Inflammatory biomarkers to predict clinical outcomes in adults after cardiac surgery in China: a prospective observational trial

Abstract

Background

Systemic inflammatory response syndrome (SIRS) is a common occurrence in patients following cardiac surgery which has potential in the prediction of adverse postoperative outcomes. This study sought to investigate the underlying association between perioperative inflammatory cytokine levels and clinical outcomes in adults undergoing cardiac surgery.

Methods

This prospective study included 2100 patients admitted to the cardiovascular surgery intensive care unit between September 1, 2023, to August 31, 2024. Serum levels of nine inflammatory biomarkers (IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12p70, IL-17, TNF-α, and IFN-γ) were measured preoperatively and on the first postoperative day. Biomarker comparisons between groups (patients with and without postoperative complications) were assessed using receiver operating characteristic (ROC) curve analysis. Multivariable logistic regression was employed to identify independent risk factors for 30-day mortality prolonged, mechanical ventilation (MV) and postoperative acute kidney injury (AKI), adjusting for confounders such as cardiopulmonary bypass (CPB) type and other perioperative variables.

Results

Among the 2100 patients, 272 (13.0 %) required prolonged MV, 374 (17.8 %) developed AKI, and 40 (1.9 %) died within 30 days postoperatively. Significant differences in IL-6, IL-12p70, and IFN-γ levels were found between patients grouped by CPB type. Elevated levels of IL-6, IL-10, IL-17, and IFN-γ were observed in patients with prolonged MV, while patients who developed AKI had higher levels of IL-6, IL-2, and IL-10. Notably, IL-10 was the only cytokine significantly elevated in non-survivors compared to survivors. The area under the curve (AUC) for predicting prolonged MV was 0.654 for IL-6, 0.649 for IL-10, 0.668 for IL-17, and 0.644 for IFN-γ. For AKI, the AUC was 0.649 for IL-6, 0.623 for IL-2, and 0.684 for IL-10. The AUC for predicting 30-day mortality was 0.810 for IL-10. Multivariable logistic regression identified IL-6, IFN-γ, and APACHE II score as independent risk factors for prolonged MV, while IL-2 and 24-h postoperative drainage were independent risk factors for AKI. None cytokines were found to be associated with 30-day mortality except for APACHE II and SOFA score.

Conclusions

Elevated postoperative inflammatory biomarkers, particularly IL-6, IL-10, and IFN-γ, are associated with worse clinical outcomes, including prolonged MV, AKI, and 30-day mortality. Identifying these biomarkers early may help stratify patients at higher risk of poor outcomes after cardiac surgery.