Orthostatic hypotension without co-existent supine hypertension is associated with impaired cerebral oxygenation: findings from the Irish Longitudinal Study on Ageing (TILDA)

Hypertension and orthostatic hypotension (OH) are common in older age, with both conditions recognized as risk factors for cardiovascular disease and end organ damage. Cerebral hypoperfusion is postulated to play a role in these adverse effects. For those with both hypertension and OH the effects on the cerebrovasculature are unclear, but there may be a risk of a higher hypotensive burden. We measured cerebral oxygenation utilizing near infrared spectroscopy, during an active stand challenge, and continuous blood pressure (BP), in The Irish Longitudinal Study on Ageing (TILDA) population. There was no difference in baseline oxygenation with supine hypertension (SH) or OH, but those with SH-OH had a higher supine BP, increased arterial stiffness and more cardiovascular conditions. Participants with SH-OH exhibited the largest BP drop and most impaired BP recovery on standing, yet the oxygenation response was not different to those with no SH and no OH. Those with OH only had the lowest BP values, lowest oxygenation values and most impaired oxygenation recovery, suggesting this group are at risk of cerebral hypotension when BP drops to low absolute values, whereas if BP is maintained at higher values as in those with SH-OH sufficient cerebral flow may be maintained.