Blood pressure in old age : exploring the relation with the structure, function and hemodynamics of the brain

With increasing age the prevalence of hypertension rises. High blood pressure at midlife is associated with cognitive impairment. Nevertheless, in older persons a lower rather than a higher blood pressure is associated with incident dementia. The main purpose of the work in this thesis was to explore the role of blood pressure in relation to cerebral structure, neurocognitive functioning and hemodynamics of the brain in old age. Therefore, we sought to determine whether discontinuation of antihypertensive therapy in persons aged 75 years and over with mild cognitive deficits and using antihypertensive medication (the Discontinuation of ANtihypertensive Treatment in Elderly people [DANTE] population) would improve their cognitive and psychological functioning. The assumption was that the increase in blood pressure after the discontinuation of antihypertensives would lead to a direct increase in cerebral blood flow and, as a consequence, to an improvement in cerebral functioning. An additional objective was to investigate possible underlying mechanisms in the relation between blood pressure and neurocognitive functioning. To enable this, brain MRI was used to determine whether (lower) blood pressure was associated with (micro)structural damage, cerebral small vessel disease and blood flow in the brain, and also whether the presence of cerebral (micro)structural damage was related to neurocognitive functioning.