Thromb Haemost 2018; 118(09): 1545-1555
DOI: 10.1055/s-0038-1667198
Coagulation and Fibrinolysis
Georg Thieme Verlag KG Stuttgart · New York

Plasma Proteolytic Cascade Activation during Neonatal Cardiopulmonary Bypass Surgery

Susan A. Maroney
1  Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin, United States
,
Julie A. Peterson
1  Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin, United States
,
Wes Zwifelhofer
1  Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin, United States
,
Nicholas D. Martinez
1  Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin, United States
,
Ke Yan
2  Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
,
Rachel S. Bercovitz
1  Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin, United States
2  Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
3  Department of Pathology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
,
Ronald K. Woods
4  Division of Pediatric Cardiothoracic Surgery, Herma Heart Center, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, United States
5  Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
,
Alan E. Mast
1  Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin, United States
6  Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
› Author Affiliations
Funding This work was supported by National Heart, Lung, and Blood Institute grant HL068835 (to A.E. Mast) and the Herma Heart Center at Children's Hospital of Wisconsin.
Further Information

Publication History

01 May 2018

08 June 2018

Publication Date:
07 August 2018 (eFirst)

Abstract

Background Neonates undergoing cardiopulmonary bypass (CPB) surgery to correct congenital heart defects often experience excessive bleeding. Exposure of blood to artificial materials during CPB may activate coagulation, complement and inflammatory pathways. In addition, the surgical stress placed on the haemostatic system may result in cross-activation of other plasma proteolytic cascades, which could further complicate physiological responses to the surgical procedure and post-operative recovery. Plasma protease inhibitors undergo distinct conformational changes upon interaction with proteases, and, thereby, can serve as endogenous biosensors to identify activation of the different proteolytic cascades. We tested the hypothesis that changes in the concentration and conformation of protease inhibitors regulating plasma proteolytic cascades during neonatal CPB are associated with post-operative bleeding.

Patients and Methods Plasma samples from 44 neonates were obtained at four time points across the surgical procedure. Anti-thrombin, antitrypsin, anti-chymotrypsin, anti-plasmin, C1-inhibitor and tissue factor pathway inhibitor (TFPI) concentrations and conformations were evaluated by enzyme-linked immunosorbent assay, transverse urea gradient gel electrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Results/Conclusion The most striking changes were observed following heparin administration and were associated with the appearance of inactive forms of anti-thrombin and an increase in the plasma concentration of TFPI. Changes in anti-thrombin and TFPI remained evident throughout surgery and into the post-operative period but were not different between patients with or without post-operative bleeding. The concentration of antitrypsin decreased across surgery, but there was no significant accumulation of inactive conformations of any inhibitor besides anti-thrombin, indicating that widespread cross-activation of other plasma proteolytic cascades by coagulation proteases did not occur.

Authors' Contributions

S.A. Maroney: designed research, performed experiments, interpreted data and wrote the manuscript. J.A. Peterson: designed research, interpreted data and wrote the manuscript. W. Zwifelhofer: performed experiments. N.D. Martinez: performed experiments. K. Yan: interpreted data and performed statistical analysis. R.S. Bercovitz: designed research and interpreted data. R.K. Woods: performed surgery, designed research and interpreted data. A.E Mast: designed research, interpreted data and wrote the manuscript.