Residual In-Stent Carotid Stenosis and Cigarette Smoking are Independent Predictors of Carotid Restenosis After Carotid Artery Stenting—Results from 738 Carotid Artery Stenting Procedures at a Single Center

BACKGROUND AND OBJECTIVES: Carotid artery stenting (CAS) has become a viable alternative to carotid endarterectomy for the management of carotid stenosis. Our aim was to determine the rate of radiographic restenosis after CAS and clinical, radiographic, and procedural predictors of in-stent restenosis. METHODS: Our single-center, prospectively maintained database was retrospectively reviewed for CAS procedures performed in symptomatic and asymptomatic patients over 12 years (2010-2022). Baseline demographic data, procedural characteristics, and preprocedural and postprocedural radiographic and clinical details were noted. Baseline characteristics of patients with and without carotid restenosis were compared using the χ 2 test for categorical variables and the Student t -test for continuous variables. Univariate and multivariate analyses were performed to determine risk factors associated with restenosis, defined as >70% on digital subtraction angiography. RESULTS: A total of 1017 consecutive CAS procedures were performed in 905 patients during the 12-year period, with 738 in 632 patients included in our study. Our cohort's overall restenosis rate was 17%, with a 14% restenosis rate at 2 years. On multivariate regression analysis, former or current smoking status (odds ratio [OR] = 2.3, 95% CI 1.2-4.1), plaque irregularity (OR 0.55, 95% CI 0.33-0.91), moderate (50.1%-75%) contralateral stenosis (OR 3.2, 95% CI 1.4-7.2), severe (75.1%-99.9%) contralateral stenosis (OR 2.8, 95% CI 1.3-6.0), and residual (>70%) in-stent stenosis after initial stenting (OR 433, 95% CI 80-2346) were significantly associated with carotid restenosis. Area under the curve for the multivariate regression model analysis was 0.78. Patients with <28.6% initial (residual) in-stent stenosis (45/517 cases) had a 9% restenosis rate, whereas those with >28.6% initial in-stent stenosis (77/221 cases) had a 35% restenosis rate. CONCLUSION: In this large, single-center study of carotid artery stenosis treated with CAS, residual in-stent carotid stenosis of approximately 30% and smoking status were independent predictors for restenosis. Maximizing treatment of initial stenosis and smoking cessation education are important steps in preventing future carotid restenosis.