Comparative Analysis of Symptomatic and Asymptomatic Carotid Plaques in Patients with Bilateral Mild Carotid Stenosis (30% - 50%)

Background: Nonstenosing carotid plaques are increasingly recognized as a potential cause of ischemic stroke, yet their contribution remains underappreciated in routine etiological classification. Objective: To compare morphological characteristics of carotid plaques between symptomatic and asymptomatic sides in patients with bilateral mild carotid stenosis (30% - 50%) and to explore their association with ischemic stroke occurrence. Methods: We conducted a retrospective, descriptive, single-center study in the Neurology Department of Ibn Rochd University Hospital, Casablanca, between January 2022 and December 2024. Patients presenting with acute ischemic stroke and bilateral carotid stenosis ranging from 30% to 50% were included. Carotid plaque characteristics were assessed primarily using computed tomography angiography (CTA), supplemented by Doppler ultrasound analysis for hemodynamic and echogenicity assessment. Stenosis severity was measured according to NASCET criteria. Results: Among 340 ischemic stroke patients, 60 were identified as having probable large-artery atherosclerotic involvement after etiological evaluation, and 10 fulfilled the inclusion criteria. The mean age was 68.5 years, with a male predominance (70%). Hypertension (80%) and diabetes mellitus (60%) were the most prevalent vascular risk factors. In this paired within-patient descriptive comparison, vulnerable plaque features appeared more frequent on the symptomatic side than on the contralateral asymptomatic side. Hypoechogenicity was observed in 5/10 symptomatic plaques versus 2/10 asymptomatic plaques, while surface irregularity was present in 5/10 versus 2/10, respectively. Mural thrombus and plaque ulceration were identified exclusively on symptomatic plaques (2/10 vs 0/10). Ipsilateral recurrence occurred in two patients during follow-up. Conclusion: High-risk nonstenosing carotid plaques were more frequently identified ipsilateral to ischemic stroke, suggesting a possible association between plaque vulnerability and stroke occurrence despite mild luminal narrowing. These findings support reconsideration of stroke classification systems that rely exclusively on luminal stenosis severity.