The role of tranexamic acid in traumatic brain injury

A Prospective Cohort Study Characterizing Incidence of Dural Venous Sinus Thrombosis in Traumatic Brain Injury Patients with Skull Fractures

BACKGROUND

Limited retrospective data suggest that dural venous sinus thrombosis (DVST) in traumatic brain injury (TBI) patients with skull fractures is common and associated with significant morbidity and mortality. Prospective data accurately characterizing the incidence of DVST in patients with high-risk TBI are sparse but are needed to develop evidence-based TBI management guidelines.

METHODS

After obtaining institutional approval, 36 adult patients with TBI with skull fractures admitted to an Australian level III adult intensive care unit between April 2022 and January 2023 were prospectively recruited and underwent computed tomography venography or magnetic resonance venography within 72 hours of injury. When available, daily maximum intracranial pressure was recorded.

RESULTS

Dural venous sinus abnormality was common (36.1%, 95% confidence interval 22.5%-52.4%) and strongly associated with DVST (P = 0.003). The incidence of DVST was 13.9% (95% confidence interval 6.1%-28.7%), which was lower than incidence reported in previous retrospective studies. Of DVSTs confirmed by computed tomography venography, 80% occurred in patients with extensive skull fractures including temporal or parietal bone fractures in conjunction with occipital bone fractures (P = 0.006). However, dural venous sinus abnormality and DVST were not associated with an increase in maximum daily intracranial pressure within the first 7 days after injury.

CONCLUSIONS

Dural venous sinus abnormality was common in TBI patients with skull fractures requiring intensive care unit admission. DVST was confirmed in more than one third of these patients, especially patients with concomitant temporal or parietal and occipital bone fractures. Computed tomography venography is recommended for this subgroup of TBI patients.

The Fibrinolytic System and Its Measurement: History, Current Uses and Future Directions for Diagnosis and Treatment

The fibrinolytic system is a key player in keeping the haemostatic balance, and changes in fibrinolytic capacity can lead to both bleeding-related and thrombosis-related disorders. Our knowledge of the fibrinolytic system has expanded immensely during the last 75 years. From the first successful use of thrombolysis in myocardial infarction in the 1960s, thrombolytic therapy is now widely implemented and has reformed treatment in vascular medicine, especially ischemic stroke, while antifibrinolytic agents are used routinely in the prevention and treatment of major bleeding worldwide. Despite this, this research field still holds unanswered questions. Accurate and timely laboratory diagnosis of disturbed fibrinolysis in the clinical setting remains a challenge. Furthermore, despite growing evidence that hypofibrinolysis plays a central role in, e.g., sepsis-related coagulopathy, coronary artery disease, and venous thromboembolism, there is currently no approved treatment of hypofibrinolysis in these settings. The present review provides an overview of the fibrinolytic system and history of its discovery; measurement methods; clinical relevance of the fibrinolytic system in diagnosis and treatment; and points to future directions for research.

Immune regulation in neurovascular units after traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Survivors may experience movement disorders, memory loss, and cognitive deficits. However, there is a lack of understanding of the pathophysiology of TBI-mediated neuroinflammation and neurodegeneration. The immune regulation process of TBI involves changes in the peripheral and central nervous system (CNS) immunity, and intracranial blood vessels are essential communication centers. The neurovascular unit (NVU) is responsible for coupling blood flow with brain activity, and comprises endothelial cells, pericytes, astrocyte end-feet, and vast regulatory nerve terminals. A stable NVU is the basis for normal brain function. The concept of the NVU emphasizes that cell-cell interactions between different types of cells are essential for maintaining brain homeostasis. Previous studies have explored the effects of immune system changes after TBI. The NVU can help us further understand the immune regulation process. Herein, we enumerate the paradoxes of primary immune activation and chronic immunosuppression. We describe the changes in immune cells, cytokines/chemokines, and neuroinflammation after TBI. The post-immunomodulatory changes in NVU components are discussed, and research exploring immune changes in the NVU pattern is also described. Finally, we summarize immune regulation therapies and drugs after TBI. Therapies and drugs that focus on immune regulation have shown great potential for neuroprotection. These findings will help us further understand the pathological processes after TBI.

Antifibrinolytics in the treatment of traumatic brain injury

PURPOSE OF REVIEW

Traumatic brain injury (TBI) is a leading cause of trauma-related deaths, and pharmacologic interventions to limit intracranial bleeding should improve outcomes. Tranexamic acid reduces mortality in injured patients with major systemic bleeding, but the effects of antifibrinolytic drugs on outcomes after TBI are less clear. We therefore summarize recent evidence to guide clinicians on when (not) to use antifibrinolytic drugs in TBI patients.

RECENT FINDINGS

Tranexamic acid is the only antifibrinolytic drug that has been studied in patients with TBI. Several recent studies failed to conclusively demonstrate a benefit on survival or neurologic outcome. A large trial with more than 12 000 patients found no significant effect of tranexamic acid on head-injury related death, all-cause mortality or disability across the overall study population, but observed benefit in patients with mild to moderate TBI. Observational evidence signals potential harm in patients with isolated severe TBI.

SUMMARY

Given that the effect of tranexamic acid likely depends on a variety of factors, it is unlikely that a 'one size fits all' approach of administering antifibrinolytics to all patients will be helpful. Tranexamic acid should be strongly considered in patients with mild to moderate TBI and should be avoided in isolated severe TBI.