Abstract 18889: Higher Serum Interieukin-6 is a Strong Postoperative Predictor of Delirium After Isolated Coronary Artery Bypass Graft Surgery

Abstract

Introduction: Postoperative delirium (POD) is a common neuropsychiatric complication after coronary artery bypass graft (CABG) surgery and contributes to the morbidity and mortality. Although the pathogenesis of POD is largely unknown, surgery induced systemic inflammation might play a role. We examined the predictive values of serum interieukin-6 (sIL-6) level in predicting the occurrence of POD. Methods: Ninety nine patients undergoing the first time elective isolated CABG were consecutively recruited. All enrolled patients were assessed for POD twice a day for 5 days using the Confusion Assessment Method for Intensive Care Unit, and divided into either POD or non-POD groups. IL-6 levels were measured by ELISA (R&D Human IL-6 Quantikine) before operation (T0) and 6 (T6), 12 (T12) and 18 (T18) hours after operation. One-way repeated ANOVA was used to test the differences in trends and patterns of sIL-6 changes over time between the two groups. Logistic regression and ROC were performed to determine the predictive values of IL-6. Results: POD developed in 42.4% (42 of 99) patients. Among them, 90.4% POD occurred within the first 2 days after CABG. Patients with POD were older and more likely to be female. The sIL-6 levels were significantly higher in POD group than those in non-POD group with the highest levels at T6 and T12 (Figure 1). One-way ANOVA for repeated measures revealed interaction effects between time and group (with p values of <0.001 and 0.019). Logistic regression showed that sIL-6 level ≥491.37 pg/mL at T18 was a strong predictor of POD (OR=4.706, 95%CI 1.998-11.082, p<0.001) even after adjusting for age and female gender (OR=10.220, 95%CI 2.465-42.365, p=0.001), with a sensitivity and specificity of 66.7% and 68.4%, respectively. Conclusions: Higher sIL-6 level is an independent predictor of POD, and the sIL-6 level above 491.37pg/mL at 18 hours after CABG has a higher specificity in predicting the occurrence of POD.