Acute Degradation of the Endothelial Glycocalyx in Infants Undergoing Cardiac Surgical Procedures

Background. There is no doubt today about the existence of the endothelial glycocalyx (EG) and its decisive role inmaintaining vascularhomeostasis inadulthumans. Shedding of the EG has been demonstrated in adults with sepsis or trauma, in patients undergoing major operations, and after ischemia/reperfusion. The aim of the present studywastodemonstratewhethersheddingoftheEGalso occurs in infants undergoing heart operations. Methods. Two major constituents of the EG (syndecan-1 and hyaluronan) were measured in the arterial serum of 42 infants during cardiac operations in a prospective observational study. The groups were defined according to the ischemic impact: cardiac operations with cardiopulmonary bypassunderbeatingheartconditions(CPBgroup,regional ischemia of lungs, n [ 10), operations with cardiopulmonarybypassandaorticclamping(CPBDACgroup,regional ischemia of heart and lungs, n [ 24), and cardiac operations with deep hypothermic circulatory arrest (CPBDACDDHCA group, whole-body ischemia, n [ 8). Results. Syndecan-1 and hyaluronan were detected in all infants, providing an indication for the presence of a glycocalyx. During the operations, no significant difference in syndecan-1 concentration was observed in the CPB group, but levels increased significantly in both other groups (maximum increases: CPBDAC 3.0-fold, CPBDACDDHCA 3.7-fold, p < 0.05). Hyaluronan increased significantly in the course of the operation in all groups (maximum increases: CPB 1.2-fold, CPBDAC 1.4fold, CPBDACDDHCA 1.7-fold, p < 0.05). Conclusions. The present data provides the first evidence for basal turnover of vascular EG in infants. Similarly to the process in adults, the shedding of this structure increases with ischemia/reperfusion, the extent being dependent on the degree of ischemic challenge.