TXA (Tranexamic Acid) Risk Evaluation in Combat Casualties (TRECC)

A 20-year retrospective analysis of deep venous thrombosis and pulmonary embolism among combat casualties requiring damage-control laparotomy at US military Role 2 surgical units

BACKGROUND

Combat casualties receiving damage-control laparotomy at forward deployed, resource-constrained US military Role 2 (R2) surgical units require multiple evacuations, but the added risk of venous thromboembolism (VTE) in this population has not been defined. To fill this gap, we retrospectively analyzed 20 years of Department of Defense Trauma Registry data to define the VTE rate in this population.

METHODS

Department of Defense Trauma Registry from 2002 to 2023 was queried for US military combat casualties requiring damage-control laparotomy at R2. All deaths were excluded in subsequent analysis. Rates of VTE were assessed, and subgroup analysis was performed on patients requiring massive transfusion.

RESULTS

Department of Defense Trauma Registry (n = 288) patients were young (mean age, 25 years) and predominantly male (98%) with severe (mean Injury Severity Score, 26), mostly penetrating injury (76%) and high mortality. Venous thromboembolism rate was high: 15.8% (DVT, 10.3%; pulmonary embolism, 7.1%). In the massively transfused population, the VTE rate was even higher (26.7% vs. 10.2%, p < 0.001).

CONCLUSION

This is the first report that combat casualties requiring damage-control laparotomy at R2 have such high VTE rates. Therefore, for military casualties, we propose screening ultrasound upon arrival to each subsequent capable echelon of care and low threshold for initiating thromboprophylaxis.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Venous Thromboembolic Events in Adult Trauma Patients Receiving Balanced Hemostatic Resuscitation (BHR): An Analysis of Their Incidence, Predictors, and Associated Mortality Rates at a Level 1 Trauma Center

Background and objective Studies assessing the incidence of venous thromboembolic (VTE) events in the setting of massive balanced transfusions and/or tranexamic acid (TXA) infusion have yielded varied outcomes. In light of this, we conducted this study to examine the incidence of VTEs in trauma patients requiring blood products, and to identify the risk factors for VTE and mortality in this population. Methods We performed a retrospective analysis of trauma patients admitted to our level 1 trauma center from January 2013 to September 2023. Clinical characteristics were compared between patients who developed VTE and those who did not. A regression analysis of potential variables associated with the development of VTEs and mortality was performed. Results Among 1305 patients (mean age: 42.4 ± 18.8 years) receiving blood products within the initial 24 hours, 4.3% (56 patients) developed a VTE. Patients with VTE experienced prolonged ICU and hospital stays and ventilation duration (p<0.001). They were also noted to have delayed initiation of VTE prophylaxis (104.2 vs. 50.3 hours, p<.001). Prolonged ventilation >7 days was the sole significant factor associated with VTE in multivariate regression analysis [odds ratio (OR): 6.2, p=0.004]. Early TXA administration (within four hours) showed a higher association with VTE than TXA within 24 hours (OR: 2.1, p=0.07 vs. OR 1.6, p=0.22). Massive transfusion was found to increase VTE risk (OR: 2.65, p<0.001). Severe head and neck (OR: 6.0, p=0.002) and chest (OR: 3.8, p=0.01) injuries were key predictors of mortality, while TXA was not significantly associated with mortality in the multivariate model. Conclusions Our study revealed an elevated risk of VTE in patients requiring massive transfusion protocol (MTP, ≥6 units). Early TXA administration was neither associated with increased VTE risk in MTP patients nor increased mortality risk. Strategies directed at reducing the risk of VTE in massively transfused patients while maintaining the survival benefits of balanced resuscitation and TXA need to be devised.

A Systematic Review of Tranexamic Acid-Associated Venous Thromboembolic Events in Combat Casualties and Considerations for Prolonged Field Care

INTRODUCTION

Tranexamic acid (TXA) is a standard component of Tactical Combat Casualty Care. Recent retrospective studies have shown that TXA use is associated with a higher rate of venous thromboembolic (VTE) events in combat-injured patients. We aim to determine if selective administration should be considered in the prolonged field care environment.

MATERIALS AND METHODS

We performed a systematic review using the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Clinical trials and observational studies of combat casualties published between January 1, 1960, and June 20, 2022, were included. We analyzed survival and VTE outcomes in TXA recipients and non-recipients. We discussed the findings of each paper in the context of current and future combat environments.

RESULTS

Six articles met criteria for inclusion. Only one study was powered to report mortality data, and it demonstrated a 7-fold increase in survival in severely injured TXA recipients. All studies reported an increased risk of VTE in TXA recipients, which exceeded rates in civilian literature. However, five of the six studies used overlapping data from the same registry and were limited by a high rate of missingness in pertinent variables. No VTE-related deaths were identified.

CONCLUSIONS

There may be an increased risk of VTE in combat casualties that receive TXA; however, this risk must be considered in the context of improved survival and an absence of VTE-associated deaths. To optimize combat casualty care during prolonged field care, it will be essential to ensure the timely administration of VTE chemoprophylaxis as soon as the risk of significant hemorrhage permits.

Peripheral Microneedle Patch for First-Aid Hemostasis

Despite the minimized puncture sizes and high efficiency, microneedle (MN) patches have not been used to inject hemostatic drugs into bleeding wounds because they easily destroy capillaries when a tissue is pierced. In this study, a shelf-stable dissolving MN patch is developed to prevent rebleeding during an emergency treatment. A minimally and site-selectively invasive hemostatic drug delivery system is established by using a peripheral MN (p-MN) patch that does not directly intrude the wound site but enables topical drug absorption in the damaged capillaries. The invasiveness of MNs is histologically examined by using a bleeding liver of a Sprague-Dawley (SD) rat as an extreme wound model in vivo. The skin penetration force is quantified to demonstrate that the administration of the p-MN patch is milder than that of the conventional MN patch. Hemostatic performance is systematically studied by analyzing bleeding weight and time and comparing them with that of conventional hemostasis methods. The superior performance of a p-MN for the heparin-pretreated SD rat model is demonstrated by intravenous injection in vivo.

Tranexamic acid administration and pulmonary embolism in combat casualties with orthopaedic injuries

Objectives:

In combat casualty care, tranexamic acid (TXA) is administered as part of initial resuscitation effort; however, conflicting data exist as to whether TXA contributes to increased risk of venous thromboembolism (VTE). The purpose of this study is to determine what factors increase risk of pulmonary embolism after combat-related orthopaedic trauma and whether administration of TXA is an independent risk factor for major thromboembolic events.

Setting:

United States Military Trauma Centers.

Patients:

Combat casualties with orthopaedic injuries treated at any US military trauma center for traumatic injuries sustained from January 2011 through December 2015. In total, 493 patients were identified.

Intervention:

None.

Main Outcome Measures:

Occurrence of major thromboembolic events, defined as segmental or greater pulmonary embolism or thromboembolism-associated pulseless electrical activity.

Results:

Regression analysis revealed TXA administration, traumatic amputation, acute kidney failure, and hypertension to be associated with the development of a major thromboembolic event for all models. Injury characteristics independently associated with risk of major VTE were Injury Severity Score 23 or greater, traumatic amputation, and vertebral fracture. The best performing model utilized had an area under curve  = 0.84, a sensitivity=0.72, and a specificity=0.84.

Conclusions:

TXA is an independent risk factor for major VTE after combat-related Orthopaedic injury. Injury factors including severe trauma, major extremity amputation, and vertebral fracture should prompt suspicion for increased risk of major thromboembolic events and increased threshold for TXA use if no major hemorrhage is present.

Level of evidence:

III, Prognostic Study

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.

Efficacy and Safety of Tranexamic Acid in Emergency Trauma: A Systematic Review and Meta-Analysis

In trauma patients, bleeding can lead to coagulopathy, hemorrhagic shock, and multiorgan failure, and therefore is of fundamental significance in regard to early morbidity. We conducted a meta-analysis to evaluate the efficacy and safety of tranexamic acid (TXA) in civil and military settings and its impact on in-hospital mortality (survival to hospital discharge or 30-day survival), intensive care unit and hospital length of stay, incidence of adverse events (myocardial infarct and neurological complications), and volume of blood product transfusion. The systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic review of the literature using PubMed, Scopus, EMBASE, Web of Science, and the Cochrane Central Register and Controlled Trials (CENTRAL) database was conducted from inception to 10 January 2021. In-hospital mortality was reported in 14 studies and was 15.5% for the TXA group as compared with 16.4% for the non-TXA group (OR = 0.81, 95% CI 0.62-1.06, I2 = 83%, p = 0.12). In a civilian TXA application, in-hospital mortality in the TXA and non-TXA groups amounted to 15.0% and 17.1%, respectively (OR = 0.69, 95% CI 0.51-0.93, p = 0.02, I2 = 78%). A subgroup analysis of the randomized control trial (RCT) studies showed a statistically significant reduction in in-hospital mortality in the TXA group (14.3%) as compared with the non-TXA group (15.7%, OR = 0.89, 95% CI 0.83-0.96, p = 0.003, I2 = 0%). To summarize, TXA used in civilian application reduces in-hospital mortality. Application of TXA is beneficial for severely injured patients who undergoing shock and require massive blood transfusions. Patients who undergo treatment with TXA should be monitored for clinical signs of thromboembolism, since TXA is a standalone risk factor of a thromboembolic event and the D-dimers in traumatic patients are almost always elevated.

Bilateral pulmonary embolism while receiving tranexamic acid: a case report

BACKGROUND

We present a case of a suspected tranexamic acid-related bilateral pulmonary embolism in a healthy and active middle-aged woman who was receiving tranexamic acid for menorrhagia with no other known significant risk factors for thromboembolism.

CASE PRESENTATION

A 46-year-old Asian woman who was usually fit and well with no remarkable past medical history except for menorrhagia of 1-year duration for which she was receiving tranexamic acid presented to our accident and emergency department with a 2-week history of intermittent pleuritic central chest pain. She was reviewed and discharged to home with a diagnosis of musculoskeletal pain on two hospital visits because she had no significant risk factors for thromboembolism and her workup investigation results for pulmonary embolism and other differential diagnoses were largely unremarkable. On her third visit to the emergency ambulatory clinic with recurring symptoms of pleuritic chest pain, a pulmonary computed tomographic angiogram confirmed bilateral subsegmental pulmonary embolism.

CONCLUSION

This case report reinforces the possible increased risk of thromboembolism in patients receiving tranexamic acid.