87 Evaluating Endothelial Dysfunction in Thermally-injured Patients with syndecan-1, Tissue Factor Pathway Inhibitor, and Thrombomodulin as Predictors of Mortality

Introduction Endotheliopathy in burn patients is largely uncharacterized. Syndecan-1 (SDC-1), thrombomodulin (TM), and tissue factor pathway inhibitor (TFPI) are components of the vascular endothelial glycocalyx. Proteolytic cleavage of these moieties may yield biomarkers for endothelial damage. The aim of this study is to evaluate endotheliopathy after burn injury by monitoring plasma levels of these biomarkers over time to investigate potential relationship to mortality. Methods Burn injured patients presenting to a regional burn center from 2012 to 2017 were prospectively enrolled. Blood samples were collected at 0, 2, 4, 8, 12, 24, 36, 48, 60, and 72 hours from admission. Plasma SDC-1, TM, and TFPI levels were quantified by ELISA. Demographic data and injury characteristics were obtained from the medical chart. Patients with concomitant inhalation injury, trauma, or < 10% total body surface area (TBSA) burns were excluded. Statistical analysis was performed using mixed-effect models with Sidak’s correction for multiple comparisons. Significance was set at p =0.05. Data are presented as mean ± standard deviation. Results A cohort of 22 patients was identified with an average age of 45±14 years, TBSA of 30±15%, with 6 patients who died from their injuries. The deceased group was older (59±13 vs. 40±10 years, p = 0.01), and there was no significant difference in burn size. Mean SDC-1 levels were higher in the deceased group at all time points (p=0.0004) and this difference was significant at hour 12 (106±11 vs. 41±31 ng/mL, p = 0.0002), hour 24 (160±39 vs. 35±20 ng/mL, p = 0.04) and hour 72 (100±3 vs. 35±38 ng/mL, p = 0.01). Mean soluble TM levels were higher in the deceased group after hour 12 (p = 0.04) and there was a trend towards higher TFPI levels after hour 12 in the deceased group. Conclusions Biomarkers are elevated in patients following burn injury who die, when inhalation injury and trauma are excluded. Given equivalent TBSA, older patients appear more sensitive to thermally induced glycocalyx degradation. SDC-1 shows the greatest promise as a prognostic indicator as levels tend to be higher among deceased patients on admission and are significantly higher as early as hour 12. Applicability of Research to Practice Reliable assessment of the patient’s endothelial damage may hold predictive value for clinicians and could assist in clinical decision making. Further research must investigate endotheliopathy in burn patients.