The Safety of Protected Carotid Artery Stenting in Patients with Unstable Plaque on Carotid High-Resolution MR Imaging

Purpose: The aim of this study was to determine the safety of the carotid artery stenting (CAS) procedure, using an embolic protection device which is based on the presence of unstable plaques on carotid MR imaging in patients who presented with severe carotid artery stenosis. Materials and Methods: This prospective study assessed 102 consecutive patients who had been noted with severe carotid stenosis. These patients underwent a preprocedural carotid MR imaging, and a periprocedural diffusion-weighted imaging (DWI) after the CAS. The unstable plaque on the carotid MR imaging was defined as characterized as intraplaque hemorrhage (IPH), thin/ruptured fibrous caps, or ulcers. We analyzed the incidence of the noted periprocedural ipsilateral ischemic events on the DWI, and noted the primary outcomes within 30 days of the CAS. Results: In the study, it is noted that 50 patients (49.0%) had IPH, 84 patients (82.4%) had thin/ruptured fibrous caps, and 43 patients (42.2%) had ulcers as seen on the carotid plaque MR imaging. The IPH was more common in the symptomatic group than in the asymptomatic group (58.7% vs. 41.1%, p = 0.12). Overall, the DWI was positive after CAS in 25.5% of cases. Additionally, the combined rate of 30-day stroke, myocardial infarction, or death was recorded at 3.9%. The new periprocedural ischemic lesions on the DWI were characteristically more frequently observed in the symptomatic group (17/46, 37.0%) than in the asymptomatic group (9/56, 16.1%) (p = 0.03). There was no significant difference in the primary outcome of the CAS, based on the type of unstable plaque of IPH, thin/ruptured fibrous caps, or ulcers. Conclusion: The protected CAS appears to be safe, regardless of the noted unstable plaque findings as seen on the carotid MR imaging. In this case, because of the higher risk of periprocedural ipsilateral ischemic events, it is therefore recommended that the symptomatic patients should receive more careful treatment during the CAS placement going forward.