6071Extent of hypertensive exposure in relation to vascular brain injury and cognitive impairment using heart-brain magnetic resonance imaging; The Heart-Brain Connection Study
Authors: Amier R , Marcks N , Hooghiemstra A M , Nijveldt R , Van Buchem M A , De Roos A , Biessels G J , Kappelle L J , Van Oostenbrugge R J , Bots M L , Niessen W J , Van Osch M J P , Van Der Flier W M , Brunner-La Rocca H P , Van Rossum A C 
Published: October 2019

Abstract

Background
Preserving brain health into advanced age has become one of the great challenges of modern medicine. Hypertension is highly prevalent and considered an independent contributor to cognitive impairment. Vascular brain injury, induced by exposure of the cerebral microcirculation to increased pressure and pulsatility, is the hypothesized link between hypertension and cognitive impairment. Hypertensive exposure can be assessed by cardiovascular magnetic resonance imaging markers, e.g. aortic stiffness by pulse wave velocity (PWV), left ventricular mass index (LVMi) and left ventricular (LV) concentricity by mass-to-volume ratio.

Purpose
To investigate the extent of hypertensive exposure in relation to cerebral small vessel disease (CSVD) and cognitive impairment, using heart-brain magnetic resonance imaging.

Methods
We included 559 participants aged 68±9 years from the Heart-Brain Connection study, consisting of three patient groups (i.e. heart failure, vascular cognitive impairment and carotid occlusive disease) and controls. LVMi, LV mass-to-volume ratio, aortic PWV and CSVD were assessed by 3.0 T heart-brain magnetic resonance imaging. Impairment in ≥1 major cognitive domain was assessed by comprehensive neuropsychological testing. Effect modification for patient groups was investigated by interaction terms; results are reported pooled or stratified accordingly.

Results
Overall prevalence of CSVD was 68.7% and prevalence of cognitive impairment was 26.9%. Figure 1 provides a visual overview of hypertensive exposure markers in relation to brain outcome. Aortic PWV (odds ratio [OR] 1.17, p=0.003 in patient groups only), LVMi (OR in carotid occlusive disease 5.69, p=0.006; OR in other groups 1.30, p=0.017) and LV mass-to-volume ratio (OR 1.81, p<0.001) were all associated with CSVD. Both aortic PWV (OR 1.07, p=0.009) and LV mass-to-volume ratio (OR 1.27, p=0.007) were also associated with cognitive impairment. Relations were independent of sociodemographics and cardiac index, and mostly persisted after correction for systolic blood pressure or medical history of hypertension. The relations of hypertensive exposure markers with cognitive impairment were attenuated when presence of CSVD was added as co-variate, (indirectly) supporting the hypothesis that CSVD is the link between hypertension and cognitive impairment.
Figure 1

Conclusion
Hypertensive exposure markers were independently associated with CSVD and cognitive impairment. Our findings indicate that hypertensive exposure markers relate to brain structure and function beyond clinical blood pressure or medical history.

Acknowledgement/Funding
Netherlands Cardiovascular Research Initiative; Dutch Heart Foundation; NFU; ZonMW; KNAW