Traumatic brain injury provokes low fibrinolytic activity in severely injured patients

BACKGROUND: Traumatic brain injury (TBI) in combination with shock has been associated with hypocoagulability. However, recent data suggest that TBI itself can promote a systemic procoagulant state via the release of brain-derived extracellular vesicles. The objective of our study was to identify if TBI was associated with differences in thrombelastography indices when controlling for other variables associated with coagulopathy following trauma. We hypothesized that TBI is independently associated with a less coagulopathic state. METHODS: Prospective study includes all highest-level trauma activations at an urban Level I trauma center, from 2014 to 2020. Traumatic brain injury was defined as Abbreviated Injury Scale head score greater than 3. Blood samples were drawn at emergency department admission. Linear regression was used to assess the role of independent predictors on trauma induced coagulopathy. Models adjusted for Injury Severity Score (ISS), shock (defined as ED SBP<70, or ED SBP<90 and ED HR>108, or first hospital base deficit >10), and prehospital Glasgow Coma Scale score. RESULTS: Of the 1,023 patients included, 291 (28%) suffered a TBI. Traumatic brain injury patients more often were female (26% vs. 19%, p = 0.01), had blunt trauma (83% vs. 43%, p < 0.0001), shock (33% vs. 25%, p = 0.009), and higher median ISS (29 vs. 10, p < 0.0001). Fibrinolysis shutdown (25% vs. 18%) was more common in the TBI group (p < 0.0001). When controlled for the confounding effects of ISS and shock, the presence of TBI independently decreases lysis at 30 minutes (LY30) (beta estimate: -0.16 ± 0.06, p = 0.004). This effect of TBI on LY30 persisted when controlling for sex and mechanism of injury in addition to ISS and shock (beta estimate: -0.13 ± 0.06, p = 0.022). CONCLUSION: Traumatic brain injury is associated with lower LY30 independent of shock, tissue injury, sex, and mechanism of injury. These findings suggest a propensity toward a hypercoagulable state in patients with TBI, possibly due to fibrinolysis shutdown. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.