In-stent restenosis after interventional treatment of carotid artery stenoses: a long-term follow-up of a single center cohort

Background Whereas in-stent restenosis (ISR) is widely discussed after coronary stenting procedures, this phenomenon is a considerable problem after interventional treatment of carotid artery stenosis as well. We sought to quantify ISR rate and to identify important respective risk factors in our cohort. We retrospectively analyzed data of our carotid artery stenting database comprising 1165 angiographically successful interventional procedures during the last 19 years. Significant ISR was assessed by Doppler ultrasound and defined as a flow velocity exceeding 300 cm/s representing a lumen narrowing > 70%. Examinations were performed the day after intervention, at follow-up visits 1, 6 and 12 months after index hospitalization and once a year afterwards. Thirty-nine patients (3.4%) developed a significant ISR > 70% during the follow-up period (median 19.6 months, IQR 5.1-49.6 months). In 13 of them, restenosis was caused by a mechanical collapse (stent crush) of the implanted stent. All patients with significant ISR were free of neurological events during follow-up and 31 patients underwent a stent-in-stent implantation. We found a shorter stent length, a narrower stent diameter, performance of post-dilatation as well as stent type to significantly influence development of ISR. ISR > 70% after carotid artery stenting is a rare finding also during long-term follow-up. Especially in patients treated with balloon-expandable stents, post-dilatation reduced ISR significantly. As ISR was rare and clinically benign, this technique seems to remain a good therapy option in patients with significant carotid artery stenosis.