Correlation between acute degradation of the endothelial glycocalyx and microcirculation dysfunction during cardiopulmonary bypass in cardiac surgery

Objective: The association between the shedding of the endothelial glycocalyx (EG) and the pathogenesis of microcirculatory perfusion disturbances has been discussed in experimental studies. This discussion, however, has limited relevance in a clinical setting. We investigated EG shedding in patients undergoing cardiopulmonary bypass (CPB) and its association with alterations in microvascular perfusion. Methods: The plasma levels of syndecan-1, heparan sulfate, and hyaluronan were used as markers of glycocalyx degradation. Microcirculatory parameters included perfused vessel density (PVD) and De Backer Scores. Sidestream dark field imaging (SDF) was applied to visualize sublingual microcirculation during the preoperative resting state (TO), after sternum splitting, after aortic clamping, 5 min before aortal declamping, 1 h after CPB (T4), 4 h after CPB, 24 h after CPB (T6), and 48 h after CPB. Results: Thirty patients undergoing cardiac surgery were recruited. The plasma levels of glycocalyx degradation markers increased after CPB. This increase indicated severe glycocalyx shedding at T4 relative to that at TO. By T6, the plasma levels of glycocalyx degradation markers had decreased to baseline levels in a stepwise manner. PVD and the De Backer Scores decreased at T4 and recovered at T6. Glycocalyx marker concentrations were correlated with microvascular alterations during cardiac surgery. Conclusions: Glycocalyx components are closely related to microcirculation perfusion disorders. Damage to the glycocalyx during surgery with CPB may play a key role in microcirculation perfusion dysfunction.