Assessment of the diagnostic value of biomarkers for predicting postoperative delirium in pediatric cardiac surgery: an observational study

BACKGROUND: Postoperative delirium in children with congenital heart disease after cardiac surgery with cardiopulmonary bypass occurs in 22%–49% of cases and is associated with prolonged hospitalization and long-term cognitive impairment. The predictive value of serum biomarkers of neurovascular unit injury [S100-β protein, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP)] remains understudied.

AIM: To analyze the prognostic value of brain injury biomarkers (S100-β, NSE, and GFAP) in young children undergoing congenital heart defect repair with cardiopulmonary bypass and to develop a diagnostic panel for predicting postoperative delirium risk.

METHODS: This prospective observational pilot study included 78 children (age 13 [9–23] months, body weight 8.7 [6.9–11.0] kg) after septal congenital heart defect repair with cardiopulmonary bypass. Postoperative delirium was diagnosed using the Cornell Assessment for Pediatric Delirium (CAPD) scale (≥ 9 points) within the first 24 hours postoperatively. Serum concentrations of S100-β, NSE, and GFAP were measured at three time points: preoperatively, immediately after cardiopulmonary bypass, and 16 hours after surgery. Statistical analysis included non-parametric tests, ROC analysis, and regression analysis.

RESULTS: Postoperative delirium was detected in 19 patients (24.05%). S100-β levels after cardiopulmonary bypass were significantly higher in the delirium group (998.10 [781.11–1825.59] ng/mL vs 594.75 [449.00–850.55] ng/mL, p = 0.0031); NSE levels were also higher compared with the control group (42.65 [19.03–55.33] ng/mL vs. 24.25 [15.70–36.11] ng/mL, p = 0.0232). GFAP levels were elevated in patients with delirium at both post-cardiopulmonary bypass time points (p = 0.0202 and p = 0.0309). ROC analysis for S100-β (cut-off 822.375 ng/mL) showed sensitivity 0.684 and specificity 0.746; 0.579 and 0.763 for NSE (36.55 ng/mL); 1.0 and 0.271 for GFAP (0.1099 ng/mL). Red blood cell transfusion volume (35.35 mL/kg vs. 17.84 mL/kg, p = 0.0005) and body weight (p = 0.0164) were independently associated with postoperative delirium.

CONCLUSION: S100-β and NSE have diagnostic value for predicting postoperative delirium in children after congenital heart defect repair with cardiopulmonary bypass. The developed three-marker panel enables risk stratification and timely implementation of neuroprotective strategies. Large multicenter studies are needed to validate these findings.