Prognostic Value of Neutrophil-to-Lymphocyte Ratio for Adverse Outcomes in Pediatric Congenital Heart Disease Surgery.

Perioperative inflammatory response is implicated in postoperative complications in pediatric patients undergoing congenital heart disease (CHD) surgery. Neutrophil-to-lymphocyte ratio (NLR) is an inflammatory biomarker that may indicate systemic stress and predict postoperative complications. This systematic review synthesizes the existing evidence on perioperative NLR in pediatric CHD surgery and its relationship with mortality and postoperative complications. A systematic review was conducted according to PRISMA guidelines. The search was performed in PubMed, Web of Science, Embase, and ProQuest. Pooled standardized mean differences (SMDs) and correlation coefficients ( r ) with 95% confidence intervals (CI) were calculated to investigate the differences in NLR values and their relationships with postoperative outcomes in pediatric CHD surgery. A total of 16 studies were selected for the systematic review. Of them, all 16 were included in the meta-analyses. Perioperative NLR showed a trend toward higher values in patients with adverse outcomes; however, none of the pooled estimates reached statistical significance. For preoperative NLR, the pooled effect size (SMD) was 0.63 (95% CI: -0.27-1.52, p  = 0.17), and for postoperative NLR, it was 0.74 (95% CI: -0.27-1.75, p  = 0.15). Meta-analyses of correlations revealed that NLR was not significantly correlated with intensive care unit length of stay ( r  = 0.39, p  = 0.19), hospital length of stay ( r  = 0.43, p  = 0.15), duration of mechanical ventilation ( r  = 0.43, p  = 0.28), or overall postoperative complications (SMD = 0.55, p  = 0.094). Perioperative NLR in pediatric CHD surgery shows a trend toward higher values in patients with adverse outcomes but does not demonstrate a statistically significant association with mortality or complications. NLR reflects the inflammatory response but may not be sufficient as an independent predictor in pediatric patients undergoing cardiac surgery. Its clinical utility may be greater when used as part of combined risk assessment strategies.