Longer Duration of Hypertension and MRI Microvascular Brain Alterations Are Associated with Lower Hippocampal Volumes in Older Individuals with Hypertension

Abstract

Background: Hippocampal atrophy is associated with cognitive decline. Determining the clinical features associated with hippocampal volume (HV)/atrophy may help in tailoring preventive strategies.

Objective: This study was aimed to investigate the association between HV (at visit 2) and vascular status (both at visit 1 and visit 2) in a cohort of individuals aged 60+ with hypertension and without overt cognitive impairment at visit 1 (visit 1 and visit 2 were separated by approximately 8 years).

Methods: Hippocampal volume was estimated in brain MRIs as HV both clinically with the Scheltens' Medial Temporal Atrophy score, and automatically with the Free Surfer Software application. A detailed medical history, somatometric measurements, cognitive tests, leukoaraiosis severity (Fazekas score), vascular parameters including pulse wave velocity, central blood pressure, and carotid artery plaques, as well as several biochemical parameters were also measured.

Results: 113 hypertensive patients, 47% male, aged 75.1±5.6 years, participated in both visit 1 and visit 2 of the ADELAHYDE study. Age (β= -0.30) and hypertension duration (β= -0.20) at visit 1 were independently associated with smaller HV at visit 2 (p < 0.05 for all). In addition to these variables, low body mass index (β= 0.18), high MRI Fazekas score (β= -0.20), and low Gröber-Buschke total recall (β= 0.27) were associated with smaller HV at visit 2 (p < 0.05 for all).

Conclusion: In a cohort of older individuals without cognitive impairment at baseline, we described several factors associated with lower HV, of which hypertension duration can potentially be modified.

Keywords: Aortic stiffness; brain MRI; cognitive decline; dementia; hippocampus; hypertension; macrovascular; microvascular; white matter lesions.

Fig.1

Hippocampal volume assessed with Free Surfer Software according to Fazekas scale (grade, category). y axis, hippocampal volume (average of left plus right hippocampal volume in mm³) divided by the total intracranial volume (in mm³) multiplied by 1000; x axis, Fazekas grade. Multiple-comparison adjusted post-hoc test: Grade 0-1 versus Grade 2-3, p = 0.50; Grade 0-1 versus Grade 4–6, p = 0.031; Grade 2-3 versus Grade 4–6, p = 0.008.

Fig.2

Statistically significant factors correlating with decreased hippocampal volume assessed by Free Surfer Software and Scheltens’ score.