Impact of New Diffusion-Weighted MRI Lesions Following Carotid Artery Stenting on Long-Term Stroke Recurrence

Objective Carotid artery stenting (CAS) has become an established alternative to carotid endarterectomy (CEA). However, new ischemic lesions, detected by diffusion-weighted imaging (DWI), are frequently observed following the procedure, and their prognostic significance remains controversial. This study aimed to evaluate the impact of new DWI lesions following CAS on long-term stroke recurrence in patients who underwent CAS for carotid artery stenosis. Methods This retrospective cohort study analyzed 46 consecutive patients who underwent CAS for symptomatic carotid stenosis between January 2008 and December 2015. All participants had a DWI performed before and within 24 hours after the procedure. Patients were stratified into DWI-positive (DWI+) and DWI-negative (DWI-) groups based on the presence of new ischemic lesions. The primary endpoint was stroke or transient ischemic attack (TIA) recurrence during long-term follow-up. Statistical analysis included the Mann-Whitney U test for continuous variables, the Chi-square test for categorical variables, and Kaplan-Meier survival analysis for time-to-event outcomes. Results New DWI lesions were identified in 20 of 46 patients (43.5%) following CAS. Of the 46 patients, eight (17.4%) were lost to follow-up; thus, 38 were analyzed (16 DWI+ and 22 DWI-). During a mean follow-up period of 36.5 months (range, 12-60 months), stroke recurrence occurred in 2 of 16 patients (12.5%) in the DWI+ group, while no stroke recurrence was observed in the 22 patients of the DWI- group (p = 0.170). No significant difference was found between groups regarding myocardial infarction development (DWI+: 2/16 (12.5%) vs. DWI-: 3/22 (13.6%), p = 1.000). Conclusion New DWI lesions following CAS may serve as a potential risk marker for long-term stroke recurrence, although statistical significance was not achieved in this cohort. These findings suggest that patients with new post-procedural DWI lesions may represent a higher-risk subgroup; however, this hypothesis requires validation in larger, adequately powered cohorts before guiding clinical practice. Validation studies in larger patient cohorts are needed to confirm these preliminary findings.