Impact of hepatic dysfunction on outcomes following adult cardiac surgery.

Objective: Laboratory abnormalities related to hepatic function are common after cardiac surgery and may reflect transient physiologic stress or early organ dysfunction. This study aimed to evaluate how postoperative liver-related laboratory abnormalities inform prognosis for 30-day mortality after adult cardiac surgery. Methods: This retrospective cohort study analyzed 16,236 adults undergoing coronary artery bypass grafting or left-sided valve surgery between 2010 and 2022 at a single institution. Receiver operating characteristic analysis was conducted to assess discriminatory performance of laboratory values for 30-day mortality. Peak postoperative aspartate aminotransferase, total bilirubin, and lactate were analyzed as markers of hepatic dysfunction. Patients were stratified by combinations of laboratory abnormalities and timing of peak elevation. Unadjusted logistic regression was used to generate probability plots illustrating the relationship between peak laboratory values and mortality. Multivariable logistic regression adjusted for postoperative complications. Results: Aspartate aminotransferase and lactate (area under the curve = 0.85) demonstrated the highest discrimination for 30-day mortality. Aspartate aminotransferase remained independently associated with mortality after multivariable adjustment (odds ratio, 1.03 per 100 U/L, Conclusions: Postoperative elevations in liver-related laboratory values-particularly when occurring in combination or peaking beyond 48 hours after surgery-identify patients at markedly increased risk of 30-day mortality. These markers provide valuable insight into physiologic stress and should be carefully managed after cardiac surgery.