Characteristics and Risk Factors of Restenosis in the Chronic Phase after Carotid Artery Stenting

Abstract

Restenosis after carotid artery stenting (CAS) can occur in the chronic phase; however, the characteristics, risk factors, and timing of occurrence remain unclear. This study aimed to analyze the features and risk factors of restenosis and to examine follow-up after CAS. Among 216 lesions for which CAS was performed between April 2008 and May 2018, 182 that were followed up for ≥12 months were included in this retrospective analysis. The follow-up period was 12-128 months (mean 52.7 months). The incidence of restenosis was 7.1% (13/182 lesions), including eight cases that developed restenosis within 12 months and five cases that occurred ＞12 months after CAS. The longest period until development is 83 months after CAS. There were 4 cases of symptomatic restenosis (2.2%), including 3 that occurred within 6 months, of which 2 occurred approximately one month after reduction of antithrombotic agents. In the multivariate analysis, younger age was the only risk factor significantly associated with restenosis (p=0.011, OR 1.13). The long-term risk of ipsilateral ischemic stroke was significantly higher in the restenosis (＋) group than in the restenosis (−) group (p=0.0011, OR 18.3). These results show that restenosis after CAS is more frequent within 12 months than after 12 months but can occur after long-term follow-up and may cause ipsilateral ischemic stroke. Restenosis may be particularly likely after the reduction of antiplatelet agents, and careful observation is important in the first 12 months after CAS.