Department of Neuroradiology, Pierre-Zobda-Quitman Hospital, University Hospital of Martinique, French West Indies.
Department of Neuroradiology, University Hospital of Brest, Brest.
J Hypertens. 2021 May 1;39(5):979-986. doi: 10.1097/HJH.0000000000002709.
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.
高血压会影响脑血管自动调节功能，增加脑血管事件和痴呆的风险。值得注意的是，高血压与脑血管重塑和较低的静息脑血流（CBF）有关。我们想用动脉自旋标记 MRI 来确定头低位倾斜（HDT）动态操作对高血压患者 CBF 的影响。
本前瞻性研究在 1.5T 磁共振上测量了 36 名患者的 CBF（18 名正常血压个体；18 名高血压患者），在仰卧位和 -15°HDT 后 4 分钟时进行。我们重建了左侧和右侧皮质核灰质、皮质灰质和白质的 CBF 图（16 个结构），以探索在动态条件下脑血管自动调节的变化。
正常血压和高血压参与者在仰卧位时 CBF 没有明显差异。HDT 后，所有人的 CBF 平均变化率（CBF-mV）都有所下降（平均下降 5.8%）（n=36），白质和灰质分别下降 6.6%和 7.6%（P<0.001）。左、右伏隔核的变化最大（分别为-9.6%和-9.2%；P<0.001）。18 名高血压患者在 HDT 后没有发现 CBF-mV 差异（0/16），而正常血压参与者的 CBF-mV 在 4 个结构（左、右伏隔核、壳核和左尾状核）和灰质中发生了显著变化。高血压患者左尾状核（P=0.039）和皮质灰质（P=0.013）的 CBF-mV 减少。在高血压患者中，有糖尿病的人比没有糖尿病的人的 CBF-mV 更小。
我们的结果突出了正常血压和高血压参与者对 HDT 的 CBF 反应有显著差异。这支持了高血压导致脑血管自动调节功能不足的假说。
