Prognostic Nutritional Index as a Novel Predictor of In-Stent Restenosis: A Retrospective Study

Background and Objectives: In-stent restenosis (ISR) is a major problem in patients undergoing percutaneous coronary intervention. The prognostic nutritional index (PNI) is a nutritional status score used in the literature to determine the prognosis of coronary artery disease. In this study, we aimed to investigate the effect of preprocedural PNI values on the risk of ISR in patients with stable coronary artery disease who underwent successful percutaneous coronary intervention. Materials and Methods: This retrospective study included 809 patients. Stent restenosis was evaluated in the follow-up coronary angiography of the patients due to stable angina pectoris or acute coronary syndrome. The patients were divided into two groups based on those with (n = 236) and without (n = 573) in-stent restenosis, and their nutritional status was compared with PNI. The PNI values before the first angiography of the patients were calculated. Results: The mean PNI score was significantly lower in patients with ISR than in those without ISR (49.5 vs. 52.3, p < 0.001). Concerning the results of the Cox regression hazard model for predictors of ISR, PNI was significantly associated with the development of ISR (HR = 0.932, 95% CI: 0.909–0.956, p < 0.001). In addition, stent type, stent length, and diabetes mellitus were associated with the development of ISR. Conclusions: A low PNI value indicates poor nutritional status, which is thought to accelerate inflammation processes and cause atherosclerosis and ISR.