Abstract：
OBJECTIVE: Our group has previously demonstrated that patients with asymptomatic carotid artery stenosis (ACAS) demonstrate cognitive impairment. One proposed mechanism for cognitive impairment in patients with ACAS is cerebral hypoperfusion due to flow-restriction. We tested whether the combination of a high-grade carotid stenosis and inadequate cross-collateralization in the Circle of Willis (CoW) resulted in worsened cognitive impairment.
METHODS: Twenty-four patients with high-grade (≥70% diameter-reducing) ACAS underwent carotid duplex ultrasound, cognitive assessment, and 3D time-of-flight magnetic resonance angiography. The cognitive battery consisted of nine neuropsychological tests assessing four cognitive domains: learning and recall, attention and working memory, motor and processing speed, and executive function. Raw cognitive scores were converted into standardized T-scores. A structured interpretation of the magnetic resonance angiography images was performed with each segment of the CoW categorized as being either normal or abnormal. Abnormal segments of the CoW were defined as segments characterized as narrowed or occluded due to congenital aplasia or hypoplasia, or acquired atherosclerotic stenosis or occlusion. Linear regression was used to estimate the association between the number of abnormal segments in the CoW, and individual cognitive domain scores. Significance was set to P < .05.
RESULTS: The mean age of the patients was 66.1 ± 9.6 years, and 79.2% (n = 19) were male. A significant negative association was found between the number of abnormal segments in the CoW and cognitive scores in the learning and recall (β = -6.5; P = .01), and attention and working memory (β = -7.0; P = .02) domains. There was a trend suggesting a negative association in the motor and processing speed (β = -2.4; P = .35) and executive function (β = -4.5; P = .06) domains that did not reach significance.
CONCLUSIONS: In patients with high-grade ACAS, the concomitant presence of increasing occlusive disease in the CoW correlates with worse cognitive function. This association was significant in the learning and recall and attention and working memory domains. Although motor and processing speed and executive function also declined numerically with increasing abnormal segments in the CoW, the relationship was not significant. Since flow restriction at a carotid stenosis compounded by inadequate collateral compensation across a diseased CoW worsens cerebral perfusion, our findings support the hypothesis that cerebral hypoperfusion underlies the observed cognitive impairment in patients with ACAS.
METHODS: Twenty-four patients with high-grade (≥70% diameter-reducing) ACAS underwent carotid duplex ultrasound, cognitive assessment, and 3D time-of-flight magnetic resonance angiography. The cognitive battery consisted of nine neuropsychological tests assessing four cognitive domains: learning and recall, attention and working memory, motor and processing speed, and executive function. Raw cognitive scores were converted into standardized T-scores. A structured interpretation of the magnetic resonance angiography images was performed with each segment of the CoW categorized as being either normal or abnormal. Abnormal segments of the CoW were defined as segments characterized as narrowed or occluded due to congenital aplasia or hypoplasia, or acquired atherosclerotic stenosis or occlusion. Linear regression was used to estimate the association between the number of abnormal segments in the CoW, and individual cognitive domain scores. Significance was set to P < .05.
RESULTS: The mean age of the patients was 66.1 ± 9.6 years, and 79.2% (n = 19) were male. A significant negative association was found between the number of abnormal segments in the CoW and cognitive scores in the learning and recall (β = -6.5; P = .01), and attention and working memory (β = -7.0; P = .02) domains. There was a trend suggesting a negative association in the motor and processing speed (β = -2.4; P = .35) and executive function (β = -4.5; P = .06) domains that did not reach significance.
CONCLUSIONS: In patients with high-grade ACAS, the concomitant presence of increasing occlusive disease in the CoW correlates with worse cognitive function. This association was significant in the learning and recall and attention and working memory domains. Although motor and processing speed and executive function also declined numerically with increasing abnormal segments in the CoW, the relationship was not significant. Since flow restriction at a carotid stenosis compounded by inadequate collateral compensation across a diseased CoW worsens cerebral perfusion, our findings support the hypothesis that cerebral hypoperfusion underlies the observed cognitive impairment in patients with ACAS.
摘要：
目的：我们小组先前已证明无症状颈动脉狭窄（ACAS）患者存在认知障碍。ACAS患者认知障碍的一种提出的机制是由于流量限制引起的脑灌注不足。我们测试了威利斯环（CoW）中高度颈动脉狭窄和交叉侧支不足的组合是否会导致认知障碍恶化。
方法：24例高度（直径缩小≥70%）ACAS患者行颈动脉超声检查，认知评估，和3D飞行时间磁共振血管造影（MRA）。认知电池由九项神经心理学测试组成，评估四个认知领域：学习和回忆，注意力和工作记忆，电机和处理速度，和执行功能。将原始认知分数转换为标准化T分数。对MRA图像进行结构化解释，将CoW的每个片段分类为正常或异常。CoW的异常节段定义为由于先天性发育不全或发育不全而狭窄或闭塞的节段。或获得性动脉粥样硬化狭窄或闭塞。线性回归用于估计CoW中异常段的数量之间的关联，和个体认知领域得分。显著性设定为p<0.05。
结果：患者的平均年龄为66.1±9.6(平均±SD)岁，79.2%(n=19)为男性。CoW中异常段的数量与学习和回忆中的认知得分之间存在显着负相关（β=-6.5，p=0.01），以及注意力和工作记忆(β=-7.0，p=0.02)域。有一种趋势表明，运动和处理速度（β=-2.4，p=0.35）和执行功能（β=-4.5，p=0.06）域呈负相关，但未达到显着性。
结论：在高级别ACAS患者中，CoW中伴随的闭塞性疾病增加与认知功能恶化相关。这种关联在学习和回忆以及注意力和工作记忆领域很重要。虽然电机和处理速度和执行功能也随着CoW中异常段的增加而数字下降，关系并不显著。由于颈动脉狭窄的血流限制加上整个患病CoW的侧支补偿不足会恶化脑灌注，我们的研究结果支持以下假设:脑灌注不足是ACAS患者所观察到的认知障碍的基础.
方法：24例高度（直径缩小≥70%）ACAS患者行颈动脉超声检查，认知评估，和3D飞行时间磁共振血管造影（MRA）。认知电池由九项神经心理学测试组成，评估四个认知领域：学习和回忆，注意力和工作记忆，电机和处理速度，和执行功能。将原始认知分数转换为标准化T分数。对MRA图像进行结构化解释，将CoW的每个片段分类为正常或异常。CoW的异常节段定义为由于先天性发育不全或发育不全而狭窄或闭塞的节段。或获得性动脉粥样硬化狭窄或闭塞。线性回归用于估计CoW中异常段的数量之间的关联，和个体认知领域得分。显著性设定为p<0.05。
结果：患者的平均年龄为66.1±9.6(平均±SD)岁，79.2%(n=19)为男性。CoW中异常段的数量与学习和回忆中的认知得分之间存在显着负相关（β=-6.5，p=0.01），以及注意力和工作记忆(β=-7.0，p=0.02)域。有一种趋势表明，运动和处理速度（β=-2.4，p=0.35）和执行功能（β=-4.5，p=0.06）域呈负相关，但未达到显着性。
结论：在高级别ACAS患者中，CoW中伴随的闭塞性疾病增加与认知功能恶化相关。这种关联在学习和回忆以及注意力和工作记忆领域很重要。虽然电机和处理速度和执行功能也随着CoW中异常段的增加而数字下降，关系并不显著。由于颈动脉狭窄的血流限制加上整个患病CoW的侧支补偿不足会恶化脑灌注，我们的研究结果支持以下假设:脑灌注不足是ACAS患者所观察到的认知障碍的基础.
