Systemic Immune-Inflammation Index Predicts Restenosis after Interventions for Lower Extremity Arteriosclerosis Obliterans

To investigate the association between the pretreatment systemic immune-inflammation index (SII) and restenosis after interventions for lower extremity arteriosclerosis obliterans (ASO).We retrospectively evaluated 309 patients with ASO who underwent endovascular interventions between January 2018 and December 2021. Pretreatment inflammatory markers, including the SII, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic inflammation response index (SIRI), aggregate index of systemic inflammation (AISI), and C-reactive protein (CRP) were collected. The logistic regression model was used to determine the associations between these inflammatory markers and restenosis. Clinical manifestations, ankle-brachial index (ABI), and quality of life after intervention also were compared.The pretreatment SII (p < 0.001), NLR (p < 0.001), PLR (p < 0.001), SIRI (p = 0.002), AISI (p < 0.001), and CRP (p = 0.036) were significantly higher in patients with restenosis than in those without restenosis. Among the four markers, SII had the highest area under the curve (AUC) in predicting restenosis (SII vs. NLR vs. PLR vs. SIRI vs. AISI vs. CRP: 0.715 vs. 0.689 vs. 0.695 vs. 0.643 vs. 0.691 vs. 0.596). Multivariate analysis revealed that the pretreatment SII was the only independent factor for restenosis (hazard ratio [HR]: 4.102; 95% confidence interval [CI]: 1.155-14.567; p = 0.029). Moreover, a lower SII was associated with significantly better improvements in clinical manifestations (Rutherford classification 1-2: 67.5% vs. 52.9%, p = 0.038) and ABI (median: 0.29 vs. 0.22; p = 0.029), together with better quality of life (p < 0.05 for physical functioning, social functioning, pain, and mental health).The pretreatment SII is an independent predictor of restenosis after interventions in patients with lower extremity ASO, providing more accurate prognosis prediction than other inflammatory markers.