Supine hypertension is associated with an impaired cerebral oxygenation response to orthostasis: Findings from the Irish Longitudinal Study on Ageing (TILDA)

Abstract

The cerebrovascular effects of supine hypertension (SH) are still poorly understood. With aging and atherosclerosis of the vascular system, it is not uncommon for SH and non-neurogenic orthostatic hypotension to co-occur. Given evidence for end organ damage and more extreme cerebral dysfunction in those with SH-orthostatic hypotension, we hypothesized that SH would be associated with impaired cerebral autoregulation. The aim of this study was to characterize the cerebrovascular response to orthostasis. Near-infrared spectroscopy was used to quantify the cerebrovascular response. We analyzed data from Wave 3 of TILDA (The Irish Longitudinal Study on Ageing; n=2750). Cerebral oxygenation and blood pressure (BP) were monitored continuously during an active stand. Responses were modeled using multilevel mixed-effects models and adjusted for important covariates such as age, sex, education, antihypertensive medications, and comorbidities. Forty-nine percent of the sample had SH. Those with SH demonstrated an impaired BP response and a slower recovery of BP after standing, graded by severity of SH. The cerebral oxygenation response was similar for both groups, but when standardized to mean arterial BP, the response was impaired in those with SH. A deficit of −0.83% (95% CI, −0.93 to −0.74) remained after 3 minutes of standing. Our study determined that cerebral oxygenation and cerebral autoregulation are impaired in those with SH. In older patients, consideration should be given to measuring SH and screening for orthostatic hypotension. Therapeutic studies are needed to better understand the relationship between cerebral oxygenation, medications, supine BP, and orthostatic hypotension.