The tissue-plasminogen activator-challenged thromboelastography provides a comprehensive assessment of fibrinolysis in the severely injured.

Background: Tissue-plasminogen activator-challenged thromboelastography (tPA-TEG) predicts massive transfusion and mortality better than conventional rapid thromboelastography (rTEG), with little concordance between their lysis values (LY30). We hypothesized that the main fibrinolytic inhibitors plasminogen activator inhibitor-1 (PAI-1) and α-2 antiplasmin (A2AP), as well as markers of fibrinolytic activation (plasmin-antiplasmin [PAP], tPA-PAI-1 complex, tPA activity), would correlate more strongly with tPA-TEG versus rTEG LY30 and may explain the recent findings of four distinct fibrinolytic phenotypes in trauma based on these two TEG methodologies.

Methods: Adult trauma patients (n = 56) had tPA-TEG, rTEG, and plasma obtained on arrival to the emergency department with institutional review board approval. Plasminogen activator inhibitor-1 activity, A2AP, PAP, and tPA-PAI-1 complex as well as tPA activity were measured. Data were analyzed using Spearman's correlations and analysis of variance.

Results: The median age was 34 years, 75% were male, and the New Injury Severity Score was 14. Mortality was 25%, and 23% required a massive transfusion. There was a significant negative correlation between PAI-1 activity and A2AP with tPA-TEG LY30 ( r = -0.77, p < 0.0001 and r = -0.62, p < 0.0001). There was a significant positive correlation between PAP complex and tPA-TEG LY30 ( r = 0.74, p < 0.0001). There was no correlation between any fibrinolytic analyte and rTEG LY30. When stratified by phenotype, patients with hypofibrinolysis and nonpathologic fibrinolysis had higher active PAI-1 ( p < 0.05) and A2AP levels ( p < 0.05), lower PAP ( p < 0.05), and tPA-PAI-1 complex ( p < 0.05). Tissue-plasminogen activator activity was higher in hyperfibrinolysis relative to the other three groups ( p < 0.05).

Conclusion: Tissue-plasminogen activator-TEG LY30 more accurately reflects fibrinolysis phenotypes in trauma patients than conventional TEG methods. This provides an explanation for tPA-TEG's superior performance over rTEG in predicting clinical outcomes.

Level Of Evidence: Diagnostic Tests/Criteria; Level III.