Association between circulating biomarkers of endothelial glycocalyx degradation and postoperative acute kidney injury in patients undergoing cardiac surgery with cardiopulmonary bypass.

Background: Postoperative acute kidney injury remains a frequent and clinically important complication after cardiac surgery with cardiopulmonary bypass, and perioperative biomarkers may help identify patients at increased renal risk. Objective: To investigate the association between circulating biomarkers of endothelial glycocalyx degradation and postoperative acute kidney injury in patients undergoing cardiac surgery with cardiopulmonary bypass. Methods: This single-center retrospective observational study included 152 patients who underwent cardiac surgery with cardiopulmonary bypass at Kunshan First People's Hospital. Syndecan-1, hyaluronic acid, and heparan sulfate were measured before cardiopulmonary bypass and at the end of cardiopulmonary bypass. Postoperative acute kidney injury was defined according to the Kidney Disease: Improving Global Outcomes criteria using postoperative serum creatinine and urine output. Between-group comparisons, paired analyses, logistic regression, and receiver operating characteristic analysis were performed. Results: Postoperative acute kidney injury occurred in 43 of 152 patients, corresponding to an incidence of 28.3%. Patients with acute kidney injury were older, had worse baseline renal function, and underwent longer cardiopulmonary bypass and aortic clamp times. At the end of cardiopulmonary bypass, syndecan-1 and heparan sulfate levels were higher in the acute kidney injury group, whereas hyaluronic acid did not differ significantly between groups. All three glycocalyx biomarkers increased significantly from baseline to the end of cardiopulmonary bypass, with greater increases in the acute kidney injury group, particularly for syndecan-1 and heparan sulfate. In multivariable analysis, older age, longer aortic clamp time, and higher syndecan-1 at the end of cardiopulmonary bypass were associated with postoperative acute kidney injury. Syndecan-1 showed the best discriminatory performance among the evaluated biomarkers, with an area under the curve of 0.743. Conclusions: Circulating glycocalyx degradation biomarkers increased during cardiac surgery with cardiopulmonary bypass. Among the biomarkers examined, syndecan-1 measured at the end of cardiopulmonary bypass showed the clearest association with postoperative acute kidney injury and the best discriminatory performance.