Abstract
BACKGROUND: In-stent restenosis (ISR) remains a significant challenge despite advancements in percutaneous interventions, often leading to adverse clinical outcomes. The neutrophil-to-lymphocyte ratio (NLR) has emerged as a potential biomarker for predicting ISR, offering opportunities for improved risk stratification and treatment personalization. This systematic review and meta-analysis assess the predictive value of NLR in ISR, providing insights into its clinical applicability. METHODS: Systematic literature search was conducted in scientific databases until 21st July 2024. Observational studies evaluating NLR in stented patients were included. Random effect meta-analysis and linear regression model were used to investigate odds ratios (OR) as predictor and linear dose-response relationship of ISR. Sensitivity and specificity of NLR to predict this outcome were pooled and a summary receiver operating characteristics (sROC) curve was generated. This study was already registered in the PROSPERO (ID: CRD42024555123). RESULTS: 15 studies with 3 889 patients were included. High NLR was associated with increased risk of ISR in coronary and non-coronary stenting [aOR = 1.61 (95%CI 1.14-2.25); aOR = 1.69 (95%CI 1.52-1.87)]. One unit increase of NLR is equal to 30% and 44% increased risk of ISR in coronary and non-coronary patients. Included studies showing NLR as a robust predictor of ISR with sensitivity and specificity of 70.5% (95%CI 60.1%-79.2%) and 74.1% (95%CI 56.7%-86.2%) for coronary stenting and 77.7% (95%CI 69.8%-84.0%) and 66.4% (95%CI 49.6%-79.8%) non-coronary stenting, with AUC of 0.77 (0.70-0.82) in the coronary and 0.79 (0.70-0.85) in the non-coronary sub-groups. CONCLUSION: In conclusion, NLR yields promising predictive and prognostic potentials in predicting ISR in coronary and non-coronary stents. Additionally, NLR appears to be more proficient in predicting early ISR compared to late ISR in both coronary and non-coronary stents.