Ultrasound Tissue Pulsatility Imaging Suggests Impairment in Global Brain Pulsatility and Small Vessels in Elderly Patients with Orthostatic Hypotension

Abstract

Background: Orthostatic hypotension (OH) is highly prevalent in the elderly, and this population can be exposed to serious complications, including falls and cognitive disorders, as well as overall mortality. However, the pathophysiology of OH is still poorly understood, and innovative methods of cerebral blood flow (CBF) assessment have been required to accurately investigate cerebrovascular reactivity in OH.

Objectives: We want to compare brain tissue pulsatility (BTP) changes during an orthostatic challenge in elderly patients over 80 with and without OH.

Materials and methods: Forty-two subjects aged 80 and over were recruited from the geriatric unit of the Hospital of Tours, France, and were divided into two groups according to the result of an orthostatic challenge. The noninclusion criteria were any general unstable medical condition incompatible with orthostatic challenge, having no temporal acoustic window, severe cognitive impairment (Mini Mental Status Examination <15), history of stroke, and legal guardianship. We used the novel and highly sensitive ultrasound technique of tissue pulsatility imaging to measure BTP changes in elderly patients with (n = 22) and without OH (n = 17) during an orthostatic challenge.

Results: We found that the mean brain tissue pulsatility related to global intracranial pulsatility, but not maximum brain tissue pulsatility related to large arteries pulsatility, decreased significantly in OH patients, with a delay compared with the immediate drop in peripheral blood pressure.

Conclusion: Global pulsatile CBF changes and small vessels pulsatility, rather than changes in only large arteries, may be key mechanisms in OH to account for the links between OH and cerebrovascular disorders.

Keywords: Orthostatic hypotension; cerebral autoregulation; neuroimaging; ultrasound.