Abstract
Purpose: This study aimed to assess the predictive accuracy of 30-day mortality with delta neutrophil index (DNI) in adult cardiac surgical patients. Methods: This study enrolled patients who underwent cardiac surgery under general anesthesia between March 2016 and May 2022 at a tertiary hospital in the Republic of Korea. DNI was measured preoperatively, on postoperative arrival to the surgical intensive care unit (ICU), and 12, 24, 48, and 72 h postoperatively. Receiver operating characteristic (ROC) analysis was employed to identify the prediction accuracy of DNI. An area under ROC curve (AUROC) ≥0.700 was defined as satisfactory predictive accuracy. An optimal cutoff point for the DNI value to maximize predictive accuracy was revealed in the ROC curve, where [sensitivity + specificity] was maximum. Results: This study included a total of 843 patients in the final analyses. The mean age of the study population was 66.9±12.2 years and 38.4% of them were female patients. The overall 30-day mortality rate was 5.2%. Surgery involving the thoracic aorta, history of prior cardiac surgery, or emergency surgery were associated with a higher mortality rate. The DNI showed satisfactory predictive accuracy at 24 h, 48 h, and 72 h postoperatively, with AUROC of 0.729, 0.711, and 0.755, respectively. The optimal cutoff points of DNI at each time point were 3.2, 3.8, and 2.3, respectively. Conclusions: Postoperative DNI is a good predictor of 30-day mortality after cardiac surgery and has the benefit of no additional financial costs or time.