Circulating Biomarkers of Endothelial Dysfunction Associated With Ventilatory Ratio and Mortality in ARDS Resulting From SARS-CoV-2 Infection Treated With Antiinflammatory Therapies.

Background: The association of plasma biomarkers and clinical outcomes in ARDS resulting from SARS-CoV-2 infection predate the evidence-based use of immunomodulators.

Research Question: Which plasma biomarkers are associated with clinical outcomes in patients with ARDS resulting from SARS-CoV-2 infection treated routinely with immunomodulators?

Study Design And Methods: We collected plasma from patients with ARDS resulting from SARS-CoV-2 infection within 24 h of admission to the ICU between December 2020 and March 2021 (N = 69). We associated 16 total biomarkers of inflammation (eg, IL-6), coagulation (eg, D-dimer), epithelial injury (eg, surfactant protein D), and endothelial injury (eg, angiopoietin-2) with the primary outcome of in-hospital mortality and secondary outcome of ventilatory ratio (at baseline and day 3).

Results: Thirty patients (43.5%) died within 60 days. All patients received corticosteroids and 6% also received tocilizumab. Compared with survivors, nonsurvivors demonstrated a higher baseline modified Sequential Organ Failure Assessment score (median, 8.5 [interquartile range (IQR), 7-9] vs 7 [IQR, 5-8]); = .004), lower Pao to Fio ratio (median, 153 [IQR, 118-182] vs 184 [IQR, 142-247]; = .04), and higher ventilatory ratio (median, 2.0 [IQR, 1.9-2.3] vs 1.5 [IQR, 1.4-1.9]; < .001). No difference was found in inflammatory, coagulation, or epithelial biomarkers between groups. Nonsurvivors showed higher median neural precursor cell expressed, developmentally down-regulated 9 (NEDD9) levels (median, 8.4 ng/mL [IQR, 7.0-11.2 ng/mL] vs 6.9 ng/mL [IQR, 5.5-8.0 ng/mL]; = .0025), von Willebrand factor domain A2 levels (8.7 ng/mL [IQR, 7.9-9.7 ng/mL] vs 6.5 ng/mL [IQR, 5.7-8.7 ng/mL]; = .007), angiopoietin-2 levels (9.0 ng/mL [IQR, 7.9-14.1 ng/mL] vs 7.0 ng/mL [IQR, 5.6-10.6 ng/mL]; = .01), and syndecan-1 levels (15.9 ng/mL [IQR, 14.5-17.5 ng/mL] vs 12.6 ng/mL [IQR, 10.5-16.1 ng/mL]; = .01). Only NEDD9 level met the adjusted threshold for significance ( < .003). Plasma NEDD9 level was associated with 60-day mortality (adjusted OR, 9.7; 95% CI, 1.6-60.4; = .015). Syndecan-1 level correlated with both baseline (ρ = 0.4; = .001) and day 3 ventilatory ratio (ρ = 0.5; < .001).

Interpretation: Biomarkers of inflammation, coagulation, and epithelial injury were not associated with clinical outcomes in a small cohort of patients with ARDS uniformly treated with immunomodulators. However, endothelial biomarkers, including plasma NEDD9, were associated with 60-day mortality.