Arterial hypertension, cognitive decline and cerebrovascular damage
Authors: Pal T , Preg Z , Tripon R G , Baroti B , Haba H , Nemes-Nagy E , German-Sallo M 
Published: October 2022

Abstract

Introduction
Arterial hypertension has been associated with increased risk of cognitive dysfunction (CD) and dementia explained by the onset of cerebral microvascular disease. However, it is not well known which are true markers of cognitive decline and how to demonstrate them.

Purpose
We aimed to evaluate cognitive functions and study microvascular disease with cerebral localization in hypertensive patients.

Methods
Patients over 50 years with arterial hypertension were included. Cognitive status was assessed by using the Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) tests. We selected 50 patients in two groups: 25 patients with mild CD (MoCA &lt;26 points, MMSE &gt;24 points), respectively 25 patients without CD (MoCA ≥26 points, MMSE ≥24 points). In these groups, magnetic resonance imaging (MRI) using GE Optima MR450w 1.5 Tesla of the brain was performed. MRI images with the RadiAnt program were studied and ImageJ was used to measure the area of the thalamus with a method developed by our team, by calculating the total area and hyperintense areas (microvascular damage) in number of pixels. For statistical analysis IBM-SPSS v.26 program was used.

Results
585 consecutive hypertensive patients were enrolled, mean age 67.9±9.5 years, 52.1% women, mean blood pressure 135/80±20/11 mmHg (with antihypertensive treatment). The MoCA test identified cognitive impairment in 66.1% of participants (mean scores 20.66±3.9) while the MMSE in 17.1% (mean scores 20.64±3.0). In the subgroup of 50 patients, the mean age was 70.9±5.5 years for the CD group and 69.9±3.9 years for the group without CD (p=0.4, between 59–79 years). No significant difference was detected between groups in mean blood pressure, ambulatory blood pressure, and hypertension duration (18.0±12 years vs. 17.7, p=0.9). Cerebrovascular disease was detected in 48 patients by brain MRI. There was no statistically significant difference between the two groups. The most frequent changes were white matter hyperintensities in 89.6%, enlarged perivascular spaces in 77.1%, and lacunar infarcts in 52.1%. In three cases silent brain infarct was unmasked. In 45 patients, we applied the modified measurement of the thalamic area and a statistically significant difference was detected in the right thalamus area in patients with CD (p=0.009) compared to patients without CD (on the left side p=0.058).

Conclusions
CD and cerebral microvascular changes were frequently present in hypertensive patients with associated cardiovascular disease in the studied group. At the level of the thalamus with the method developed by our team, we demonstrated that microvascular alterations on the right side are associated with cognitive decline. The methodology developed for the quantitative measurement of the injured thalamic area proved to be objective and repeatable. The innovative method, the analysis of imaging data with pixels is a promising way to continue the research.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Hungarian Academy of Science