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Viscoelastic measurements of platelet function, not fibrinogen function, predicts sensitivity to tissue‐type plasminogen activator in trauma patients
Author(s) -
Moore H. B.,
Moore E. E.,
Chapman M. P.,
Gonzalez E.,
Slaughter A. L.,
Morton A. P.,
D'Alessandro A.,
Hansen K. C.,
Sauaia A.,
Banerjee A.,
Silliman C. C.
Publication year - 2015
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.13067
Subject(s) - fibrinogen , platelet , viscoelasticity , plasminogen activator , sensitivity (control systems) , tissue plasminogen activator , function (biology) , medicine , materials science , biology , composite material , microbiology and biotechnology , engineering , electronic engineering
Summary 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 ( LY 30) variable. Multivariate linear regression was used to identify which TEG variable correlated with t‐ PA ‐ LY 30 (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 mE q L −1 . TEG parameters that significantly predicted t‐ PA ‐ LY 30 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.