Clot activators do not expedite the time to predict massive transfusion in trauma patients analyzed with tissue plasminogen activator thrombelastography

Abstract

Background: Trauma patients with hypersensitivity to tissue plasminogen activator mediated fibrinolysis quantified by tissue plasminogen activator thromboelastography are at increased risk of massive transfusion. The tissue plasminogen activator thromboelastography assay has been tested in trauma patients using native thromboelastography with no exogenous activator. We hypothesize that adding an activator will expedite the time to results.

Methods: Healthy whole blood was assayed with and without exogenous plasmin, which acts to deplete inhibitors of fibrinolysis, mimicking trauma blood. Samples were assessed using native, kaolin, and rapid thromboelastography with and without tissue plasminogen activator. The tissue plasminogen activator thromboelastography indices of time to maximum amplitude and lysis at 30 minutes were contrasted between healthy blood with and without plasmin using the three different activators. The activators were then used with a tissue plasminogen activator thromboelastography in 100 trauma patients to assess performance in predicting massive transfusion.

Results: In healthy blood, regardless of activator, lysis at 30 minutes did not increase with plasmin alone, but did increase with tissue plasminogen activator (P = .012). Adding tissue plasminogen activator and plasmin increased lysis at 30 minutes (P = .036). Time to maximum amplitude was reduced with tissue plasminogen activator and plasmin compared with tissue plasminogen activator alone (P = .012). Activated thromboelastographies had increased lysis at 30 minutes (P = .002), but no difference in time to maximum amplitude compared with native thromboelastographies. In trauma patients, native tissue plasminogen activator thromboelastography had greater performance in predicting massive transfusion than activated tissue plasminogen activator thromboelastographies with no difference in time to maximum amplitude.

Conclusion: Adding an activator to tissue plasminogen activator thromboelastography does not expedite time to maximum amplitude in healthy blood depleted of fibrinolysis inhibitors. Activated tissue plasminogen activator thromboelastographies are inferior to native tissue plasminogen activator thromboelastography for predicting massive transfusion and do not reduce the time to results.