Klop Marjolein, Claassen Jurgen A H R, Mol Arjen, Trappenburg Marijke C, van Wezel Richard J A, Maier Andrea B, Meskers Carel G M
Department of Neurobiology, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; Department of Geriatric Medicine, Radboud University Medical Center, Nijmegen, the Netherlands.
Department of Geriatric Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.
Auton Neurosci. 2025 Aug;260:103291. doi: 10.1016/j.autneu.2025.103291. Epub 2025 May 24.
Baroreflex sensitivity (BRS), maintaining blood pressure (BP), and cerebral autoregulation, maintaining cerebral blood flow (CBF), are regulatory mechanisms to counteract posture-related BP changes and their effect on CBF. These mechanisms may fail in geriatric conditions such as orthostatic hypotension (OH) and cause symptoms and falls. This study aimed to determine the association of age, sex, antihypertensive use, comorbidity, and OH with BRS and cerebral oxygenation after postural change. Thirty-four younger adults (median age 25 years), 30 older adults (median age 77 years), and 41 geriatric outpatients (median age 76 years) performed 2-3 supine-stand transitions, while heart rate (electrocardiogram), BP (volume-clamp photoplethysmography), and cerebral oxygenation (near-infrared spectroscopy) were measured continuously. BRS, cerebral oxygenation and cerebral autoregulation were determined in the time and frequency domain. Associations were investigated using linear regression and group comparisons. Higher age and presence of OH (OH in at least one supine-stand transition during a continuous BP measurement) were associated with lower BRS (1 % per year, 30 % when having OH). Higher age was associated with higher cerebral oxygenation recovery (0.1 μmol/L per year) after 30 s, while OH was associated with lower cerebral oxygenation recovery (1.3 μmol/L when having OH) at 1 min after postural change. No evidence of cerebral autoregulation impairment was found across all three groups. Reduced BRS and cerebral oxygenation recovery specifically in participants with OH are in line with their assumed susceptibility to cerebral hypoxia. The role of cerebral autoregulation as a compensatory mechanism for failing BRS could not be confirmed.
压力反射敏感性（BRS）可维持血压（BP），而脑自动调节可维持脑血流量（CBF），它们是抵消与体位相关的血压变化及其对脑血流量影响的调节机制。这些机制在诸如体位性低血压（OH）等老年疾病中可能失效，并导致症状和跌倒。本研究旨在确定年龄、性别、抗高血压药物使用、合并症和OH与体位改变后BRS和脑氧合之间的关联。34名年轻成年人（中位年龄25岁）、30名老年人（中位年龄77岁）和41名老年门诊患者（中位年龄76岁）进行了2 - 3次仰卧位到站立位的转换，同时连续测量心率（心电图）、血压（容积钳光电容积脉搏波描记法）和脑氧合（近红外光谱法）。在时域和频域中确定BRS、脑氧合和脑自动调节。使用线性回归和组间比较来研究关联。年龄较大和存在OH（在连续血压测量期间至少一次仰卧位到站立位转换中出现OH）与较低的BRS相关（每年1%，存在OH时为30%）。年龄较大与30秒后较高的脑氧合恢复相关（每年0.1μmol/L），而OH与体位改变后1分钟时较低的脑氧合恢复相关（存在OH时为1.3μmol/L）。在所有三组中均未发现脑自动调节受损的证据。特别是在患有OH的参与者中，BRS降低和脑氧合恢复降低与他们假定的脑缺氧易感性一致。脑自动调节作为BRS失效的一种代偿机制的作用尚未得到证实。
