FIBTEM Improves the Sensitivity of Hyperfibrinolysis Detection in Severe Trauma Patients: A Retrospective Study Using Thromboelastometry

siRNA-mediated reduction of a circulating protein in swine using lipid nanoparticles

Genetic manipulation of animal models is a fundamental research tool in biology and medicine but is challenging in large animals. In rodents, models can be readily developed by knocking out genes in embryonic stem cells or by knocking down genes through in vivo delivery of nucleic acids. Swine are a preferred animal model for studying the cardiovascular and immune systems, but there are limited strategies for genetic manipulation. Lipid nanoparticles (LNPs) efficiently deliver small interfering RNA (siRNA) to knock down circulating proteins, but swine are sensitive to LNP-induced complement activation-related pseudoallergy (CARPA). We hypothesized that appropriately administering optimized siRNA-LNPs could knock down circulating levels of plasminogen, a blood protein synthesized in the liver. siRNA-LNPs against plasminogen (siPLG) reduced plasma plasminogen protein and hepatic plasminogen mRNA levels to below 5% of baseline values. Functional assays showed that reducing plasminogen levels modulated systemic blood coagulation. Clinical signs of CARPA were not observed, and occasional mild and transient hepatotoxicity was present in siPLG-treated animals at 5 h post-infusion, which returned to baseline by 7 days. These findings advance siRNA-LNPs in swine models, enabling genetic engineering of blood and hepatic proteins, which can likely expand to proteins in other tissues in the future.

Older females have increased mortality after trauma as compared with younger females and males, associated with increased fibrinolysis

INTRODUCTION

Female sex may provide a survival benefit after trauma, possibly attributable to protective effects of estrogen. This study aimed to compare markers of coagulation between male and female trauma patients across different ages.

METHODS

Secondary analysis of a prospective cohort study that was conducted at six trauma centers. Trauma patients presenting with full trauma team activation were eligible for inclusion. Patients with a penetrating trauma or traumatic brain injury were excluded. Upon hospital arrival, blood was drawn for measurement of endothelial and coagulation markers and for rotational thromboelastometry measurement. Trauma patients were divided into four categories: males younger than 45 years, males 45 years or older, females younger than 45 years, and females 45 years or older. In a sensitivity analysis, patients between 45 and 55 years old were excluded to control for menopausal transitioning. Groups were compared with a Kruskal-Wallis test with Bonferroni correction. A logistic regression was performed to assess whether the independent effect of sex and age on mortality.

RESULTS

A total of 1,345 patients were available for analysis. Compared with the other groups, mortality was highest in females 45 years or older, albeit not independent from injury severity and shock. In the group of females 45 years or older, there was increased fibrinolysis, demonstrated by increased levels of plasmin-antiplasmin complexes with a concomitant decrease in α2-antiplasmin. Also, a modest decrease in coagulation factors II and X was observed. Fibrinogen levels were comparable between groups. The sensitivity analysis in 1,104 patients demonstrated an independent relationship between female sex, age 55 years or older, and mortality. Rotational thromboelastometry profiles did not reflect the changes in coagulation tests.

CONCLUSION

Female trauma patients past their reproductive age have an increased risk of mortality compared with younger females and males, associated with augmented fibrinolysis and clotting factor consumption. Rotational thromboelastometry parameters did not reflect coagulation differences between groups.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

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.

Point-of-care, goal-directed management of bleeding in trauma patients

PURPOSE OF REVIEW

The purpose of this review is to consider the clinical value of point-of-care (POC) testing in coagulopathic trauma patients with traumatic brain injury (TBI) and trauma-induced coagulopathy (TIC).

RECENT FINDINGS

Patients suffering from severe TBI or TIC are at risk of developing pronounced haemostatic disorders. Standard coagulation tests (SCTs) are insufficient to reflect the complexity of these coagulopathies. Recent evidence has shown that viscoelastic tests (VETs) identify haemostatic disorders more rapidly and in more detail than SCTs. Moreover, VET results can guide coagulation therapy, allowing individualised treatment, which decreases transfusion requirements. However, the impact of VET on mortality remains uncertain. In contrast to VETs, the clinical impact of POC platelet function testing is still unproven.

SUMMARY

POC SCTs are not able to characterise the complexity of trauma-associated coagulopathy. VETs provide a rapid estimation of underlying haemostatic disorders, thereby providing guidance for haemostatic therapy, which impacts allogenic blood transfusion requirements. The value of POC platelet function testing to identify platelet dysfunction and guide platelet transfusion is still uncertain.

A retrospective validation of ROTEM algorithms for detecting hyperfibrinolysis demonstrates poor agreement for prediction of in-hospital mortality and transfusion requirement in a general, non-cardiac, surgical population

INTRODUCTION

Hyperfibrinolysis diagnosed on Rotational Thromboelastography (ROTEM) is associated with increased transfusion requirements and mortality in trauma. The diagnosis and significance of hyperfibrinolysis in a mixed, non-cardiac, general surgical population has not been investigated. We aimed to measure agreement between four ROTEM algorithms for diagnosing hyperfibrinolysis and transfusion requirements and mortality in general surgical patients. These algorithms mostly incorporate measures of early or late clot amplitude reduction on the Extrinsic Clotting Pathway Test with Tissue Factor (EXTEM) channel.

METHOD

Four hospital administrative data sets were linked from 2019 to 2022. Adults >18 years were included if a ROTEM was performed during their surgery (intraoperative period) or within 24-h of the surgery completion (postoperative period). The four hyperfibrinolysis criteria were applied to the ROTEM data and assessed for their agreement, intraoperative and postoperative transfusion requirements and in-patient mortality.

RESULTS

We linked 933 ROTEMs to 558 patient-procedures. One algorithm identified hyperfibrinolysis on only three patients so was excluded. Agreement between the remaining three was slight (Cohens Kappa 0.18 (p < 0.001)) with hyperfibrinolysis diagnosed between 22 and 69 % of the procedures. The association between hyperfibrinolysis diagnosis and intraoperative or postoperative transfusion requirement was inconsistent between the criteria. However, an algorithm put forward by Goerling et al. was more often associated with transfusion requirement and inpatient mortality.

DISCUSSION

The poor agreement between criteria suggests that some ROTEM criteria may not transfer directly to general surgical patients. Future research should focus on optimising hyperfibrinolysis cut-off values to update algorithms for bleeding general surgical patients.

Is ROTEM Diagnostic in Trauma Care Associated with Lower Mortality Rates in Bleeding Patients?—A Retrospective Analysis of 7461 Patients Derived from the TraumaRegister DGU®

Introduction: Death from uncontrolled trauma haemorrhage and subsequent trauma-induced coagulopathy (TIC) is potentially preventable. Point-of-care devices such as rotational thromboelastometry (ROTEM^®) are advocated to detect haemostatic derangements more rapidly than conventional laboratory diagnostics. Regarding reductions in RBC transfusion, the use of ROTEM has been described as being efficient and associated with positive outcomes in several studies. Objective: The effect of ROTEM use was assessed on three different outcome variables: (i) administration of haemostatics, (ii) rate of RBC transfusions and (iii) mortality in severely injured patients. Methods and Material: A retrospective analysis of a large data set of severely injured patients collected into the TraumaRegister DGU^® between 2009 and 2016 was conducted. The data of 7461 patients corresponded to the inclusion criteria and were subdivided into ROTEM-using and ROTEM-non-using groups. Both groups were analysed regarding (i) administration of haemostatics, (ii) rate of RBC transfusions and (iii) mortality. Results: A lower mortality rate in ROTEM-using groups was observed (p = 0.043). Furthermore, more patients received haemostatic medication when ROTEM was used. In ROTEM-using groups, there was a statistically relevant higher application of massive transfusion. Conclusions: In this retrospective study, the use of ROTEM was associated with reduced mortality and an increased application of haemostatics and RBC transfusions. Prospective evidence is needed for further evidence-based recommendations.

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.

Viscoelastic Hemostatic Assays for Orthopedic Trauma and Elective Procedures

The application of viscoelastic hemostatic assays (VHAs) (e.g., thromboelastography (TEG) and rotational thromboelastometry (ROTEM)) in orthopedics is in its relative infancy when compared with other surgical fields. Fortunately, several recent studies describe the emerging use of VHAs to quickly and reliably analyze the real-time coagulation and fibrinolytic status in both orthopedic trauma and elective orthopedic surgery. Trauma-induced coagulopathy—a spectrum of abnormal coagulation phenotypes including clotting factor depletion, inadequate thrombin generation, platelet dysfunction, and dysregulated fibrinolysis—remains a potentially fatal complication in severely injured and/or hemorrhaging patients whose timely diagnosis and management are aided by the use of VHAs. Furthermore, VHAs are an invaluable compliment to common coagulation tests by facilitating the detection of hypercoagulable states commonly associated with orthopedic injury and postoperative status. The use of VHAs to identify hypercoagulability allows for an accurate venous thromboembolism (VTE) risk assessment and monitoring of VTE prophylaxis. Until now, the data have been insufficient to permit an individualized approach with regard to dosing and duration for VTE thromboprophylaxis. By incorporating VHAs into routine practice, orthopedic surgeons will be better equipped to diagnose and treat the complete spectrum of coagulation abnormalities faced by orthopedic patients. This work serves as an educational primer and up-to-date review of the current literature on the use of VHAs in orthopedic surgery.

The coagulopathy underlying rotational thromboelastometry derangements in trauma patients: a prospective observational multicenter study

BACKGROUND

Viscoelastic hemostatic assays such as rotational thromboelastometry (ROTEM®) are used to guide treatment of trauma induced coagulopathy. We hypothesized that ROTEM derangements reflect specific coagulation factor deficiencies after trauma.

METHODS

Secondary analysis of a prospective cohort study in six European trauma centers in patients presenting with full trauma team activation. Patients with dilutional coagulopathy and patients on anticoagulants were excluded. Blood was drawn on arrival for measurement of ROTEM®, coagulation factor levels and markers of fibrinolysis. ROTEM® cut-off values to define hypocoagulability were: EXTEM clotting time (CT) >80s, EXTEM clot amplitude after 5 minutes (CA5) <40mm, EXTEM lysis at 30 minutes (Li30) <85%, FIBTEM clot amplitude after 5 minutes (CA5) <10mm and FIBTEM lysis at 30 minutes (Li30) <85%. Based on these, patients were divided into 7 deranged ROTEM® profiles and compared to the reference group (ROTEM® values within reference range). The primary endpoint was coagulation factors levels and fibrinolysis.

RESULTS

Of 1828 patients, 40% had ROTEM® derangements 40.0%, most often consisting of a combined decrease in EXTEM and FIBTEM CA5, that was present in 217 (11.9%) patients. While an isolated EXTEM CT>80s had no impact on mortality, all other ROTEM® derangements were associated with increased mortality. Also, coagulation factor levels in this group were similar to patients with a normal ROTEM®. Of coagulation factors, decrease was most apparent for fibrinogen (with a nadir of 0.78 g/L) and for factor V levels (with a nadir of 22.8%). In addition, increased fibrinolysis can be present when LI30 is normal but EXTEM and FIBTEM CA5 is decreased.

CONCLUSION

Coagulation factor levels and mortality in the group with an isolated clotting time prolongation is similar to patients with a normal ROTEM ®. Other ROTEM ® derangements are associated with mortality and reflect a depletion of fibrinogen and factor V. Increased fibrinolysis can be present when lysis after 30 minutes is normal.

Rotational thromboelastometry for diagnosis of fibrinolysis induced by urokinase in an in-vitro model

Fibrinolysis can be abnormally activated in several critical care settings but it's often misdiagnosed by standard laboratory tests. Although rotational thromboelastometry can assess the whole coagulative process, its ability to detect fibrinolysis has been questioned. Aim of this study was to investigate the ability of thromboelastometry in detecting induced fibrinolysis in an in-vitro model. Whole blood samples were taken from 18 healthy volunteers. Each sample was split and added with increasing urokinase concentrations till to reach 0, 50, 75 and 100 IU/ml. Thromboelastometry tests, extem and aptem, were performed on the obtained samples. If significant lysis at 50 IU/ml was recorded, also 10, 25 and 35 IU/ml drug concentrations were tested. No lytic effects were detected in 10 IU/ml samples. Lysis variables were the most sensitive in detecting fibrinolysis even at 25 IU/ml (P < 0.05). Clot firmness parameters were also affected by urokinase, but only at the two highest drug concentrations (P < 0.05). Extem/aptem ratio enhanced the sensitivity of these parameters only if lysis was more marked. Analysing groups of different lysis severity, the time to achieve maximum clot firmness could anticipate an ongoing fulminant or intermediate lysis with 100% sensitivity and 100% specificity (P < 0.05) when lower than 1341.5 s. Rotational thromboelastometry could detect fibrinolysis when it was induced in vitro by 25 IU/ml urokinase or more. Apart from the parameters specific for lysis, time to achieve maximum clot firmness appeared as the earliest indicator of fibrinolysis with high sensitivity and specificity especially if a more intense lysis was going on.

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 talk": expanding clinical roles for thromboelastography and rotational thromboelastometry

Viscoelastic assays (VEAs) that include thromboelastography and rotational thromboelastometry add value to the investigation of coagulopathies and goal-directed management of bleeding by providing a complete picture of clot formation, strength, and lysis in whole blood that includes the contribution of platelets, fibrinogen, and coagulation factors. Conventional coagulation assays have several limitations, such as their lack of correlation with bleeding and hypercoagulability; their inability to reflect the contribution of platelets, factor XIII, and plasmin during clot formation and lysis; and their slow turnaround times. VEA-guided transfusion algorithms may reduce allogeneic blood exposure during and after cardiac surgery and in the emergency management of trauma-induced coagulopathy and hemorrhage. However, the popularity of VEAs for other indications is driven largely by extrapolation of evidence from cardiac surgery, by the drawbacks of conventional coagulation assays, and by institution-specific preferences. Robust diagnostic studies validating and standardizing diagnostic cutoffs for VEA parameters and randomized trials comparing VEA-guided algorithms with standard care on clinical outcomes are urgently needed. Lack of such studies represents the biggest barrier to defining the role and impact of VEA in clinical care.

Initial clinical experience with the Quantra QStat System in adult trauma patients

Background

Whole blood viscoelastic testing (VET) devices are routinely used in a variety of clinical settings to assess hemostasis. The Quantra QStat System is a cartridge-based point of care VET device that measures changes in clot stiffness during coagulation and fibrinolysis using ultrasound detection of resonance. The objective of this study was to assess the ability of the Quantra QStat System to detect coagulopathies in trauma patients.

Methods

A multicenter observational study was conducted on adult subjects at two level 1 trauma centers. For each subject, whole blood samples were drawn upon arrival to the emergency department and again, in some cases, after administration of blood products and/or antifibrinolytics. Samples were analyzed on the Quantra in parallel to ROTEM delta. The QStat cartridge provides measures of Clot Time (CT), Clot Stiffness (CS), Fibrinogen and Platelet Contributions to clot stiffness (FCS and PCS), and Clot Stability to Lysis (CSL). Data analyses included linear regression of Quantra and ROTEM parameters and an assessment of the concordance of the two devices for the assessment of hyperfibrinolysis.

Results

A total of 56 patients were analyzed. 42% of samples had a low QStat CS value suggestive of an hypocoagulable state. The low stiffness values could be attributed to either low PCS, FCS or combination. Additionally, 13% of samples showed evidence of hyperfibrinolysis based on the QStat CSL parameter. Samples analyzed with ROTEM assays showed a lower prevalence of low CS and hyperfibrinolysis based on EXTEM and FIBTEM results. The correlation of CS, FCS and CT versus equivalent ROTEM parameters was strong with r-values of 0.83, 0.79 and 0.79, respectively.

Discussion

This first clinical experience with the Quantra in trauma patients showed that the QStat Cartridge was strongly correlated with ROTEM parameters and that it could detect coagulopathies associated with critical bleeding.

Level of evidence

Diagnostic test, Level II.