Effect of carotid artery stenosis on cortical microinfarcts, white matter integrity, and brain volume: An...

Carotid artery stenosis could contribute to gradual loss of brain function through chronic hypoxia and ischemia.

We included consecutive participants of the population-based Rotterdam Study with unilateral ≥50 % stenosis at the carotid artery bifurcation on time-of-flight carotid MR angiography, and compared between hemispheres the presence of ischemic lesions, tissue volumes, and white matter integrity on structural brain MRI.

Among 50 participants (mean age 76 years, 50 % women), flow was lower in the affected carotid artery than on the unaffected side (160mL/min versus 202mL/min; flow reduction [95 %CI] per 1 % increase in stenosis: 1.7 mL/min [1.0-2.5]). Twelve individuals had radiographic evidence of cortical infarction, of whom 8 had cortical microinfarcts, all on the side of the stenosis (P = 0.001). Downstream of the stenotic artery, parenchymal volume was lower than in the contralateral hemisphere (mean difference: -2.7 mL [-4.9;-0.4]), similar for grey and white matter. Differences were most profound in the frontoparietal lobes, and increased with severity of stenosis to roughly 5 mL in individuals with ≥70 % stenosis. White matter hyperintensity volume and microstructural integrity did not differ between hemispheres.

Carotid artery stenosis is associated with downstream presence of cortical microinfarcts as well as lower parenchymal tissue volume.