Effects of tranexamic acid on coagulofibrinolytic markers during the early stage of severe trauma: A propensity score-matched analysis

Time-Dependent Association of Preinjury Anticoagulation on Traumatic Brain Injury-Induced Coagulopathy: A Retrospective, Multicenter Cohort Study

BACKGROUND AND OBJECTIVES

The impact of preinjury anticoagulation on coagulation parameters over time after traumatic brain injury (TBI) has remained unclear. Based on the hypothesis that preinjury anticoagulation significantly influences the progression and persistence of TBI-induced coagulopathy, we retrospectively examined the association of preinjury anticoagulation with various coagulation parameters during the first 24 hours postinjury in 5 periods.

METHODS

Data from the Japanese registry of patients with TBI aged ≥65 years admitted between 2019 and 2021 were used. Time since injury was classified into 5 categories through a graphical analysis of coagulation parameters. We examined the association between preinjury anticoagulation and the platelet count, prothrombin time-international normalized ratio (PT-INR), activated partial thromboplastin time (APTT), D-dimer level, and fibrinogen level during each period by analysis of covariance using 10 clinical factors as confounding factors.

RESULTS

Data from 545 patients and 795 blood tests were analyzed. The patients' mean age was 78.9 years, and 87 (16%) received anticoagulation therapy. The preinjury anticoagulation group had significantly greater Rotterdam computed tomography scores and poorer outcomes at discharge than the control group, with significantly lower D-dimer levels and higher fibrinogen levels. Analysis of covariance revealed significant associations between the D-dimer level and preinjury anticoagulation within 2 to 24 hours postinjury, APTT and preinjury anticoagulation within 1 to 24 hours, and PT-INR and preinjury anticoagulation throughout all periods up to 24 hours postinjury.

CONCLUSION

Despite more severe TBI signs and poorer outcomes, the preinjury anticoagulation group had significantly lower D-dimer levels, especially within 2 to 24 hours postinjury. Thus, D-dimer levels during this period may not reliably represent TBI severity in patients receiving anticoagulation therapy before injury. Preinjury anticoagulation was also associated with an elevated PT-INR and prolonged APTT from early to 24 hours postinjury, highlighting the importance of aggressive anticoagulant reversal early after injury.

Phenotypes of Disseminated Intravascular Coagulation

Two phenotypes of disseminated intravascular coagulation (DIC) are systematically reviewed. DIC is classified into thrombotic and fibrinolytic phenotypes characterized by thrombosis and hemorrhage, respectively. Major pathology of DIC with thrombotic phenotype is the activation of coagulation, insufficient anticoagulation with endothelial injury, and plasminogen activator inhibitor-1-mediated inhibition of fibrinolysis, leading to microvascular fibrin thrombosis and organ dysfunction. DIC with fibrinolytic phenotype is defined as massive thrombin generation commonly observed in any type of DIC, combined with systemic pathologic hyperfibrinogenolysis caused by underlying disorder that results in severe bleeding due to excessive plasmin formation. Three major pathomechanisms of systemic hyperfibrinogenolysis have been considered: (1) acceleration of tissue-type plasminogen activator (t-PA) release from hypoxic endothelial cells and t-PA-rich storage pools, (2) enhancement of the conversion of plasminogen to plasmin due to specific proteins and receptors that are expressed on cancer cells and endothelial cells, and (3) alternative pathways of fibrinolysis. DIC with fibrinolytic phenotype can be diagnosed by DIC diagnosis followed by the recognition of systemic pathologic hyperfibrin(ogen)olysis. Low fibrinogen levels, high fibrinogen and fibrin degradation products (FDPs), and the FDP/D-dimer ratio are important for the diagnosis of systemic pathologic hyperfibrin(ogen)olysis. Currently, evidence-based treatment strategies for DIC with fibrinolytic phenotypes are lacking. Tranexamic acid appears to be one of the few methods to be effective in the treatment of systemic pathologic hyperfibrin(ogen)olysis. International cooperation for the elucidation of pathomechanisms, establishment of diagnostic criteria, and treatment strategies for DIC with fibrinolytic phenotype are urgent issues in the field of thrombosis and hemostasis.