Evaluation of the Comprehensive Complication Index Versus the Clavien–Dindo Classification for Predicting Clinical Outcomes After Cardiac Surgery in Adult Patients

Background: Adult patients undergoing cardiac surgery are at an elevated risk of experiencing postoperative complications. However, there is currently no consensus on the most accurate instrument for assessing clinical outcomes following the occurrence of such complications in cardiac surgery. Objective: The objective was to validate the comprehensive complication index (CCI®) and Clavien–Dindo classification (CDC) regarding their ability to evaluate clinical outcomes in adult cardiac surgery. Methods: This retrospective study included 1896 adult patients who underwent cardiac surgery between September 2023 and October 2024. Among these patients, 849 developed postoperative complications. Complications were graded using the CDC, which were then converted to the CCI®. The validation of the CCI and CDC was evaluated. The strength of the correlation between the CCI®/CDC and clinical outcomes, including ICU stay duration, length of hospital stay, and hospitalization cost were compared using Spearman’s ρ and Fisher’s z-transformation. We also employed generalized linear models to analyze the variables that influenced clinical outcomes. Results: The median age of the patients was 58.0 years; the median CCI® score was 0.0 (interquartile range [IQR]: 0.0, 20.9). Pneumonia (92.8%) was the most common complication. The correlation of the CCI® with postoperative outcomes was stronger than the CDC: ICU stay (ρ = 0.786 vs. 0.401, p < 0.001), LOS (ρ = 0.465 vs. 0.342, p = 0.002), and hospitalization cost (ρ = 0.602 vs. 0.354, p < 0.001). Conclusions: Both the CCI® and CDC are valid tools for evaluating postoperative outcomes, while the CCI® has superior discriminative ability for evaluation ICU stay duration, LOS, and hospitalization cost in adult cardiac surgery patients.