Outcomes of tranexamic acid administration in military trauma patients with intracranial hemorrhage: a cohort study

Delayed tranexamic acid after traumatic brain injury impedes learning and memory: Early tranexamic acid is favorable but not in sham animals

BACKGROUND

Early but not late tranexamic acid (TXA) after TBI preserves blood-brain-barrier integrity, but it is unclear if and how dose timing affects cognitive recovery beyond hours postinjury. We hypothesized that early (1 hour post-TBI) but not late (24 hours post-TBI) TXA administration improves cognitive recovery for 14 days.

METHODS

CD1 male mice (n = 25) were randomized to severe TBI (injury [I], by controlled cortical impact) or sham craniotomy (S) followed by intravenous saline at 1 hour (placebo [P1]) or 30 mg/kg TXA at 1 hour (TXA1) or 24 hours (TXA24). Daily body weights, Garcia Neurological Test scores, brain/lung water content, and Morris water maze exercises quantifying swimming traffic in the platform quadrant (zone [Z] 1) and platform area (Z5) were recorded for up to 14 days.

RESULTS

Among injured groups, I-TXA1 demonstrated fastest weight gain for 14 days and only I-TXA1 showed rapid (day 1) normalization of Garcia Neurological Test ( p = 0.01 vs. I-P1, I-TXA24). In cumulative spatial trials, compared with I-TXA1, I-TXA24 hindered learning (distance to Z5 and % time in Z1, p < 0.05). Compared with I-TXA1, I-TXA24 showed poorer memory with less Z5 time (0.51 vs. 0.16 seconds, p < 0.01) and Z5 crossing frequency. Unexpectedly, TXA in uninjured animals (S-TXA1) displayed faster weight gain but inferior learning and memory.

CONCLUSION

Early TXA appears beneficial for cognitive and behavioral outcomes following TBI, although administration 24 hours postinjury consistently impairs cognitive recovery. Tranexamic acid in sham animals may lead to adverse effects on cognition.

Does tranexamic acid increase venous thromboembolism risk among trauma patients? A prospective multicenter analysis across 17 level I trauma centers

IMPORTANCE

The early use of tranexamic acid (TXA) has demonstrated benefit among some trauma patients in hemorrhagic shock. The association between TXA administration and thromboembolic events (including deep vein thrombosis (DVT), pulmonary embolism (PE) and pulmonary thrombosis (PT)) remains unclear. We aimed to characterize the risk of venous thromboembolism (VTE) subtypes among trauma patients receiving TXA and to determine whether TXA is associated with VTE risk and mortality.

METHODS

We analyzed a prospective, observational, multicenter cohort data from the Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study group. The study was conducted across 17 US level I trauma centers between January 1, 2018, and December 31,2020. We studied trauma patients ages 18-40 years, admitted for at least 48 h with a minimum of 1 VTE risk factor and followed until hospital discharge or 30 days. We compared TXA recipients to non-recipients for VTE and mortality using inverse probability weighted Cox models. The primary outcome was the presence of documented venous thromboembolism (VTE). The secondary outcome was mortality. VTE was defined as DVT, PE, or PT.

RESULTS

Among the 7,331 trauma patients analyzed, 466 (6.4%) received TXA. Patients in the TXA group were more severely injured than patients in the non-TXA group (ISS 16+: 69.1% vs. 48.5%, p < 0.001) and a higher percentage underwent a major surgical procedure (85.8% vs. 73.6%, p < 0.001). Among TXA recipients, 12.5% developed VTE (1.3% PT, 2.4% PE, 8.8% DVT) with 5.6% mortality. In the non-TXA group, 4.6% developed VTE (1.1% PT, 0.5% PE, 3.0% DVT) with 1.7% mortality. In analyses adjusting for patient demographic and clinical characteristics, TXA administration was not significantly associated with VTE (aHR 1.00, 95%CI: 0.69-1.46, p = 0.99) but was significantly associated with increased mortality (aHR 2.01, 95%CI: 1.46-2.77, p < 0.001).

CONCLUSION

TXA was not clearly identified as an independent risk factor for VTE in adjusted analyses, but the risk of VTE among trauma patients receiving TXA remains high (12.5%). This supports the judicious use of TXA in resuscitation, with consideration of early initiation of DVT prophylaxis in this high-risk group.

Postinjury Treatment to Mitigate the Effects of Aeromedical Evacuation After TBI in a Porcine Model

INTRODUCTION

Early aeromedical evacuation after traumatic brain injury (TBI) has been associated with worse neurologic outcomes in murine studies and military populations. The goal of this study was to determine if commonly utilized medications, including allopurinol, propranolol, or tranexamic acid (TXA), could mitigate the secondary traumatic brain injury experienced during the hypobaric and hypoxic environment of aeromedical evacuation.

METHODS

Porcine TBI was induced via controlled cortical injury. Twenty nonsurvival pigs were separated into four groups (n = 5 each): TBI+25 mL normal saline (NS), TBI+4 mg propranolol, TBI+100 mg allopurinol, and TBI+1g TXA. The pigs then underwent simulated AE to an altitude of 8000 ft for 4 h with an SpO₂ of 82-85% and were sacrificed 4 h later. Hemodynamics, serum cytokines, and hippocampal p-tau accumulation were assessed. An additional survival cohort was partially completed with TBI/NS (n = 5), TBI/propranolol (n = 2) and TBI/allopurinol groups (n = 2) survived to postinjury day 7.

RESULTS

There were no significant differences in hemodynamics, tissue oxygenation, cerebral blood flow, or physiologic markers between treatment groups and saline controls. Transient differences in IL-1b and IL-6 were noted but did not persist. Neurological Severity Score (NSS) was significantly lower in the TBI + allopurinol group on POD one compared to NS and propranolol groups. P-tau accumulation was decreased in the nonsurvival animals treated with allopurinol and TXA compared to the TBI/NS group.

CONCLUSIONS

Allopurinol, propranolol, and TXA, following TBI, do not induce adverse changes in systemic or cerebral hemodynamics during or after a simulated postinjury flight. While transient changes were noted in systemic cytokines and p-tau accumulation, further investigation will be needed to determine any persistent neurological effects of injury, flight, and pharmacologic treatment.

Association of Tranexamic Acid Administration With Mortality and Thromboembolic Events in Patients With Traumatic Injury: A Systematic Review and Meta-analysis

IMPORTANCE

Tranexamic acid is widely available and used off-label in patients with bleeding traumatic injury, although the literature does not consistently agree on its efficacy and safety.

OBJECTIVE

To examine the association of tranexamic acid administration with mortality and thromboembolic events compared with no treatment or with placebo in patients with traumatic injury in the literature.

DATA SOURCES

On March 23, 2021, PubMed, Embase, and the Cochrane Library were searched for eligible studies published between 1986 and 2021.

STUDY SELECTION

Randomized clinical trials and observational studies investigating tranexamic acid administration compared with no treatment or placebo among patients with traumatic injury and traumatic brain injury who were 15 years or older were included. Included studies were published in English or German. The electronic search yielded 1546 records, of which 71 were considered for full-text screening. The selection process was performed independently by 2 reviewers.

DATA EXTRACTION AND SYNTHESIS

The study followed the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were extracted by 2 independent reviewers and pooled using the inverse-variance random-effects model.

MAIN OUTCOMES AND MEASURES

Outcomes were formulated before data collection and included mortality at 24 hours and 28 and 30 days (1 month) as well as the incidence of thromboembolic events and the amount of blood products administered. Owing to missing data, overall mortality was added and the amount of blood products administered was discarded.

RESULTS

Thirty-one studies with a total of 43 473 patients were included in the systematic review. The meta-analysis demonstrated that administration of tranexamic acid was associated with a significant decrease in 1-month mortality compared with the control cohort (risk ratio, 0.83 [95% CI, 0.71-0.97]; I2 = 35%). The results of meta-analyses for 24-hour and overall mortality and thromboembolic events were heterogeneous and could not be pooled. Further investigations on clinical heterogeneity showed that populations with trauma and trial conditions differed markedly.

CONCLUSIONS AND RELEVANCE

These findings suggest that tranexamic acid may be beneficial in various patient populations with trauma. However, reasonable concerns about potential thromboembolic events with tranexamic acid remain.

Epidemiology, patterns of care and outcomes of traumatic brain injury in deployed military settings: implications for future military operations

BACKGROUND

Traumatic brain injury (TBI) is prevalent and highly morbid among Service Members. A better understanding of TBI epidemiology, outcomes, and care patterns in deployed settings could inform potential approaches to improve TBI diagnosis and management.

METHODS

A retrospective cohort analysis of Service Members who sustained a TBI in deployed settings between 2001 and 2018 was conducted. Among individuals hospitalized with TBI, we compared the demographic characteristics, mechanism of injury, injury type, and severity between combat and non-combat injuries. We compared diagnostic tests and procedures, evacuation patterns, return to duty rates and days in care between individuals with concussion and those with severe TBI.

RESULTS

There were 46,309 Service Members with TBI and 9,412 who were hospitalized; of those hospitalized, 55% (4,343) had isolated concussion and 9% (796) had severe TBI, of whom 17% (132/796) had polytrauma. Overall mortality was 2% and ranged from 0.1% for isolated concussion to 18% for severe TBI. The vast majority of TBI were evacuated by rotary wing to Role 3 or higher, including those with isolated concussion. As compared to severe TBI, individuals with isolated concussion had fewer diagnostic or surgical procedures performed. Only 6% of Service Members with severe TBI were able to return to duty as compared to 54% of those with isolated concussion. TBI resulted in 123,677 lost duty days; individuals with isolated concussion spent a median of 2 days in care and those with severe TBI spent a median of 17 days in care and a median of 6 days in the intensive care unit.

CONCLUSIONS

While most TBI in the deployed setting is mild, TBI is frequently associated with hospitalization and polytrauma. Over-triage of mild TBI is common. Improved TBI capabilities applicable to forward settings will be critical to the success of future multi-domain operations with limitations in air superiority.

LEVEL OF EVIDENCE

Prognostic, Level III.

Efficacy and safety of tranexamic acid in aneurysmal subarachnoid hemorrhage: A meta-analysis of randomized controlled trials

INTRODUCTION

Tranexamic acid, as a traditional hemostatic agent, is commonly used to treat or prevent excessive blood loss. However, the role of tranexamic acid in promoting good clinical outcomes and reducing mortality and risk of adverse events during the treatment of aneurysmal subarachnoid hemorrhage remains unclear.

METHODS

In strict accordance with the inclusion and exclusion criteria, Cochrane Library, Embase, Web of Science, and PubMed databases were assessed for randomized controlled trials (published between 1980 and 2021). Data were analyzed using STATA 16.0 and RevMan 5.3. In addition, the fixed-effects model (M-H method) and effect size (risk difference; RD) were used as a pooled measure to combine data. We also performed a post hoc sensitivity analysis and subgroup analysis to evaluate each outcome with low heterogeneity.

RESULTS

A meta-analysis revealed that although tranexamic acid was related to less rebleeding (RD = -0.06; 95% CI [-0.09, -0.03]; P = 0.0006), there is evidence that it has no an effect on good clinical outcomes or mortality (RD = -0.01; 95% CI [-0.05, 0.02]; P = 0.51; RD = 0.00; 95% CI [-0.03, 0.04]; P = 0.91). Tranexamic acid was associated with increased hydrocephalus (RD = 0.04; 95% CI [0.01, 0.08]; P = 0.02) and seizure (RD = 0.04; 95% CI [0.00, 0.08]; P = 0.05). The incidence of thromboembolic complications or delayed cerebral ischemia was not different in the two groups (RD = -0.01; 95% CI [-0.04, 0.03]; P = 0.62; RD = 0.00; 95% CI [-0.03, 0.03]; P = 0.96), and significant drug-related overall adverse events were identified (RD = 0.02; 95% CI [0.00, 0.04]; P = 0.03).

CONCLUSIONS

These findings indicate that the routine use of tranexamic acid is not suggested for patients with aneurysmal subarachnoid hemorrhage.

An Analysis of Intracranial Hemorrhage in Wartime Pediatric Casualties

BACKGROUND

Children make up a significant cohort of patients treated at combat support hospitals. Where traumatic head injury, including intracranial hemorrhage (ICH), is well studied in military adults, such research is lacking regarding pediatric patients. We seek to describe the incidence and outcomes of ICH within this population.

METHODS

This is a secondary analysis of a previously published dataset from the Department of Defense Trauma Registry for all pediatric casualties in Iraq and Afghanistan from January 2007 to January 2016. Within our dataset, we searched for casualties with an ICH.

RESULTS

Of the 3439 pediatric encounters in our dataset, we identified 495 (14%) casualties that had at least 1 type of ICH. Most were between 5 and 12 years of age, male (74%), and injured by an explosive (42%). Of the casualties with ICHs, 82 had epidural (16.6%), 237 had subdural (47.9%), 153 had subarachnoid (30.9%), 157 had parenchymal bleeds (31.7%), and 239 had ICHs not otherwise specified (48.3%). In the hospital setting, the epidural group was more frequently treated with skull decompression (41%) and craniotomy with skull elevation (28%). The subdural group was more frequently treated with a craniectomy (17%) and the parenchymal group had more frequent intracranial pressure monitoring (18%). In our dataset, 22 received ketamine prehospital (4.4%) and most were discharged alive from the hospital (79%).

CONCLUSIONS

Within our dataset, we identified 495 cases of ICH in pediatric patients. Most survived to hospital discharge despite less than half undergoing a decompression procedure.

Civilian Firearm-Inflicted Brain Injury: Coagulopathy, Vascular Injuries, and Triage

PURPOSE OF REVIEW

Civilian firearm-inflicted penetrating brain injury (PBI) carries high morbidity and mortality. Concurrently, the evidence base guiding management decisions remains limited. Faced with large volume of PBI patients, we have made observations in relation to coagulopathy and cerebrovascular injuries. We here review this literature in addition to the question about early prognostication as it may inform neurosurgical decision-making.

RECENT FINDINGS

The triad of coagulopathy, low motor score, and radiographic compression of basal cisterns comprises a phenotype of injury with exceedingly high mortality. PBI leads to high rates of cerebral arterial and venous injuries, and projectile trajectory is emerging as an independent predictor of outcome. The combination of coagulopathy with cerebrovascular injury creates a specific endophenotype. The nature and role of coagulopathy remain to be deciphered, and consideration to the use of tranexamic acid should be given. Prospective controlled trials are needed to create clinical evidence free of patient selection bias.

Fibrinolysis in Traumatic Brain Injury: Diagnosis, Management, and Clinical Considerations

Posttraumatic coagulopathy involves disruption of both the coagulation and fibrinolytic pathways secondary to tissue damage, hypotension, and inflammatory upregulation. This phenomenon contributes to delayed complications after traumatic brain injury (TBI), including intracranial hemorrhage progression and systemic disseminated intravascular coagulopathy. Development of an early hyperfibrinolytic state may result in uncontrolled bleeding and is associated with increased mortality in patients with TBI. Although fibrinolytic assays are not routinely performed in the assessment of posttraumatic coagulopathy, circulating biomarkers such as D-dimer and fibrin degradation products have demonstrated potential utility in outcome prediction. Unfortunately, the relatively delayed nature of these tests limits their clinical utility. In contrast, viscoelastic tests are able to provide a rapid global assessment of coagulopathy, although their ability to reliably identify disruptions in the fibrinolytic cascade remains unclear. Limited evidence supports the use of hypertonic saline, cryoprecipitate, and plasma to correct fibrinolytic disruption; however, some studies suggest more harm than benefit. Recently, early use of tranexamic acid in patients with TBI and confirmed hyperfibrinolysis has been proposed as a strategy to further improve clinical outcomes. Moving forward, further delineation of TBI phenotypes and the clinical implications of fibrinolysis based on phenotypic variation is needed. In this review, we summarize the clinical aspects of fibrinolysis in TBI, including diagnosis, treatment, and clinical correlates, with identification of targeted areas for future research efforts.

Post-traumatic pulmonary embolism: incidence, physiopathology, risk factors of early occurrence, and impact outcome. A narrative review

BACKGROUND

Venous thromboembolism (VTE) is a well-established complication of trauma. So far, the factors that are related to early post-traumatic pulmonary embolism (PE) occurrence have been given little attention.

AIMS

We have conducted this literature review in order to analyze the incidence and the physiopathology of post-traumatic PE among intensive care unit (ICU) trauma patients, analyze the incidence of early post-traumatic PE, and elucidate risk factors associated with post-traumatic PE. Moreover, we aim to study the impact/outcome of post-traumatic PE in the ICU.

METHODS

We used the PubMed and EMBASE databases and entered the following key words in MeSH research: Deep vein thrombosis (DVT), Post-traumatic Pulmonary embolism, Early pulmonary-embolism, risk factors, and Prognosis.

RESULTS

The incidence of PE among trauma patients varies considerably, ranging from 0.35% to 24%. The incidence of early post-traumatic PE varies widely from 10 to 42%. After a traumatic injury, many factors have been found to be responsible for the formation of DVT and PE. In addition to the risk factors of hypercoagulability described by Virchow in his original triad, inflammation acting via endothelial damage may be considered as a fourth factor. The literature review showed that lower limb fractures and age are the most frequent factors associated with PE (particularly in early PE). The heterogeneity among studies limits reliable conclusions regarding the true risk factors for the timing of the occurrence of post-traumatic PE. Fatality from pulmonary embolism (PE) is close to 50% in some series. Moreover, high mortality rates, a high rate of nosocomial infections, and a prolonged stay in an ICU and/or in a hospital were found to be associated with the development of PE.

CONCLUSION

Post-traumatic PE is frequent in ICUs. Inflammation acting via endothelial damage may be considered as a fourth factor in addition to the Virchow's triad of risk factors for venous thrombosis. Fractures of the lower extremities, obesity, and age happen to be the most frequent factors associated with PE (in particular early PE). PE development was associated with high rates of mortality, nosocomial infections, and a prolonged stay in an ICU and/or in a hospital. Therefore, prevention is warranted.