Silent Brain Infarcts and White Matter Lesions in Patients with Asymptomatic Carotid Stenosis

The association of carotid atherosclerosis with silent brain infarcts (SBIs) and white matter lesions (WMLs) currently remains unknown. This study aims to compare SBIs, deep white matter lesions (DWMLs), and periventricular white matter lesions (PWMLs) in ipsilateral and contralateral hemispheres to internal carotid artery (ICA) stenosis, and investigate their association with stenosis grade in patients with asymptomatic ≥ 50% unilateral extracranial ICA stenosis. Patients without previous history of stroke and/or transient ischemic attack who had ≥ 50% stenosis in unilateral ICA on carotid color Doppler ultrasound were enrolled in the study. Patient demographics, vascular risk factors and ICA stenosis grades; number, location, and size of SBIs, DWMLs, and PWMLs in ICA territory were evaluated in both hemispheres using magnetic resonance imaging of the brain. Of the 69 patients, 53 had 50–69% (76.8%) and 16 had ≥ 70% (23.2%) unilateral ICA stenosis. There was no statistically significant difference in SBIs between ipsilateral and contralateral hemispheres to ≥ 50% ICA stenosis. Comparison of ICA stenoses as 50–69% and ≥ 70% revealed a greater number of patients with SBI in ipsilateral hemisphere to ≥ 70% stenosis compared to contralateral (p = 0.025). The number of SBIs was also higher in ipsilateral hemisphere to ≥ 70% stenosis compared to contralateral (p = 0.022). While DWMLs and PWMLs did not differ between hemispheres, frequency of Fazekas grade 1 DWMLs was lower in ipsilateral hemisphere to either 50–69% or ≥ 70% ICA stenosis compared to contralateral (p = 0.035 and p = 0.025, respectively). Results of the present study indicate that stenosis grade may be relevant in the association between asymptomatic carotid stenosis and SBIs, and ≥ 70% stenosis may pose a risk of SBI development.