Viscoelastic measurements of platelet function, not fibrinogen function, predicts sensitivity to tissue-type plasminogen activator in trauma patients

J Thromb Haemost. 2015 Oct;13(10):1878-87. doi: 10.1111/jth.13067. Epub 2015 Sep 22.


Background: Systemic hyperfibrinolysis is a lethal phenotype of trauma-induced coagulopathy. Its pathogenesis is poorly understood. Recent studies have support a central role of platelets in hemostasis and in fibrinolysis regulation, implying that platelet impairment is integral to the development of postinjury systemic hyperfibrinolysis.

Objective: The objective of this study was to identify if platelet function is associated with blood clot sensitivity to fibrinolysis. We hypothesize that platelet impairment of the ADP pathway correlates with fibrinolysis sensitivity in trauma patients.

Methods: A prospective observational study of patients meeting the criteria for the highest level of activation at an urban trauma center was performed. Viscoelastic parameters associated with platelet function (maximum amplitude [MA]) were measured with native thrombelastography (TEG), and TEG platelet mapping of the ADP pathway (ADP-MA). The contribution of fibrinogen to clotting was measured with TEG (angle) and the TEG functional fibrinogen (FF) assay (FF-MA). Another TEG assay containing tissue-type plasminogen activator (t-PA) (75 ng mL(-1) ) was used to assess clot sensitivity to an exogenous fibrinolytic stimulus by use of the TEG lysis at 30 min (LY30) variable. Multivariate linear regression was used to identify which TEG variable correlated with t-PA-LY30 (quantification of fibrinolysis sensitivity).

Results: Fifty-eight trauma patients were included in the analysis, with a median injury severity score of 17 and a base deficit of 6 mEq L(-1) . TEG parameters that significantly predicted t-PA-LY30 were related to platelet function (ADP-MA, P = 0.001; MA, P < 0.001) but not to fibrinogen (FF-MA, P = 0.773; angle, P = 0.083). Clinical predictors of platelet ADP impairment included calcium level (P = 0.001), base deficit (P = 0.001), and injury severity (P = 0.001).

Results and conclusions: Platelet impairment of the ADP pathway is associated with increased sensitivity to t-PA. ADP pathway inhibition in platelets may be an early step in the pathogenesis of systemic hyperfibrinolysis.

Keywords: blood platelet disorder; fibrinogen; fibrinolysis; platelet function tests; trauma.

Publication types

  • Observational Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / blood
  • Adult
  • Biomarkers / blood
  • Blood Platelets / drug effects*
  • Blood Platelets / metabolism
  • Blood Viscosity
  • Calcium / blood
  • Elasticity
  • Female
  • Fibrinogen / metabolism*
  • Fibrinolysis / drug effects*
  • Fibrinolytic Agents / therapeutic use*
  • Humans
  • Injury Severity Score
  • Linear Models
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Patient Selection
  • Platelet Function Tests*
  • Predictive Value of Tests
  • Prospective Studies
  • Thrombolytic Therapy / methods*
  • Tissue Plasminogen Activator / therapeutic use*
  • Treatment Outcome
  • Wounds and Injuries / blood
  • Wounds and Injuries / diagnosis
  • Wounds and Injuries / drug therapy*


  • Biomarkers
  • Fibrinolytic Agents
  • Adenosine Diphosphate
  • Fibrinogen
  • Tissue Plasminogen Activator
  • Calcium