(868) Syndecan-1 as a Biomarker for Fluid Overload After High-Risk Pediatric Cardiac Surgery: A Pilot

Introduction: Fluid overload (FO) after pediatric cardiac surgery with cardiopulmonary bypass (CPB) is common and has been associated with poor outcomes. The endothelial glycocalyx plays an important role in regulating vascular permeability and is damaged after exposure to CPB. We aimed to describe the relationship between plasma concentrations of syndecan-1 (SD1), a biomarker of endothelial glycocalyx injury, and FO in a cohort of children undergoing high-risk cardiac surgery.

Methods: We recruited 15 children undergoing Society of Thoracic Surgeons - European Association for Cardio-Thoracic Surgery congenital heart surgery mortality category 3, 4 and 5 cardiac surgeries with CPB. Blood samples were obtained preoperatively and at 4 hours postoperatively and processed for plasma. SD1 concentrations were quantified via enzyme-linked immunosorbent assays (ELISA) and compared to FO on post-operative days 1, 2 and 3. We also compared SD1 concentration to peak percent fluid overload, defined as the highest percent FO occurring in the first 7 days following surgery.

Results: SD1 discriminated FO greater than 10% on post-operative days 1, 2 and 3 with an area under the receiver operating characteristic curve (AUROC) of 0.74, 0.84 and 0.88 respectively. SD1 also discriminated peak FO greater than 10% occurring on any day over the first 7 postoperative days with an AUROC of 0.94. Patients with greater than 10% FO on postoperative day 2 (p= 0.037), day 3 (p= 0.020) or peak (p= 0.021) had significantly elevated delta SD1 when compared to patients with a cumulative fluid balance of less than 10%.

Conclusions: Plasma SD1 was associated with FO in pediatric patients undergoing high-risk cardiac surgery with CPB. Further studies exploring the clinical utility of SD1 as a biomarker for FO in the postoperative management of children who undergo cardiac surgery with CPB should be pursued.