Effects of arterial hypertension on cerebral hemodynamics: Impact of head-down position on cerebral blood flow (asl–mri) in healthy and hypertensive subjects

Background Hypertension affects cerebrovascular regulation. Purpose To show that cerebral blood flow is altered in hypertensive subjects exposed to dynamic maneuvers: head down tilt (HD). Study type Prospective. Population: 36 subjects (18 normotensive subjects (NT); 53,2 ± 8,8 years/18 Hypertensive subjects (HT); 53,7 ± 8,5 years). Field Strength/Sequence: 1.5 T/ASL in supine position and after 4 minutes of HD position. DWI/T2*/3D-TOF/FLAIR. Assessment Regions of interest from reconstructed cerebral blood-flow (CBF) maps: sub-cortical nuclear grey matter (Accumbens, amygdala, caudate, hippocampus, pallidum, putamen, thalamus), cortical gray matter (cGM) and white matter (WM). Hemodynamics parameters were monitored. Statistical tests Shapiro and Wilk, Fisher test, univariate and multivariate simple linear regression, Pearson correlation, Student's t-test. Results There was no significant CBF difference between NT and HT group in supine position. After head down tilt, the mean CBF across all structures fell by 5.8% on average in whole study group (n = 36) with a decrease of 6.6% and 7.6% respectively in white and gray matter (p  Data . Conclusion Our study highlights the significant different reaction of CBF to head position between NT and HT subjects. This supports the hypothesis that hypertension is responsible for a deficient cerebral regulation.