Prognostic nutritional index and long-term outcomes after coronary artery bypass grafting.

Aims: This study examined whether preoperative prognostic nutritional index (PNI) was related to long-term major adverse cardiovascular events (MACE), all-cause mortality, and cardiovascular mortality in patients with coronary heart disease (CHD) undergoing coronary artery bypass grafting (CABG).

Methods: This single-center retrospective cohort study analyzed 550 patients with CHD who underwent CABG at the First Affiliated Hospital of Nanchang University between January 2014 and August 2025. PNI was treated as both a continuous variable and tertiles. Multivariable Cox models were used to evaluate its associations with study outcomes, and Kaplan-Meier as well as receiver operating characteristic (ROC) analyses were additionally performed. Subgroup analyses, a sensitivity analysis excluding patients with chronic kidney disease (CKD), and supplementary comparisons with the Geriatric Nutritional Risk Index (GNRI) and EuroSCORE II were also undertaken.

Results: Over a median follow-up of 46.1 months, 113 patients developed MACE, 94 died from any cause, and 61 died from cardiovascular causes. After multivariable adjustment, higher PNI remained independently related to lower risks of MACE (HR per 1-unit increase: 0.948, 95% CI 0.917-0.979; P = 0.001), all-cause mortality (HR 0.938, 95% CI 0.904-0.973; P < 0.001), and cardiovascular mortality (HR 0.939, 95% CI 0.900-0.980; P = 0.004). Patients in the highest tertile had lower risks of MACE and cardiovascular mortality than those in the lowest tertile. Similar overall patterns were observed in subgroup, quartile, and sensitivity analyses. Although PNI was significantly correlated with all three outcomes, its discriminatory performance was modest (AUCs: 0.596 for MACE, 0.616 for all-cause mortality, and 0.608 for cardiovascular mortality). GNRI and EuroSCORE II yielded numerically higher AUC values, and the combination of PNI with EuroSCORE II also showed a numerical improvement, but none of these differences reached statistical significance.

Conclusion: Lower preoperative PNI corresponded to higher long-term risks of MACE, all-cause mortality, and cardiovascular mortality after CABG. However, these findings should be interpreted cautiously due to the single-center retrospective design and the limited discriminatory performance of PNI.