Cerebral Hemodynamics And Carotid Atherosclerosis In Patients With Subcortical Ischemic Vascular Dementia

Background: In recent years,several studies both nationally and internationally have suggested that pathophysiological changes in the large blood vessels of the brain,especially atherosclerotic changes,may be associated with the onset,progression and prognosis of cerebral small vessel disease(CSVD)and ultimately contribute to an overall cognitive decline in community-based population.Purpose: The purpose of this study is to investigate the role of large-vessel lesions in the development and progression of subcortical ischemic vascular dementia(SIVD)by studying the characteristics and changes of intracranial hemodynamics and carotid atherosclerosis in patients with SIVD,who usually have small-vessel disease as the main cause,and to provide a basis for further research on the diagnosis and treatment of patients with subcortical ischemic vascular dementia.Methods: This was a case-control study of 104 subjects recruited from August 2017 to August 2019.The subjects was consisted of 44 patients with clinically confirmed subcortical ischemic vascular dementia,30 patients with clinically confirmed Alzheimer’s disease dementia(AD),and 30 healthy controls(HC).The diagnosis of subcortical ischemic vascular dementia was made with reference to the Diagnostic and Statistical Manual of Mental Disorders,5th edition(DSM-5)and the Diagnostic Criteria for Vascular Behavioral and Cognitive Disorders(VASCOG);the diagnosis of Alzheimer’s disease dementia was made with reference to the International Working Group on Classic Alzheimer’s Disease Diagnostic Criteria,2nd edition(IWG-2),and all subjects signed the enrollment agreement and underwent ethical review.After enrollment,Cerebral hemodynamics and carotid atherosclerosis characteristics were measured by transcranial doppler(TCD)and carotid ultrasound in three groups of subjects,and mean flow velocity(MFV)and pulsatility index(PI)of intracranial and extracranial vessels were collected by transcranial doppler.Carotid artery plaque and lumen internal diameter of the common carotid artery,internal carotid artery and vertebral artery were measured by carotid ultrasound,where carotid artery plaque was quantified by total plaque count,number of arteries with plaque and carotid plaque score.The cognitive function of all subjects was assessed by the simple mental state examination(MMSE),and the characteristics of cerebral hemodynamics and carotid atherosclerosis in SIVD patients were analyzed by comparing the differences of MFV and PI,carotid plaque,and arterial lumen internal diameter parameters between the three groups.Analyzing the correlation between the above parameters and MMSE was used to explore the relationship between cerebral macrovascular lesions and cognitive dysfunction in patients with SIVD and AD.Meanwhile,we assessed the location and the severity of cerebral white matter lesions in SIVD patients by 3T magnetic resonance imaging(MRI).We assessed the severity of cerebral white matter lesions in SIVD patients by Fazekas score.We compared the cerebral hemodynamic parameters and carotid atherosclerosis characteristics in SIVD patients between different locations and different severity to investigate the potential relationship between macrovascular lesions and the severity of cerebral white matter lesions in SIVD.Results: Both patients with subcortical ischemic dementia and patients with Alzheimer’s disease dementia were found to have lower mean flow velocity(MFV)and higher arterial pulsatility index(PI)of cerebral blood flow compared to healthy controls.Patients with subcortical ischemic vascular dementia had lower mean flow velocity and higher arterial pulsatility index in the bilateral posterior cerebral arteries.Increased carotid lumen diameter and increased number of arteries with both internal carotid and common carotid atherosclerotic plaques were found in patients with subcortical ischemic vascular dementia,but not in patients with Alzheimer’s disease dementia.Scores on the MMSE were positively correlated with the mean flow rate of cerebral blood flow in most major cerebral arteries,negatively correlated with the arterial beat index in most major cerebral arteries,and negatively correlated with the lumen diameter of the common carotid artery,the number of arteries with atherosclerotic plaques,and the score of atherosclerotic plaques in the total carotid artery in patients with dementia.The deep white matter lesions were more serious and the lumen diameter of RVA and LCCA were more larger and carotid atherosclerosis were more serious.But there is no significant difference in cerebral hemodynamics and carotid atherosclerosis characteristics in the ventricles lesions of SIVD patients.Conclusion: Cerebral hemodynamics and carotid atherosclerotic parameters are objective indicators of pathological changes in large vessel structure and function,and the differences in these indicators between three groups suggest that large vessel lesions in the brain may be involved in the pathogenesis of SIVD or AD,which providing a new target for pathophysiological studies and intervention methods in SIVD.