690 Residual In-stent Carotid Stenosis and Cigarette Smoking are Predictors of Restenosis After Stenting (CAS)

INTRODUCTION: Atherosclerosis of the internal carotid artery remains a significant contributor to stroke morbidity and mortality. While patient risk factors have been identified to be associated with carotid restenosis after carotid stenting (CAS), conflicting theroies exist on whether residual stenosis is an independent risk factor. METHODS: A single-center, prospectively maintained database was retrospectively reviewed for CAS procedures over a 12-year period. Patient demographic, procedural characteristics, radiographic and clinical details were noted. Comparison of baseline characteristics of patients with and without carotid restenosis were performed using chi-squared test for categorical variables and 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: 1017 consecutive carotid artery stenting (CAS) procedures were performed in 905 patients over the 12-year period, with 738 CAS procedures in 632 patients included after exclusion criteria. Overall restenosis rate was 17%, with a 14% restenosis rate at 2 years-time. Multivariable analysis demonstrated former/current smoking status (OR=2.1 [95%CI 1.2-3.9]), moderate contralateral stenosis (OR 3.0 [95%CI 1.4-6.7]), severe contralateral stenosis (OR3.0 [1.4-6.3]), and residual stenosis (OR 454 [95% 85-2413]) were associated with restenosis. AUC for the multivariable model was 0.78. Cut-point degree for residual stenosis was ∼30%, where there was a 9% and 35% rate of restenosis in those less than, and greater than, 30% residual stenosis, respectively. CONCLUSIONS: We present the largest single-center data in the US to date on carotid artery stenosis treated with CAS, and factors associated with restenosis. Residual in-stent carotid stenosis and smoking history were independent predictors. Maximizing treatment of initial stenosis within stent for carefully selected patients and aggressive smoking cessation education are important steps in preventing future carotid restenosis.