Endothelial glycocalyx degradation induces endogenous heparinization in patients with severe injury and early traumatic coagulopathy

Abstract

BACKGROUND: There is emerging evidence that early trauma-induced coagulopathy (TIC) is mechanistically linked to disruption of the vascular endothelium and its glycocalyx, assessed by thrombomodulin and syndecan 1, respectively. This study evaluated if degradation of the endothelial glycocalyx and ensuing release of its heparin-like substances induce autoheparinization and thereby contributes to TIC. METHODS: Prospective observational study of 77 trauma patients admitted to a Level I trauma center having blood sampled at admission. Data on demography, hematology, Injury Severity Score, transfusion requirements, 30-day mortality, and thrombelastography (TEG, concurrent kaolin-activated/kaolin-heparinase-activated) were recorded. Retrospective analysis of plasma/serum for biomarkers reflecting endothelial glycocalyx and cell damage (syndecan 1, thrombomodulin), tissue injury (histone-complexed DNA fragments), sympathoadrenal activation (adrenaline, noradrenaline), coagulation activation/anticoagulation (prothrombin fragment 1+2, fibrinogen, von Willebrand factor, factor XIII, antithrombin, protein C, activated protein C, tissue factor pathway inhibitor), fibrinolysis (tissue-type plasminogen activator, plasminogen activator inhibitor 1) and inflammation (interleukin 6, terminal complement complex). Stratification of patients was according to the degree of TEG-measured heparinization. RESULTS: Four patients (5.2%) displayed evidence of high-degree autoheparinization, and these patients had higher Injury Severity Score (median [interquartile range], 31 [26-37] vs. 17 [10-26]), increased glucose (median, 13.6 vs. 8.0 mmol/L), and lower hemoglobin level (median, 5.8 vs. 8.4 mmol/L) and received more transfusions during the first 1 hour (median, 5 vs. 0) and 24 hours (median, 10 vs. 0) (all p < 0.05). Importantly, patients with autoheparinization had fourfold higher syndecan 1 levels (median [interquartile range], 116 ng/mL [78-140 ng/mL] vs. 31 ng/mL [18-49 ng/mL]), and they had higher international normalized ratio (median, 1.4 vs. 1.1), thrombomodulin (median, 4.1 vs. 1.7 ng/mL) and interleukin 6 (median, 129 vs. 71 pg/mL) but lower protein C (85% vs. 109%) (all p < 0.05), indicating profound endothelial damage, coagulopathy and inflammation. CONCLUSION: Five percent of the patients with trauma in the present study had evidence of acute endogenous coagulopathy with autoheparinization by TEG, which appeared mechanistically linked to endothelial glycocalyx degradation. Acute endogenous autoheparinization may contribute to TIC. LEVEL OF EVIDENCE: Prognostic study, level III.