Protamine Enhances Fibrinolysis by Decreasing Clot Strength: Role of Tissue Factor- Initiated Thrombin Generation  Vance G. Nielsen, MD  The Annals of Thoracic Surgery  Volume 81, Issue 5, Pages 1720-1727 (May 2006) DOI: 10.1016/j.athoracsur.2005.12.027 Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

Fig 1 Elastic modulus-based and time-based thromboelastograph variables of clot growth and disintegration. A clot growth-disintegration velocity curve and corresponding thromboelastogram are depicted. (ACL = area of clot lysis [-dynes/cm2]; CDT = clot duration time [CGT+CLT, seconds]; CGT = clot growth time [seconds]; CLT = clot lysis time [seconds]; MRL = maximum rate of lysis [-dynes/cm2/second]; MTG = maximum rate of thrombus generation [dynes/cm2/second]; TMG = time to maximum rate of thrombus generation [seconds]; TML = time to maximum rate of lysis [seconds]; TTG = total thrombus generation [dynes/cm2]). The Annals of Thoracic Surgery 2006 81, 1720-1727DOI: (10.1016/j.athoracsur.2005.12.027) Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

Fig 2 Representative thromboelastograms and clot growth-disintegration velocity curves of the effects of protamine on fibrinolysis. All plasma samples were exposed to 100 U/mL tissue type plasminogen activator. Data collection occurred over a 30 minute period. (A) and (B) are the thromboelastogram and velocity curve, respectively, of a plasma sample with no protamine added. (C) and (D) are the thromboelastogram and velocity curve of a plasma sample with 25 μg/mL of protamine. The Annals of Thoracic Surgery 2006 81, 1720-1727DOI: (10.1016/j.athoracsur.2005.12.027) Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

Fig 3 Effects of protamine on factor XIII (FXIII)-deficient and normal plasma after celite or tissue factor activation. Representative thromboelastograms with corresponding clot growth velocity curves are displayed for each condition. (A) Celite activated FXIII-deficient plasma, no protamine. (B) Celite-activated FXIII-deficient plasma, 50 μg/mL of protamine. (C) Celite-activated normal plasma, no protamine. (D) Celite-activated normal plasma, 50 μg/mL of protamine. (E) Tissue factor (0.01%) activated normal plasma, no protamine. (F) Tissue factor (0.01%) activated normal plasma, 50 μg/mL of protamine. The Annals of Thoracic Surgery 2006 81, 1720-1727DOI: (10.1016/j.athoracsur.2005.12.027) Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

Fig 4 Effects of increasing tissue factor concentration on protamine-mediated enhancement of fibrinolysis. Representative thromboelastograms with corresponding clot growth velocity curves are displayed for each condition. All plasma samples were exposed to 100 U/mL tissue type plasminogen activator. (A) Tissue factor (0.01%) activated normal plasma. (B) Tissue factor (0.01%) activated normal plasma, 25 μg/mL of protamine. (C) Tissue factor (0.1%) activated normal plasma, 25 μg/mL of protamine. The Annals of Thoracic Surgery 2006 81, 1720-1727DOI: (10.1016/j.athoracsur.2005.12.027) Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

Fig 5 Mechanism by which protamine decreases clot strength and enhances fibrinolysis. Protamine inhibits tissue factor (TF) mediated activation of factor (F) VII, which in turn decreases activation of factor X and prothrombin, and ultimately decreases thrombin generation. Further, protamine inhibits thrombin-mediated fibrinogen polymerization and factor XIII activation, decreasing fibrin polymer formation and cross-linking that subsequently decreases clot strength. The Annals of Thoracic Surgery 2006 81, 1720-1727DOI: (10.1016/j.athoracsur.2005.12.027) Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions