Factors associated with restenosis after carotid artery stenting differ between closed-cell and open-cell stents.

Background: There is currently a lack of research comparing factors associated with in-stent restenosis (ISR) after carotid artery stenting (CAS) between closed-cell stents (CCS) and open-cell stents (OCS). The objective of this study was to assess and compare ISR incidence and clinical outcomes in CCS and OCS cohorts, proposing that ISR-related risk factors may differ based on stent design. Materials and methods: We retrospectively analyzed clinical data from patients who underwent CAS at our institution between 2020 and 2023. The median follow-up was 15.0 months, ranging from 11.0 to 23.0 months, with the longest follow-up period being 61 months. Patients with less than 6 months of follow-up were excluded from analysis. ISR was identified by either a peak systolic velocity (PSV) exceeding 300 cm/s or stenosis equal to or greater than 50%, as evaluated by CTA or DSA. Risk factors linked to ISR within CCS and OCS groups were initially examined through univariate Cox regression analysis. Multivariate Cox regression models were developed by employing stepwise regression and backward elimination methods. Results: This study included a total of 257 CAS procedures, comprising 129 CCS-treated patients and 128 OCS-treated patients. No significant differences were found between groups in demographic factors, comorbid conditions, or perioperative and follow-up clinical outcomes. Compared with the OCS group, the CCS cohort demonstrated significantly greater preoperative stenosis, higher frequency of post-dilation interventions, and lower residual stenosis rates (all p < 0.05). Despite these differences, ISR rates between the two groups were not statistically significant (log-rank p = 0.073). Patients who experienced ISR exhibited a notably greater degree of preoperative stenosis (p = 0.039). Within the CCS cohort, symptomatic atherosclerotic stenosis was significantly related to ISR (p = 0.038). Conversely, in the OCS cohort, significant predictors of ISR included residual stenosis severity and the presence of diabetes mellitus (both p < 0.05). Conclusion: Although initial analysis indicated no statistically significant ISR differences between CCS and OCS groups, multivariate regression analyses highlighted distinct independent risk factors for ISR based on stent type. Specifically, symptomatic atherosclerotic stenosis emerged as a significant risk factor in CCS-treated patients, while residual stenosis severity and diabetes mellitus were principal risk factors in the OCS-treated group.