Carotid Artery Stenting for Patients with Radiation-Induced Carotid Artery Stenosis

Objective: In radiation-induced carotid artery stenosis (RIS), morphological characteristics, such as bilateral and long lesion distances and in-stent stenosis, have been reported as common after carotid artery stenting (CAS). Here, we present 25 cases at our hospital wherein CAS was performed for RIS and compare the morphological characteristics and the safety of the treatment with cases of atherosclerotic carotid artery stenosis (AS). Methods: Twenty-five lesions from 21 patients underwent CAS for RIS at our hospital between March 2002 and July 2020. The procedure was performed at a mean of 10.0 +/- 5.2 years after radiation therapy with 60-72 Gy, with a median follow-up of 45 months. We retrospectively selected consecutive patients with AS with comparable follow-up times from the beginning of the study as controls. We compared the patients' background, stenosis findings including plaque MRI, perioperative period, and postoperative course. Results: All patients in both groups completed the procedure, and the median follow-up time for the RIS and AS groups was 45 and 40 months, respectively (p = 0.1479). Patients in the RIS group had a lower mean age (69.9 +/- 6.9 vs. 75.3 +/- 7.04, p = 0.0075), a higher stenosis rate (79.1 +/- 8.7% vs. 68.6 +/- 11.7%, p = 0.0032), and longer stenosis greater than one vertebra (long lesions) (10 vs. 1, p = 0.0046) compared with the patients in the AS group. Although there was no significant difference in outcomes between the two groups, restenosis tended to be more common in the RIS group. Plaque MRI was characterized by a significantly higher T2WI signal (p = 0.0381) in the RIS group, which was attributable to the fact that a necrotic core has been reported commonly in the plaque tissue Conclusion: RIS has a high likelihood of restenosis both morphologically and in terms of plaque characteristics. Thus, close follow-up is crucial.