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Missingness matters: a secondary analysis of thromboelastography measurements from a recent prehospital randomized tranexamic acid clinical trial
Donohue, J. K., Iyanna, N., Lorence, J. M., Brown, J. B., Guyette, F. X., Eastridge, B. J., Nirula, R., Vercruysse, G. A., O'Keeffe, T., Joseph, B., et al
Trauma surgery & acute care open. 2024;9(1):e001346
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Abstract
BACKGROUND Tranexamic acid (TXA) has been hypothesized to mitigate coagulopathy in patients after traumatic injury. Despite previous prehospital clinical trials demonstrating a TXA survival benefit, none have demonstrated correlated changes in thromboelastography (TEG) parameters. We sought to analyze if missing TEG data contributed to this paucity of findings. METHODS We performed a secondary analysis of the Study of Tranexamic Acid During Air Medical and Ground Prehospital Transport Trial. We compared patients that received TEG (YES-TEG) and patients unable to be sampled (NO-TEG) to analyze subgroups in which to investigate TEG differences. TEG parameter differences across TXA intervention arms were assessed within subgroups disproportionately present in the NO-TEG relative to the YES-TEG cohort. Generalized linear models controlling for potential confounders were applied to findings with p<0.10 on univariate analysis. RESULTS NO-TEG patients had lower prehospital systolic blood pressure (SBP) (100 (78, 140) vs 125 (88, 147), p<0.01), lower prehospital Glascow Coma Score (14 (3, 15) vs 15 (12, 15), p<0.01), greater rates of prehospital intubation (39.4% vs 24.4%, p<0.01) and greater mortality at 30 days (36.4% vs 6.8%, p<0.01). NO-TEG patients had a greater international normalized ratio relative to the YES-TEG subgroup (1.2 (1.1, 1.5) vs 1.1 (1.0, 1.2), p=0.04). Within a severe prehospital shock cohort (SBP<70), TXA was associated with a significant decrease in clot lysis at 30 min on multivariate analysis (β=-27.6, 95% CI (-51.3 to -3.9), p=0.02). CONCLUSIONS Missing data, due to the logistical challenges of sampling certain severely injured patients, may be associated with a lack of TEG parameter changes on TXA administration in the primary analysis. Previous demonstration of TXA's survival benefit in patients with severe prehospital shock in tandem with the current findings supports the notion that TXA acts at least partially by improving clot integrity. LEVEL OF EVIDENCE Level II.
PICO Summary
Population
Patients at risk for haemorrhage receiving tranexamic acid before hospitalization, enrolled in the Study of Tranexamic Acid During Air Medical and Ground Prehospital Transport (STAAMP) Trial (n= 903).
Intervention
Prehospital tranexamic acid (TXA) (n= 447).
Comparison
Placebo (n= 456).
Outcome
This study was a secondary analysis of the STAAMP trial, comparing patients that received thromboelastography (TEG) (YES-TEG, n= 837) and patients unable to be sampled (NO-TEG, n= 66) to analyze subgroups in which to investigate TEG differences. NO-TEG patients had lower prehospital systolic blood pressure (SBP) (100 (78, 140) vs. 125 (88, 147)), lower prehospital Glascow Coma Score (14 (3, 15) vs. 15 (12, 15)), greater rates of prehospital intubation (39.4% vs. 24.4%) and greater mortality at 30 days (36.4% vs. 6.8%). NO-TEG patients had a greater international normalized ratio relative to the YES-TEG subgroup (1.2 (1.1, 1.5) vs. 1.1 (1.0, 1.2)). Within a severe prehospital shock cohort (SBP< 70), TXA was associated with a significant decrease in clot lysis at 30 min on multivariate analysis (β= -27.6; 95% CI [-51.3, -3.9].
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Prehospital Tranexamic Acid for Severe Trauma
Gruen, R. L., Mitra, B., Bernard, S. A., McArthur, C. J., Burns, B., Gantner, D. C., Maegele, M., Cameron, P. A., Dicker, B., Forbes, A. B., et al
The New England journal of medicine. 2023
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Editor's Choice
Abstract
BACKGROUND Whether prehospital administration of tranexamic acid increases the likelihood of survival with a favorable functional outcome among patients with major trauma and suspected trauma-induced coagulopathy who are being treated in advanced trauma systems is uncertain. METHODS We randomly assigned adults with major trauma who were at risk for trauma-induced coagulopathy to receive tranexamic acid (administered intravenously as a bolus dose of 1 g before hospital admission, followed by a 1-g infusion over a period of 8 hours after arrival at the hospital) or matched placebo. The primary outcome was survival with a favorable functional outcome at 6 months after injury, as assessed with the use of the Glasgow Outcome Scale-Extended (GOS-E). Levels on the GOS-E range from 1 (death) to 8 ("upper good recovery" [no injury-related problems]). We defined survival with a favorable functional outcome as a GOS-E level of 5 ("lower moderate disability") or higher. Secondary outcomes included death from any cause within 28 days and within 6 months after injury. RESULTS A total of 1310 patients were recruited by 15 emergency medical services in Australia, New Zealand, and Germany. Of these patients, 661 were assigned to receive tranexamic acid, and 646 were assigned to receive placebo; the trial-group assignment was unknown for 3 patients. Survival with a favorable functional outcome at 6 months occurred in 307 of 572 patients (53.7%) in the tranexamic acid group and in 299 of 559 (53.5%) in the placebo group (risk ratio, 1.00; 95% confidence interval [CI], 0.90 to 1.12; P = 0.95). At 28 days after injury, 113 of 653 patients (17.3%) in the tranexamic acid group and 139 of 637 (21.8%) in the placebo group had died (risk ratio, 0.79; 95% CI, 0.63 to 0.99). By 6 months, 123 of 648 patients (19.0%) in the tranexamic acid group and 144 of 629 (22.9%) in the placebo group had died (risk ratio, 0.83; 95% CI, 0.67 to 1.03). The number of serious adverse events, including vascular occlusive events, did not differ meaningfully between the groups. CONCLUSIONS Among adults with major trauma and suspected trauma-induced coagulopathy who were being treated in advanced trauma systems, prehospital administration of tranexamic acid followed by an infusion over 8 hours did not result in a greater number of patients surviving with a favorable functional outcome at 6 months than placebo. (Funded by the Australian National Health and Medical Research Council and others; PATCH-Trauma ClinicalTrials.gov number, NCT02187120.).
PICO Summary
Population
Adult patients with severe trauma and at risk for trauma induced coagulopathy, enrolled in the PATCH-Trauma trial in 15 emergency medical services in Australia, New Zealand, and Germany (n= 1,310).
Intervention
Tranexamic acid (n= 661).
Comparison
Placebo (n= 646).
Outcome
Survival with a favorable functional outcome at 6 months occurred in 307 of 572 patients (53.7%) in the tranexamic acid group and in 299 of 559 (53.5%) in the placebo group (risk ratio, 1.00; 95% confidence interval (CI), [0.90, 1.12]. At 28 days after injury, 113 of 653 patients (17.3%) in the tranexamic acid group and 139 of 637 (21.8%) in the placebo group had died (risk ratio, 0.79; 95% CI [0.63, 0.99]. By 6 months, 123 of 648 patients (19.0%) in the tranexamic acid group and 144 of 629 (22.9%) in the placebo group had died (risk ratio, 0.83; 95% CI [0.67, 1.03]. The number of serious adverse events, including vascular occlusive events, did not differ meaningfully between the groups.
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Prehospital tranexamic acid is associated with a dose-dependent decrease in syndecan-1 after trauma: A secondary analysis of a prospective randomized trial
Gruen DS, Brown JB, Guyette FX, Johansson PI, Stensballe J, Li SR, Leeper CM, Eastridge BJ, Nirula R, Vercruysse GA, et al
The journal of trauma and acute care surgery. 2023
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Abstract
BACKGROUND In the Study of Tranexamic Acid During Air and Ground Prehospital Transport (STAAMP) Trial, prehospital tranexamic acid (TXA) was associated with lower mortality in specific patient subgroups. The underlying mechanisms responsible for a TXA benefit remain incompletely characterized. We hypothesized that TXA may mitigate endothelial injury and sought to assess whether TXA was associated with decreased endothelial or tissue damage markers among all patients enrolled in the STAAMP Trial. METHODS We collected blood samples from STAAMP Trial patients and measured markers of endothelial function and tissue damage including syndecan-1, soluble thrombomodulin (sTM), and platelet endothelial cell adhesion molecule-1 (PECAM-1) at hospital admission (0 hours) and 12, 24, and 72 hours after admission. We compared these marker values for patients in each treatment group during the first 72 hours, and modeled the relationship between TXA and marker concentration using regression analysis to control for potential confounding factors. RESULTS We analyzed samples from 766 patients: 383 placebo, 130 abbreviated dosing, 119 standard dosing, and 130 repeat dosing. Lower levels of syndecan-1, TM, and PECAM measured within the first 72 hours of hospital admission were associated with survival at 30 days (P < 0.001). At hospital admission, syndecan-1 was lower in the TXA group (28.30 [20.05, 42.75] vs. 33.50 [23.00, 54.00] P = 0.001) even after controlling for patient, injury, and prehospital factors (P = 0.001). For every 1 g increase in TXA administered over the first 8 hours of prehospital transport and hospital admission, there was a 4 ng/mL decrease in syndecan-1 at 12 hours controlling for patient, injury, and treatment factors (P = 0.03). CONCLUSIONS Prehospital TXA was associated with decreased syndecan-1 at hospital admission. Syndecan-1 measured 12 hours after admission was inversely related to the dose of TXA received. Early pre- and in-hospital TXA may decrease endothelial glycocalyx damage or upregulate vascular repair mechanisms in a dose-dependent fashion. LEVEL OF EVIDENCE Level II, Secondary analysis of a prospective randomized trial.
PICO Summary
Population
Injured patients who received prehospital tranexamic acid (TXA) and were at risk for haemorrhage enrolled in the STAAMP randomised controlled trial (n= 766).
Intervention
Abbreviated dose: 1g of TXA (n= 130). Standard dose: 2g of TXA (n= 119). Repeat dose: 3g of TXA (n= 130).
Comparison
Placebo (saline), (n= 383).
Outcome
Blood samples were collected to measure markers of endothelial function and tissue damage including syndecan-1, soluble thrombomodulin (sTM), and platelet endothelial cell adhesion molecule-1 (PECAM-1) at hospital admission and 12, 24, and 72 hours after admission. Lower levels of syndecan-1, TM, and PECAM measured within the first 72 hours of hospital admission were associated with survival at 30 days. At hospital admission (mean ng/mL [IQR]), syndecan-1 was lower in the TXA group than the placebo group (28.30 [20.05, 42.75] vs. 33.50 [23.00, 54.00]) even after controlling for patient, injury, and prehospital factors. For every 1g increase in TXA administered over the first 8 hours of prehospital transport and hospital admission, there was a 4 ng/mL decrease in syndecan-1 at 12 hours controlling for patient, injury, and treatment factors.
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Tranexamic Acid for Traumatic Injury in the Emergency Setting: A Systematic Review and Bias-Adjusted Meta-Analysis of Randomized Controlled Trials
Fouche, P. F., Stein, C., Nichols, M., Meadley, B., Bendall, J. C., Smith, K., Anderson, D., Doi, S. A.
Annals of emergency medicine. 2023
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Abstract
STUDY OBJECTIVE Traumatic injury causes a significant number of deaths due to bleeding. Tranexamic acid (TXA), an antifibrinolytic agent, can reduce bleeding in traumatic injuries and potentially enhance outcomes. Previous reviews suggested potential TXA benefits but did not consider the latest trials. METHODS A systematic review and bias-adjusted meta-analysis were performed to assess TXA's effectiveness in emergency traumatic injury settings by pooling estimates from randomized controlled trials. Researchers searched Medline, Embase, and Cochrane Central for randomized controlled trials comparing TXA's effects to a placebo in emergency trauma cases. The primary endpoint was 1-month mortality. The methodological quality of the trials underwent assessment using the MASTER scale, and the meta-analysis applied the quality-effects method to adjust for methodological quality. RESULTS Seven randomized controlled trials met the set criteria. This meta-analysis indicated an 11% decrease in the death risk at 1 month after TXA use (odds ratio [OR] 0.89, 95% confidence interval [CI] 0.84 to 0.95) with a number needed to treat of 61 to avoid 1 additional death. The meta-analysis also revealed reduced 24-hour mortality (OR 0.76, 95% CI 0.65 to 0.88) for TXA. No compelling evidence of increased vascular occlusive events emerged (OR 0.96, 95% CI 0.73 to 1.27). Subgroup analyses highlighted TXA's effectiveness in general trauma versus traumatic brain injury and survival advantages when administered out-of-hospital versus inhospital. CONCLUSIONS This synthesis demonstrates that TXA use for trauma in emergencies leads to a reduction in 1-month mortality, with no significant evidence of problematic vascular occlusive events. Administering TXA in the out-of-hospital setting is associated with reduced mortality compared to inhospital administration, and less mortality with TXA in systemic trauma is noted compared with traumatic brain injury specifically.
PICO Summary
Population
Patients with traumatic injuries in emergency settings (7 randomised controlled trials).
Intervention
Tranexamic acid (TXA).
Comparison
Placebo.
Outcome
The primary endpoint was 1-month mortality. The meta-analysis indicated an 11% decrease in the death risk at 1 month after TXA use (odds ratio [OR] 0.89; 95% confidence interval (CI) [0.84, 0.95]) with a number needed to treat of 61 to avoid 1 additional death. The meta-analysis also revealed reduced 24-hour mortality (OR 0.76; 95% CI [0.65, 0.88]) for TXA. No compelling evidence of increased vascular occlusive events emerged (OR 0.96; 95% CI [0.73, 1.27]). Subgroup analyses highlighted TXA's effectiveness in general trauma versus traumatic brain injury and survival advantages when administered out-of-hospital versus in-hospital.
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Factors that influence the administration of tranexamic acid (TXA) to trauma patients in prehospital settings: a systematic review
Nicholson, H., Scotney, N., Briscoe, S., Kirby, K., Bedson, A., Goodwin, L., Robinson, M., Taylor, H., Thompson Coon, J., Voss, S., et al
BMJ open. 2023;13(5):e073075
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Abstract
OBJECTIVE In the UK there are around 5400 deaths annually from injury. Tranexamic acid (TXA) prevents bleeding and has been shown to reduce trauma mortality. However, only 5% of UK major trauma patients who are at risk of haemorrhage receive prehospital TXA. This review aims to examine the evidence regarding factors influencing the prehospital administration of TXA to trauma patients. DESIGN Systematic literature review. DATA SOURCES AMED, CENTRAL, CINAHL, Cochrane Database of Systematic Reviews, Conference Proceedings Citation Index-Science, Embase and MEDLINE were searched from January 2010 to 2020; searches were updated in June 2022. CLINICALTRIALS gov and OpenGrey were also searched and forward and backwards citation chasing performed. ELIGIBILITY CRITERIA All primary research reporting factors influencing TXA administration to trauma patients in the prehospital setting was included. DATA EXTRACTION AND SYNTHESIS Two independent reviewers performed the selection process, quality assessment and data extraction. Data were tabulated, grouped by setting and influencing factor and synthesised narratively. RESULTS Twenty papers (278 249 participants in total) were included in the final synthesis; 13 papers from civilian and 7 from military settings. Thirteen studies were rated as 'moderate' using the Effective Public Health Practice Project Quality Assessment Tool. Several common factors were identified: knowledge and skills; consequences and social influences; injury type (severity, injury site and mechanism); protocols; resources; priorities; patient age; patient sex. CONCLUSIONS This review highlights an absence of high-quality research. Preliminary evidence suggests a host of system and individual-level factors that may be important in determining whether TXA is administered to trauma patients in the prehospital setting. FUNDING AND REGISTRATION This review was supported by Research Capability Funding from the South Western Ambulance Service NHS Foundation Trust and the National Institute for Health Research Applied Research Collaboration South West Peninsula. PROSPERO REGISTRATION NUMBER CRD42020162943.
PICO Summary
Population
Any trauma patients in prehospital settings (20 studies, n= 278,249).
Intervention
Exposure: Factors influencing the decision to administer tranexamic acid (TXA).
Comparison
Outcome
This systematic review included 13 studies from civilian settings and 7 studies from military settings. This review highlighted a lack of high-quality research addressing the factors that influence prehospital TXA administration, particularly in children or patients with isolated head injuries. Common factors identified suggested a host of system and individual-level factors including: knowledge and skills, consequences and social influences, injury type (including severity, injury site and mechanism of injury), protocols, resources, priorities, patient age, and patient sex.
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Effects of tranexamic acid treatment in severely and non-severely injured trauma patients
Ageron FX, Shakur-Still H, Roberts I
Transfusion. 2022
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Abstract
BACKGROUND Urgent treatment with tranexamic acid (TXA) reduces bleeding deaths but there is disagreement about which patients should be treated. We examine the effects of TXA treatment in severely and non-severely injured trauma patients. STUDY DESIGN AND METHODS We did an individual patient data meta-analysis of randomized trials with over 1000 trauma patients that assessed the effects of TXA on survival. We defined the severity of injury according to characteristics at first assessment: systolic blood pressure of less than 90 mm Hg and a heart rate greater than 120 beats per minute or Glasgow Coma Scale score of less than nine or any GCS with one or more fixed dilated pupils. The primary measure was survival on the day of the injury. We examined the effect of TXA on survival in severely and non-severely injured patients and how these effects vary with the time from injury to treatment. RESULTS We obtained data for 32,944 patients from two randomized trials. Tranexamic acid significantly increased survival on the day of the injury (OR = 1.22, 95% CI 1.11-1.34; p < .01). The effect of tranexamic acid on survival in non-severely injured patients (OR = 1.25, 1.03-1.50) was similar to that in severely injured patients (OR = 1.22, 1.09-1.37) with no significant heterogeneity (p = .87). In severely and non-severely injured pateints, treatment within the first hour after injury was the most effective. DISCUSSION Early tranexamic acid treatment improves survival in both severely and non-severely injured trauma patients. Its use should not be restricted to the severely injured.
PICO Summary
Population
Severely and non-severely injured trauma patients enrolled in the two large randomised controlled trials: CRASH-2 and CRASH-3 (n= 32,944).
Intervention
Tranexamic acid (n= 16,499).
Comparison
Placebo (n= 16,445).
Outcome
Tranexamic acid significantly increased survival on the day of the injury (odd ratio (OR)= 1.22). The effect of tranexamic acid on survival in non-severely injured patients (OR= 1.25) was similar to that in severely injured patients (OR= 1.22) with no significant heterogeneity. In severely and non-severely injured patients, treatment within the first hour after injury was the most effective.
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Traumatic injury clinical trial evaluating tranexamic acid in children (TIC-TOC): a pilot randomized trial
Nishijima DK, VanBuren JM, Linakis SW, Hewes HA, Myers SR, Bobinski M, Tran NK, Ghetti S, Adelson PD, Roberts I, et al
Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2022
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Abstract
BACKGROUND The antifibrinolytic drug tranexamic acid (TXA) improves survival in adults with traumatic hemorrhage; however, the drug has not been evaluated in a trial in injured children. We evaluated the feasibility of a large-scale trial evaluating the effects of TXA in children with severe hemorrhagic injuries. METHODS Severely injured children (0 up to 18(th) birthday) were randomized into a double-blind randomized trial of 1) TXA 15 mg/kg bolus dose, followed by 2 mg/kg/hr infusion over 8 hours, 2) TXA 30 mg/kg bolus dose, followed by 4 mg/kg/hr infusion over 8 hours, or 3) normal saline placebo bolus and infusion. The trial was conducted at 4 pediatric Level I trauma centers in the United States between June 2018 and March 2020. We enrolled patients under federal exception from informed consent (EFIC) procedures when parents were unable to provide informed consent. Feasibility outcomes included the rate of enrollment, adherence to intervention arms, and ability to measure the primary clinical outcome. Clinical outcomes included global functioning (primary), working memory, total amount of blood products transfused, intracranial hemorrhage progression, and adverse events. The target enrollment rate was at least 1.25 patients per site per month. RESULTS A total of 31 patients were randomized with a mean age of 10.7 years (standard deviation [SD] 5.0 years) and 22 (71%) patients were male. The mean time from injury to randomization was 2.4 hours (SD 0.6 hours). Sixteen (52%) patients had isolated brain injuries and 15 (48%) patients had isolated torso injuries. The enrollment rate using EFIC was 1.34 patients per site per month. All eligible enrolled patients received study intervention (9 patients TXA 15 mg/kg bolus dose, 10 patients TXA 30 mg/kg bolus dose, and 12 patients placebo) and had the primary outcome measured. No statistically significant differences in any of the clinical outcomes were identified. CONCLUSION Based on enrollment rate, protocol adherence, and measurement of the primary outcome in this pilot trial, we confirmed the feasibility of conducting a large-scale, randomized trial evaluating the efficacy of TXA in severely injured children with hemorrhagic brain and/or torso injuries using EFIC.
PICO Summary
Population
Severely injured children enrolled in the TIC-TOC trial across four centers in US (n= 31).
Intervention
15 mg/kg of tranexamic acid (TXA) dose, followed by 2 mg/kg/hr infusion (n= 9).
Comparison
30 mg/kg of TXA dose, followed by 4 mg/kg/hr infusion (n= 10). Saline placebo and infusion (n= 12).
Outcome
All patients had their primary outcome measured. Feasibility outcomes included the rate of enrollment, adherence to intervention arms, and ability to measure the primary clinical outcome. Clinical outcomes included global functioning (primary), working memory, total amount of blood products transfused, intracranial hemorrhage progression, and adverse events. The mean time from injury to randomization was 2.4 hours (SD 0.6 hours). Sixteen (52%) patients had isolated brain injuries and 15 (48%) patients had isolated torso injuries. No statistically significant differences in any of the clinical outcomes were identified.
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The Impact of Pre-Hospital TXA on Mortality among Bleeding Trauma Patients: A Systematic Review and Meta-Analysis
Almuwallad A, Cole E, Ross J, Perkins Z, Davenport R
The journal of trauma and acute care surgery. 2021
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Abstract
BACKGROUND Tranexamic acid (TXA) is an antifibrinolytic drug associated with improved survival among trauma patients with haemorrhage. TXA is considered a primary haemostatic intervention in pre-hospital for treatment of bleeding alongside blood product transfusion. METHODS A Systematic Review and Meta-Analysis was conducted to investigate the impact of pre-hospital TXA on mortality among trauma patients with bleeding. A systematic search was conducted using the National Institute for Health and Care Excellence (NICE) Healthcare Databases Advanced Search (HDAS) library which contain the following of databases: EMBASE, Medline, PubMed, BNI, EMCARE, and HMIC. Other databases searched included SCOPUS and the Cochrane Central Register for Clinical Trials Library (CENTRAL). Quality assessment tools were applied among included studies; Cochrane Risk of Bias (ROB) for Randomised Control Trials RCTs and Newcastle-Ottawa Scale (NOS) for cohort observational studies. RESULTS A total of 797 publications were identified from the initial database search. After removing duplicates and applying inclusion/exclusion criteria, Four studies were included in the review and meta-analysis which identified a significant survival benefit in patients who received pre-hospital TXA vs no TXA. Three observational cohort and one RCT were included into the review with a total of 2347 patients (TXA: 1169 vs No TXA: 1178). There was a significant reduction in 24 hours mortality; Odds ratios (OR) 0.60 (95% CI: 0.37-0.99). No Statistical significant differences in 28 to 30 days mortality OR 0.69 (95% CI: 0.47-1.02), or VTE OR 1.49 (95% CI: 0.90 - 2.46) were found. CONCLUSION This review demonstrates that pre-hospital TXA is associated with significant reductions in the early (24 hour) mortality of trauma patients with suspected or confirmed haemorrhage but no increase in the incidence of VTE. LEVEL OF EVIDENCE (I) Systematic review and meta-analysis.
PICO Summary
Population
Trauma patients with bleeding (4 studies, n= 2,347).
Intervention
Prehospital tranexamic acid (TXA, n= 1,169).
Comparison
No TXA (n= 1,178).
Outcome
There was a significant reduction in 24 hour mortality with pre-hospital TXA; (Odds ratios (OR) 0.60.) There were no statistically significant differences in 28 to 30 day mortality (OR 0.69), or VTE (OR 1.49).
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Effect of tranexamic acid on intracranial haemorrhage and infarction in patients with traumatic brain injury: a pre-planned substudy in a sample of CRASH-3 trial patients
Mahmood A, Needham K, Shakur-Still H, Harris T, Jamaluddin SF, Davies D, Belli A, Mohamed FL, Leech C, Lotfi HM, et al
Emergency medicine journal : EMJ. 2021;38(4):270-278
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Abstract
BACKGROUND Early tranexamic acid (TXA) treatment reduces head injury deaths after traumatic brain injury (TBI). We used brain scans that were acquired as part of the routine clinical practice during the CRASH-3 trial (before unblinding) to examine the mechanism of action of TXA in TBI. Specifically, we explored the potential effects of TXA on intracranial haemorrhage and infarction. METHODS This is a prospective substudy nested within the CRASH-3 trial, a randomised placebo-controlled trial of TXA (loading dose 1 g over 10 min, then 1 g infusion over 8 hours) in patients with isolated head injury. CRASH-3 trial patients were recruited between July 2012 and January 2019. Participants in the current substudy were a subset of trial patients enrolled at 10 hospitals in the UK and 4 in Malaysia, who had at least one CT head scan performed as part of the routine clinical practice within 28 days of randomisation. The primary outcome was the volume of intraparenchymal haemorrhage (ie, contusion) measured on a CT scan done after randomisation. Secondary outcomes were progressive intracranial haemorrhage (post-randomisation CT shows >25% of volume seen on pre-randomisation CT), new intracranial haemorrhage (any haemorrhage seen on post-randomisation CT but not on pre-randomisation CT), cerebral infarction (any infarction seen on any type of brain scan done post-randomisation, excluding infarction seen pre-randomisation) and intracranial haemorrhage volume (intraparenchymal + intraventricular + subdural + epidural) in those who underwent neurosurgical haemorrhage evacuation. We planned to conduct sensitivity analyses excluding patients who were severely injured at baseline. Dichotomous outcomes were analysed using relative risks (RR) or hazard ratios (HR), and continuous outcomes using a linear mixed model. RESULTS 1767 patients were included in this substudy. One-third of the patients had a baseline GCS (Glasgow Coma Score) of 3 (n=579) and 24% had unilateral or bilateral unreactive pupils. 46% of patients were scanned pre-randomisation and post-randomisation (n=812/1767), 19% were scanned only pre-randomisation (n=341/1767) and 35% were scanned only post-randomisation (n=614/1767). In all patients, there was no evidence that TXA prevents intraparenchymal haemorrhage expansion (estimate=1.09, 95% CI 0.81 to 1.45) or intracranial haemorrhage expansion in patients who underwent neurosurgical haemorrhage evacuation (n=363) (estimate=0.79, 95% CI 0.57 to 1.11). In patients scanned pre-randomisation and post-randomisation (n=812), there was no evidence that TXA reduces progressive haemorrhage (adjusted RR=0.91, 95% CI 0.74 to 1.13) and new haemorrhage (adjusted RR=0.85, 95% CI 0.72 to 1.01). When patients with unreactive pupils at baseline were excluded, there was evidence that TXA prevents new haemorrhage (adjusted RR=0.80, 95% CI 0.66 to 0.98). In patients scanned post-randomisation (n=1431), there was no evidence of an increase in infarction with TXA (adjusted HR=1.28, 95% CI 0.93 to 1.76). A larger proportion of patients without (vs with) a post-randomisation scan died from head injury (38% vs 19%: RR=1.97, 95% CI 1.66 to 2.34, p<0.0001). CONCLUSION TXA may prevent new haemorrhage in patients with reactive pupils at baseline. This is consistent with the results of the CRASH-3 trial which found that TXA reduced head injury death in patients with at least one reactive pupil at baseline. However, the large number of patients without post-randomisation scans and the possibility that the availability of scan data depends on whether a patient received TXA, challenges the validity of inferences made using routinely collected scan data. This study highlights the limitations of using routinely collected scan data to examine the effects of TBI treatments. TRIAL REGISTRATION NUMBER ISRCTN15088122.
PICO Summary
Population
Patients with traumatic brain injury from 10 hospitals in the UK and 4 in Malaysia, enrolled in the CRASH-3 trial (n= 1,767).
Intervention
Tranexamic acid (TXA).
Comparison
Placebo.
Outcome
One-third of the patients had a baseline Glasgow Coma Score of 3 (n= 579) and 24% had unilateral or bilateral unreactive pupils. 46% of patients were scanned pre-randomisation and post-randomisation (n= 812/1767), 19% were scanned only pre-randomisation (n= 341/1767) and 35% were scanned only post-randomisation (n= 614/1767). In all patients, there was no evidence that TXA prevents intraparenchymal haemorrhage expansion (estimate= 1.09) or intracranial haemorrhage expansion in patients who underwent neurosurgical haemorrhage evacuation (n= 363), (estimate= 0.79). In patients scanned pre-randomisation and post-randomisation (n= 812), there was no evidence that TXA reduces progressive haemorrhage and new haemorrhage. When patients with unreactive pupils at baseline were excluded, there was evidence that TXA prevents new haemorrhage. In patients scanned post-randomisation (n= 1431), there was no evidence of an increase in infarction with TXA. A larger proportion of patients without (vs. with) a post-randomisation scan died from head injury (38% vs 19%).
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Tranexamic acid to reduce head injury death in people with traumatic brain injury: the CRASH-3 international RCT
Roberts I, Shakur-Still H, Aeron-Thomas A, Beaumont D, Belli A, Brenner A, Cargill M, Chaudhri R, Douglas N, Frimley L, et al
Health technology assessment (Winchester, England). 2021;25(26):1-76
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Abstract
BACKGROUND Tranexamic acid safely reduces mortality in traumatic extracranial bleeding. Intracranial bleeding is common after traumatic brain injury and can cause brain herniation and death. We assessed the effects of tranexamic acid in traumatic brain injury patients. OBJECTIVE To assess the effects of tranexamic acid on death, disability and vascular occlusive events in traumatic brain injury patients. We also assessed cost-effectiveness. DESIGN Randomised trial and economic evaluation. Patients were assigned by selecting a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients, caregivers and those assessing outcomes were masked to allocation. All analyses were by intention to treat. We assessed the cost-effectiveness of tranexamic acid versus no treatment from a UK NHS perspective using the trial results and a Markov model. SETTING 175 hospitals in 29 countries. PARTICIPANTS Adults with traumatic brain injury within 3 hours of injury with a Glasgow Coma Scale score of ≤ 12 or any intracranial bleeding on computerised tomography scan, and no major extracranial bleeding, were eligible. INTERVENTION Tranexamic acid (loading dose 1 g over 10 minutes then infusion of 1 g over 8 hours) or matching placebo. MAIN OUTCOME MEASURES Head injury death in hospital within 28 days of injury in patients treated within 3 hours of injury. Secondary outcomes were early head injury deaths, all-cause and cause-specific mortality, disability, vascular occlusive events, seizures, complications and adverse events. RESULTS Among patients treated within 3 hours of injury (n = 9127), the risk of head injury death was 18.5% in the tranexamic acid group versus 19.8% in the placebo group (855/4613 vs. 892/4514; risk ratio 0.94, 95% confidence interval 0.86 to 1.02). In a prespecified analysis excluding patients with a Glasgow Coma Scale score of 3 or bilateral unreactive pupils at baseline, the results were 12.5% in the tranexamic acid group versus 14.0% in the placebo group (485/3880 vs. 525/3757; risk ratio 0.89, 95% confidence interval 0.80 to 1.00). There was a reduction in the risk of head injury death with tranexamic acid in those with mild to moderate head injury (166/2846 vs. 207/2769; risk ratio 0.78, 95% confidence interval 0.64 to 0.95), but in those with severe head injury (689/1739 vs. 685/1710; risk ratio 0.99, 95% confidence interval 0.91 to 1.07) there was no apparent reduction (p-value for heterogeneity = 0.030). Early treatment was more effective in mild and moderate head injury (p = 0.005), but there was no obvious impact of time to treatment in cases of severe head injury (p = 0.73). The risk of disability, vascular occlusive events and seizures was similar in both groups. Tranexamic acid is highly cost-effective for mild and moderate traumatic brain injury (base case of £4288 per quality-adjusted life-year gained). CONCLUSION Early tranexamic acid treatment reduces head injury deaths. Treatment is cost-effective for patients with mild or moderate traumatic brain injury, or those with both pupils reactive. FUTURE WORK Further trials should examine early tranexamic acid treatment in mild head injury. Research on alternative routes of administration is needed. LIMITATIONS Time to treatment may have been underestimated. TRIAL REGISTRATION Current Controlled Trials ISRCTN15088122, ClinicalTrials.gov NCT01402882, EudraCT 2011-003669-14, Pan African Clinical Trial Registry PACTR20121000441277. FUNDING The project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 26. See the NIHR Journals Library website for further project information. In addition, funding was provided by JP Moulton Charitable Trust, Joint Global Health Trials (Medical Research Council, Department for International Development and the Wellcome Trust). This project was funded by the NIHR Global Health Trials programme.
PICO Summary
Population
Adults with traumatic brain injury enrolled in the CRASH-3 trial (n=9127).
Intervention
Tranexamic acid (TXA), (n= 4613).
Comparison
Matching placebo (n= 4514).
Outcome
The risk of head injury death was 18.5% in the TXA group versus 19.8% in the placebo group. In a pre-specified analysis excluding patients with a Glasgow Coma Scale score of 3 or bilateral unreactive pupils at baseline, the results were 12.5% in the TXA group versus 14.0% in the placebo group. There was a reduction in the risk of head injury death with tranexamic acid in those with mild to moderate head injury, but in those with severe head injury there was no apparent reduction. Early treatment was more effective in mild and moderate head injury, but there was no obvious impact of time to treatment in cases of severe head injury. The risk of disability, vascular occlusive events and seizures was similar in both groups.