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.
Methods: 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.
Results: 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.
Conclusion: 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.
Keywords: Carotid artery stenosis; Carotid artery stenting; In-stent restenosis.