for blood loss via peripheral vasoconstriction, maintaining heart rate and blood pressure in a normal range until over 1 L of blood has been lost. A significant decrease in blood pressure along with marked tachycardia (>120 bpm) may not be seen until 30% to 40% of blood volume has been lost, or 2.0 to 2.6 L in a healthy term pregnant patient, after which the patient may rapidly decompensate. In resource-poor settings especially, the narrow window between the emergence of significant vital sign abnormalities and clinical decompensation may prove catastrophic. Once hemorrhage is detected, decisions regarding blood product transfusion are routinely made on the basis of inaccurate estimates of blood loss, placing patients at risk of underresuscitation (increasing the risk of hemorrhagic shock and end-organ damage) or overresuscitation (increasing the risk of transfusion reaction, fluid overload, and alloimmunization). We will review novel technologies that have emerged to assist both in the early and accurate detection of postpartum hemorrhage and in decisions regarding blood product transfusion.

Modified Rotational Thromboelastometry Protocol Using Tissue Plasminogen Activator for Detection of Hypofibrinolysis and Hyperfibrinolysis

Viscoelastic testing includes thromboelastography (TEG^®) and thromboelastometry (ROTEM^®) and is widely used in bleeding patients to detect hypocoagulability and guide transfusion therapy. However, the ability of standard viscoelastic tests to assess fibrinolytic capacity is limited. We here describe a modified ROTEM^® protocol with addition of tissue plasminogen activator that can be used to identify hypofibrinolysis or hyperfibrinolysis.

Viscoelastic testing: an illustrated review of technology and clinical applications

Viscoelastic testing (VET), including thromboelastography and thromboelastometry, provides a rapid and comprehensive picture of whole blood coagulation dynamics and hemostasis that can be reviewed and evaluated at the point-of-care. This technology is over 50 years old; however, over the past few years, there has been a significant increase in research examining the use of VET. Best practice guidelines for the use of VET exist in both the United States and Europe, particularly for elective cardiac surgery, although recommendations for implementation are somewhat limited in some clinical areas by the lack of studies constituting high-grade evidence. Other challenges to implementation surround validation of the technology in some care settings as well as lack of training. Nevertheless, there is a wide range of potential clinical applications, such as treating coagulopathies in liver disease and transplant surgery, critical care, as well as within obstetrical hemorrhage. In this illustrated review, we provide an overview of viscoelastic testing technology (also called viscoelastic hemostatic assays) and describe how the assays can be used to provide a broad overview of hemostasis from clot formation to clot lysis, while highlighting the contribution of coagulation factors and platelets. We then summarize the major clinical applications for viscoelastic testing, including more recent applications, such as in COVID-19. Each section describes the clinical context, and key publications, followed by a representative algorithm and key guidelines.

Individualized Management of Coagulopathy in Patients with End-Stage Liver Disease

Over the last decades, individualized approaches and a better understanding of coagulopathy complexity in end-stage liver disease (ESLD) patients has evolved. The risk of both thrombosis and bleeding during minimally invasive interventions or surgery is associated with a worse outcome in this patient population. Despite deranged quantitative and qualitative coagulation laboratory parameters, prophylactic coagulation management is unnecessary for patients who do not bleed. Transfusion of red blood cells (RBCs) and blood products carries independent risks for morbidity and mortality, including modulation of the immune system with increased risk for nosocomial infections. Optimal coagulation management in these complex patients should be based on the analysis of standard coagulation tests (SCTs) and viscoelastic tests (VETs). VETs represent an individualized approach to patients and can provide information about coagulation dynamics in a concise period of time. This narrative review will deliver the pathophysiology of deranged hemostasis in ESLD, explore the difficulties of evaluating the coagulopathies in liver disease patients, and examine the use of VET assays and management of coagulopathy using coagulation factors. Methods: A selective literature search with PubMed as the central database was performed with the following.

Real-time monitoring of intravenous thrombolysis in acute ischemic stroke using rotational thromboelastometry: a feasibility pilot study

INTRODUCTION

Rotational thromboelastometry (ROTEM) records whole blood coagulation in vitro. Data on dynamic changes of clot patterns during intravenous thrombolysis (IVT) in acute ischemic stroke is scarce. We investigated the feasibility of ROTEM as a potential point-of-care assessment tool for IVT.

METHODS

In this prospective pilot study, patients with acute stroke symptoms received IVT. Whole blood coagulation was tracked on the ROTEM analyzer. Blood samples were analyzed before, and then 2, 15, 30 and 60 min after beginning IVT. In vitro clots (iCLs) were described by their maximum clot firmness (MCF), the time needed to reach MCF (MCF-t), as well as the area under the curve (AR10). National Institutes of Health Stroke Scale (NIHSS) was used as early clinical outcome parameter.

RESULTS

We analyzed 288 iCLs from 12 patients undergoing IVT. In all iCLs, an early fibrinolysis (91% within the first 10 min) was detected during IVT. Three different curve progression patterns were observed: a low-responder pattern with a continuous clot increase, a high-responder pattern with a sustained clot decrease or total clotting suppression and an intermediate-responder pattern with alternating clot characteristics. There was a difference among these groups in early clinical outcome (AR10 and MCF each p = 0.01, MCF-t p = 0.02, Kruskal-Wallis Test).

CONCLUSION

The fibrinolysis patterns determined using ROTEM allow for the monitoring of IVT in patients with acute ischemic stroke. This pilot study found a correlation between the in vitro fibrinolysis patterns and early clinical outcomes. These findings support a potential for individualization of IVT in the future.

Clinical Application of Thromboelastography in Acute Ischemic Stroke

Acute ischemic stroke (AIS), characterized by high morbidity and mortality, has imposed a considerable burden on society. Despite rapid development in the treatment of AIS, there is still a high risk of recurrence. Furthermore, there is a time delay in waiting for the results of conventional coagulation tests in candidate patients for intravenous thrombolysis therapy. Heterogeneous responses to antiplatelet, intravascular thrombolysis, and endovascular therapies also worsen the situation. Thromboelastography (TEG), as a global and portable detection method for hemostasis, facilitates clinicians in disease monitoring, treatment evaluation, and prognosis prediction in AIS. In this narrative review, we provided a comprehensive summary of the clinical application of TEG in ischemic stroke and gave insights to further studies.

The Addition of ROTEM Parameter Did Not Significantly Improve the Massive Transfusion Prediction in Severe Trauma Patients

Background

Rotational thrombelastometry (ROTEM) has been used to evaluate the coagulation state, predict transfusion, and optimize hemostatic management in trauma patients. However, there were limited studies on whether the prediction value could be improved by adding the ROTEM parameter to the prediction model for in-hospital mortality and massive transfusion (MT) in trauma patients.

Objective

This study assessed whether ROTEM data could improve the MT prediction model.

Method

This was a single-center, retrospective study. Patients who presented to the trauma center and underwent ROTEM between 2016 and 2020 were included. The primary and secondary outcomes were massive transfusions and in-hospital mortality, respectively. We constructed two models using multivariate logistic regression with backward conditional stepwise elimination (Model 1: without the ROTEM parameter and Model 2: with the ROTEM parameter). The area under the receiver operating characteristic curve (AUROC) was calculated to assess the predictive ability of the models.

Result

In total, 969 patients were included; 196 (20.2%) received MT. The in-hospital mortality rate was 14.1%. For MT, the AUROC was 0.854 (95% confidence interval [CI], 0.825-0.883) and 0.860 (95% CI, 0.832-0.888) for Model 1 and 2, respectively. For in-hospital mortality, the AUROC was 0.886 (95% CI, 0.857-0.915) and 0.889 (95% CI, 0.861-0.918) for models 1 and 2, respectively. The AUROC values for models 1 and 2 were not statistically different for either MT or in-hospital mortality.

Conclusion

We found that the addition of the ROTEM parameter did not significantly improve the predictive power of MT and in-hospital mortality in trauma patients.

Aspirin for the Primary Prevention of Cardiovascular Disease: Time for a Platelet-Guided Approach

Aspirin protects against atherothrombosis while increasing the risk of major bleeding. Although it is widely used to prevent cardiovascular disease (CVD), its benefit does not outweigh its risk for primary CVD prevention in large population settings. The recent United States Preventive Services Task Force guidelines on aspirin use to prevent CVD reflect this clinical tradeoff as well as the persistent struggle to define a population that would benefit from prophylactic aspirin therapy. Past clinical trials of primary CVD prevention with aspirin have not included consideration of a biomarker relevant to aspirin's mechanism of action, platelet inhibition. This approach is at odds with the paradigm used in other key areas of pharmacological CVD prevention, including antihypertensive and statin therapy, which combine cardiovascular risk assessment with the measurement of mechanistic biomarkers (eg, blood pressure and LDL [low-density lipoprotein]-cholesterol). Reliable methods for quantifying platelet activity, including light transmission aggregometry and platelet transcriptomics, exist and should be considered to identify individuals at elevated cardiovascular risk due to a hyperreactive platelet phenotype. Therefore, we propose a new, platelet-guided approach to the study of prophylactic aspirin therapy. We think that this new approach will reveal a population with hyperreactive platelets who will benefit most from primary CVD prevention with aspirin and usher in a new era of precision-guided antiplatelet therapy.

CREST: clinical bleeding and risk evaluation in hematology-oncology patients: a systematic review and meta-analysis of thromboelastography's role

Thrombocytopenia and bleeding are common complications of hematologic malignancies. Often, prophylactic platelets are administered to minimize bleeding risk, based on total platelet count (TPC). However, TPC is a poor predictor, and does not provide rapid information. This review presents a novel prospective in the use of point-of-care viscoelastic studies to assess bleeding risk and guide transfusion therapy in a haematological oncological population, where its use can be extended to a ward level as a bedside test. Monitoring TEG maximum amplitude trends may be useful to guide transfusion protocols, especially for patients with total platelet counts ranging 30-100 × 10 9 /l. Fibrinogen assessment in this group of patients may identify other blood components that require replacing to reduce bleeding risk. Normal maximum amplitude parameters for patients with low platelet counts can be a reassuring sign. This meta-analysis serves to remind the reader that absolute platelet quantity does not equate to the quality of clot formation.

Comparison of Jugular vs. Saphenous Blood Samples, Intrarater and In-Between Device Reliability of Clinically Used ROTEM S Parameters in Dogs

Rotational Thromboelastometry (ROTEM) allows for the global assessment of hemostasis in whole blood samples. Preanalytical and analytical factors may influence test results, and data about the reliability and reproducibility of lyophilized ROTEM tests are scarce. Therefore, the objective of this study was to evaluate the influence of blood collection site on ROTEM S parameters and to assess intrarater and in-between device variability. A total of thirty, healthy, staff-owned dogs were included. Blood collection and ROTEM analysis were performed by trained staff according to a standardized protocol. Extrinsically activated (tissue factor; Ex-TEM S), with the addition of cytochalasin for platelet inhibition (Fib-TEM S), and intrinsically activated (In-TEM) analyses were performed. Analysis of our data showed significant variability for various Ex-TEM S and Fib-TEM S parameters from different collection sites and intrarater and in-between device measurements. We conclude that serial monitoring with ROTEM should be performed on the same device, with blood always taken from the same collection site using a standardized blood sampling technique. While In-TEM S, apart from maximum lysis, showed very stable and reliable results, we suggest interpreting especially clotting and clot formation parameters from Ex-TEM S and Fib-TEM S tests with caution and using duplicate measurements to detect outliers and to prevent initiation of incorrect therapies.

To Investigate Whether Hematocrit Affects Thromboelastography Parameters

Background

Thromboelastogram (TEG) is an experiment to detect coagulation function with whole blood. Red blood cell (RBC) is the most abundant component of blood. Whether RBC has an impact on the results of thromboelastogram? Study Design and Methods. The correlation between hematocrit (HCT) and TEG was analyzed. 17 samples were reconstituted with different HCT. They were tested separately. Correction tests were performed on 17 samples from patients with anemia. HCT was corrected to 0.40 in female and 0.45 in males. The correction formula was determined according to the experimental correction.

Results

HCT was negatively correlated with TEG parameters. As HCT increased, CI and angle decreased (P < 0.05, P < 0.001) and K increased (P < 0.001) in reconstituted samples. In the correction test, the angle measured value was 69.48 ± 4.98 and corrected value was 62.48 ± 6.25, MA measured value was 61.44 ± 7.10 and corrected value was 55.94 ± 7.12, K measured value was 1.45 ± 0.48 and corrected value was 2.11 ± 0.79, and CI measured value was 1.07 ± 1.67 and corrected value was -0.45 ± 1.64. There was a significant difference. The correction formulas of anemia were derived from the experimental correction results. K Correction value = (0.7903∗ A 2 - 2.1803A + 2.8268)∗ K Measured value; Tan angleCorrection value = Tan angleMeasured value/(0.6596∗ A 2 - 1.7478A + 2.4608); MACorrection value = MAMeasured value/(0.1853ln (A) + 1.0197); CICorrection value = -0.6516RMeasured value - 0.3772K Correction value + 0.1224MACorrection value + 0.0759angleCorrection value - 7.7922.

Conclusion

HCT has a negative impact on TEG parameters. Coagulation state of anemia patients is overestimated by TEG. The test results of anemia patients need to be corrected whether through the experimental correction or the formula correction.

Operability of a Resonance-Based Viscoelastic Haemostatic Analyzer in the High-Vibration Environment of Air Medical Transport

Trauma and bleeding are associated with a high mortality, and most of these deaths occur early after injury. Viscoelastic haemostatic tests have gained increasing importance in goal-directed transfusion and bleeding management. A new generation of small-sized and thus portable ultrasound-based viscoelastic analysers have been introduced in clinical practice. We questioned whether a promising candidate can be used in emergency helicopters, with a focus on the susceptibility to vibration stress. We investigated whether the high vibration environment of an emergency helicopter would affect the operability of an ultrasound-based viscoelastic analyser and would yield reproducible results in flight and on the ground. We drew blood from 27 healthy volunteers and performed simultaneous analyses on two TEG 6s. Each measurement was performed in-flight on board an Airbus H135 emergency helicopter and was repeated on the ground, close to the flight area. Results from both measurements were compared, and the recorded tracings and numeric results were analysed for artifacts. Vibratometric measurements were performed throughout the flight in order to quantify changes in the magnitude and character of vibrations in different phases of helicopter operation. The high vibration environment was associated with the presence of artifacts in all recorded tracings. There were significant differences in citrated Kaolin + Heparinase measurements in-flight and on the ground. All other assays increased in variability but did not show significant differences between the two time points. We observed numerous artifacts in viscoelastic measurements that were performed in flight. Some parameters that were obtained from the same sample showed significant differences between in-flight and on-ground measurements. Performing resonance-based viscoelastic tests in helicopter medical service is prone to artifacts. However, a 10 min delay between initiation of measurement and take-off might produce more reliable results.

Viscoelastic Monitoring in Liver Transplantation

Cirrhosis and liver transplantation (LT) surgery are associated with substantial alterations to the patient's coagulation status. Accurate monitoring of these changes during LT can help manage bleeding proactively and potentially reduce transfusion requirements. Unlike conventional coagulation tests (CCTs), viscoelastic monitoring (VEM) can provide an accurate, real-time, point-of-care assessment of coagulation status during LT and hence has become an invaluable tool for anesthetists and intensive care physicians. However, it remains an enigmatic subject for transplantation surgeons who are more conversant with CCTs. This review discusses the principles of VEM, provides a primer to understanding and interpreting its output, and explains how it can be used to make real-world clinical decisions during LT.

Faster Time to Treatment Decision of Viscoelastic Coagulation Test Results through Improved Perception with the Animated Visual Clot: A Multicenter Comparative Eye-Tracking Study

As the interpretation of viscoelastic coagulation test results remains challenging, we created Visual Clot, an animated blood clot aiming to facilitate raw rotational thromboelastometry (ROTEM) parameters. This study investigated anesthesia personnel’s cognitive processing in managing simulated bleeding scenarios using eye-tracking technology. This multicenter, international, computer-based study across five large, central European hospitals included 35 participants with minimal to no prior experience interpreting viscoelastic test results. Using eye-tracking technology and an iPad tagged with quick response codes, we defined the time to treatment decision and the time on screen surface in seconds of correctly solved scenarios as our outcomes. The median time to treatment decision was 52 s for Visual Clot and 205 s for ROTEM (p < 0.0001). The probability of solving the scenario correctly was more than 8 times higher when using Visual Clot than when using ROTEM (Hazard ratio [HR] 8.54, 95% CI from 6.5 to 11.21; p < 0.0001). Out of 194 correctly answered scenarios of participants with the eye-tracker, 154 (79.4%) were solved with Visual Clot and 40 (20.6%) with ROTEM. Participants spent on average 30 s less looking at the screen surface with Visual Clot compared to ROTEM (Coefficient −30.74 s, 95% CI from −39.27 to −22.27; p < 0.0001). For a comparison of the two modalities in terms of information transfer, we calculated the percentage of time on the screen surface of the overall time to treatment decision, which with Visual Clot was 14 percentage points shorter than with ROTEM (Coefficient −14.55, 95% CI from −20.05 to −9.12; p < 0.0001). Visual Clot seems to improve perception and detection of coagulopathies and leads to earlier initiation of the appropriate treatment. In a high-pressure working environment such as the operating and the resuscitation room, correct and timely decisions regarding bleeding management may have a relevant impact on patients’ outcomes.

Thromboelastography for the Prevention of Perioperative Venous Thromboembolism in Orthopedics

We have reviewed a large number of relevant literature to determine the deficiencies of orthopedics in the diagnosis and prevention of venous thromboembolism（VTE）events during the perioperative period, and found that the TEG technology has been widely used after liver transplantation, which may make up for the deficiencies. This review expounds the detection principle and latest thromboelastography (TEG) development, and highlights the advantages of TEG over previous screening methods in diagnosing hypercoagulability. By analyzing the correlation and consistency between TEG and conventional coagulation test, reliable indexes for diagnosing hypercoagulability and important parameters for guiding perioperative anticoagulation treatment were summarized. Furthermore, our work contributes to further studies of TEG in orthopedics. Based on the research results, we believe that TEG may help orthopedists to identify and predict VTE events, use anticoagulants, eventually reduce the occurrence of VTE events.

"In Less than No Time": Feasibility of Rotational Thromboelastometry to Detect Anticoagulant Drugs Activity and to Guide Reversal Therapy

Anticoagulant drugs (i.e., unfractionated heparin, low-molecular-weight heparins, vitamin K antagonists, and direct oral anticoagulants) are widely employed in preventing and treating venous thromboembolism (VTE), in preventing arterial thromboembolism in nonvalvular atrial fibrillation (NVAF), and in treating acute coronary diseases early. In certain situations, such as bleeding, urgent invasive procedures, and surgical settings, the evaluation of anticoagulant levels and the monitoring of reversal therapy appear essential. Standard coagulation tests (i.e., activated partial thromboplastin time (aPTT) and prothrombin time (PT)) can be normal, and the turnaround time can be long. While the role of viscoelastic hemostatic assays (VHAs), such as rotational thromboelastometry (ROTEM), has successfully increased over the years in the management of bleeding and thrombotic complications, its usefulness in detecting anticoagulants and their reversal still appears unclear.

Point-of-Care Viscoelastic Tests in the Management of Obstetric Hemorrhage

Obstetric hemorrhage remains the leading cause of maternal morbidity and mortality worldwide. Thromboelastography and rotational thromboelastometry are laboratory methods of assessing the kinetics of blood clot formation through real-time measurement of viscoelastic clot strength and may aid in management of severe hemorrhage. Although first described more than 70 years ago, viscoelastic testing devices are now available that allow for rapid point-of-care use of this technology to aid in real-time management of blood product replacement in cases of severe hemorrhage. These devices can be used to visually estimate multiple facets of hemostasis-coagulation, platelet function, and fibrinolysis-within 10-20 minutes. They have been used successfully in cardiac surgery, trauma, and liver transplantation and have potential for use in management of obstetric hemorrhage. Goals with their use include targeted transfusion of blood and its components for specific coagulation deficiencies. To date, however, published experiences with the use of these viscoelastic tests for obstetric hemorrhage have been limited. Because of the increasing use of the point-of-care tests by anesthesiologists, surgeons, and intensivists, the purpose of this report is to familiarize obstetricians with the technology involved and its use in severe hemorrhage complicating pregnancy.

Questions about COVID-19 associated coagulopathy: possible answers from the viscoelastic tests

Abnormal coagulation parameters are often observed in patients with coronavirus disease 2019 (COVID-19) and the severity of derangement has been associated with a poor prognosis. The COVID-19 associated coagulopathy (CAC) displays unique features that include a high risk of developing thromboembolic complications. Viscoelastic tests (VETs), such as thromboelastometry (ROTEM), thromboelastography (TEG) and Quantra Hemostasis Analyzer (Quantra), provide "dynamic" data on clot formation and dissolution; they are used in different critical care settings, both in hemorrhagic and in thrombotic conditions. In patients with severe COVID-19 infection VETs can supply to clinicians more information about the CAC, identifying the presence of hypercoagulable and hypofibrinolysis states. In the last year, many studies have proposed to explain the underlying characteristics of CAC; however, there remain many unanswered questions. We tried to address some of the important queries about CAC through VETs analysis.

Thromboelastography is predictive of mortality, blood transfusions, and blood loss in patients with traumatic pelvic fractures: a retrospective cohort study

PURPOSE

In patients with traumatic pelvic fractures, thromboelastography (TEG) is a useful tool to rapidly evaluate and identify coagulation disturbances. The purpose of this study was to examine the coagulation kinetics of patients with traumatic pelvic fractures (pelvic ring and/or acetabulum) by analyzing the TEG results at initial presentation and its relationship with mortality and blood loss.

METHODS

A retrospective review at our Level-1 trauma center was conducted to identify Full Trauma Team activations (FTTa) with traumatic pelvic and/or acetabular fractures who were evaluated with a TEG on initial presentation between 2012 and 2016. In-hospital mortality, product transfusion, and hemoglobin changes were analyzed. Subgroup analysis was performed based on pelvic fracture type.

RESULTS

141 patients with a mean age of 49.0 ± 20.8 years and mean Injury Severity Score (ISS) of 25.18 ± 12.8 met inclusion criteria. PRBC transfusion occurred in 78.0% of patients; a total of 1486 blood products were transfused. A total of 65 patients (46.1%) underwent operative treatment for the pelvic injuries, and 18 patients (12.7%) required embolization. The overall in-hospital mortality rate was 14.9%. The degree of clot lysis at 30 min (LY30) was significantly associated with blood loss (p < 0.0001), units of packed red blood cells (PRBCs) transfused (p < 0.0001), and mortality rate (p = 0.0002).

CONCLUSION

Increased fibrinolysis evidenced by an elevated LY30 on initial TEG in patients with traumatic pelvic fractures is associated with increased blood loss, blood product transfusions, and mortality. Future studies should evaluate the clinical utility of reversing hyperfibrinolysis on initial TEG.

LEVEL OF EVIDENCE

Prognostic level III.

Hemorrhagic Resuscitation Guided by Viscoelastography in Far-Forward Combat and Austere Civilian Environments: Goal-Directed Whole-Blood and Blood-Component Therapy Far from the Trauma Center

Modern approaches to resuscitation seek to bring patient interventions as close as possible to the initial trauma. In recent decades, fresh or cold-stored whole blood has gained widespread support in multiple settings as the best first agent in resuscitation after massive blood loss. However, whole blood is not a panacea, and while current guidelines promote continued resuscitation with fixed ratios of blood products, the debate about the optimal resuscitation strategy-especially in austere or challenging environments-is by no means settled. In this narrative review, we give a brief history of military resuscitation and how whole blood became the mainstay of initial resuscitation. We then outline the principles of viscoelastic hemostatic assays as well as their adoption for providing goal-directed blood-component therapy in trauma centers. After summarizing the nascent research on the strengths and limitations of viscoelastic platforms in challenging environmental conditions, we conclude with our vision of how these platforms can be deployed in far-forward combat and austere civilian environments to maximize survival.

The Role of TEG and ROTEM in Damage Control Resuscitation

ABSTRACT

Trauma-induced coagulopathy is associated with very high mortality, and hemorrhage remains the leading preventable cause of death after injury. Directed methods to combat coagulopathy and attain hemostasis are needed. The available literature regarding viscoelastic testing, including thrombelastography (TEG) and rotational thromboelastometry (ROTEM), was reviewed to provide clinically relevant guidance for emergency resuscitation. These tests predict massive transfusion and developing coagulopathy earlier than conventional coagulation testing, within 15 min using rapid testing. They can guide resuscitation after trauma, as well. TEG and ROTEM direct early transfusion of fresh frozen plasma when clinical gestalt has not activated a massive transfusion protocol. Reaction time and clotting time via these tests can also detect clinically significant levels of direct oral anticoagulants. Slowed clot kinetics suggest the need for transfusion of fibrinogen via concentrates or cryoprecipitate. Lowered clot strength can be corrected with platelets and fibrinogen. Finally, viscoelastic tests identify fibrinolysis, a finding associated with significantly increased mortality yet one that no conventional coagulation test can reliably detect. Using these parameters, guided resuscitation begins within minutes of a patient's arrival. A growing body of evidence suggests this approach may improve survival while reducing volumes of blood products transfused.

A Systematic Review of Thromboelastography Utilization in Vascular and Endovascular Surgery

OBJECTIVE

Thromboelastography (TEG) is diagnostic modality that analyzes real-time blood coagulation parameters. Clinically, TEG primarily allows for directed blood component resuscitation among patients with acute blood loss and coagulopathy. The utilization of TEG has been widely adopted in among other surgical specialties; however, its use in vascular surgery is less prominent. We aimed to provide an up-to-date review of TEG utilization in vascular and endovascular surgery.

METHODS

Using PRISMA guidelines, a literature review with the Medical Subject Headings (MeSH) terms "TEG and arterial events", "TEG and vascular surgery", "TEG and vascular", "TEG and endovascular surgery", "TEG and endovascular", "TEG and peripheral artery disease", "TEG and prediction of arterial events", "TEG and prediction of complications ", "TEG and prediction of thrombosis", "TEG and prediction of amputation", and "TEG and amputation" was performed in Cochrane and PubMed databases to identify all peer-reviewed studies of TEG utilization in vascular surgery, written between 2000-2021 in the English language. The free text and MeSH subheadings search terms included diagnosis, complications, physiopathology, surgery, mortality, and therapy to further restrict the articles. Studies were excluded if they were not in humans or pertaining to vascular or endovascular surgery. Additionally, case reports and studies with limited information regarding TEG utilization were excluded. Each study was independently reviewed by two researchers to assess for eligibility.

RESULTS

Of the 262 studies identified through the MeSH strategy, 15 studies met inclusion criteria and were reviewed and summarized. Literature on TEG utilization in vascular surgery spanned cerebrovascular disease (n=3), peripheral arterial disease (n=3), arteriovenous malformations (n=1), venous thromboembolic events (n=7), and perioperative bleeding and transfusion (n=1). In cerebrovascular disease, TEG may predict the presence and stability of carotid plaques, analyze platelet function before carotid stenting, and compare efficacy of antiplatelet therapy after stent deployment. In peripheral arterial disease, TEG has been used to predict disease severity and analyze the impact of contrast on coagulation parameters. In venous disease, TEG may predict hypercoagulability and thromboembolic events among various patient populations. Finally, TEG can be utilized in the postoperative setting to predict hemorrhage and transfusion requirements.

CONCLUSIONS

This systematic review provides an up-to-date summarization of TEG utilization in multiple facets of vascular and endovascular surgery.

Gender Differences do not Influence the Blood Coagulopathy in Patients Undergoing Total Knee Arthroplasty: A Retrospective Thromboelastography Analysis

Objective

Deep vein thrombosis (DVT) is one of the severe complications after total knee arthroplasty (TKA). Gender has been considered to influence the incidence of the thrombosis formation in TKA patients. However, it remains controversial which gender would be more prone to form thrombosis. The aim of this study was to assess the effects of gender differences on coagulation status after TKA via the thromboelastography (TEG).

Methods

A total of 57 male patients who underwent primary TKA from September 2015 to January 2021 were included in this study. According to the matching principle of age, body mass index (BMI), and anticoagulation treatment, 60 female patients were selected. The conventional coagulation tests, routine blood tests, and thromboelastography were conducted before the operation, 1 day and 7 days after the operation. In addition, Doppler ultrasound was also performed 1 day before the operation and at the 7 days after the operation. The parameters of conventional coagulation tests, routine blood tests, and thromboelastography were compared between the two groups.

Results

There were no significant differences in the blood transfusion rate, the incidence of DVT during the perioperative period, D-dimer (D-D), fibrin degradation products (FDP), hemoglobin (HB), hematocrit (HCT), prothrombin time (PT), activated partial thromboplastin time (APTT), and C-reactive protein (CRP) at any corresponding time point between the male group and the female group (P > .05). There were no significant differences in neutrophil-to-lymphocyte ratio (NLR) preoperatively; however, there were significant differences in NLR 1 day after the surgery and 7 days after the surgery between the two groups (P < .05). There were significant differences in reaction time (R) and α angle 1 day after the surgery between the two groups (P < .05), but there were no significant differences in other TEG indexes at any corresponding time point between the two groups (P > .05). Binary logistic regression analysis demonstrated that gender, age, BMI, tourniquet application time were not independent predictors (P > .05).

Conclusion

Gender differences have no significant influence in TKA patients with regard to conventional coagulation tests and thromboelastography.

Diagnostic Value of Thromboelastography (TEG) for the Diagnosis of Death in Infected Patients

In this study, we want to investigate the clinical value of each index of thromboelastography (TEG) on the prognosis of infected patients.The clinical baseline data and TEG test results of 431 infected patients in our hospital's emergency department between January 2018 and December 2018 were selected. And the patients were divided into death and survival groups to analyze the predictive value of each index of TEG and the joint model on the death of infected patients.In the correlation study of C-reactive protein (CRP) and procalcitonin (PCT) with each TEG parameter, CRP was positively correlated with maximum amplitude (MA, r  =  0.145, P  =  .003) and elasticity constants (E, r  =  0.098, P  =  .043), respectively. PCT was positively correlated with coagulation reaction time (R, r  =  0.124, P  =  .010) and time to MA (TMA) (r  =  0.165, P  =  .001), respectively; PCT was negatively correlated with α-Angle (r  =  0.124, P  =  .010) and coagulation index (CI, r  =  -0.108, P  =  .026), respectively. Multifactorial regression analysis showed that granulocytes, thrombocytes, platelet distribution width (PDW), and infection site were independent influences on infected patients' death. Diagnostic data showed that all eight TEG indicators had good specificity for predicting death, but all had poor sensitivity; thrombodynamic potential index (TPI) had the best diagnostic value (area under the curve, AUC  =  0.609, P  =  .002). The eight-indicator modeling of TEG showed that the TEG model combined with PCT and CRP, respectively, had lower diagnostic efficacy than PCT (AUC  =  0.756, P < .001); however, TEG had better specificity (82.73%) when diagnosed independently.The granulocytes, thrombocytes, PDW, and infection site are independent influencing factors of death in infected patients. Each index of TEG has better specificity in the diagnosis of death in infected patients.

Thromboelastometry assessment of hemostatic properties in various murine models with coagulopathy and the effect of factor VIII therapeutics

BACKGROUND

Rotational thromboelastometry (ROTEM) has been commonly used to assess the viscoelastic properties of the blood clotting process in the clinic for patients with a hemostatic or prothrombotic disorder.

OBJECTIVE

To evaluate the capability of ROTEM in assessing hemostatic properties in whole blood from various mouse models with genetic bleeding or clotting disease and the effect of factor VIII (FVIII) therapeutics in FVIIInull mice.

METHODS

Mice with a genetic deficiency in either a coagulation factor or a platelet glycoprotein were used in this study. The properties of platelet- or plasma-FVIII were also assessed. Citrated blood from mice was recalcified and used for ROTEM analysis.

RESULTS

We found that blood collected from the vena cava could generate reliable results from ROTEM analysis, but not blood collected from the tail vein, retro-orbital plexus, or submandibular vein. Age and sex did not significantly affect the hemostatic properties determined by ROTEM analysis. Clotting time (CT) and clot formation time (CFT) were significantly prolonged in FVIIInull (5- and 9-fold, respectively) and FIXnull (4- and 5.7-fold, respectively) mice compared to wild-type (WT)-C57BL/6J mice. Platelet glycoprotein (GP)IIIanull mice had significantly prolonged CFT (8.4-fold) compared to WT-C57BL/6J mice. CT and CFT in factor V (FV) Leiden mice were significantly shortened with an increased α-angle compared to WT-C57BL/6J mice. Using ROTEM analysis, we showed that FVIII expressed in platelets or infused into whole blood restored hemostasis of FVIIInull mice in a dose-dependent manner.

CONCLUSION

ROTEM is a reliable and sensitive assay for assessing therapeutics on hemostatic properties in mouse models with a bleeding or clotting disorder.

TEG® and ROTEM® Traces: Clinical Applications of Viscoelastic Coagulation Monitoring in Neonatal Intensive Care Unit

The concentration of the majority of hemostatic proteins differs considerably in early life, especially in neonates compared to adulthood. Knowledge of the concept of developmental hemostasis is an essential prerequisite for the proper interpretation of conventional coagulation tests (CCT) and is critical to ensure the optimal diagnosis and treatment of hemorrhagic and thrombotic diseases in neonatal age. Viscoelastic tests (VETs) provide a point-of-care, real-time, global, and dynamic assessment of the mechanical properties of the coagulation system with the examination of both cellular and plasma protein contributions to the initiation, formation, and lysis of clots. In this work, we provide a narrative review of the basic principles of VETs and summarize current evidence regarding the two most studied point-of-care VETs, thromboelastography (TEG®) and rotational thromboelastometry (ROTEM®), in the field of neonatal care. A literature analysis shows that viscoelastic hemostatic monitoring appears to be a useful additive technique to CCT, allowing targeted therapy to be delivered quickly. These tools may allow researchers to determine the neonatal coagulation profile and detect neonatal patients at risk for postoperative bleeding, coagulation abnormalities in neonatal sepsis, and other bleeding events in a timely manner, guiding transfusion therapies using the goal-oriented transfusion algorithm. However, diagnosis and treatment algorithms incorporating VETs for neonatal patients in a variety of clinical situations should be developed and applied to improve clinical outcomes. Further studies should be performed to make routinary diagnostic and therapeutic application possible for the neonatal population.

Effect of Dabigatran on Clotting Time in the Clotpro Ecarin Clotting Assay: A Prospective, Single-Arm, Open-Label Study

Routine coagulation tests do not enable rapid, accurate determination of direct oral anticoagulant (DOAC) therapy. The ecarin clotting assay (ECA), performed on the ClotPro viscoelastic testing device, may enable sensitive and specific detection of dabigatran. We assessed the association between trough plasma dabigatran concentration and clotting time (CT) in the ClotPro ECA, in patients with non-valvular atrial fibrillation (NVAF). Each patient provided a single venous blood sample, ∼1 hour before dabigatran dosing. The study included 118 patients, of whom 64 were receiving dabigatran 110 mg twice daily and 54 were receiving 150 mg twice daily. ECA CT was moderately correlated with trough plasma dabigatran concentration (r = 0.80, p < 0.001). Slight trends toward increased plasma dabigatran concentration and prolonged ECA CT were apparent with 150 mg versus the 110 mg dose (differences not statistically significant). Individuals with creatinine clearance below 50 mL/minute had significantly higher plasma dabigatran concentrations and significantly prolonged ECA CT versus those with creatinine clearance ≥50 mL/minute. In conclusion, this preliminary study has demonstrated that CT in the ClotPro ECA reflects the plasma concentration of dabigatran in patients with NVAF. The ECA could potentially be used to assess the impact of dabigatran on a patient’s coagulation status.

Burn-Induced Coagulopathies: a Comprehensive Review

Burn-induced coagulopathy is not well understood, and consensus on diagnosis, prevention, and treatments are lacking. In this review, literature on burn-induced (and associated) coagulopathy is presented along with the current understanding of the effects of burn injury on the interactions among coagulation, fibrinolysis, and inflammation in the acute resuscitative phase and reconstructive phase of care. The role of conventional tests of coagulopathy and functional assays like thromboelastography or thromboelastometry will also be discussed. Finally, reported methods for the prevention and treatment of complications related to burn-induced coagulopathy will be reviewed.

The coagulopathy of liver disease: a shift in thinking

The coagulopathy of chronic liver disease causes derangement of the results of traditional laboratory tests. As such, there is an expectation that when undergoing invasive procedures patients with cirrhosis are at increased risk of bleeding. Standard practice is to optimise laboratory values with prophylactic transfusions of platelets, plasma and fibrinogen to reduce perceived bleeding risk. There has been a shift in thinking regarding coagulation in patients with chronic liver disease, whereby a rebalancing of haemostasis occurs with reduction in both procoagulants and anticoagulants. Guidelines for the preprocedural management of patients with chronic liver disease are inconsistent and may not account for this new paradigm. The risk of prophylactic transfusion should be measured against the risk of bleeding while considering the rebalancing of haemostasis. Future management may be guided by whole blood viscoelastic tests or use of thrombopoietin receptor agonists to optimise patients in these scenarios.

Effects of an Animated Blood Clot Technology (Visual Clot) on the Decision-Making of Users Inexperienced in Viscoelastic Testing: Multicenter Trial

BACKGROUND

Viscoelastic test-guided coagulation management has become increasingly important in assessing hemostasis. We developed Visual Clot, an animated, 3D blood clot that illustrates raw rotational thromboelastometry (ROTEM) parameters in a user-centered and situation awareness-oriented method.

OBJECTIVE

This study aimed to evaluate the applicability of Visual Clot by examining its effects on users that are novices in viscoelastic-guided resuscitation.

METHODS

We conducted an investigator-initiated, international, multicenter study between September 16, 2020, and October 6, 2020, in 5 tertiary care hospitals in central Europe. We randomly recruited medical students and inexperienced resident physicians without significant prior exposure to viscoelastic testing. The 7 participants per center managed 9 different ROTEM outputs twice, once as standard ROTEM tracings and once as the corresponding Visual Clot. We randomly presented the 18 viscoelastic cases and asked the participants for their therapeutic decisions. We assessed the performance, diagnostic confidence, and perceived workload in managing the tasks using mixed statistical models and adjusted for possible confounding factors.

RESULTS

Analyzing a total of 630 results, we found that the participants solved more cases correctly (odds ratio [OR] 33.66, 95% CI 21.13-53.64; P<.001), exhibited more diagnostic confidence (OR 206.2, 95% CI 93.5-454.75; P<.001), and perceived less workload (coefficient -41.63; 95% CI -43.91 to -39.36; P<.001) using Visual Clot compared to using standard ROTEM tracings.

CONCLUSIONS

This study emphasizes the practical benefit of presenting viscoelastic test results in a user-centered way. Visual Clot may allow inexperienced users to be involved in the decision-making process to treat bleeding-associated coagulopathy. The increased diagnostic confidence, diagnostic certainty, reduced workload, and positive user feedback associated with this visualization may promote the further adoption of viscoelastic methods in diverse health care settings.

Net platelet clot strength of thromboelastography platelet mapping assay for the identification of high on-treatment platelet reactivity in post-PCI patients

High-on treatment platelet reactivity (HTPR) leads to more prevalence of thrombotic event in patients undergoing percutaneous coronary interventions (PCI). Dual antiplatelet therapy with aspirin in addition to one P2Y₁₂ inhibitor is commonly administrated to reduce HTPR. However, ‘one size fits all’ antiplatelet strategy is widely implemented due to lacking benefits with tailored strategy. One reason for the failure of tailored treatment might be less specificity of the current indicators for HTPR. Therefore, searching for specific indicators for HTPR is critical. Thromboelastograph with platelet mapping (TEGpm) assay has been explored for identifying HTRP. Variables of TEGpm assay, including maximum amplitude (MA) induced by thrombin (MAthrombin), R time, platelet aggregation rate induced by ADP (TEGaradp) and MA induced by ADP (MAadp) have been demonstrated to be able to identify HTPR in post-PCI patients. However, these variables for HTPR might be less specific. Thus, in the present study, a novel variable nMAadp was derived by removing fibrin contribution from MAadp and analyzed for its usefulness in determining HTPR. In addition, MAthrombin, R time, MAadp and TEGaradp were also examined for determining HTPR. In conclusion, nMAadp and TEGaradp were demonstrated to be independent indicators for HTPR; nMAadp had the strongest power to identify HTPR with cutoff value of 26.3 mm; MAthrombin and R time were not significantly different between patients with and without HTPR; combination of TEGaradp and nMAadp further improved the ability to identify HTPR with an AUC of 0.893.