Investigating the effects of antihypertensive medication use in AD patients using multi‐modal neuroimaging

Abstract

AbstractBackgroundHypertension is a known risk factor for Alzheimer’s disease (AD). Both conditions cause significant irreversible damage to cerebral constituents that can result in a more severe AD phenotype. Although there are no effective treatments available for AD, hypertension is a modifiable risk factor and its detrimental effects can be alleviated with antihypertensive drug treatments and through primary prevention.MethodPatients with mild to moderate AD (N = 133) were divided into two groups to examine differences in cerebral constituents and cognitive function in patients who were medicated (n = 71) and unmedicated (n = 62) for hypertension. Within the medicated patient group, a post hoc analysis was conducted to examine differences in patients based on the class of antihypertensive treatment. We used multi‐modal neuroimaging to explore these differences in cerebral blood flow (CBF), white matter integrity, grey matter volume (GMV) and vascular burden.ResultNo differences were detected between the medicated and unmedicated AD patients in the multi‐modal comparisons, although the medicated group showed a slightly better cognitive profile than the unmedicated group, despite having a higher burden of cardiovascular comorbidities and similar blood pressure readings to the unmedicated group. In the post hoc analysis, AD patients who were on beta‐blockers only, presented with higher GMV, CBF and neuropsychological scores and also a lower vascular burden compared to AD patients on other classes of antihypertensive treatment or a combination of the two. In the post hoc analysis of the unmedicated AD patient subgroup, variability in pulse pressure (the difference between systolic and diastolic blood pressure) was linked with lower CBF in subcortical structures.ConclusionThe use of antihypertensive treatment in AD could mitigate progression of damage to cerebral constituents related to chronically elevated blood pressure. The class of antihypertensive treatment used has varied effects on cerebral constituents in AD patients, pointing towards the need for future longitudinal studies exploring these effects. Evidence from this study also suggests that implementation of antihypertensive treatment could be beneficial in AD patients with uncontrolled hypertension. Measures to promote early identification of comorbidities and targeted interventions could thus help reduce AD severity in patients.