Redefining postinjury fibrinolysis phenotypes using two viscoelastic assays

Hemogram-Based Phenotypes of the Immune Response and Coagulopathy in Blunt Thoracic Trauma

Background: Blunt thoracic trauma possesses unique physiopathological traits due to the complex interaction of immune and coagulation systems in the lung tissue. Hemogram-based ratios such as neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), neutrophil-to-lymphocyte × platelet (NLPR) ratios have been studied as proxies for immune dysregulation and survival in trauma. We hypothesized that blunt thoracic trauma patients exhibit distinct patterns of coagulation and inflammation abnormalities identifiable by the use of readily available hemogram-derived markers. Methods: The present study represents a retrospective observational analysis that included 86 patients with blunt thoracic trauma from a single high-volume level one trauma center. The primary outcome was mortality prediction in blunt thoracic trauma patients using these derived biomarkers. Secondary outcomes included phenotypes of the immune response and coagulopathy and the prediction of non-fatal adverse events. Results: A U-shaped distribution of mortality was found, with high rates of early deaths in patients with an NLPR value of <3.1 and high rates of late deaths in patients with NLPR > 9.5. A subgroup of blunt thoracic trauma patients expressing moderate inflammation and inflammation-induced hypercoagulation objectified as NLPR between 3.1 and 9.5 may have a survival benefit (p < 0.0001). The NLPR cut-off for predicting early deaths and the need for massive transfusion was 3.1 (sensitivity = 80.00% and specificity = 71.05%). Conclusions: These findings suggest that blunt thoracic trauma patients exhibit distinct phenotypes of the immune response and coagulopathy from the early stages. A controlled, balanced interaction of immune, coagulation, and fibrinolytic systems might effectively achieve tissue repair and increase survival in thoracic trauma patients and should be subject to further research.

A multi-center, double-blind, placebo-controlled, randomized, parallel-group, non-inferiority study to compare the efficacy of goal-directed tranexamic acid administration based on viscoelastic test versus preemptive tranexamic acid administration on postoperative bleeding in cardiovascular surgery (GDT trial)

BACKGROUND

Tranexamic acid (TXA) effectively attenuates hyperfibrinolysis and preemptive administration has been employed to reduce bleeding and blood transfusions in various surgical settings. However, TXA administration could be associated with adverse effects, such as seizures and thromboembolic risks. While patients with fibrinolysis shutdown showed greater thromboembolic complications and mortality, TXA administration may aggravate the degree of shutdown in these patients. Selective TXA administration based on the results of rotational thromboelastometry (ROTEM) would be non-inferior to preemptive TXA administration in reducing postoperative bleeding and beneficial in reducing its risks in patients undergoing cardiovascular surgery.

METHODS

This non-inferiority, randomized, double-blind, placebo-controlled, multicenter trial will be performed in 3 tertiary university hospitals from August 2023 to March 2025. Seven hundred sixty-four patients undergoing cardiovascular surgery will be randomly allocated to get TXA as a preemptive (Group-P) or goal-directed strategy (Group-GDT) in each institution (with a 1:1 allocation ratio). After anesthesia induction, TXA (10 mg/kg and 2 mg/kg/h) and a placebo are administered after anesthesia induction in Group-P and Group-GDT, respectively. ROTEM tests are performed immediately before weaning from CPB and at the considerable bleeding post-CPB period. After getting the test results, a placebo is administered in Group-P (regardless of the test results). In Group-GDT, placebo or TXA is administered according to the results: placebo is administered if the amplitude at 10 min (A10-EXTEM) is ≥ 40 mm and lysis within 60 min (LI60-EXTEM) of EXTEM assay is ≥ 85%, or TXA (20 mg/kg) is administered if A10-EXTEM is < 40 mm or LI60-EXTEM is < 85%. The primary outcome is inter-group comparisons of postoperative bleeding (for 24 h). The secondary measures include comparisons of perioperative blood transfusion, coagulation profiles, reoperation, thromboembolic complications, seizures, in-hospital mortality, fibrinolysis phenotypes, and hospital costs.

DISCUSSION

The absence of inter-group differences in postoperative bleeding would support the selective strategy's non-inferiority in reducing postoperative bleeding in these patients. The possible reduction in thromboembolic risks, seizures, and fibrinolysis shutdown in Group-GDT would support its superiority in reducing TXA-induced adverse events and the cost of their management.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov with the registration number NCT05806346 on March 28, 2023.

TRIAL STATUS

recruiting. Issue date: 2023 March 28 (by Tae-Yop Kim, MD, PhD). The trial was registered in the clinical registration on March 28, 2023 (ClinicalTrials.gov, NCT05806346) and revised to the latest version of its protocol (version no. 8, August 26, 2024) approved by the institutional review boards (IRBs) of all 3 university hospitals (Konkuk University Medical Center, 2023-07-005-001, Asan Medical Center, 2023-0248, and Samsung Medical Center, SMC 2023-06-048-002). Its recruitment was started on August 1, 2023, and will be completed on December 31, 2024. Protocol amendment number: 08 (protocol version 08, August 26, 2024). Revision chronology: 2023 March 28:Original. 2023 April 10:Amendment No 01. The primary reason for the amendment is the modification of Arms (adding one arm for sub-group analyses) and Interventions, Outcome Measures, Study Design, Study Description, Study Status, Eligibility, and Study Identification. 2023 May 03:Amendment No 02. The primary reason for the amendment is to modify the Outcome Measures and update the study status. 2023 July 06:Amendment No 03. The primary reason for amendment is to update the chronological study status. 2023 July 07:Amendment No 04. The primary reason for the amendment is the modification of study information (the treatment category was changed to diagnostic, and Phase 4 was changed to not applicable) and a chronological update on the study status. 2023 September 12:Amendment No 06. The primary reason for the amendment is a chronological update in the study status and the inclusion of additional information regarding contacts/locations and oversight. 2023 December 29:Amendment No 07. The primary reason for the amendment is to modify the outcome measures (including detailed information on outcome measures, addition of extra secondary measures, and chronological updates in study status). 2024 August 26:Amendment No 08. The primary reason for the amendment is to add detailed descriptions regarding data handling and the names and roles of the participating institutions and to update the chronological process of the trial.

Markers of Futile Resuscitation in Traumatic Hemorrhage: A Review of the Evidence and a Proposal for Futility Time-Outs during Massive Transfusion

The reduction in the blood supply following the 2019 coronavirus pandemic has been exacerbated by the increased use of balanced resuscitation with blood components including whole blood in urban trauma centers. This reduction of the blood supply has diminished the ability of blood banks to maintain a constant supply to meet the demands associated with periodic surges of urban trauma resuscitation. This scarcity has highlighted the need for increased vigilance through blood product stewardship, particularly among severely bleeding trauma patients (SBTPs). This stewardship can be enhanced by the identification of reliable clinical and laboratory parameters which accurately indicate when massive transfusion is futile. Consequently, there has been a recent attempt to develop scoring systems in the prehospital and emergency department settings which include clinical, laboratory, and physiologic parameters and blood products per hour transfused as predictors of futile resuscitation. Defining futility in SBTPs, however, remains unclear, and there is only nascent literature which defines those criteria which reliably predict futility in SBTPs. The purpose of this review is to provide a focused examination of the literature in order to define reliable parameters of futility in SBTPs. The knowledge of these reliable parameters of futility may help define a foundation for drawing conclusions which will provide a clear roadmap for traumatologists when confronted with SBTPs who are candidates for the declaration of futility. Therefore, we systematically reviewed the literature regarding the definition of futile resuscitation for patients with trauma-induced hemorrhagic shock, and we propose a concise roadmap for clinicians to help them use well-defined clinical, laboratory, and viscoelastic parameters which can define futility.

Validation of the time to attain maximal clot amplitude after reaching maximal clot formation velocity parameter as a measure of fibrinolysis using rotational thromboelastometry and its application in the assessment of fibrinolytic resistance in septic patients: a prospective observational study: communication from the ISTH SSC Subcommittee on Fibrinolysis

BACKGROUND

In sepsis, fibrinolysis resistance correlates with worse outcomes. Practically, rotational thromboelastometry (ROTEM) is used to report residual clot amplitude relative to maximum amplitude at specified times after clot formation clot lysis indices (CLIs). However, healthy individuals can exhibit similar CLIs, thus making it challenging to solely diagnose the low fibrinolytic state. Furthermore, CLI does not include the kinetics of clot formation, which can affect overall fibrinolysis. Therefore, a more nuanced analysis, such as time to attain maximal clot amplitude after reaching maximal clot formation velocity (t-AUCi), is needed to better identify fibrinolysis resistance in sepsis.

OBJECTIVES

To evaluate the correlation between the degree of fibrinolytic activation and t-AUCi in healthy or septic individuals.

METHODS

Whole blood (n = 60) from septic or healthy donors was analyzed using tissue factor-activated (EXTEM) and nonactivated (NATEM) ROTEM assays. Lysis was initiated with tissue-type plasminogen activator, and CLI and t-AUCi were calculated. Standard coagulation tests and plasma fibrinolysis markers (D-dimer, plasmin-α2-antiplasmin complex, plasminogen activator inhibitor type 1, and plasminogen) were also measured.

RESULTS

t-AUCi values decreased with increasing fibrinolytic activity and correlated positively with CLI for different degrees of clot lysis both in EXTEM and NATEM. t-AUCi cutoff value of 1962.0 seconds in EXTEM predicted low fibrinolytic activity with 81.8% sensitivity and 83.7% specificity. In addition, t-AUCi is not influenced by clot retraction.

CONCLUSION

Whole-blood point-of-care ROTEM analyses with t-AUCi offers a more rapid and parametric evaluation of fibrinolytic potential compared with CLI, which can be used for a more rapid and accurate diagnosis of fibrinolysis resistance in sepsis.

Analysis of fibrinolytic shutdown in trauma patients with traumatic brain injury

BACKGROUND

Coagulation profiles following major trauma vary depending on injury pattern and degree of shock. The physiologic mechanisms involved in coagulation function at any given time are varied and remain poorly understood. Thromboelastography (TEG) has been used evaluate coagulation profiles in the trauma population with some reports demonstrating a spectrum of fibrinolysis to fibrinolytic shutdown on initial presentation. The objective of this study was to evaluate the fibrinolytic profile of patients with TBI using thromboelastography (TEG). We hypothesized that patients with TBI would demonstrate low fibrinolytic activity.

METHODS

All trauma activations at an ACS-verified level 1 trauma center received a TEG analysis upon arrival from December 2019 to June 2021. A retrospective review of the results and outcomes was conducted, and TBI patients were compared to patients without TBI. Linear regression was used to evaluate the effect of patient and injury factors on fibrinolysis. Hyperfibrinolysis was defined as LY30 ​> ​7.7%, physiologic fibrinolysis as LY30 0.6-7.7%, and fibrinolytic shutdown as LY30 ​< ​0.6%.

RESULTS

A total of 1369 patients received an admission TEG analysis. Patients with TBI had a significantly higher median ISS (16 vs. 8, p ​< ​0.001), lower median admission Glasgow Coma Scale (14 vs. 15, p ​< ​0.001), longer intensive care unit length of stay (3 vs. 2 days, p ​< ​0.0001), increased ventilator days (216 vs. 183, p ​< ​0.001), higher mortality (14.6% vs. 5.1%, p ​< ​0.001), but lower shock index (0.6 vs. 0.7, p ​< ​0.0001) compared to those without TBI. Median LY30 was found to be decreased in the TBI group (0.1 vs. 0.2, p ​= ​0.0006). Patients with TBI were found to have a higher rate of fibrinolytic shutdown compared those without TBI (68.7% vs. 63.5%, p ​= ​0.054). ISS, sex, and shock index were found to be predictive of LY30 on linear regression, but TBI was not (Β: 0.09, SE: 0.277, p ​= ​0.745). The rate of DVT/PE did not appear to be elevated in patients with TBI (0.8%) and without TBI (1.2%).

CONCLUSIONS

Trauma patients with and without TBI were found to have high rates of fibrinolytic shutdown. Although there was a high incidence of fibrinolytic shutdown, it did not appear to have an impact on the rate of thrombotic complications. The clinical significance of these results is unclear and differs significantly from recent reports which demonstrated that TBI is associated with a 25% rate of fibrinolytic shutdown. Further investigation is needed to better define the fibrinolytic pathway in patients with trauma and TBI to develop optimal treatment algorithms.

Mechanisms and management of the coagulopathy of trauma and sepsis: trauma-induced coagulopathy, sepsis-induced coagulopathy, and disseminated intravascular coagulation

Disseminated intravascular coagulation can occur due to different causes but commonly following sepsis. Trauma-induced coagulopathy (TIC) occurs on hospital arrival in approximately 25% of seriously injured patients who initially presents with impaired hemostasis and a bleeding phenotype that can later progress to a prothrombotic phase. Following traumatic injury, ineffective hemostasis is driven by massive blood loss, tissue damage, and hyperfibrinolysis. This initial impaired hemostasis continues until surgical or other management strategies not only to stop the causes of hemorrhage but also progresses to a prothrombotic and hypofibrinolytic state, also termed fibrinolytic shutdown. Prothrombotic progression is also promoted by inflammatory mediator release, endothelial injury, and platelet dysregulation, which is commonly seen in sepsis with increased mortality. Unlike TIC, the early phase of sepsis is frequently complicated by multiorgan dysfunction described as sepsis-induced coagulopathy (SIC) that lacks a hemorrhagic phase. The phenotypes of SIC and TIC are different, especially in their initial presentations; however, patients who survive TIC may also develop subsequent infections and potentially sepsis and SIC. Although the pathophysiology of SIC and TIC are different, endothelial injury, dysregulated fibrinolysis, and coagulation abnormalities are common. Management includes treatment of the underlying cause, tissue injury vs infection is critical, and supportive therapies, such as hemostatic resuscitation and circulatory support are essential, and adjunct therapies are recommended in guidelines. Based on clinical studies and certain guidelines, additional therapies include tranexamic acid in the limited timing of initial traumatic injury and anticoagulants, such as antithrombin and recombinant thrombomodulin in disseminated intravascular coagulation.

Predictive value of coagulation variables and glycocalyx shedding in hospitalized COVID-19 patients - a prospective observational study

OBJECTIVES

Covid-19 disease causes an immense burden on the healthcare system. It has not yet been finally clarified which patients will suffer from a severe course and which will not. Coagulation disorders can be detected in many of these patients. The aim of the present study was therefore to identify variables of the coagulation system including standard and viscoelastometric tests as well as components of glycocalyx damage that predict admission to the intensive care unit.

METHODS

Adult patients were included within 24 h of admission. Blood samples were analyzed at hospital admission and at ICU admission if applicable. We analyzed group differences and furthermore performed receiver operator characteristics (ROC).

RESULTS

This study included 60 adult COVID-19 patients. During their hospital stay, 14 patients required ICU treatment. Comparing ICU and non-ICU patients at time of hospital admission, D-dimer (1450 µg/ml (675/2850) vs. 600 µg/ml (500/900); p = 0.0022; cut-off 1050 µg/ml, sensitivity 71%, specificity 89%) and IL-6 (47.6 pg/ml (24.9/85.4 l) vs. 16.1 pg/ml (5.5/34.4); p = 0.0003; cut-off 21.25 pg/ml, sensitivity 86%, specificity 65%) as well as c-reactive protein (92 mg/dl (66.8/131.5) vs. 43.5 mg/dl (26.8/83.3); p = 0.0029; cutoff 54.5 mg/dl, sensitivity 86%, specificity 65%) were higher in patients who required ICU admission. Thromboelastometric variables and markers of glycocalyx damage (heparan sulfate, hyaluronic acid, syndecan-1) at the time of hospital admission did not differ between groups.

CONCLUSION

General inflammatory variables continue to be the most robust predictors of a severe course of a COVID-19 infection. Viscoelastometric variables and markers of glycocalyx damage are significantly increased upon admission to the ICU without being predictors of ICU admission.

A proposed clinical coagulation score for research in trauma-induced coagulopathy

BACKGROUND

Trauma-induced coagulopathy (TIC) has been the subject of intense study for greater than a century, and it is associated with high morbidity and mortality. The Trans-Agency Consortium for Trauma-Induced Coagulopathy, funded by the National Health Heart, Lung and Blood Institute, was tasked with developing a clinical TIC score, distinguishing between injury-induced bleeding from persistent bleeding due to TIC. We hypothesized that the Trans-Agency Consortium for Trauma-Induced Coagulopathy clinical TIC score would correlate with laboratory measures of coagulation, transfusion requirements, and mortality.

METHODS

Trauma activation patients requiring a surgical procedure for hemostasis were scored in the operating room (OR) and in the first ICU day by the attending trauma surgeon. Conventional and viscoelastic (thrombelastography) coagulation assays, transfusion requirements, and mortality were correlated to the coagulation scores using the Cochran-Armitage trend test or linear regression for numerical variables.

RESULTS

Increased OR TIC scores were significantly associated with abnormal conventional and viscoelastic measurements, including hyperfibrinolysis incidence, as well as with higher mortality and more frequent requirement for massive transfusion ( p < 0.0001 for all trends). Patients with OR TIC score greater than 3 were more than 31 times more likely to have an ICU TIC score greater than 3 (relative risk, 31.6; 95% confidence interval, 12.7-78.3; p < 0.0001).

CONCLUSION

A clinically defined TIC score obtained in the OR reflected the requirement for massive transfusion and mortality in severely injured trauma patients and also correlated with abnormal coagulation assays. The OR TIC score should be validated in multicenter studies.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Assays to quantify fibrinolysis: strengths and limitations. Communication from the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee on fibrinolysis

Fibrinolysis is a series of enzymatic reactions that degrade insoluble fibrin. Plasminogen activators convert the zymogen plasminogen to the active serine protease plasmin, which cleaves and solubilizes crosslinked fibrin clots into fibrin degradation products. The quantity and quality of fibrinolytic enzymes, their respective inhibitors, and clot structure determine overall fibrinolysis. The quantity of protein can be measured by antigen-based assays, and both quantity and quality can be assessed using functional assays. Furthermore, variations of commonly used assays have been reported, which are tailored to address the role(s) of specific fibrinolytic factors and cellular elements (eg, platelets, neutrophils, and red blood cells). Although the concentration and/or activity of a protein can be quantified, how these individual components contribute to the overall fibrinolysis outcome can be challenging to determine. This difficulty is due to temporal changes within and around the thrombi during the clot breakdown, particularly the fibrin matrix structure, and composition. Furthermore, terms such as "fibrinolytic activity/potential," "plasminogen activation," and "plasmin activity" are often used interchangeably despite having different definitions. The purpose of this review is to 1) summarize the assays measuring fibrinolysis activity and potential, 2) facilitate the interpretation of data generated by these assays, and 3) summarize the strengths and limitations of these assays.

Fibrinolysis shutdown and elevated D-dimer levels have high prognostic capacity for postoperative thromboembolic complications in patients with bone tumors

Surgical resection of malignant bone tumors is associated with a high risk of venous thromboembolism (VTE). The purpose of this study was to evaluate the association between rotational thromboelastometry (ROTEM) parameters and VTE following oncologic resections, and to evaluate their prognostic capacity for this complication. A prospective observational study was conducted including 113 patients who underwent surgical resection of malignant bone tumors. ROTEM analysis and conventional coagulation studies were performed preoperatively and on the 2nd postoperative day, while patients were followed for the development of VTE. Logistic regression was used to assess the association between ROTEM parameters and occurrence of VTE. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity were calculated as measures of discrimination and predictive accuracy. Fourteen patients (12.4%) developed symptomatic VTE. Development of VTE was associated with shortened INTEM CFT (Odds Ratio [OR] 0.90, 95% Confidence Interval [CI] 0.84 - 0.96, p = 0.004), higher INTEM A10 (OR 1.21, 95% CI 1.07 - 1.36, p = 0.002), higher INTEM MCF (OR 1.22, 95% CI 1.08 - 1.37, p = 0.001) and higher INTEM LI60 (OR 2.10, 95% CI 1.38 - 3.21, p = 0.001). An INTEM LI60 value indicative of fibrinolysis shutdown (≥ 98%) had the best predictive accuracy for VTE (AUC = 0.887, 95% CI 0.824 - 0.951, sensitivity = 100%, specificity = 67.0%), higher than that of D-dimer levels (p = 0.028). ROTEM parameters were promising predictors of symptomatic VTE. Fibrinolysis shutdown as reflected by ROTEM LI60 and high D-dimer levels can aid the identification of high-risk patients. Future studies should evaluate whether the addition of ROTEM findings to an expanded risk-assessing model can improve the predictive capacity and provide better guidance in thromboprophylaxis.

Reply to Bareille et al. Are Viscoelastometric Assays of Old Generation Ready for Disposal? Comment on "Volod et al. Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices. J. Clin. Med. 2022, 11, 860"

We are pleased to see that Bareille et al. have written a Commentary: "Are viscoelastometric assays of old generation ready for disposal?" [...].

SHock-INduced Endotheliopathy (SHINE): A mechanistic justification for viscoelastography-guided resuscitation of traumatic and non-traumatic shock

Irrespective of the reason for hypoperfusion, hypocoagulable and/or hyperfibrinolytic hemostatic aberrancies afflict up to one-quarter of critically ill patients in shock. Intensivists and traumatologists have embraced the concept of SHock-INduced Endotheliopathy (SHINE) as a foundational derangement in progressive shock wherein sympatho-adrenal activation may cause systemic endothelial injury. The pro-thrombotic endothelium lends to micro-thrombosis, enacting a cycle of worsening perfusion and increasing catecholamines, endothelial injury, de-endothelialization, and multiple organ failure. The hypocoagulable/hyperfibrinolytic hemostatic phenotype is thought to be driven by endothelial release of anti-thrombogenic mediators to the bloodstream and perivascular sympathetic nerve release of tissue plasminogen activator directly into the microvasculature. In the shock state, this hemostatic phenotype may be a counterbalancing, yet maladaptive, attempt to restore blood flow against a systemically pro-thrombotic endothelium and increased blood viscosity. We therefore review endothelial physiology with emphasis on glycocalyx function, unique biomarkers, and coagulofibrinolytic mediators, setting the stage for understanding the pathophysiology and hemostatic phenotypes of SHINE in various etiologies of shock. We propose that the hyperfibrinolytic phenotype is exemplified in progressive shock whether related to trauma-induced coagulopathy, sepsis-induced coagulopathy, or post-cardiac arrest syndrome-associated coagulopathy. Regardless of the initial insult, SHINE appears to be a catecholamine-driven entity which early in the disease course may manifest as hyper- or hypocoagulopathic and hyper- or hypofibrinolytic hemostatic imbalance. Moreover, these hemostatic derangements may rapidly evolve along the thrombohemorrhagic spectrum depending on the etiology, timing, and methods of resuscitation. Given the intricate hemochemical makeup and changes during these shock states, macroscopic whole blood tests of coagulative kinetics and clot strength serve as clinically useful and simple means for hemostasis phenotyping. We suggest that viscoelastic hemostatic assays such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are currently the most applicable clinical tools for assaying global hemostatic function-including fibrinolysis-to enable dynamic resuscitation with blood products and hemostatic adjuncts for those patients with thrombotic and/or hemorrhagic complications in shock states.

BLOOD TYPE O IS A RISK FACTOR FOR HYPERFIBRINOLYSIS AND MASSIVE TRANSFUSION AFTER SEVERE INJURY

ABSTRACT

Background: Blood type O is the most common blood type and has lower von Willebrand factor (vWF) levels (25%-35% lower than non-O blood types). von Willebrand factor is important for initiating platelet attachment and binding factor VIII. We hypothesized that patients with type O blood are at an increased risk of trauma-induced coagulopathy and bleeding post injury. Study Design: Adult trauma activations with known blood type at a level I trauma center with field systolic blood pressure < 90 mm Hg were studied retrospectively. The relationships of blood group O versus non-O to coagulation assays, massive transfusion (MT), ventilator-free days, and mortality were adjusted for confounders. Hyperfibrinolysis (HF) was defined as thromboelastogram of percent lysis in 30 min > 3%, and fibrinolysis shutdown was defined as percent lysis in 30 min < 0.9%. von Willebrand factor activity was quantified on 212 injured patients using a STAGO apparatus. Results: Overall, 268 patients met criteria. Type O patients were more likely to develop HF than non-type O blood patients (43% vs. 29%, P = 0.06) and had significantly lower vWF activity (222% vs. 249%, P = 0.01). After adjustment for New Injury Severity Score and blunt mechanism, type O had higher odds of HF (odds ratio, 1.94, 95% confidence interval, 1.09-3.47) and increased odds of MT (odds ratio, 3.02; 95% confidence interval, 1.22-7.49). Other outcomes were not significantly affected. Conclusion: Type O patients with hypotension had increased HF and MT post injury, and these were associated with lower vWF activity. These findings have implications for the monitoring of HF in patients receiving type O whole-blood transfusions post injury.

Role of Viscoelastic and Conventional Coagulation Tests for Management of Blood Product Replacement in the Bleeding Patient

An important aim of viscoelastic testing (VET) is to implement transfusion algorithms based on coagulation test results to help reduce transfusion rates and improve patient outcomes. Establishing a rapid diagnosis and providing timely treatment of coagulopathy is the cornerstone of management of severely bleeding patients in trauma, postpartum hemorrhage, and major surgery. As the nature of acute bleeding and trauma leads to an unstable and tenuous physiologic state, conventional coagulation tests (CCTs) are too slow to diagnose, manage, and also course correct any hemostatic abnormalities that accompany an acute critical illness. Viscoelastic point-of-care tests strongly correlate with results from standard laboratory tests but are designed to enable clinicians to make timely, informed bleeding management decisions when time to intervene is critical. These assays provide an individualized and goal-oriented approach to patient blood management and are increasingly becoming involved in transfusion algorithms. The scope of this review aims to evaluate the current literature on VETs and their impact on actionable outputs in clinical decision making and their relationship to CCT.

Advances in the Management of Coagulopathy in Trauma: The Role of Viscoelastic Hemostatic Assays across All Phases of Trauma Care

Uncontrolled bleeding is the leading cause of preventable death following injury. Trauma-induced coagulopathy can manifest as diverse phenotypes ranging from hypocoagulability to hypercoagulability, which can change quickly during the acute phase of trauma care. The major advances in understanding coagulation over the past 25 years have resulted from the cell-based concept, emphasizing the key role of platelets and their interaction with the damaged endothelium. Consequently, conventional plasma-based coagulation testing is not accurate in predicting bleeding and does not provide an assessment of which blood products are indicated. Viscoelastic hemostatic assays (VHA), conducted in whole blood, have emerged as a superior method to guide goal-directed transfusion. The major change in resuscitation has been the shift from unbridled crystalloid loading to judicious balanced blood product administration. Furthermore, the recognition of the rapid changes from hypocoagulability to hypercoagulability has underscored the importance of ongoing surveillance beyond emergent surgery. While the benefits of VHA testing are maximized when used as early as possible, current technology limits use in the pre-hospital setting and the time to results compromises its utility in the emergency department. Thus, most of the reported experience with VHA in trauma is in the operating room and intensive care unit, where there is compelling data to support its value. This overview will address the current and potential role of VHA in the seriously injured patient, throughout the continuum of trauma management.

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.

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.

Immuno-Thrombotic Complications of COVID-19: Implications for Timing of Surgery and Anticoagulation

Early in the coronavirus disease 2019 (COVID-19) pandemic, global governing bodies prioritized transmissibility-based precautions and hospital capacity as the foundation for delay of elective procedures. As elective surgical volumes increased, convalescent COVID-19 patients faced increased postoperative morbidity and mortality and clinicians had limited evidence for stratifying individual risk in this population. Clear evidence now demonstrates that those recovering from COVID-19 have increased postoperative morbidity and mortality. These data-in conjunction with the recent American Society of Anesthesiologists guidelines-offer the evidence necessary to expand the early pandemic guidelines and guide the surgeon's preoperative risk assessment. Here, we argue elective surgeries should still be delayed on a personalized basis to maximize postoperative outcomes. We outline a framework for stratifying the individual COVID-19 patient's fitness for surgery based on the symptoms and severity of acute or convalescent COVID-19 illness, coagulopathy assessment, and acuity of the surgical procedure. Although the most common manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is COVID-19 pneumonitis, every system in the body is potentially afflicted by an endotheliitis. This endothelial derangement most often manifests as a hypercoagulable state on admission with associated occult and symptomatic venous and arterial thromboembolisms. The delicate balance between hyper and hypocoagulable states is defined by the local immune-thrombotic crosstalk that results commonly in a hemostatic derangement known as fibrinolytic shutdown. In tandem, the hemostatic derangements that occur during acute COVID-19 infection affect not only the timing of surgical procedures, but also the incidence of postoperative hemostatic complications related to COVID-19-associated coagulopathy (CAC). Traditional methods of thromboprophylaxis and treatment of thromboses after surgery require a tailored approach guided by an understanding of the pathophysiologic underpinnings of the COVID-19 patient. Likewise, a prolonged period of risk for developing hemostatic complications following hospitalization due to COVID-19 has resulted in guidelines from differing societies that recommend varying periods of delay following SARS-CoV-2 infection. In conclusion, we propose the perioperative, personalized assessment of COVID-19 patients' CAC using viscoelastic hemostatic assays and fluorescent microclot analysis.

Point of care coagulation management in anesthesiology and critical care

Point of care (POC) devices are increasingly used in the ICU and in anesthesia. Besides POC-devices for blood gas analysis, several devices are available for coagulation measurements. Although basic principles for thromboelastographic measurements are not novel, some promising developments were made during the last decade improving both user-friendliness and measurement reliability. For instance, POC measurements of activated clotting time (ACT) for heparin monitoring is still regarded as standard-of-care in cardiac interventions and surgery. In the field of anesthesia and intensive care medicine, POC-devices for thromboelastographic and platelet aggregation measurements are widely used. Their impact in case of bleeding and patient blood management for cardiothoracic and trauma surgery is well known. Moreover, there are promising concepts for anticoagulation monitoring including new oral anticoagulant drugs. Coagulation POC-devices may also identify patients at specific risk for thromboembolic events quickly. On the other hand, benefits of POC-devices need to be balanced against limitations, which include technical restrictions and operator related errors, mainly affecting reproducibility and interpretation of results. Therefore, it is recommendable to consider results of POC-coagulation testing in comparison to standard laboratory tests (SLT). Nevertheless, in urgent or emergency situations POC results enable fast decision making to optimize patient care.

Precision Medicine: Clinical Tolerance to Hyperfibrinolysis Differs by Shock and Injury Severity

The definition of hyperfibrinolysis based on thrombelastogram LY30 measurements should vary with trauma patient characteristics, i.e., as anatomic injury or shock severity increase, the ability to tolerate even mild degrees of fibrinolysis is markedly reduced. This trend is independent of institutional practice patterns. The management of hyperfibrinolysis, particularly with anti-fibrinolytics administration, should be interpreted in the context of injury severity/shock and managed on an individual patient basis.

TRAUMATIC BRAIN INJURY PROVOKES LOW FIBRINOLYTIC ACTIVITY IN SEVERELY INJURED PATIENTS

BACKGROUND

Traumatic brain injury (TBI) in combination with shock has been associated with hypocoagulability. However, recent data suggest that TBI itself can promote a systemic procoagulant state via the release of brain-derived extracellular vesicles. The objective of our study was to identify if TBI was associated with differences in thrombelastography (TEG) indices when controlling for other variables associated with coagulopathy following trauma. We hypothesized that TBI is independently associated with a less coagulopathic state.

METHODS

Prospective study including all highest-level trauma activations at an urban level 1 trauma center, from 2014-2020. TBI was defined as AIS Head ≥3. Blood samples were drawn at ED admission. Linear regression was used to assess the role of independent predictors on TIC. Models adjusted for ISS, shock (defined as ED SBP < 70, or ED SBP < 90 and ED HR > 108, or first hospital base deficit ≥10), and prehospital GCS.

RESULTS

Of the 1,023 patients included, 291 (28%) suffered a TBI. TBI patients more often were female (26% vs. 19%, p = 0.01), had blunt trauma (83% vs. 43%, p < 0.0001), shock (33% vs. 25%, p = 0.009), and higher median ISS (29 vs. 10, p < 0.0001). Fibrinolysis shutdown (25% vs. 18%) was more common in the TBI group (p < 0.0001). When controlled for the confounding effects of ISS and shock, the presence of TBI independently decreases LY30 (Beta estimate: - 0.16 ± 0.06, p = 0.004). This effect of TBI on LY30 persisted when controlling for sex and mechanism of injury in addition to ISS and shock (Beta estimate: -0.13 ± 0.06, p = 0.022).

CONCLUSIONS

TBI is associated with lower LY30 independent of shock, tissue injury, sex, and mechanism of injury. These findings suggest a propensity toward a less coagulopathic state in patients with TBI, possibly due to fibrinolysis shutdown. Tranexamic acid has been reported to improve outcomes following TBI. Our data suggest the mechanism may be independent of changes in fibrinolysis.

LEVEL OF EVIDENCE

Level III, Prognostic and Epidemiological.

Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices

Viscoelastic hemostatic assay (VHAs) are whole blood point-of-care tests that have become an essential method for assaying hemostatic competence in liver transplantation, cardiac surgery, and most recently, trauma surgery involving hemorrhagic shock. It has taken more than three-quarters of a century of research and clinical application for this technology to become mainstream in these three clinical areas. Within the last decade, the cup and pin legacy devices, such as thromboelastography (TEG^® 5000) and rotational thromboelastometry (ROTEM^® delta), have been supplanted not only by cartridge systems (TEG^® 6S and ROTEM^® sigma), but also by more portable point-of-care bedside testing iterations of these legacy devices (e.g., Sonoclot^®, Quantra^®, and ClotPro^®). Here, the legacy and new generation VHAs are compared on the basis of their unique hemostatic parameters that define contributions of coagulation factors, fibrinogen/fibrin, platelets, and clot lysis as related to the lifespan of a clot. In conclusion, we offer a brief discussion on the meteoric adoption of VHAs across the medical and surgical specialties to address COVID-19-associated coagulopathy.

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.

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.

Fibrinolytic system activation immediately following trauma was quickly and intensely suppressed in a rat model of severe blunt trauma

In severe trauma, excessive fibrinolytic activation is associated with an increase in the transfusion volume and mortality rate. However, in the first several hours after a blunt trauma, changes in fibrinolytic activation, suppression, and activation–suppression balance have not yet been elucidated, which the present study aimed to clarify. Anesthetized 9-week-old male Wistar S/T rats experienced severe blunt trauma while being placed inside the Noble–Collip drum. Rats were randomly divided into four groups of seven. The no-trauma group was not exposed to any trauma; the remaining groups were analysed 0, 60, and 180 min after trauma. Immediately following trauma, total tissue-plasminogen activator (tPA) levels significantly increased in the plasma, and the balance of active tPA and active plasminogen activator inhibitor-1 (PAI-1) significantly tipped toward fibrinolytic activation. After trauma, both tPA and PAI-1 levels increased gradually in various organs and active and total PAI-1 levels increased exponentially in the plasma. Total plasma tPA levels 60 min after trauma returned quickly to levels comparable to those in the no-trauma group. In conclusion, fibrinolytic activation was observed only immediately following trauma. Therefore, immediately after trauma, the fibrinolytic system was activated; however, its activation was quickly and intensely suppressed.

Viscoelastic Testing in Traumatic Brain Injury: Key Research Insights

The role of viscoelastic testing in the evaluation and management of traumatic brain injury (TBI) remains a subject of ongoing exploration. This review highlights four key publications that provide significant insights into this subject. Holcomb et al. provided early evidence of the relationship between thromboelastography (TEG) and conventional coagulation tests (CCTs). Later, Samuels et al. used TEG to identify a unique coagulopathy phenotype in TBI characterized by a notable absence of fibrinolytic abnormalities. Dixon et al. built upon these findings by exploring the application of TEG in the context of antifibrinolytic administration, noting a similar lack of effect on LY30. Finally, Guillotte et al. demonstrated the utility of TEG-PM in assessing platelet dysfunction in TBI. While these studies provide key early support for the utility of viscoelastic testing in the TBI, further exploration is needed to define evidence-based guidelines for clinical application.

Viscoelastic monitoring in trauma resuscitation

BACKGROUND

Traumatic injury results in both physical and physiologic insult. Successful care of the trauma patient depends upon timely correction of both physical and biochemical injury. Trauma-induced coagulopathy is a derangement of hemostasis and thrombosis that develops rapidly and can be fatal if not corrected. Viscoelastic monitoring (VEM) assays have been developed to provide rapid, accurate, and relatively comprehensive depictions of an individual's coagulation profile. VEM are increasingly being integrated into trauma resuscitation guidelines to provide dynamic and individualized guidance to correct coagulopathy.

STUDY DESIGN AND METHODS

We performed a narrative review of the search terms viscoelastic, thromboelastography, thromboelastometry, TEG, ROTEM, trauma, injury, resuscitation, and coagulopathy using PubMed. Particular focus was directed to articles describing algorithms for management of traumatic coagulopathy based on VEM assay parameters.

RESULTS

Our search identified 16 papers with VEM-guided resuscitation strategies in adult patients based on TEG, 12 such protocols in adults based on ROTEM, 1 protocol for children based on TEG, and 2 protocols for children based on ROTEM.

CONCLUSIONS

This review presents evidence to support VEM use to detect traumatic coagulopathy, discusses the role of VEM in trauma resuscitation, provides a summary of proposed treatment algorithms, and discusses pending questions in the field.

Viscoelastic testing in oncology patients (including for the diagnosis of fibrinolysis): Review of existing evidence, technology comparison, and clinical utility

The quantification of the coagulopathic state associated with oncologic and hematologic diseases is imperfectly assessed by common coagulation tests such as prothrombin time, activated partial thromboplastin time, fibrinogen levels, and platelet count. These tests provide a static representation of a component of hemostatic integrity, presenting an incomplete picture of coagulation in these patients. Viscoelastic tests (VETs), such as rotational thromboelastometry (ROTEM) and thromboelastography (TEG), as whole blood analyses, provide data related to the cumulative effects of blood components and all stages of the coagulation and fibrinolytic processes. The utility of VETs has been demonstrated since the late 1960s in guiding blood component therapy for patients undergoing liver transplantation. Since then, the scope of viscoelastic testing has expanded to become routinely used for cardiac surgery, obstetrics, and trauma. In the past decade, VETs' expanded usage has been most significant in trauma resuscitation. However, use of VETs for patients with malignancy-associated coagulopathy (MAC) and hematologic malignancies is increasing. For the purposes of this narrative review, we discuss the similarities between trauma-induced coagulopathy (TIC) and MAC. These similarities center on the thrombomodulin-thrombin complex as it switches between the thrombin-activatable fibrinolysis inhibitor coagulation pathway and activating the protein C anticoagulation pathway. This produces a spectrum of coagulopathy and fibrinolytic alterations ranging from shutdown to hyperfibrinolysis that are common to TIC, MAC, and hematologic malignancies. There is expanding literature regarding the utility of TEG and ROTEM to describe the hemostatic integrity of patients with oncologic and hematologic conditions, which we review here.

The Safety and Efficacy of Tranexamic Acid in Oncology Patients Undergoing Endoprosthetic Reconstruction and a ROTEM-Based Evaluation of Their Hemostatic Profile: A Pilot Study

Simple Summary

Tranexamic acid can be an effective and safe way to reduce perioperative bleeding following an endoprosthetic reconstruction of a lower limb after a bone tumor resection. Tranexamic acid does not result in a complete shutdown of the fibrinolysis, supporting its safe use without increasing the risk of thromboembolic complications.

Abstract

Background: An endoprosthetic reconstruction in musculoskeletal oncology patients is associated with significant blood loss. The purpose of this study is to evaluate the safety and efficacy of tranexamic acid (TXA) for these patients and to assess any changes in their hemostatic profile using rotational thromboelastometry (ROTEM). Methods: A retrospective observational study was performed including 61 patients with primary or metastatic bone tumors who underwent surgery. Group A (n = 30) received both intravenous and local TXA whereas Group B (n = 31) was the control group. The primary outcomes were perioperative blood loss and blood unit transfusions and the secondary outcomes included the incidence of thromboembolic complications and a change in blood coagulability as reflected by ROTEM parameters. Results: The median difference in blood loss between the two groups was 548.5 mL, indicating a 29.2% reduction in the 72 h blood loss following TXA administration (p < 0.001). TXA also led to a reduced transfusion of 1 red blood cell (RBC) unit per patient (p < 0.001). The two groups had similar rates of thromboembolic complications (p = 0.99). The antifibrinolytic properties of TXA were confirmed by the significantly higher INTEM, FIBTEM and EXTEM LI60 (p < 0.001, p = 0.005 and p < 0.001, respectively) values in the TXA group. Conclusion: Tranexamic acid was associated with a significant reduction in perioperative blood loss and transfusion requirements without a complete shutdown of the fibrinolysis. Larger studies are warranted to assess the frequency of these outcomes in musculoskeletal oncology patients.

Getting hit by the bus around the world - a global perspective on goal directed treatment of massive hemorrhage in trauma

PURPOSE OF REVIEW

Major trauma remains one of the leading causes of death worldwide with traumatic brain injury and uncontrolled traumatic bleeding as the main determinants of fatal outcome. Interestingly, the therapeutic approach to trauma-associated bleeding and coagulopathy shows differences between geographic regions, that are reflected in different guidelines and protocols.

RECENT FINDINGS

This article summarizes main principles in coagulation diagnostics and compares different strategies for treatment of massive hemorrhage after trauma in different regions of the world. How would a bleeding trauma patient be managed if they got hit by the bus in the United States, United Kingdom, Germany, Switzerland, Austria, Denmark, Australia, or in Japan?

SUMMARY

There are multiple coexistent treatment standards for trauma-induced coagulopathy in different countries and different trauma centers. Most of them initially follow a protocol-based approach and subsequently focus on predefined clinical and laboratory targets.

The Procoagulant Effect of COVID-19 on the Thrombotic Risk of Patients with Hip Fractures Due to Enhanced Clot Strength and Fibrinolysis Shutdown

Introduction: Coronavirus disease 2019 (COVID-19) in patients with hip fractures is associated with increased incidence of venous thromboembolism (VTE). The purpose of this study was to evaluate the hemostatic alterations of COVID-19 that are associated with a higher thrombotic risk using rotational thromboelastometry (ROTEM). Methods: A retrospective observational study was performed including 20 COVID-19 patients with hip fractures. To compare the coagulopathy of patients with mild COVID-19 and hip fractures with the coagulopathy associated with each of these two conditions separately, we used two previously recruited groups of patients; 198 hip fracture patients without COVID-19 and 21 COVID-19 patients without hip fractures. The demographics, clinical parameters, conventional coagulation parameters and ROTEM findings of the three groups were analyzed and compared. Results: COVID-19 hip fracture patients had higher amplitude of clot firmness at 10 min (p < 0.001), higher alpha angle (p < 0.001), higher lysis index at 60 min (p < 0.001), and shorter clot formation time (p < 0.001) than non-COVID-19 hip fracture patients, indicating increased clot strength and impaired fibrinolysis due to COVID-19. The value of lysis index at 60 min (99%) in COVID-19 patients with hip fractures was consistent with fibrinolysis shut down. Multivariable linear regression analysis further confirmed that COVID-19 resulted in increased amplitude of clot firmness at 10 min (p < 0.001), increased maximum clot firmness (p < 0.001), increased lysis index at 60 min (p < 0.001) and increased alpha angle (p < 0.001), but significantly shortened clot formation time (p < 0.001). Discussion: The higher thrombotic risk in COVID-19 patients with hip fractures is characterized by increased clot strength and fibrinolysis shutdown, as shown by ROTEM findings. Further prospective studies are warranted to evaluate the need for modification of thromboprophylaxis to balance the hemostatic derangements of COVID-19 patients with hip fractures.

Inhalation Injury is Associated with Endotheliopathy and Abnormal Fibrinolytic Phenotypes in Burn Patients: A Cohort Study

Burn injury is associated with endothelial dysfunction and coagulopathy and concomitant inhalation injury increases morbidity and mortality. The aim of this work is to identify associations between inhalation injury (IHI), coagulation homeostasis, vascular endothelium, and clinical outcomes in burn patients. One-hundred and twelve patients presenting to a regional burn center were included in this retrospective cohort study. Whole blood was collected at set intervals from admission through 24 hours and underwent viscoelastic assay with rapid TEG (rTEG). Syndecan-1 (SDC-1) on admission was quantified by ELISA. Patients were grouped by the presence (n=28) or absence (n=84) of concomitant IHI and rTEG parameters, fibrinolytic phenotypes, SDC-1, and clinical outcomes were compared. Of the 112 thermally injured patients, 28 (25%) had IHI. Most patients were male (68.8%) with a median age of 40 (IQR, 29-57) years. Patients with IHI had higher overall mortality (42.68% vs. 8.3%; p<0.0001). rTEG LY30 was lower in patients with IHI at hours 4 and 12 (p<0.05). There was a pattern of increased abnormal fibrinolytic phenotypes among IHI patients. There was a greater proportion of IHI patients with endotheliopathy (SDC-1 > 34 ng/mL) (64.7% vs. 26.4%; p=0.008). There was a pattern of increased mortality among patients with inhalation injury and endotheliopathy (0% vs. 72.7%; p=0.004). Significant differences between patients with and without IHI were found in measures assessing fibrinolytic potential and endotheliopathy. Mortality was associated with abnormal fibrinolysis, endotheliopathy, and inhalation injury. However, the extent to which IHI associated dysfunction is independent of TBSA burn size remains to be elucidated.

Fibrinolytic shutdown diagnosed with rotational thromboelastometry represents a moderate form of coagulopathy associated with transfusion requirement and mortality: A retrospective analysis

BACKGROUND

Viscoelastic techniques have made it possible to describe specific fibrinolytic phenotypes (physiological, hyperfibrinolysis and shutdown) and to establish a relationship of these phenotypes with outcome. However, there remains a debate as to whether shutdown is a state of hypercoagulability or rather a coagulopathy with moderate fibrinolysis and fibrinogen consumption.

OBJECTIVES

Our objectives were to describe the relationship between fibrinolytic phenotypes and outcomes, and to report the effects of tranexamic acid (TXA) administration.

DESIGN

This was a retrospective analysis of prospectively acquired data from a trauma registry.

SETTING

An academic level 1 trauma centre in the Lyon Region, from March 2011 to December 2016.

PATIENTS

We included all injured patients who had a rotational thromboelastometry analysis at admission. Fibrinolytic phenotypes were determined according to the maximum lysis: shutdown less than 3%, physiological 3 to 15%, hyperfibrinolysis more than 15%.

MAIN OUTCOME MEASURE

Mortality at 24 h and at hospital discharge.

RESULTS

During the study period, 473 patients were included with the following phenotypes: physiological (344 patients, 73%), shutdown (107 patients, 23%) and hyperfibrinolysis (22 patients, 5%). There was an increase in injury severity, prothrombin time ratio, fibrin degradation products and transfusion requirements from the physiological to the shutdown and hyperfibrinolysis phenotypes. Prehospital TXA administration increased the rate of shutdown and decreased the maximum lysis value at admission. After adjustment, multivariate analysis showed that fibrinolytic phenotypes, but not TXA, were independently associated with an increased risk of early death and death before hospital discharge: shutdown [odds ratio (95% confidence interval)] 2.4 (1.2 to 4.8) and hyperfibrinolysis 67.9 (7.4 to 624.2).

CONCLUSION

The results of the current study suggest that shutdown, which is associated with injury severity and mortality, probably reflects a moderate form of coagulopathy and fibrinolysis rather than a hypercoagulopathy. Therefore, the observation of shutdown fibrinolysis on thromboelastography/rotational thromboelastometry should not lead to withholding but rather to the administration of TXA.

Early abnormal fibrinolysis and mortality in patients with thermal injury: a prospective cohort study

INTRODUCTION

Abnormal fibrinolysis early after injury has been associated with increased mortality in trauma patients, but no studies have addressed patients with burn injury. This prospective cohort study aimed to characterize fibrinolytic phenotypes in burn patients and to see if they were associated with mortality.

METHODS

Patients presenting to a regional burn centre within 4 h of thermal injury were included. Blood was collected for sequential viscoelastic measurements using thromboelastography (RapidTEG™) over 12 h. The percentage decrease in clot strength 30 min after the time of maximal clot strength (LY30) was used to categorize patients into hypofibrinolytic/fibrinolytic shutdown (SD), physiological (PHYS) and hyperfibrinolytic (HF) phenotypes. Injury characteristics, demographics and outcomes were compared.

RESULTS

Of 115 included patients, just over two thirds were male. Overall median age was 40 (i.q.r. 28-57) years and median total body surface area (TBSA) burn was 13 (i.q.r. 6-30) per cent. Some 42 (36.5 per cent) patients had severe burns affecting over 20 per cent TBSA. Overall mortality was 18.3 per cent. At admission 60.0 per cent were PHYS, 30.4 per cent were SD and 9.6 per cent HF. HF was associated with increased risk of mortality on admission (odds ratio 12.61 (95 per cent c.i. 1.12 to 142.57); P = 0.041) but not later during the admission when its incidence also decreased. Admission SD was not associated with mortality, but incidence increased and by 4 h and beyond, SD was associated with increased mortality, compared with PHYS (odds ratio 8.27 (95 per cent c.i. 1.16 to 58.95); P = 0.034).

DISCUSSION

Early abnormal fibrinolytic function is associated with mortality in burn patients.

The role of rotational thromboelastometry during the COVID-19 pandemic: a narrative review

The coronavirus disease 2019 (COVID-19) pandemic is currently recognized as a global health crisis. This viral infection is frequently associated with hypercoagulability, with a high incidence of thromboembolic complications that can be fatal. In many situations, the standard coagulation tests (SCT) fail to detect this state of hypercoagulability in patients with COVID-19 since clotting times are either not or only mildly affected. The role of viscoelastic tests such as rotational thromboelastometry (ROTEM®) during this pandemic is explored in this review. COVID-19-associated coagulopathy, as measured using the rotational thromboelastometry parameters, can vary from hypercoagulability due to increased fibrin polymerization and decreased fibrinolysis to bleeding from hypocoagulability. The use of a multimodal diagnostic and monitoring approach, including both rotational thromboelastometry and SCT, such as plasma fibrinogen and D-dimer concentrations, is recommended. Rotational thromboelastometry provides comprehensive information about the full coagulation status of each patient and detects individual variations. Since COVID-19-associated coagulopathy is a very dynamic process, the phenotype can change during the course of infection and in response to anticoagulation therapy. Data from published literature provide evidence that the combination of rotational thromboelastometry and SCT analysis is helpful in detecting hemostasis issues, guiding anticoagulant therapy, and improving outcomes in COVID-19 patients. However, more research is needed to develop evidence-based guidelines and protocols.

Greater Fibrinolysis Resistance but No Greater Platelet Aggregation in Critically Ill COVID-19 Patients

Background:

The hemostatic balance in patients with coronavirus disease 2019 (COVID-19) seems to be shifted toward a hypercoagulable state. The aim of the current study was to assess the associated coagulation alterations by point-of-care-diagnostics, focusing on details of clot formation and lysis in these severely affected patients.

Methods:

The authors’ prospective monocentric observational study included critically ill patients diagnosed with COVID-19. Demographics and biochemical data were recorded. To assess the comprehensive hemostatic profile of this patient population, aggregometric (Multiplate) and viscoelastometric (CloPro) measures were performed in the intensive care unit of a university hospital at a single occasion. Coagulation analysis and assessment of coagulation factors were performed. Data were compared to healthy controls.

Results:

In total, 27 patients (21 male; mean age, 60 yr) were included. Impedance aggregometry displayed no greater platelet aggregability in COVID-19 in comparison with healthy controls (area under the curve [AUC] in adenosine diphosphate test, 68 ± 37 U vs. 91 ± 29 U [−27 (Hodges–Lehmann 95% CI, −48 to −1); P = 0.043]; AUC in arachidonic acid test, 102 ± 54 U vs. 115 ± 26 U [−21 (Hodges–Lehmann 95% CI, −51 to 21); P = 0.374]; AUC in thrombin receptor activating peptide 6 test, 114 ± 61 U vs. 144 ± 31 U [−31 (Hodges–Lehmann 95% CI, −69 to −7); P = 0.113]). Comparing the thromboelastometric results of COVID-19 patients to healthy controls, the authors observed significant differences in maximum clot firmness in fibrin contribution to maximum clot firmness assay (37 ± 11 mm vs. 15 ± 4 mm [21 (Hodges–Lehmann 95% CI, 17 to 26); P < 0.001]) and lysis time in extrinsic activation and activation of fibrinolysis by tissue plasminogen activator assay (530 ± 327 s vs. 211 ± 80 s [238 (Hodges–Lehmann 95% CI, 160 to 326); P < 0.001]).

Conclusions:

Thromboelastometry in COVID-19 patients revealed greater fibrinolysis resistance. The authors did not find a greater platelet aggregability based on impedance aggregometric tests. These findings may contribute to our understanding of the hypercoagulable state of critically ill patients with COVID-19.

Despite increases in von Willebrand factor, platelet aggregability based on impedance aggregometry testing was not increased in critically ill COVID-19, although viscoelastometric testing noted fibrinolysis resistance. These findings contribute to our understanding of the hypercoagulable state of COVID-19 and may have important considerations for management strategies.

Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review

This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.

Hemostatic defects in massive transfusion: an update and treatment recommendations

INTRODUCTION

Acute hemorrhage is a global healthcare issue, and remains the leading preventable cause of death in trauma. Acute severe hemorrhage can be related to traumatic, peripartum, gastrointestinal, and procedural causes. Hemostatic defects occur early in patients requiring massive transfusion. Early recognition and treatment of hemorrhage and hemostatic defects are required to save lives and to achieve optimal patient outcomes.

AREAS COVERED

This review discusses current evidence and trials aimed at identifying the optimal treatment for hemostatic defects in hemorrhage and massive transfusion. Literature search included PubMed and Embase.

EXPERT OPINION

Patients with acute hemorrhage requiring massive transfusion commonly develop coagulopathy due to specific hemostatic defects, and accurate diagnosis and prompt correction are required for definitive hemorrhage control. Damage control resuscitation and massive transfusion protocols are optimal initial treatment strategies, followed by goal-directed individualized resuscitation using real-time coagulation monitoring. Distinct phenotypes exist in trauma-induced coagulopathy, including 'Bleeding' or 'Thrombotic' phenotypes, and hyperfibrinolysis vs. fibrinolysis shutdown. The trauma 'lethal triad' (hypothermia, coagulopathy, acidosis) has been updated to the 'lethal diamond' (including hypocalcemia). A number of controversies in optimal management exist, including whole blood vs. component therapy, use of factor concentrates vs. blood products, optimal use of tranexamic acid, and prehospital plasma and tranexamic acid administration.

Effects of Blood Components and Whole Blood in a Model of Severe Trauma-Induced Coagulopathy

BACKGROUND

Plasma resuscitation ameliorates hyperfibrinolysis (HF) and trauma-induced coagulopathy (TIC). However, the use of other blood components to reduce HF has not been evaluated. Therefore, our aim was to determine the effect of individual blood components and whole blood (WB) on an in vitro model of severe HF/TIC.

METHODS

A "TIC" solution was made with 1:1 dilution of WB with saline and exacerbated with tissue plasminogen activator (tPA). Components were added in proportions equivalent to the thromboelastography (TEG) based goal-directed resuscitation used at our institution. Whole blood was added at proportions equal to what has been transfused in injured patients. Samples (n = 9) underwent citrated native and tPA-challenge (75 ng/mL) TEG with analysis of R-time, angle, MA, and LY30. Statistical analyses were completed employing the nonparametric Kruskal-Wallis and Dunn's multiple comparisons tests.

RESULTS

TIC solution, when compared to control, had a decrease in clot strength (MA 41 mm versus 51.5 mm, P < 0.01). The addition of tPA resulted in a severe coagulopathy (MA 24.5 mm versus 41 mm and LY30 52.8% versus 2.4%, P < 0.03 for all). The addition of 4U of WB improved clot strength compared to TIC + tPA (P = 0.03). No individual blood component resulted in improved fibrinolysis (P > 0.7). Cryoprecipitate improved R-time (7.5 versus 11.9 min, P < 0.01), angle (56.8 versus 30.2°) and MA (49 mm versus 36.25 mm), while platelets improved MA (44 mm versus 36.25 mm) compared to TIC + tPA (P < 0.03 for all).

CONCLUSIONS

No single blood component or volume of whole blood led to attenuation of tPA-mediated fibrinolysis in an in vitro model of TIC. Cryoprecipitate was the most effective at improving coagulation function.

Detection of early allograft dysfunction at 30 min of reperfusion in liver transplantation: An intraoperative diagnostic tool with real time assessment of graft function

INTRODUCTION

During the anhepatic phase of liver transplantation (LT), fibrinolytic activity increases, since the liver clears tissue plasminogen activator (tPA). We hypothesize that patients who fail to reduce fibrinolytic activity following graft reperfusion will have an increased rate of early allograft dysfunction (EAD).

METHODS

Assessment of fibrinolysis in liver transplant recipients was quantified with thrombelastography (TEG) LY30. Changes in LY30 were assessed after graft reperfusion. The 30-min post-reperfusion LY30 was subtracted from the anhepatic LY30 quantifying fibrinolytic changes (delta-LY30).

RESULTS

Seventy-three primary LT patients were included in the analysis. Receiver operating characteristic curve (ROC) analysis identified an inflection point of delta-LY30-5.3% as a risk factor for EAD. EAD occurred in 44% of these patients compared to 5% in high delta-LY30 (p = 0.002).

CONCLUSION

LT recipients that develop hyperfibrinolysis who fail to reduce fibrinolytic activity 30 min after graft reperfusion had an EAD rate 8-fold higher than patients who had a large reduction in LY30 following reperfusion.

Hyper- and hypocoagulability in COVID-19 as assessed by thromboelastometry -two case reports

BACKGROUND

Coronavirus disease (COVID-19)-associated coagulopathy is most often characterized by elevated D-dimer, interleukin-6, and plasma fibrinogen concentrations as well as hypercoagulability in thromboelastometry with increased clot firmness in the EXTEM, INTEM, and FIBTEM assays. Clinically, it manifests with a very high incidence of thrombosis, particularly in the pulmonary system, whereas bleeding complications are infrequent.

CASE

Here, we describe two critically ill patients with COVID-19 admitted to our intensive care unit demonstrating different thromboelastometry and biomarker patterns. One patient presented with hypercoagulability and the other patient with hypocoagulability and fibrinolysis shutdown in thromboelastometry. The pathophysiology and the potential impact on treatment options are discussed.

CONCLUSIONS

A combination of biomarkers and thromboelastometry results can be helpful in the future to decide which therapeutic strategy might be most appropriate for critically ill patients with COVID-19. This would be an important step to establish precision medicine in this high-risk patient population.

High D dimers and low global fibrinolysis coexist in COVID19 patients: what is going on in there?

BACKGROUD

COVID-19 coagulopathy linked to increased D-dimer levels has been associated with high mortality (Fei Z et al. in Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet (London, England) 395(10229):1054-62, 2020). While D-dimer is accepted as a disseminated intravascular coagulation marker, rotational thromboelastometry (ROTEM) also detects fibrinolysis (Wright FL et al. in Fibrinolysis shutdown correlates to thromboembolic events in severe COVID-19 infection. J Am Coll Surg (2020). Available from https://pubmed.ncbi.nlm.nih.gov/32422349/ [cited 14 Jun 2020]; Schmitt FCF et al. in Acute fibrinolysis shutdown occurs early in septic shock and is associated with increased morbidity and mortality: results of an observational pilot study. Ann Intensive Care 9(1):19, 2019). We describe the ROTEM profile in severely ill COVID-19 patients and compare it with the standard laboratory coagulation test.

METHODS

Adult patients diagnosed with COVID-19 admitted to the ICU were prospectively enrolled after Ethics Committee approval (HCB/2020/0371). All patients received venous thromboembolism prophylaxis; those on therapeutic anticoagulation were excluded. The standard laboratory coagulation test and ROTEM were performed simultaneously at 24-48 h after ICU admission. Sequential organ failure assessment (SOFA), disseminated intravascular coagulation (DIC) and sepsis-induced coagulopathy (SIC) scores were calculated at sample collection.

RESULTS

Nineteen patients were included with median SOFA-score of 4 (2-6), DIC-score of 1 (0-3) and SIC-score of 1.8 (0.9). Median fibrinogen, D-dimer levels and platelet count were 6.2 (4.8-7.6 g/L), 1000 (600-4200 ng/ml) and 236 (136-364 10⁹/L), respectively. Clot firmness was above the normal range in the EXTEM and FIBTEM tests while clot lysis was decreased. There was no significant correlation between ROTEM or D-dimer parameters and the SOFA score.

CONCLUSION

In COVID-19 patients, the ROTEM pattern was characterized by a hypercoagulable state with decreased fibrinolytic capacity despite a paradoxical increase in D-dimer levels. We suggest that, in COVID-19 patients, the lungs could be the main source of D-dimer, while a systemic hypofibrinolytic state coexists. This hypothesis should be confirmed by future studies.

Severe traumatic brain injury is associated with a unique coagulopathy phenotype

BACKGROUND

Traumatic brain injury (TBI) patients present on a spectrum from hypocoagulability to hypercoagulability, depending on the injury complexity, severity, and time since injury. Prior studies have found a unique coagulopathy associated with TBI using conventional coagulation assays such as INR; however, few studies have assessed the association of TBI and coagulopathy using viscoelastic assays that comprehensively evaluate the coagulation in whole blood. This study aims to reevaluate the TBI-specific trauma-induced coagulopathy using arrival thrombelastography. Because brain tissue is high in key procoagulant molecules, we hypothesize that isolated TBI is associated with procoagulant and hypofibrinolytic profiles compared with injuries of the torso, extremities, and polytrauma, including TBI.

METHODS

Data are from the prospective Trauma Activation Protocol study. Activated clotting time (ACT), angle, maximum amplitude (MA), 30-minute percent lysis after MA (LY30), and functional fibrinogen levels (FFLEV) were recorded. Patients were categorized into isolated severe TBI (I-TBI), severe TBI with torso and extremity injuries (TBI + TORSO/EXTREMITIES), and isolated torso and extremity injuries (I-TORSO/EXTREMITIES). Poisson regression was used to adjust for multiple confounders.

RESULTS

Overall, 572 patients (48 I-TBI, 45 TBI + TORSO/EXTREMITIES, 479 I-TORSO/EXTREMITIES) were included in this analysis. The groups differed in INR, ACT, angle, MA, and FFLEV but not in 30-minute percent lysis. When compared with I-Torso/Extremities, after adjustment for confounders, severe I-TBI was independently associated with ACT less than 128 seconds (relative risk [RR], 1.5; 95% confidence interval [CI], 1.1-2.2), angle less than 65 degrees (RR, 2.2; 95% CI, 1.4-3.6), FFLEV less than 356 (RR, 1.7; 95% CI, 1.2-2.4) but not MA less than 55 mm, hyperfibrinolysis, fibrinolysis shutdown, or partial thromboplastin time (PTT) greater than 30.

CONCLUSION

Severe I-TBI was independently associated with a distinct coagulopathy with delayed clot formation but did not appear to be associated with fibrinolysis abnormalities. Low fibrinogen and longer ACT values associated with I-TBI suggest that early coagulation factor replacement may be indicated in I-TBI patients over empiric antifibrinolytic therapy. Mechanisms triggering coagulopathy in TBI are unique and warrant further investigation.

LEVEL OF EVIDENCE

Retrospective cohort study, prognostic, level III.

Obesity is associated with postinjury hypercoagulability

BACKGROUND

Obesity is linked to hypercoagulability with an increased risk of venous thromboembolic events (VTE) in the uninjured population. Therefore, we hypothesize that obesity (body mass index [BMI] ≥30 kg/m [BMI30]) is associated with a hypercoagulable state postinjury characterized by increased clot strength and resistance to fibrinolysis.

METHODS

Our prospective Trauma Activation Protocol database includes all trauma activations patients for whom a rapid thrombelastography is obtained within 60 minutes postinjury prior to any transfusions. The data set was then stratified by BMI and subjects with BMI30 were compared with those with BMI less than 30 kg/m). The following thrombelastography measurements were obtained: activated clotting time, clot formation rate (angle), maximum clot strength (MA), and % clot lysis 30 minutes after MA (LY30, %). Fibrinolysis shutdown (SD) was defined as LY30 < 0.6% and hyperfibrinolysis (HF) as LY30 greater than 7.6%. Continuous variables are expressed as median (interquartile range).

RESULTS

Overall, 687 patients were included of whom 161 (23%) had BMI30. The BMI30 group was older, had a lower proportion of males and of blunt trauma, and was less severely injured. After adjustment for confounders, BMI30 was independently associated with lower odds of MA less than 55 mm (odds ratio [OR], 0.28; 95% confidence interval [CI], 0.13-0.60) and of HF (OR, 0.31; 95% CI, 0.10-0.97) and higher odds of SD (OR, 1.82; 95% CI, 1.09-3.05). No independent association was observed with angle less than 65° (OR 0.57 95% CI 0.30-1.05). While VTEs were more frequent among BMI30 patients (5.0 vs. 3.3%), this did not reach significance after confounding adjustment (p = 0.11).

CONCLUSION

Obesity was protective against diminished clot strength and hyperfibrinolysis, and obesity was associated with an increased risk of fibrinolytic SD in severely injured patients. These findings suggest a relative hypercoagulability. Although no difference in VTEs was noted in this study, these findings may explain the higher rate of VTEs reported in other studies.

LEVEL OF EVIDENCE

Prognostic and Epidemiological, level III.

The current status of viscoelastic testing in septic coagulopathy

Sepsis can be associated with different degrees of coagulopathy, ranging from a mild activation of the coagulation system to disseminated intravascular coagulation (DIC). The evaluation of haemostasis in the context of sepsis is important since it has been shown that anticoagulant therapies were beneficial mainly in patients with sepsis-induced DIC, but not in the general population of septic patients. Sepsis-induced haemostatic disturbances are not adequately reflected by standard coagulation tests (SCTs) which only consider the plasmatic components of the haemostatic system and not the cellular components. In addition, SCTs only assess the initiation phase of coagulation and reflect the activity of pro-coagulant factors, but lack sensitivity for the anticoagulant drive and the fibrinolytic activity. Viscoelastic tests (VET) are whole-blood tests which can assess clot formation and dissociation, and the contribution of both plasmatic and cellular components with a shorter turnaround time compared to SCTs. The use of VET in septic patients has proved useful for the assessment of the fibrinolytic activity, detecting hypercoagulable status and for the diagnosis of DIC and mortality risk prediction. While having relevant advantages over SCTs, the VET also present some blind spots or limitations leaving space for future improvement by the development of new reagents or new viscoelastic parameters.