The Immunologic Effect of Early Intravenous Two and Four Gram Bolus Dosing of Tranexamic Acid Compared to Placebo in Patients With Severe Traumatic Bleeding (TAMPITI): A Randomized, Double-Blind, Placebo-Controlled, Single-Center Trial

Dose-Dependent Tranexamic Acid Blunting of Penumbral Leukocyte Mobilization and Blood-Brain Barrier Permeability Following Traumatic Brain Injury: An In Vivo Murine Study

BACKGROUND

Early posttraumatic brain injury (TBI) tranexamic acid (TXA) may reduce blood-brain barrier (BBB) permeability, but it is unclear if this effect is fixed regardless of dose. We hypothesized that post-TBI TXA demonstrates a dose-dependent reduction of in vivo penumbral leukocyte mobilization, BBB microvascular permeability, and enhancement of neuroclinical recovery.

METHODS

CD1 male mice (n = 40) were randomly assigned to TBI by controlled cortical impact (injury [I]) or sham TBI (S), followed by intravenous bolus of either saline (placebo [P]) or TXA (15, 30, or 60 mg/kg). At 48 h, in vivo pial intravital microscopy visualized live penumbral BBB microvascular leukocytes and albumin leakage. Neuroclinical recovery was assessed by Garcia Neurological Test scores and animal weight changes at 24 h and 48 h after injury.

RESULTS

I + TXA60 reduced live penumbral leukocyte rolling compared with I + P (p < 0.001) and both lower TXA doses (p = 0.017 vs. I + TXA15, p = 0.012 vs. I + TXA30). Leukocyte adhesion was infrequent and similar across groups. Only I + TXA60 significantly reduced BBB permeability compared with that in the I + P (p = 0.004) group. All TXA doses improved Garcia Test scores relative to I + P at both 24 h and 48 h (p < 0.001 vs. I + P for all at both time points). Mean 24-h body weight loss was greatest in the I + P (- 8.7 ± 1.3%) group and lowest in the I + TXA15 (- 4.4 ± 1.0%, p = 0.051 vs. I + P) group.

CONCLUSIONS

Only higher TXA dosing definitively abrogates penumbral leukocyte mobilization, preserving BBB integrity post TBI. Some neuroclinical recovery is observed, even with lower TXA dosing. Better outcomes with higher dose TXA after TBI may occur secondary to blunting of leukocyte-mediated penumbral cerebrovascular inflammation.

Population pharmacokinetic modelling and simulation of tranexamic acid in adult trauma patients

AIMS

The aim of this study is to describe the disposition of tranexamic acid (TXA) in adult trauma patients and derive a dosing regimen that optimizes exposure based on a predefined exposure target.

METHODS

We performed a population pharmacokinetic (popPK) analysis of participants enrolled in the Tranexamic Acid Mechanisms and Pharmacokinetics in Traumatic Injury (TAMPITI) trial (≥18 years with traumatic injury, given ≥1 blood product and/or requiring immediate transfer to the operating room) who were randomized to a single dose of either 2 or 4 g of TXA ≤2 h from time of injury. PopPK analysis was conducted using nonlinear mixed-effects modelling (NONMEM). Simulations were then performed using the final model to generate estimated plasma TXA concentrations in 1000 simulated participants. Dosing schemes were evaluated to determine maintenance of TXA plasma concentrations >10 mg/L for ≥8 h after administration of the initial dose.

RESULTS

TXA PK was best described by a two-compartment model with proportional residual error and allometric scaling on all parameters. Platelet count, skeletal muscle oxygen saturation measured by near-infrared spectroscopy and interleukin-8 concentration were significant covariates on TXA clearance. Based on simulations, a 2 g IV bolus dose, repeated 3 h later, best achieved the target exposure.

CONCLUSIONS

According to simulations from a popPK model of TXA, a 2 g IV bolus with a repeated dose 3 h later would be most likely to maintain concentrations >10 mg/L for 8 h in >95% of adult trauma patients and should be considered for patients with ongoing haemorrhage.

Differentiating Pathologic from Physiologic Fibrinolysis: Not as Simple as Conventional Thrombelastography

BACKGROUND

Conventional rapid thrombelastography (rTEG) cannot differentiate fibrinolysis shutdown from hypofibrinolysis, as both of these patient populations have low fibrinolytic activity. Tissue plasminogen activator (tPA) TEG can identify depletion of fibrinolytic inhibitors, and its use in combination with rTEG has the potential to differentiate all 3 pathologic fibrinolytic phenotypes after trauma. We hypothesize tPA-TEG and rTEG in combination can further stratify fibrinolysis phenotypes postinjury to better stratify risk for mortality.

STUDY DESIGN

Adult trauma patients (981) with both rTEG and tPA-TEG performed less than 2 hours postinjury were included. rTEG lysis at 30 minutes after maximum amplitude (LY30) was used to initially define fibrinolysis phenotypes (hyperfibrinolysis >3%, physiologic 0.9% to 3%, and shutdown <0.9%), with Youden Index then used to define pathologic extremes of tPA-TEG LY30 (tPA sensitive [depletion of fibrinolytic inhibitors] vs resistant) resulting in 9 groups that were assessed for risk of death.

RESULTS

The median New Injury Severity Score was 22, 21% were female, 45% had penetrating injury, and overall mortality was 13%. The tPA-TEG LY30 inflection point for increased mortality was >35.5% (tPA sensitive, odds ratio mortality 9.2, p < 0.001) and <0.3% (tPA resistance, odds ratio mortality 6.3, p = 0.04). Of the 9 potential fibrinolytic phenotypes, 5 were associated with increased mortality. Overall, the 9 phenotypes provided a significantly better prediction of mortality than rTEG or tPA-TEG alone (areas under the operating characteristics curves = 0.80 vs 0.63 and 0.75, respectively, p < 0.0001). These could be condensed to 3 pathologic phenotypes (true hyperfibrinolysis, early fibrinolysis shutdown, and hypofibrinolysis).

CONCLUSIONS

The combination of rTEG and tPA-TEG increases the ability to predict mortality and suggests patient-specific strategies for improved outcomes.

Dosing of tranexamic acid in trauma

PURPOSE OF REVIEW

Tranexamic acid is routinely used as part of the management of traumatic bleeding. The dose recommendation in trauma was extrapolated from other clinical settings and the results of pragmatic randomized trials rather than pharmaco-kinetic and -dynamic evaluations. The review addresses current evidence on dosing of tranexamic acid in traumatized patients with a focus on efficacy, safety and risk-benefit profile.

RECENT FINDINGS

A majority, but not all, of existing randomized clinical trials reports a reduction in mortality and/or blood loss with tranexamic acid administration. Increasing dose above the general recommendation (1 g bolus + 1 g infusion/8 h intravenously) has not been shown to further increase efficacy and could potentially increase side effects.

SUMMARY

The benefit of tranexamic acid as adjuvant therapy in the management of bleeding trauma patients on mortality and transfusion requirements is clear and well documented, being most effective if given early and to patients with clinical signs of hemorrhagic shock. Recent reports suggest that in some patients presenting with a shutdown of their fibrinolytic pathway the administration of tranexamic acid could be associated with an increased risk of thromboembolic events and poor outcomes. A more personalized approach based on bedside assessment of fibrinolytic activation and pharmacokinetic-based dose regimen should be developed moving forward.

Blood failure: traumatic hemorrhage and the interconnections between oxygen debt, endotheliopathy, and coagulopathy

This review explores the concept of "blood failure" in traumatic injury, which arises from the interplay of oxygen debt, the endotheliopathy of trauma (EoT), and acute traumatic coagulopathy (ATC). Traumatic hemorrhage leads to the accumulation of oxygen debt, which can further exacerbate hemorrhage by triggering a cascade of events when severe. Such events include EoT, characterized by endothelial glycocalyx damage, and ATC, involving platelet dysfunction, fibrinogen depletion, and dysregulated fibrinolysis. To manage blood failure effectively, a multifaceted approach is crucial. Damage control resuscitation strategies such as use of permissive hypotension, early hemorrhage control, and aggressive transfusion of blood products including whole blood aim to minimize oxygen debt and promote its repayment while addressing endothelial damage and coagulation. Transfusions of red blood cells, plasma, and platelets, as well as the use of tranexamic acid, play key roles in hemostasis and countering ATC. Whole blood, whether fresh or cold-stored, is emerging as a promising option to address multiple needs in traumatic hemorrhage. This review underscores the intricate relationships between oxygen debt, EoT, and ATC and highlights the importance of comprehensive, integrated strategies in the management of traumatic hemorrhage to prevent blood failure. A multidisciplinary approach is essential to address these interconnected factors effectively and to improve patient outcomes.

Ruggedized Self-Propelling Hemostatic Gauze Delivers Low Dose of Thrombin and Systemic Tranexamic Acid and Achieves High Survival in Swine With Junctional Hemorrhage

INTRODUCTION

Hemorrhage is responsible for 91% of preventable prehospital deaths in combat. Bleeding from anatomic junctions such as the groin, neck, and axillae make up 19% of these deaths, and reports estimate that effective control of junctional hemorrhage could have prevented 5% of fatalities in Afghanistan. Hemostatic dressings are effective but are time-consuming to apply and are limited when proper packing and manual pressure are not feasible, such as during care under fire. CounterFlow-Gauze is a hemostatic dressing that is effective without compression and delivers thrombin and tranexamic acid into wounds. Here, an advanced prototype of CounterFlow-Gauze, containing a range of low thrombin doses, was tested in a lethal swine model of junctional hemorrhage. Outcomes were compared with those of Combat Gauze, the current dressing recommended by Tactical Combat Casualty Care.

MATERIALS AND METHODS

CounterFlow-Gauze containing thrombin doses of 0, 20, 200, and 500 IU was prepared. Swine received femoral arteriotomies, and CounterFlow-Gauze was packed into wounds without additional manual compression. In a separate study using a similar model of junctional hemorrhage without additional compression, CounterFlow-Gauze containing 500 IU thrombin was tested and compared with Combat Gauze. In both studies, the primary outcomes were survival to 3 h and volume of blood loss.

RESULTS

CounterFlow-Gauze with 200 and 500 IU had the highest 3-h survival, achieving 70 and 75% survival, respectively. CounterFlow-Gauze resulted in mean peak plasma tranexamic acid concentrations of 9.6 ± 1.0 µg/mL (mean ± SEM) within 3 h. In a separate study with smaller injury, CounterFlow-Gauze with 500 IU achieved 100% survival to 3 h compared with 92% in Combat Gauze animals.

CONCLUSIONS

An advanced preclinical prototype of CounterFlow-Gauze formulated with a minimized thrombin dose is highly effective at managing junctional hemorrhage without compression. These results demonstrate that CounterFlow-Gauze could be developed into a feasible alternative to Combat Gauze for hemorrhage control on the battlefield.

Prehospital tranexamic acid in trauma patients: a systematic review and meta-analysis of randomized controlled trials

Background

Prehospital tranexamic acid (TXA) may hold substantial benefits for trauma patients; however, the data underlying its efficacy and safety is scarce.

Methods

We searched PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov from inception to July 2023 for all randomized controlled trials (RCTs) investigating prehospital TXA in trauma patients as compared to placebo or standard care without TXA. Data were pooled under a random-effects model using RevMan 5.4 with risk ratio (RR) and mean difference (MD) as the effect measures.

Results

A total of three RCTs were included in this review. Regarding the primary outcomes, prehospital TXA reduced the risk of 1-month mortality (RR 0.82, 95% CI 0.69-0.97) but did not increase survival with a favorable functional outcome at 6 months (RR 1.00, 95% CI 0.93-1.09). Prehospital TXA also reduced the risk of 24-h mortality but did not affect the risk of mortality due to bleeding and traumatic brain injury. There was no significant difference between the TXA and control groups in the incidence of RBC transfusion, and the number of ventilator- and ICU-free days. Prehospital TXA did not increase the risk of adverse events except for a small increase in the incidence of infections.

Conclusion

Prehospital TXA is useful in reducing mortality in trauma patients without a notable increase in the risk of adverse events. However, there was no effect on the 6-month favorable functional status. Further large-scale trials are required to validate the aforementioned findings.

Systematic review registration

PROSPERO (CRD42023451759).

Heterogeneity in defining multiple trauma: a systematic review of randomized controlled trials

INTRODUCTION

While numerous randomized controlled trials (RCTs) have been conducted in the field of trauma, a substantial portion of them are yielding negative results. One potential contributing factor to this trend could be the lack of agreement regarding the chosen definitions across different trials. The primary objective was to identify the terminology and definitions utilized for the characterization of multiple trauma patients within randomized controlled trials (RCTs).

METHODS

A systematic review of the literature was performed in MEDLINE, EMBASE and clinicaltrials.gov between January 1, 2002, and July 31, 2022. RCTs or RTCs protocols were eligible if they included multiple trauma patients. The terms employed to characterize patient populations were identified, and the corresponding definitions for these terms were extracted. The subsequent impact on the population recruited was then documented to expose clinical heterogeneity.

RESULTS

Fifty RCTs were included, and 12 different terms identified. Among these terms, the most frequently used were "multiple trauma" (n = 21, 42%), "severe trauma" (n = 8, 16%), "major trauma" (n = 4, 8%), and trauma with hemorrhagic shock" (n = 4, 8%). Only 62% of RCTs (n = 31) provided a definition for the terms used, resulting a total of 21 different definitions. These definitions primarily relied on the injury severity score (ISS) (n = 15, 30%), displaying an important underlying heterogeneity. The choice of the terms had an impact on the study population, affecting both the ISS and in-hospital mortality. Eleven protocols were included, featuring five different terms, with "severe trauma" being the most frequent, occurring six times (55%).

CONCLUSION

This systematic review uncovers an important heterogeneity both in the terms and in the definitions employed to recruit trauma patients within RCTs. These findings underscore the imperative of promoting the use of a unique and consistent definition.

Tranexamic acid for haemostasis and beyond: does dose matter?

Tranexamic acid (TXA) is a widely used antifibrinolytic agent that has been used since the 1960's to reduce blood loss in various conditions. TXA is a lysine analogue that competes for the lysine binding sites in plasminogen and tissue-type plasminogen activator impairing its interaction with the exposed lysine residues on the fibrin surface. The presence of TXA therefore, impairs the plasminogen and tPA engagement and subsequent plasmin generation on the fibrin surface, protecting fibrin clot from proteolytic degradation. However, critical lysine binding sites for plasmin(ogen) also exist on other proteins and on various cell-surface receptors allowing plasmin to exert potent effects on other targets that are unrelated to classical fibrinolysis, notably in relation to immunity and inflammation. Indeed, TXA was reported to significantly reduce post-surgical infection rates in patients after cardiac surgery unrelated to its haemostatic effects. This has provided an impetus to consider TXA in other indications beyond inhibition of fibrinolysis. While there is extensive literature on the optimal dosage of TXA to reduce bleeding rates and transfusion needs, it remains to be determined if these dosages also apply to blocking the non-canonical effects of plasmin.

[The chapters "Stop the bleed-prehospital" and "Coagulation management and volume therapy (emergency departement)" in the new S3 guideline "Polytrauma/severe injury treatment"]

The S3 guideline on the treatment of patients with severe/multiple injuries by the German Association of the Scientific Medical Societies was updated between 2020 and 2022. This article describes the essence of the new chapter "Stop the bleed-prehospital" and the revised chapter "Coagulation management and volume therapy".

Tranexamic Acid and Plasminogen/Plasmin Glaring Paradox in COVID-19

Coronavirus disease 2019 (COVID-19) is caused by a severe acute respiratory syndrome, coronavirus type 2 (SARS-CoV-2), leading to acute tissue injury and an overstated immune response. In COVID-19, there are noteworthy changes in the fibrinolytic system with the development of coagulopathy. Therefore, modulation of the fibrinolytic system may affect the course of COVID-19. Tranexamic acid (TXA) is an anti-fibrinolytic drug that reduces the conversion of plasminogen to plasmin, which is necessary for SARS-CoV-2 infectivity. In addition, TXA has anti-inflammatory, anti-platelet, and anti-thrombotic effects, which may attenuate the COVID-19 severity. Thus, in this narrative review, we try to find the beneficial and harmful effects of TXA in COVID-19.

Systemic hemostatic agents initiated in trauma patients in the pre-hospital setting: a systematic review

Purpose

The effect of systemic hemostatic agents initiated during pre-hospital care of severely injured patients with ongoing bleeding or traumatic brain injury (TBI) remains controversial. A systematic review and meta-analysis was therefore conducted to assess the effectiveness and safety of systemic hemostatic agents as an adjunctive therapy in people with major trauma and hemorrhage or TBI in the context of developing the Italian National Institute of Health guidelines on major trauma integrated management.

Methods

PubMed, Embase, and Cochrane Library databases were searched up to October 2021 for studies that investigated pre-hospital initiated treatment with systemic hemostatic agents. The certainty of evidence was evaluated with the Grading of Recommendations Assessment, Development, and Evaluation approach, and the quality of each study was determined with the Cochrane risk-of-bias tool. The primary outcome was overall mortality, and secondary outcomes included cause-specific mortality, health-related quality of life, any adverse effects and blood product use, hemorrhage expansion, and patient-reported outcomes.

Results

Five trials of tranexamic acid (TXA) met the inclusion criteria for this meta-analysis. With a high certainty of evidence, when compared to placebo TXA reduced mortality at 24 h (relative risk = 0.83, 95% confidence interval = 0.73–0.94) and at 1 month among trauma patients (0.91, 0.85–0.97). These results depend on the subgroup of patients with significant hemorrhage because in the subgroup of TBI there are no difference between TXA and placebo. TXA also reduced bleeding death and multiple organ failure whereas no difference in health-related quality of life.

Conclusion

Balancing benefits and harms, TXA initiated in the pre-hospital setting can be used for patients experiencing major trauma with significant hemorrhage since it reduces the risk of mortality at 24 h and one month with no difference in terms of adverse effects when compared to placebo. Considering the subgroup of severe TBI, no difference in mortality rate was found at 24 h and one month. These results highlight the need to conduct future studies to investigate the role of other systemic hemostatic agents in the pre-hospital settings.

Cellular immunophenotype of major spine surgery in adults

PURPOSE

ASD reconstructions are a major, sterile traumatic insult, likely causing perturbations to the immune systems. The immune response to surgery is associated with outcomes. The purpose of this study was to examine for a detectable immune signature associated with ASD surgery.

METHODS

Consecutive patients undergoing ASD surgery were approached and enrolled. Peripheral blood was drawn before incision, 4 h after, and 24 h after incision. Blood was stabilized and comprehensive flow cytometric immunophenotyping performed. Leukocyte population frequency, absolute number and activation marker expression were defined. Immunologic features were defined and analyzed by hierarchical clustering and principal component analysis (PCA). Changes over time were evaluated by repeated measures ANOVA (RMANOVA) and were corrected for a 1% false discovery rate. Post hoc testing was by Dunn's test. p values of <  = 0.05 were considered significant.

RESULTS

Thirteen patients were enrolled; 11(85%) F, 65.4 years (± 7.5), surgical duration 418 ± 83 min, EBL 1928 ± 1253 mL. Hierarchical clustering and PCA found consistent time from incision-dependent changes. HLA-DR and activating co-stimulatory molecule CD86 were depressed at 4 h and furthermore at 24 h on monocyte surfaces. CD4 + HLA-DR + T cells, but not CD8 +, increased over time with increased expression of PD-1 at 4 and 24 h.

CONCLUSIONS

Despite surgery and patient heterogeneity, we identified an immune signature associated with the sterile trauma of ASD surgery. Circulating leukocyte populations change in composition and signaling protein expression after incision and persisting to 24 h after incision, suggesting an immunocompromised state. Further work may determine relationships between this state and poor outcomes after surgery.

Coagulopathy management of multiple injured patients - a comprehensive literature review of the European guideline 2019

The European guideline on the management of trauma-induced major bleeding and coagulopathy summarises the most relevant recommendations for trauma coagulopathy management. The management of trauma-induced major bleeding should interdisciplinary follow algorithms which distinguish between life-threatening and non-life-threatening bleeding. Point-of-care viscoelastic methods (VEM) assist target-controlled haemostatic treatment. Neither conventional coagulation assays nor VEM should delay treatment in life-threatening trauma-induced bleeding. Adjustments may be rational due to local circumstances, including the availability of blood products, pharmaceuticals, and employees.

Tranexamic acid: Beyond antifibrinolysis

Tranexamic acid (TXA) is a popular antifibrinolytic drug widely used in hemorrhagic trauma patients and cardiovascular, orthopedic, and gynecological surgical patients. TXA binds plasminogen and prevents its maturation to the fibrinolytic enzyme plasmin. A number of studies have demonstrated the broad life-saving effects of TXA in trauma, superior to those of other antifibrinolytic agents. Besides preventing fibrinolysis and blood loss, TXA has been reported to suppress posttraumatic inflammation and edema. Although the efficiency of TXA transcends simple inhibition of fibrinolysis, little is known about its mechanisms of action besides the suppression of plasmin maturation. Understanding the broader effects of TXA at the cell, organ, and organism levels are required to elucidate its potential mechanisms of action transcending antifibrinolytic activity. In this article, we provide a brief review of the current clinical use of TXA and then focus on the effects of TXA beyond antifibrinolytics such as its anti-inflammatory activity, protection of the endothelial and epithelial monolayers, stimulation of mitochondrial respiration, and suppression of melanogenesis.

The risk of thromboembolic events with early intravenous 2- and 4-g bolus dosing of tranexamic acid compared to placebo in patients with severe traumatic bleeding: A secondary analysis of a randomized, double-blind, placebo-controlled, single-center trial

BACKGROUND

Screening for the risk of thromboembolism (TE) due to tranexamic acid (TXA) in patients with severe traumatic injury has not been performed in randomized clinical trials. Our objective was to determine if TXA dose was independently-associated with thromboembolism.

STUDY DESIGN AND METHODS

This is a secondary analysis of a single-center, double-blinded, randomized controlled trial comparing placebo to a 2-g or 4-g intravenous TXA bolus dose in trauma patients with severe injury. We used multivariable discrete-time Cox regression models to identify associations with risk for thromboembolic events within 30 days post-enrollment. Event curves were created using discrete-time Cox regression.

RESULTS

There were 50 patients in the placebo group, 49 in the 2-g, and 50 in the 4-g TXA group. In adjusted analyses for thromboembolism, a 2-g dose of TXA had an hazard ratio (HR, 95% confidence interval [CI]) of 3.20 (1.12-9.11) (p = .029), and a 4-g dose of TXA had an HR (95% CI) of 5.33 (1.94-14.63) (p = .001). Event curves demonstrated a higher probability of thromboembolism for both doses of TXA compared to placebo. Other parameters independently associated with thromboembolism include time from injury to TXA administration, body mass index, and total blood products transfused.

DISCUSSION

In patients with severe traumatic injury, there was a dose-dependent increase in the risk of at least one thromboembolic event with TXA. TXA should not be withheld, but thromboembolism screening should be considered for patients receiving a dose of at least 2-g TXA intravenously for traumatic hemorrhage.

Tranexamic acid for major trauma patients in Ireland

BACKGROUND

The Clinical Randomisation of an Anti-fibrinolytic in Significant Hemorrhage-2 (CRASH-2) is the largest randomized control trial (RCT) examining circulatory resuscitation for trauma patients to date and concluded a statistically significant reduction in all-cause mortality in patients administered tranexamic acid (TXA) within 3 hours of injury. Since the publication of CRASH-2, significant geographical variance in the use of TXA for trauma patients exists. This study aims to assess TXA use for major trauma patients with hemorrhagic shock in Ireland after the publication of CRASH-2.

METHODS

A retrospective cohort study was conducted using data derived from the Trauma Audit and Research Network (TARN). All injured patients in Ireland between January 2013 and December 2018 who had evidence of hemorrhagic shock on presentation (as defined by systolic blood pressure [SBP] <100 mmHg [1 mmHg=0.133 kPa] and administration of blood products) were eligible for inclusion. Death at hospital discharge was the primary outcome.

RESULTS

During the study period, a total of 234 patients met the inclusion criteria. Among injured patients presenting with hemorrhagic shock, 133 (56.8%; 95% confidence interval [CI] 50.2%-63.3%) received TXA. Of patients that received TXA, a higher proportion of patients presented with shock index >1 (70.68% vs.57.43%) and higher Injury Severity Score (ISS >25; 49.62% vs. 23.76%). Administration of TXA was not associated with mortality at hospital discharge (odds ratio [OR] 0.86, 95% CI 0.31-2.38).

CONCLUSIONS

Among injured Irish patients presenting with hemorrhagic shock, TXA was administered to 56.8% of patients. Patients administered with TXA were on average more severely injured. However, a mortality benefit could not be demonstrated.

Effectiveness and Safety of Tranexamic Acid Use in Acute Traumatic Injury in the Prehospital and In-hospital Settings: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background and Objectives

This systematic review and meta-analysis of randomized controlled trials (RCTs) aims to assess efficacy and safety of tranexamic acid (TXA) use in acute traumatic injuries.

Methods

PubMed and Cochrane libraries were searched for relevant RCTs published between January 2011 and January 3, 2021. Cohen's Q Test for heterogeneous effects was used to determine the appropriateness of fixed versus random effects models.

Results

Twenty-two studies met inclusion criteria. Meta-analysis of relative risk of mortality between treatment and placebo groups in the in-hospital, and perioperative settings was not significant. However, the risk of mortality is significantly lower in the treatment versus placebo group when TXA was given as loading dose only. Ten of the 11 studies evaluating perioperative use of TXA included in systematic review found significantly lower blood loss in the treatment compared with placebo groups, but results of meta-analysis showed no significant difference. Results of meta-analysis indicate that the risk of venous thromboembolism (VTE) in the in-hospital treatment group is greater than that of the placebo. In subset analysis of studies using only a single loading dose, there were no significant differences in VTE.

Conclusions

Systematic review supports TXA benefits are most evident when given shortly after injury and meta-analysis supports TXA reduces mortality as a single loading dose. Systematic review supports perioperative use of TXA when large volume blood loss is anticipated. Meta-results showed no significant difference in risk of thromboembolism in single-dose TXA treatment compared with placebo. These findings suggest that TXA is safe and effective for control of traumatic bleeding.

Clinical use of tranexamic acid: evidences and controversies

Tranexamic acid (TXA) significantly reduces blood loss in a wide range of surgical procedures and improves survival rates in obstetric and trauma patients with severe bleeding. Although it mainly acts as a fibrinolysis inhibitor, it also has an anti-inflammatory effect, and may help attenuate the systemic inflammatory response syndrome found in some cardiac surgery patients. However, the administration of high doses of TXA has been associated with seizures and other adverse effects that increase the cost of care, and the administration of TXA to reduce perioperative bleeding needs to be standardized. Tranexamic acid is generally well tolerated, and most adverse reactions are considered mild or moderate. Severe events are rare in clinical trials, and literature reviews have shown tranexamic acid to be safe in several different surgical procedures. However, after many years of experience with TXA in various fields, such as orthopedic surgery, clinicians are now querying whether the dosage, route and interval of administration currently used and the methods used to control and analyze the antifibrinolytic mechanism of TXA are really optimal. These issues need to be evaluated and reviewed using the latest evidence to improve the safety and effectiveness of TXA in treating intracranial hemorrhage and bleeding in procedures such as liver transplantation, and cardiac, trauma and obstetric surgery.

Prehospital Tranexamic Acid (TXA) in Patients with Traumatic Brain Injury (TBI)

Traumatic brain injury (TBI) remains a significant medical and socioeconomic challenge. The initial injury may be complicated by haemostatic derangements leading to exacerbation of lesions and haemorrhagic progression. The results from the CRASH-3 trial have promoted the implementation of the antifibrinolytic tranexamic acid (TXA) into prehospital Emergency Medical Services (EMS) protocols. Very recently, the efficacy and safety of early out-of-hospital TXA compared to placebo was assessed in patients with moderate or severe TBI in a prospective, multicenter phase II trial, e.g. "The Prehospital TXA for TBI"-trial. Simultaneously, the results from a retrospective analysis of prospectively collected observational data into the Dutch pre-hospital TBI database were published which had assessed whether prehospital administration of TXA may be associated with mortality and functional outcomes in patients with severe TBI. Both studies are reviewed against their limitations and windows of opportunity are highlighted.

Tranexamic acid for the prevention and treatment of bleeding in surgery, trauma and bleeding disorders: a narrative review

OBJECTIVES

We review the evidence for tranexamic acid (TXA) for the treatment and prevention of bleeding caused by surgery, trauma and bleeding disorders. We highlight therapeutic areas where evidence is lacking and discuss safety issues, particularly the concern regarding thrombotic complications.

METHODS

An electronic search was performed in PubMed and the Cochrane Library to identify clinical trials, safety reports and review articles.

FINDINGS

TXA reduces bleeding in patients with menorrhagia, and in patients undergoing caesarian section, myomectomy, hysterectomy, orthopedic surgery, cardiac surgery, orthognathic surgery, rhinoplasty, and prostate surgery. For dental extractions in patients with bleeding disorders or taking antithrombotic drugs, as well as in cases of idiopathic epistaxis, tonsillectomy, liver transplantation and resection, nephrolithotomy, skin cancer surgery, burn wounds and skin grafting, there is moderate evidence that TXA is effective for reducing bleeding. TXA was not effective in reducing bleeding in traumatic brain injury and upper and lower gastrointestinal bleeding. TXA reduces mortality in patients suffering from trauma and postpartum hemorrhage. For many of these indications, there is no consensus about the optimal TXA dose. With certain dosages and with certain indications TXA can cause harm, such as an increased risk of seizures after high TXA doses with brain injury and cardiac surgery, and an increased mortality after delayed administration of TXA for trauma events or postpartum hemorrhage. Whereas most trials did not signal an increased risk for thrombotic events, some trials reported an increased rate of thrombotic complications with the use of TXA for gastro-intestinal bleeding and trauma.

CONCLUSIONS

TXA has well-documented beneficial effects in many clinical indications. Identifying these indications and the optimal dose and timing to minimize risk of seizures or thromboembolic events is work in progress.

The Efficacy and Safety of Tranexamic Acid Treatment in Orthopaedic Trauma Surgery

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Tranexamic acid (TXA) is a drug used to control hemorrhage by preventing the breakdown of fibrin.

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TXA is a cost-effective treatment for trauma patients across a variety of economic settings.

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Concerns of TXA causing thromboembolic events (TEEs) in orthopaedic trauma patients are not supported by evidence.

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TXA has been shown to reduce blood loss in hip fracture surgery.

Plasminogen: an enigmatic zymogen

Plasminogen is an abundant plasma protein that exists in various zymogenic forms. Plasmin, the proteolytically active form of plasminogen, is known for its essential role in fibrinolysis. To date, therapeutic targeting of the fibrinolytic system has been for 2 purposes: to promote plasmin generation for thromboembolic conditions or to stop plasmin to reduce bleeding. However, plasmin and plasminogen serve other important functions, some of which are unrelated to fibrin removal. Indeed, for >40 years, the antifibrinolytic agent tranexamic acid has been administered for its serendipitously discovered skin-whitening properties. Plasmin also plays an important role in the removal of misfolded/aggregated proteins and can trigger other enzymatic cascades, including complement. In addition, plasminogen, via binding to one of its dozen cell surface receptors, can modulate cell behavior and further influence immune and inflammatory processes. Plasminogen administration itself has been reported to improve thrombolysis and to accelerate wound repair. Although many of these more recent findings have been derived from in vitro or animal studies, the use of antifibrinolytic agents to reduce bleeding in humans has revealed additional clinically relevant consequences, particularly in relation to reducing infection risk that is independent of its hemostatic effects. The finding that many viruses harness the host plasminogen to aid infectivity has suggested that antifibrinolytic agents may have antiviral benefits. Here, we review the broadening role of the plasminogen-activating system in physiology and pathophysiology and how manipulation of this system may be harnessed for benefits unrelated to its conventional application in thrombosis and hemostasis.

Trauma-induced coagulopathy

Uncontrolled haemorrhage is a major preventable cause of death in patients with traumatic injury. Trauma-induced coagulopathy (TIC) describes abnormal coagulation processes that are attributable to trauma. In the early hours of TIC development, hypocoagulability is typically present, resulting in bleeding, whereas later TIC is characterized by a hypercoagulable state associated with venous thromboembolism and multiple organ failure. Several pathophysiological mechanisms underlie TIC; tissue injury and shock synergistically provoke endothelial, immune system, platelet and clotting activation, which are accentuated by the 'lethal triad' (coagulopathy, hypothermia and acidosis). Traumatic brain injury also has a distinct role in TIC. Haemostatic abnormalities include fibrinogen depletion, inadequate thrombin generation, impaired platelet function and dysregulated fibrinolysis. Laboratory diagnosis is based on coagulation abnormalities detected by conventional or viscoelastic haemostatic assays; however, it does not always match the clinical condition. Management priorities are stopping blood loss and reversing shock by restoring circulating blood volume, to prevent or reduce the risk of worsening TIC. Various blood products can be used in resuscitation; however, there is no international agreement on the optimal composition of transfusion components. Tranexamic acid is used in pre-hospital settings selectively in the USA and more widely in Europe and other locations. Survivors of TIC experience high rates of morbidity, which affects short-term and long-term quality of life and functional outcome.

The European Perspective on the Management of Acute Major Hemorrhage and Coagulopathy after Trauma: Summary of the 2019 Updated European Guideline

Non-controlled hemorrhage with accompanying trauma-induced coagulopathy (TIC) remains the most common cause of preventable death after multiple injury. Rapid identification followed by aggressive treatment is the key for improved outcomes. Treatment of trauma hemorrhage begins at the scene, with manual compression, the use of tourniquets and (non) commercial pelvic slings, and rapid transfer to an adequate trauma center. Upon hospital admission, coagulation monitoring and support are to be initiated immediately. Bleeding is controlled surgically following damage control principles. Modern coagulation management includes goal-oriented, individualized therapies, guided by point-of-care viscoelastic assays. Idarucizumab can be used as an antidote to the thrombin inhibitor dabigatran, andexanet alpha as an antidote to factor Xa inhibitors. This review summarizes the key recommendations of the 2019 updated European guideline on the management of major bleeding and coagulopathy following trauma. These evidence-based recommendations may form the backbone of algorithms adapted to local logistics and infrastructure.