Carotid artery thickening and neurocirculatory abnormalities in de novo Parkinson disease

Cognitive dysfunction constitutes a major non-motor manifestation of Parkinson disease (PD), but the mechanisms remain incompletely understood. Neurocirculatory abnormalities such as supine hypertension (SH) and orthostatic hypotension (OH), white matter hyperintensities upon magnetic resonance imaging, and dementia are inter-related in PD, even in patients with early, levodopa-untreated disease. These abnormalities might in turn be associated with carotid atherosclerosis which, by a variety of interacting means could contribute to repeated episodes of cerebral hypo- and hyper-perfusion. We investigated inter-correlations among neurocirculatory and carotid sonographic measurements [intimal-medial thickness (IMT) and wall:lumen ratios (WLR)] in 65 patients with levodopa-untreated, de novo PD who underwent tilt table testing and 24-h ambulatory blood pressure monitoring. Increased mean IMT and WLR were associated with OH and supine and overnight blood pressures. Across individuals the orthostatic fall in systolic pressure was correlated with both IMT and WLR. Since arteriosclerosis would be expected to splint carotid sinus baroreceptors, complex positive interactions among carotid wall thickening, SH, and OH may result in myriad episodes of cerebral hypo- and hyper-perfusion, contributing to microvascular injury and consequently to the cognitive dysfunction attending PD.