Objectives: Known associations between enterocyte injury and early mortality in adult patients following cardiac surgery highlight the critical role of timely detection and intervention. Elevated postoperative levels of intestinal fatty acid-binding protein (I-FABP) have been identified as a promising indicator for early identification of intestinal damage, potentially enhancing the risk prediction and treatment of critically ill patients after surgery. This study investigates the correlation between postoperative I-FABP levels and early mortality in patients at higher risk for early mortality undergoing cardiac surgery.
Methods: 500 consecutive patients undergoing cardiac surgery with extracorporeal circulation were enrolled. Blood samples were collected at five time points perioperatively. The target population included 101 patients at high risk for systemic inflammation identified by lactic acidosis >4 mmol/L and IL-6 >600 pg/mL; these were categorized as survivors and non-survivors.
Results: The mean age of patients in the target group was 66.5±12.3 y. Notably, 42% of patients developed septic shock within 12 hours of intensive care unit (ICU) admission, and the in-hospital mortality rate was 17%. Elevated serum I-FABP levels were significantly associated with non-survivors (MD 6945 pg/ml, 95%CI [2990.3 to 10899.8]; p=0.001), where the optimal threshold value for the I-FABP with >2527.3 pg/ml measured 12 h post-ICU admission predicted mortality with an AUC of 0.698 (95%CI [0.493-0.830], p=0.019). Univariate and multivariable logistic regression identified re-thoracotomy as a significant predictor of mortality, whereas lower age and body mass index indicated a survival advantage.
Conclusion: Serum I-FABP level at 12 h after ICU admission was able to identify patients with a high risk of mortality, with >2527.3 pg/ml as the optimal cut-off value. Even if lactate and IL-6 levels are high, they cannot discriminate between patients with/without early death risk.