Completeness of circle of Willis and white matter hyperintensities in patients with severe internal carotid artery stenosis

Background We investigated whether completeness of the circle of Willis (CoW) protected patients with severe internal carotid artery (ICA) stenosis against white matter hyperintensities (WMHs). Methods We included 115 patients with unilateral ICA stenosis 70%. The completeness of CoW was assessed and WMHs were rated on a visual scale. The score of deep and periventricular WMHs was compared between patients with complete and incomplete CoW and between the two hemispheres, ipsilateral and contralateral to stenosed ICA. Results We included 115 patients with severe ICA stenosis, 60 patients had a complete CoW (52.17%) and 55 had an incomplete CoW (47.83%). The patients with incomplete CoW had higher score of deep WMHs (OR=1.82, 95% CI 1.08-3.06, P=0.023) and periventricular WMHs (OR=4.53, 95% CI 2.09-9.81, P=0.000) than those with complete CoW. In the patients with incomplete CoW, the score of deep WMHs (OR=4.14, 95% CI 1.33-12.93, P=0.014) and periventricular WMHs (OR=5.46, 95% CI 1.16-25.62, P=0.032) was higher in the hemisphere ipsilateral to stenosed ICA than that in the contralateral hemisphere. In the patients with complete CoW, there was no significant difference in the score of deep WMHs (OR=2.10, 95% CI 0.37-11.91, P=0.401) and periventricular WMHs (OR=2.83, 95% CI 0.99-8.05, P=0.051) between the ipsilateral and contralateral hemispheres to stenosed ICA. Conclusion The completeness of CoW protected patients with severe ICA stenosis against WMHs.