Evidence of endothelial dysfunction in patients with functionally univentricular physiology before completion of the Fontan operation

Introduction: Postoperative thrombosis after a cavopulmonary connection has been widely described. Abnormalities in coagulation seem to occur early in the course of patients with functionally univentricular physiology, and may precede surgery. Endothelial abnormalities due to chronic hypoxia, and hyperviscosity, may contribute to this scene. The purpose of our study was to investigate if patients with a superior cavopulmonary connection have altered levels of endothelial and coagulative markers in the plasma. Methods: We compared findings in 10 patients, aged from 4 to 19 years, with 6 age-matched normal controls. We measured levels of von Willebrand factor antigen, thrombomodulin, tissue-type plasminogen activator, plasminogen activator inhibitor-1 and D-dimer in the plasma using enzyme-linked immunosorbent assay. Results: We found increased levels of von Willebrand factor antigen (p = 0.01), tissue-type plasminogen activator (p = 0.01), and decreased levels of thrombomodulin (p = 0.008) in the patients when compared to controls, while levels of plasminogen activator inhibitor-1 were not different. Values of D-dimer were within the reference range. Levels of tissue-type plasminogen activator had a positive correlation with von Willebrand factor antigen (r = 0.66, p = 0.008). Conclusions: Altered levels of endothelial markers in the plasma, in the presence of normal levels of D-dimer, suggest that endothetial dysfunction may precede the occurrence of intravascular coagulation and thrombosis in patients with functionally univentricular physiology. These observations may have therapeutical implications.