Background: The Prognostic Nutritional Index (PNI) is a tool that combines serum albumin levels and lymphocyte count to assess a patient’s nutritional and immune status. Malnutrition, often undetected in coronary bypass (CABG) patients may cause increased morbidity and mortality. PNI is a potential preoperative marker to identify high-risk patients who may benefit from nutritional support.

Aim: To investigate the association between the prognostic nutritional index (PNI) and 30-day mortality and morbidity in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB).

Methods: Consecutive patients aged 60 years or older who underwent coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) at a single institute between 2021 and 2022 were included in the study. The Prognostic Nutritional Index (PNI) was calculated for each patient, and comparisons were made between those with and without mortality and morbidity. Multivariate analysis was conducted out to investigate the association between PNI and both mortality and morbidity.

Results: A total of 435 patients were included in the study. The mean age was 68.61±5.16 years, and 114 patients (26.2%) were female. The mean EuroSCORE II was 1.71±0.93, and the mean PNI was 50.65±6.33. Patients who experienced mortality or morbidity had significantly lower PNI scores compared to those who did not.

Conclusion: Lower PNI values were associated with increased postoperative mortality and morbidity in patients over 60 years old undergoing CABG with CPB.