Associations Between Circle Of Willis Morphology And White Matter Hyperintensities In Patients With Carotid Artery Stenosis

Objective: Internal carotid artery(ICA)stenosis has a high prevalence in our country.We are focusing on acute injury caused by cerebral infarction attributed to ICA stenosis.But we do not pay enough attention to silent cerebrovascular diseases which are the most commonly encountered incidental finding on brain imaging and related with chronic damage of brain.With increasing evidences for a relationship between ICA disease and white matter hyperintensities(WMHs),we intended to analyze the association between the circle of Willis morphology and WMHs in patients with severe ICA stenosis.Methods: We retrospectively recruited patients with unilateral ≥70% ICA stenosis andcontralateral <50% ICA stenosis who were referred to the Department of Neurology in our hospital between April 2016 and September 2017.Medical risk factors were recorded in this study,including age,gender,diabetes mellitus,atrial fibrillation,prior stroke,tobacco smoking,hypertension,coronary artery disease,blood pressure at baseline,and relevant blood tests.Subcortical and periventricular WMHs score,lacunar infarction score,the incidence of perivascular space was graded in bilateral hemispheres separately,and ICA stenosis and the circle of Willis morphology was also assessed.The general information,risk factors,imaging data were compared between the two groups with or without complete circle of Willis.At the same time imaging data were compared between the two groups as well as between ipsilateral and contralateral hemisphere of the stenosed ICA.Imaging data were further compared respectively with complete circle of Willis and incomplete circle of Willis in ipsilateral and contralateral hemisphere of the stenosed ICA.Results:(1)A total of 115 patients with ICA stenosis were enrolled in this study,including 60 patients in the complete circle of Willis group and 55 patients in the incomplete circle of Willis group.The mean age(70.22 ± 10.43 vs 64.42 ± 10.15,P = 0.003),the proportion of prior stroke history [23(41.82%)vs 14(23.33%),P=0.034] of the incomplete circle of Willis were higher than those of the complete circle of Willis group.Subcortical WMHs score [3.00(2.00-3.00)vs 1.00(0.00-1.75),P=0.000],periventricular WMHs score[2.00(1.00-2.00)vs 1.00(0.00-1.00),P=0.000],lacunar infarct score [1.00(0.00-1.00)vs 0.00(0.0 0-1.00),P=0.022] and the incidence of perivascular space [32(58.18%)vs 22(36.67%),P= 0.021] of ipsilateral ICA stenosis in the incomplete circle of Willis group was significant higher than those in complete circle of Willis group.Logistic regression analysis showed subcortical WMHs score(OR = 1.990,95% CI: 1.134-3.490,P = 0.016)and periventricular WMHs score(OR = 5.868,95% CI: 2.396-14.370,P = 0.000)were significantly higher in incomplete circle of Willis group than those in the complete circle of Willis group.(2)Comparing the bilateral imaging data of 115 patients with ICA stenosis,the score of subcortical WMHs [2.00(0.00-3.00)vs 1.00(0.00-2.00),P=0.000] and periventricular WMHs [1.00(1.00-2.00)vs 1.00(0.00-2.00),P=0.000] in the hemisphere ipsilateral to the stenosed ICA was significant higher than those contralateral to the stenosed ICA.There was no significant difference in the score of lacunar infarct and the incidence of perivascular space between ipsilateral and contralateral hemisphere of the stenosed ICA.Conditional logistic regression analysis showed that the score of subcortical WMHs(OR=3.956,95% CI:1.606-9.745,P=0.003)and periventricular WMHs(OR=3.366,95% CI 1.477-7.671,P=0.004)in the hemisphere ipsilateral to the stenosed ICA was significant higher than those contralateral to the stenosed ICA.(3)Comparing the bilateral imaging data of 60 patients with the complete circle of Willis in case of ICA stenosis group,the periventricular WMHs score [1.00(0.00-2.00)vs 1.00(0.00-1.00),P=0.028] in ipsilateral ICA stenosis was higher than those in contralateral to the stenosed ICA.Bilateral subcortical WMHs score,lacunar infarct score,the incidence of perivascular space was no difference.Conditional logistic regression analysis showed that subcortical WMHs score,periventricular WMHs score,lacunar infarct score and the incidence of perivascular space of ipsilateral ICA stenosis in the complete circle of Willis group had no significant difference compared with contralateral to the stenosed ICA.(4)Comparing the bilateral imaging data of 55 patients with incomplete circle of Willis in case of ICA stenosis group,the score of subcortical WMHs [3.00(2.00-3.00)vs 2.00(1.00-3.00),P=0.000] and periventricular WMHs score [2.00(1.00-3.00)vs 2.00(1.00-2.00),P=0.000] in the hemisphere ipsilateral to the stenosed ICA were higher than the contralateral to the stenosed ICA.Bilateral lacunar infarct score and the incidence of perivascular space had no difference.Conditional logistic regression analysis showed that subcortical WMHs score(OR=4.144,95%CI:1.328-12.929,P=0.014)and periventricular WMHs score(OR=5.455,95%CI:1.161-25.620,P=0.032)in the hemisphere ipsilateral to the stenosed ICA was significant higher than thosecontralateral to the stenosed ICA in the group of incomplete circle of Willis.Conclusion: This study showed that WMHs in the hemisphere ipsilateral to the stenosis was associated with ≥70% ICA stenosis.The incomplete circle of Willis in case of ≥70% ICA stenosis was related to WMHs in the hemisphere ipsilateral to the stenosis.The complete circle of Willis in case of ≥70% ICA stenosis may not be related to WMHs in the hemisphere ipsilateral to the stenosis.