Combined Prognostic Value of Nutritional and Inflammatory Indices for Predicting Functionally Significant Coronary Stenosis Verified by FFR: The PNI–SII–GINI Study

Background: Systemic inflammatory and nutritional indices have been associated with coronary artery disease burden and prognosis; however, their ability to predict lesion-level functional ischemia remains uncertain. This study evaluated whether the Prognostic Nutritional Index (PNI), Systemic Immune-Inflammation Index (SII), and Global Inflammation-Nutrition Index (GINI) are associated with functionally significant coronary stenosis assessed by fractional flow reserve (FFR). Methods: In this single-center observational study, patients with angiographically intermediate coronary lesions who underwent FFR assessment were included. PNI, SII, and GINI were calculated from routine laboratory parameters. Functionally significant stenosis was defined as FFR ≤ 0.80. Discriminative performance was evaluated using receiver-operating-characteristic (ROC) analysis, and associations were assessed with binary logistic regression. Results: A total of 113 patients were analyzed, of whom 48 (42.5%) had FFR ≤ 0.80. Baseline clinical characteristics and inflammatory-nutritional indices were comparable between patients with FFR ≤ 0.80 and FFR > 0.80. ROC analysis demonstrated limited discriminative ability for all indices, with area under the curve values of 0.544 for PNI, 0.461 for SII, and 0.554 for GINI (all p > 0.05). In logistic regression analysis, none of the indices independently predicted FFR-defined ischemia. Conclusion: Systemic inflammatory and nutritional indices, including PNI, SII, and GINI, did not reliably identify functionally significant coronary stenosis defined by FFR. These findings highlight the distinction between global inflammatory-nutritional status and lesion-specific coronary physiology, reinforcing the continued importance of direct physiological assessment for ischemia-guided management.