Association Between Prognostic Nutritional Index and Clinical Outcomes After Percutaneous Coronary Intervention in Elderly Patients with Chronic Total Occlusion

Background: This study aimed to investigate the association between the prognostic nutritional index (PNI) and long-term all-cause mortality and major adverse cardiovascular events (MACEs) in elderly patients with chronic total occlusion (CTO) after successful percutaneous coronary intervention (PCI). Methods: This retrospective study enrolled 745 consecutive patients aged ≥ 60 years with successfully revascularized CTO between February 2011 and April 2023. All-cause mortality was the primary endpoint. MACE, defined as the first occurrence of all-cause mortality, non-fatal myocardial infarction, stroke, or target-vessel revascularization (TVR), was the secondary endpoint. Cox proportional hazards models and restricted cubic spline (RCS) analyses were used to evaluate associations. Results: During a median follow-up of 813 days, 58 (7.8%) all-cause mortality and 101 (13.6%) MACE occurred. In the primary multivariable model (Model 2), each 1-unit increase in PNI was associated with a 15% reduced risk of all-cause mortality (HR 0.85, 95% CI 0.81–0.90; p < 0.001) and an 8% reduced risk of MACE (HR 0.92, 95% CI 0.88–0.96; p < 0.001). Compared with the T1 group, patients in the T2 group had a significantly lower risk of all-cause mortality (HR = 0.21, 95% CI: 0.10–0.44; p < 0.001) and MACE (HR = 0.38, 95% CI: 0.23–0.63; p = 0.002). Similarly, the T3 group showed a significantly lower risk of all-cause mortality (HR = 0.24, 95% CI: 0.11–0.52; p = 0.003) and MACE (HR = 0.49, 95% CI: 0.30–0.82; p = 0.007). These associations remained directionally consistent in exploratory models with more extensive covariate adjustment. RCS indicated a linear association between PNI and all-cause mortality (p = 0.959) and a nonlinear association with MACE (p = 0.017). Conclusion: In this single-center retrospective cohort of elderly patients after successful CTO-PCI, lower baseline PNI was associated with higher risks of all-cause mortality and MACE. PNI may be a useful risk stratification tool, but its clinical utility requires confirmation in prospective, externally validated studies before implementation.