H. Nagai, F. Nakagawa, H. Eda, S. Higiwara, M. Daisu, T. Uemura, T. Miyazaki, Y. Akiyama
Department of Neurosurgery, Shimane University Faculty of Medicine – Izumo, Japan

Objective: In-stent restenosis (ISR) is a major problem that can occur during long-term follow-up after carotid artery stenting (CAS). Patients who undergo CAS are usually followed using three-dimensional enhanced computed tomography angiography (3D-CTA) for two years after the procedure, and with carotid duplex sonography (CDU) thereafter. However, it is not clear which factors serve as predictors of late-onset ISR or how to use data from CDU to make subsequent management decisions. Therefore, we compared the differences between patients without ISR (no-ISR group) and patients with high-grade ISR (defined as more than 40% stenosis according to the NASCET method).

Material and Methods: Among 70 carotid arteries that had undergone CAS at our institution, patients who were evaluated with a final 3D-CTA at two years of CAS and who subsequently underwent CDU were analyzed in this study. A total of 22 vessels met the study’s inclusion criteria at the date of IRB approval (Study#1171).

Results: No significant difference was observed due to small number, when comparing the no-ISR group and the high-grade ISR group. However, more patients in the ISR group had a history of cancer than did those in the no-ISR group. The in-stent max intima-media thickness (IMT) of 3D-CTA correlated with that of CDU. The result was suggested that there was no ISR in the IMT of CDU less than 1.0mm.

Discussion: We found the cancer-history as the risk factor of late-onset ISR. The in-stent max IMT of CDU was a predictor of late-onset ISR. We advocated aftercare management by CDU for the stented patient.

Key words: carotid artery stent, carotid duplex ultrasound, in-stent restenosis.