Comparison between thromboelastography and thromboelastometry

Mapping the landscape of machine learning models used for predicting transfusions in surgical procedures: a scoping review

Massive transfusion of blood products poses challenges in determining the need for transfusion and the appropriate volume of blood products. This review explores the use of machine learning (ML) models to predict transfusion risk during surgical procedure, focusing on the methodology, variables, and software employed to predict transfusion. This scoping review investigates the development and current state of machine learning models for predicting transfusion risk during surgical procedure, aiming to inform physicians about the field's progress and potential directions.The review was conducted using the databases Cochrane, Embase, and PubMed. The search included keywords related to blood transfusion, statistical models, and surgical procedures. Peer-reviewed articles were included, while literature reviews, case reports, and non-human studies were excluded.A total of 40 studies met the inclusion criteria. The most frequently studied biological variables included haemoglobin, platelet count, international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, creatinine, white blood cells, and albumin. Clinical variables of importance included age, sex, surgery type, blood pressure, weight, surgery duration, american society of anesthesiology (ASA) status, blood loss, and body mass index (BMI). The software employed varied, with Python, R, SPSS, and SAS being the most commonly used. Logistic regression was the predominant methodology used in 20 studies.Our scoping review highlights the need for improved reporting and transparency in methodology, variables, and software used. Future research should focus on providing detailed descriptions and open access to codes of respective models, promoting reproducibility, and enhancing the clinical relevance of transfusion risk prediction models.

Evaluation of coagulation profile in dogs with ACTH-dependent hyperadrenocorticism compared to healthy dogs by rotational thromboelastometry (ROTEM)

Despite their low morbidity, thromboembolic events in hyperadrenocorticism are associated with high mortality. Identifying the main hemostatic abnormalities will improve the prophylactic approach of these canine patients. The aim of this study was to evaluate hemostatic alterations related with ACTH-dependent HAC and its association with hypercoagulable state. For this purpose, 25 dogs diagnosed with ACTH-dependent HAC were compared with 28 healthy dogs as a control group. The hemostatic variables included platelet count, antithrombin, fibrinogen, D-dimer, PT, aPTT, rotational thromboelastometry (ROTEM) and platelet aggregation. Results showed a hypercoagulable state in 32% (8/25) dogs by ROTEM, which had at least 2 of the next features: decreased coagulation time (CT) or clot formation time (CFT) on INTEM (5/25) or EXTEM (4/25); increased maximum clot firmness (MCF) on INTEM (9/25), EXTEM (6/25) and FIBTEM (9/25). These same variables had a significant difference (P≤ 0.05) compared with the control group, as well as the parameters of α-angle and CT. Median fibrinogen levels (310 vs.178 mg/dL), mean platelet aggregation (11.1 vs. 7.9 Ohms), median platelet count (360 vs. 225 ×103/µL) and mean antithrombin activity (140 vs. 119%) were increased in ACTH-dependent HAC dogs compared to control group. PT (7.1 vs. 8.0 seconds) and aPTT (11.6 vs. 15.2 seconds) were also shortened in ACTH-dependent HAC dogs. Our findings confirm the presence of a hypercoagulable tendency in dogs with HAC. Although multifactorial, fibrinogen concentration and MCF FIBTEM showed the relevance of this protein for hypercoagulability in HAC.

Investigation of thrombin concentration at the time of clot formation in simultaneous thrombin and fibrin generation assays

Thrombin generation (TG) and fibrin clot formation represent the central process of blood coagulation. Up to 95% of thrombin is considered to be generated after the clot is formed. However, this was not investigated in depth. In this study, we conducted a quantitative analysis of the Thrombin at Clot Time (TCT) parameter in 5758 simultaneously recorded TG and clot formation assays using frozen plasma samples from commercial sources under various conditions of activation. These samples were supplemented with clotting factor concentrates, procoagulant lipid vesicles and a fluorogenic substrate and triggered with tissue factor (TF). We found that TCT is often close to a 10% of thrombin peak height (TPH) yet it can be larger or smaller depending on whether the sample has low or high TPH value. In general, the samples with high TPH are associated with elevated TCT. TCT appeared more sensitive to some procoagulant phenotypes than other commonly used parameters such as clotting time, TPH or Thrombin Production Rate (TPR). In a minority of cases, TCT were not predicted from TG parameters. For example, elevated TCT (above 15% of TPH) was associated with either very low or very high TPR values. We conclude that clotting and TG assays may provide complementary information about the plasma sample, and that the TCT parameter may serve as an additional marker for the procoagulant potential in plasma sample.

Analysis of Sex Hormones, Insulin Dosage, and Risk Factors Associated With Male Diabetic Patients

The purpose of this study is to assess the influence of sex hormones and other indicators on risk factors for hypercoagulable states in male patients with type 2 diabetes mellitus. Ninety-two diabetic patients were divided into two groups based on testosterone levels: T1 group (testosterone <12 mmol/L) and T2 group (testosterone >12 mmol/L). Fifty-four non-diabetic patients were used as the control group. Sex hormone index, glucose, insulin, C-peptide, 24-h urinary free cortisol, thromboelastography, and insulin resistance index were measured by radioimmunoassay. Testosterone was lower in the diabetic men than in the control group (12.02 vs 14.77, p < .05), and was inversely related to blood coagulation status, blood glucose level, and cortisol level. Body mass index was positively correlated with estradiol and insulin resistance index. Testosterone was independently associated with the clotting process after controlling for age. Low testosterone is a risk factor for hypercoagulable state in diabetic men. Elevated estradiol and insulin resistance are influential factors for increased body mass index.

The role of viscoelastic hemostatic assays for postpartum hemorrhage management and bedside intrapartum care

Viscoelastic hemostatic assays are point-of-care devices that assess coagulation and fibrinolysis in whole blood samples. These technologies provide numeric and visual information of clot initiation, clot strength, and clot lysis under low-shear conditions, and have been used in a variety of clinical settings and subpopulations, including trauma, cardiac surgery, and obstetrics. Emerging data indicate that these devices are useful for detecting important coagulation defects during major postpartum hemorrhage (especially low plasma fibrinogen concentration [hypofibrinogenemia]) and informing clinical decision-making for blood product use. Data from observational studies suggest that, compared with traditional formulaic approaches to transfusion management, targeted or goal-directed transfusion approaches using data from viscoelastic hemostatic assays are associated with reduced hemorrhage-related morbidity and lower blood product requirement. Viscoelastic hemostatic assays can also be used to identify and treat coagulation defects in patients with inherited or acquired coagulation disorders, such as factor XI deficiency or immune-mediated thrombocytopenia, and to assess hemostatic profiles of patients prescribed anticoagulant medications to mitigate the risk of epidural hematoma after neuraxial anesthesia and postpartum hemorrhage after delivery.

Guidelines for the management of coagulation disorders in patients with cirrhosis

Coagulation management in the patient with cirrhosis has undergone a significant transformation since the beginning of this century, with the concept of a rebalancing between procoagulant and anticoagulant factors. The paradigm that patients with cirrhosis have a greater bleeding tendency has changed, as a result of this rebalancing. In addition, it has brought to light the presence of complications related to thrombotic events in this group of patients. These guidelines detail aspects related to pathophysiologic mechanisms that intervene in the maintenance of hemostasis in the patient with cirrhosis, the relevance of portal hypertension, mechanical factors for the development of bleeding, modifications in the hepatic synthesis of coagulation factors, and the changes in the reticuloendothelial system in acute hepatic decompensation and acute-on-chronic liver failure. They address new aspects related to the hemorrhagic complications in patients with cirrhosis, considering the risk for bleeding during diagnostic or therapeutic procedures, as well as the usefulness of different tools for diagnosing coagulation and recommendations on the pharmacologic treatment and blood-product transfusion in the context of hemorrhage. These guidelines also update the knowledge regarding hypercoagulability in the patient with cirrhosis, as well as the efficacy and safety of treatment with the different anticoagulation regimens. Lastly, they provide recommendations on coagulation management in the context of acute-on-chronic liver failure, acute liver decompensation, and specific aspects related to the patient undergoing liver transplantation.

Testing strategies used in the diagnosis of rare inherited bleeding disorders

INTRODUCTION

Rare Bleeding Disorders have a low population prevalence and may not be recognized by most clinicians. In addition, knowledge gaps of the indicated laboratory tests and their availability add to the potential for delayed diagnosis or misdiagnosis. The lack of widely available commercial, regulatory body approved esoteric tests limit them to reference laboratories, thus limiting easy access for patients.

AREAS COVERED

A literature search of Pubmed, Medline, Embase and review of international society guidelines was performed. Additional references from published articles were reviewed. A patient-centered approach to recognition and evaluation of RBD is discussed.

EXPERT OPINION

Recognition of RBD relies on obtaining a detailed patient personal and family hemostatic history. Inquiry into a history of involvement of other organ systems is important and if present should lead to suspicion of an inherited platelet disorder or a variant of Ehlers Danlos Syndrome. Multiple factors contribute to the complexity of development of efficient algorithms for diagnostic testing. Limitations in diagnostic sensitivity and specificity of screening tests, diagnostic tests, and esoteric tests further compound the complexity of establishing a diagnosis. Educational efforts focusing on clinician awareness of RBDs and available testing options are vital for optimal management of such patients.

New under the sun: ClotPro's ECA-test detects hyperfibrinolysis in a higher number of patients, more frequently and 9 min earlier

Liver diseases result in a re-balanced state of the haemostatic system with decreased haemostatic reserves. Increased fibrinolytic activity is commonly seen during liver transplants. The aim of this study was to assess whether ClotPro's ECA-test is able to detect hyperfibrinolysis earlier and with higher frequency than ClotPro's conventional viscoelastic assays for the intrinsic and the extrinsic coagulation pathway. From 25 liver transplant recipients, systemic blood samples were collected during surgery. Viscoelastic haemostatic assays with ClotPro's IN-test, EX-test and ECA-test were performed simultaneously from each blood sample. Hyperfibrinolysis was defined on the basis of the manufacturer's prespecified threshold value (maximal lysis >15%). The incidence of hyperfibrinolysis detected with each test was compared with the McNemar test. For each assay, lysis detection time (LDT) was calculated and analysed with the nonparametric Kruskal-Wallis test. A total of 125 tests were performed simultaneously. Compared with the IN-test and the EX-test, the ECA-test detected hyperfibrinolysis in significantly ( P  < 0.001) higher number of patients (9; 11; 14, respectively) and in more measurement points (14; 18; 28, respectively). The analysis of LDT values revealed significant superiority of the ECA-test to the IN-test ( P  = 0.046) and to the EX-test ( P  = 0.035), indicating the profibrinolytic state of the haemostasis 8.9 ± 0.65 and 8.7 ± 0.17 min earlier, respectively. These are preliminary results of the study NCT0424637. ClotPro's ECA-test appeared to detect fibrinolysis in a higher number of patients, more frequently, and the mean time of detection was 9 min earlier than that of the IN-test and the EX-test.

Fibrinogen function indexes are potential biomarkers for evaluating the occurrence and severity of diabetic foot

BACKGROUND AND OBJECTIVES

Research suggests that fibrinogen (Fib) concentrations are used to assess the occurrence and severity of diabetic foot (DF) and to monitor the progression of diabetic foot in patients. However, its correlation with Fib function has not been reported. Here, angle α and k value, reflecting the Fib function, were used to analyse its correlation with DF, and their potential as biological indicators for evaluating the occurrence and severity of DF was explored.

SUBJECTS AND METHODS

This clinical study enrolled 163 type 2 diabetes mellitus (T2DM) patients, who were divided into the diabetes with DF (84 cases) group, diabetes with no DF (79 cases) group. Meanwhile, 90 healthy unrelated subjects were enrolled as controls.

RESULTS

Angle α and fibrinogen levels increased greatly in subjects with DF compared with those without. The k value levels greatly decreased in subjects with DF compared with those without (P < 0.01). Spearman correlation analysis showed that angle α and fibrinogen were positively correlated with DF grading (r = 0.635, P < 0.01; r = 0.616, P < 0.01), k value was negatively correlated with DF (r= - 0.589, P < 0.01). ROC curve analysis showed that the optimal cut-off point for angle α to distinguish patients with DF from those without was 62.85 deg, with a sensitivity of 78.6% and specificity of 78.7%. The optimal cut-off point for k value was 1.75 min, with a sensitivity of 82.1% and specificity of 65.8%. The optimal cut-off point for fibrinogen was 3.85 g/l, with a sensitivity of 63.1% and specificity of 98.2%. The optimal cut-off point for angle α to evaluate the risk of diabetic foot progression was 70.20 deg, with a sensitivity of 73.2% and specificity of 90.7%. The optimal cut-off point for k value was 1.25 min, with a sensitivity of 67.9% and specificity of 90.8%. The optimal cut-off point for fibrinogen was 4.12 g/l, with a sensitivity of 85.7% and specificity of 93.5%.

CONCLUSION

Angle α, k-value and fibrinogen have clinical significance on the risk of occurrence and development of diabetic foot, which can contribute to early diagnosis and early clinical intervention in DF.

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.

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.

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.

Thromboelastography-Guided Anticoagulant Therapy for the Double Hazard of Thrombohemorrhagic Events in COVID-19: A Report of 3 Cases

Case series

Patients: Female, 72-year-old • Female, 55-year-old • Female, 43-year-old

Final Diagnosis: COVID provoked thromboembolism • COVID-19 • pulmonary embolism • rectus sheath hematoma

Symptoms: Cough • fever • shortness of breath

Medication: —

Clinical Procedure: —

Specialty: Critical Care Medicine • Diagnostics, Laboratory • Hematology • Infectious Diseases

Assessing Plasmin Generation in Health and Disease

Fibrinolysis is an important process in hemostasis responsible for dissolving the clot during wound healing. Plasmin is a central enzyme in this process via its capacity to cleave fibrin. The kinetics of plasmin generation (PG) and inhibition during fibrinolysis have been poorly understood until the recent development of assays to quantify these metrics. The assessment of plasmin kinetics allows for the identification of fibrinolytic dysfunction and better understanding of the relationships between abnormal fibrin dissolution and disease pathogenesis. Additionally, direct measurement of the inhibition of PG by antifibrinolytic medications, such as tranexamic acid, can be a useful tool to assess the risks and effectiveness of antifibrinolytic therapy in hemorrhagic diseases. This review provides an overview of available PG assays to directly measure the kinetics of plasmin formation and inhibition in human and mouse plasmas and focuses on their applications in defining the role of plasmin in diseases, including angioedema, hemophilia, rare bleeding disorders, COVID-19, or diet-induced obesity. Moreover, this review introduces the PG assay as a promising clinical and research method to monitor antifibrinolytic medications and screen for genetic or acquired fibrinolytic disorders.

Viscoelastic testing in liver transplantation

Despite the lack of large randomized clinical studies, viscoelastic tests (VETs) have been a critical armamentarium for hemostatic control in liver transplantation (LT) since the 1960s. Many transplant institutions have adopted VETs in their clinical practice. Several small-size randomized clinical trials on LT patients have suggested that VET-guided hemostatic treatment algorithms have led to decreased indications for and amounts of transfused blood products, especially fresh-frozen plasma, compared to standard laboratory-based hemostatic management. VETs have also been reported to offer insight into the diagnosis and prediction of LT patients' development of hypercoagulability-related morbidity and mortality. There is still a need for VET device-specific hemostatic algorithms in LT, and clinicians must take into account the tendency to underestimate the coagulation capacity of VETs in patients with end-stage liver disease where hemostasis is rebalanced.