A higher vertebrobasilar pulsatility index is associated with lower parietal perfusion in Alzheimer's disease

BackgroundWhile cerebrovascular hemodynamics exhibits critical interplay with the pathogenesis of dementia, limited articles have examined the impact of vertebrobasilar (VB) hemodynamics on cerebral blood flow (CBF), and to what extent it varies by dementia subtypes.ObjectiveTo explore the associations between VB hemodynamics and CBF by dementia subtypes.MethodsThis research recruited a total of 120 dementia patients [43 subcortical ischemic vascular dementia (SIVD); 59 Alzheimer's disease (AD); 18 mixed dementia] and 40 older adults with normal cognition and compared their transcranial doppler (TCD) flow parameters and arterial spin labeling-measured CBF. Using the partial correlation analysis, the associations between TCD parameters and CBF values were explored among the defined subgroups.ResultsA higher VB pulsatility index (PI) was related to lower parietal CBF and lower VB end-diastolic velocity (EDV). Moreover, the significance of flow parameters in the basilar artery (BA) to parietal CBF was identified: peak-systolic velocity (PSV) unanimously showed positive correlations among all subgroups except SIVD, and both PSV and EDV showed positive correlations in AD. Of note, there were more noticeable "BA flow-frontoparietal CBF" associations among the high than low VB PI group, and AD than SIVD group.ConclusionsThe findings indicate that VB-resistance-related parietal vulnerability and topological CBF associations vary by dementia subtypes. Given VB hemodynamics-CBF relationships, the current research extends our understanding of the vasocognopathic effects among dementia patients.