The Predictive Role of a Novel Risk Index in Patients Undergoing Carotid Artery Stenting: Systemic Immune-Inflammation Index

Background: Inflammatory mechanisms play an important role in both atherosclerosis and stroke. There are several inflammatory peripheral blood count markers associated with carotid artery stenosis degree, symptomatic carotid artery lesions and carotid artery stent restenosis that reported in previous studies. However, the prognostic role of the blood cell counts and their ratios in predicting in-hospital and long-term outcomes in patients undergoing carotid artery stenting (CAS) has not been comprehensively investigated. Systemic immune-inflammation index (SII) proved its' efficiency in patients with solid tumors and its' role was rarely examined in cardiovascular disorders and stroke. The current study evaluated the effect of this novel risk index on in-hospital and long-term outcomes in a large patient population who underwent CAS. Method: A total of 732 patients with carotid artery stenosis who underwent CAS were enrolled to the study. SII was calculated using the following formula: neutrophil-to-lymphocyte ratio pound total platelet count in the peripheral blood (per mm3) and the patients were stratified accordingly: T1, T2 and T3. In-hospital and 5-year outcomes were compared between the tertiles of SII. Results: During the hospitalization, major stroke, ipsilateral stoke, myocardial infarction, death and major adverse cardiovascular events (MACE) rates were significantly higher in high SII level (T3) compared to SII levels (T1 and 2). In longterm outcomes, ipsilateral stroke, major stroke, transient ischemic attack, death, and MACE were significantly higher in the patients with higher SII level (T3). The 5-year Kaplan-Meier overall survival for T1, T2, and T3 were 97.5%, 96.7% and 86.0% respectively. In-hospital and 5-year regression analyses demonstrated that high SII was independently associated with MACE and mortality. Conclusion: SII was independently associated with in-hospital and long-term clinical outcomes in patients undergoing CAS. Immune and inflammation status, as assessed easily and quickly using SII, has a good discriminative value in these patients.