Antihypertensive use differentially associated with lower cerebral blood flow in older people with hypertension

Consistent cerebral blood flow (CBF) is fundamental to brain function. Cerebral autoregulation ensures CBF stability. Chronic hypertension can lead to disrupted cerebral autoregulation in older people, potentially leading to blood pressure levels interfering with CBF. We investigated the associations of CBF with blood pressure and antihypertensive treatment, using arterial spin labelling MRI, in a prospective longitudinal cohort of 186 community-dwelling older individuals (77±3 years, 53% female) with hypertension, 125 (67%) of whom with 3-year follow-up. We assessed concurrent and longitudinal associations of diastolic blood pressure, systolic blood pressure, mean arterial pressure, pulse pressure, and antihypertensive drug use, with grey matter and white matter CBF (mL/100g/min), and the CBF spatial coefficient of variation (SCoV): a measure of CBF heterogeneity which may be more sensitive to cerebrovascular damage. We found no associations between blood pressure and concurrent CBF, nor between changes in blood pressure and CBF over 3-year follow-up. Antihypertensive use was associated with lower CBF and higher SCoV. Within antihypertensive types, calcium channel blockers and angiotensin receptor blockers were not associated with lower CBF. This aligns with previous evidence suggesting a protective effect of these antihypertensive classes on dementia, and may provide an important lead for future research.