Arterial hypertension and cerebral hemodynamics: impact of head-down tilt on cerebral blood flow (arterial spin-labeling-MRI) in healthy and hypertensive patients.

Ian Seiller, Aude Pavilla, Julien Ognard, Nathalie Ozier-Lafontaine, Sylvie Colombani, Yamilet Cepeda Ibarra, Mehdi Mejdoubi

Journal of hypertension 2021 May 01

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Hypertension affects cerebrovascular autoregulation and increases the risk of cerebrovascular events and dementia. Notably, it is associated with cerebrovascular remodeling and lower resting cerebral blood flow (CBF). We wanted to determine, using arterial spin-labeling-MRI, the impact of a head-down tilt (HDT) dynamic maneuver on CBF in hypertensive patients. The current prospective study measured 36 patients' CBFs (18 normotensive individuals; 18 hypertensive patients) on 1.5T arterial spin-labeling-MRI in the supine position and after 4 min at -15° HDT. We reconstructed CBF maps of left and right subcortical nuclear gray matter, cortical gray matter and white matter (16 structures) to explore cerebrovascular autoregulation modification under dynamic conditions. Normotensive and hypertensive participants had no significant CBF differences in the supine position. After HDT, CBF mean variations (CBF-mVs) across all structures declined (mean -5.8%) for the whole population (n = 36), with -6.6 and -7.6% decreases, respectively, in white matter and gray matter (P < 0.001). Left and right accumbens nuclei had the largest changes (-9.6 and -9.2%, respectively; P < 0.001). No CBF-mV difference (0/16) was found in hypertensive patients after HDT, whereas normotensive participants' CBF-mVs changed significantly in four structures (left and right accumbens, putamen and left caudate nucleus) and gray matter. Hypertensive patients exhibited fewer CBF-mVs in left caudate nuclei (P = 0.039) and cortical gray matter (P = 0.013). Among hypertensive patients, people with diabetes had smaller CBF-mVs than people without diabetes. Our results highlight the significantly different CBF reactions to HDT of normotensive and hypertensive participants. They support the hypothesis that hypertension is responsible for deficient cerebrovascular autoregulation. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Citation

Ian Seiller, Aude Pavilla, Julien Ognard, Nathalie Ozier-Lafontaine, Sylvie Colombani, Yamilet Cepeda Ibarra, Mehdi Mejdoubi. Arterial hypertension and cerebral hemodynamics: impact of head-down tilt on cerebral blood flow (arterial spin-labeling-MRI) in healthy and hypertensive patients. Journal of hypertension. 2021 May 01;39(5):979-986