SS–01 Independent Predictors of in-Stent Restenosis in Young Patients qith Acute Coronary Syndrome: The Role of the Naples Prognostic Score and Procedural Risk Factors

Abstract

Introduction and Aim: In-stent restenosis (ISR) following percutaneous coronary intervention (PCI) in young (≤50 years) patients with acute coronary syndrome (ACS) remains a significant concern that adversely affects clinical outcomes. This study aimed to identify independent clinical, angiographic, and laboratory-based predictors of 1-year ISR development in a young ACS population, and to evaluate, for the first time in this population, the Naples Prognostic Score (NPS), a composite index reflecting nutritional and inflammatory status.

Methods: Patients aged ≤50 years who underwent PCI for ACS were retrospectively analyzed. ISR was defined as ≥50% luminal narrowing within the stent. The NPS was calculated based on four threshold criteria—serum albumin (<40 g/L), total cholesterol (<180 mg/ dL), neutrophil-to-lymphocyte ratio (NLR, >2.96), and lymphocyte-to-monocyte ratio (LMR, <4.44)—yielding a score of 0–4, and patients were stratified into low- (0), intermediate- (1–2), and highrisk (3–4) groups. One-year ISR-free survival was assessed using the Kaplan-Meier method, with between-group comparisons performed by the log-rank test; independent predictors were determined using multivariable Cox regression analysis.

Results: After patients meeting the exclusion criteria were removed from the study, a total of 326 patients were analyzed, of whom 40 (12.3%) developed ISR. NPS was significantly higher in patients with restenosis (1.85±1.05 vs. 1.35±0.97; p=0.002), with a clear dose-response relationship observed across risk groups (ISR rates of 5.7%/11.8%/25.0% in the low-/intermediate-/high-risk groups, respectively; χ²=9.46; p=0.009). Kaplan-Meier analysis demonstrated a significant difference in 12-month event-free survival according to NPS group (log-rank p=0.014). In the multivariable Cox regression model, multivessel involvement (HR=5.43; 95% CI 2.50–11.82; p<0.001), stent length (HR=1.08 per 1-mm increase; 95% CI 1.05–1.11; p<0.001), diabetes mellitus (DM) (HR=2.11; 95% CI 1.12–3.99; p=0.022), and NPS (HR=1.49; 95% CI 1.09–2.04; p=0.012) were identified as independent predictors. Hemoglobin, which was significant in univariable analysis (HR=0.85; p=0.039), lost its independent significance in the multivariable model (p=0.235).

Conclusion: Multivessel involvement and stent length emerged as the strongest procedural risk factors for ISR in young ACS patients, while DM was confirmed as a classic independent comorbid risk factor. The Naples Prognostic Score was shown, for the first time in this population, to be an independent and dose-dependent predictor of restenosis. This easily calculable, cost-free score derived from routine blood tests may contribute to clinical risk stratification and the determination of more intensive angiographic follow-up strategies in young ACS patients.