Autonomic Medicine Section, National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), 9000 Rockville Pike 10/8C260, Bethesda, MD, 20892, USA.
Department of Neurology, Mayo Clinic, Rochester, MN, USA.
Clin Auton Res. 2021 Aug;31(4):543-551. doi: 10.1007/s10286-021-00788-4. Epub 2021 Mar 12.
Patients with neurogenic orthostatic hypotension in the setting of Lewy body diseases (LBnOH) typically have baroreflex failure and peripheral noradrenergic deficiency. Either or both of these abnormalities might determine the magnitude of OH in individual patients. We retrospectively correlated the orthostatic fall in systolic blood pressure (∆BPs) during active standing or 5 min of head-up tilt at 90° from horizontal as a function of several baroreflex and sympathetic noradrenergic indices.
Physiological, neurochemical, and sympathetic neuroimaging data from the Valsalva maneuver, head-up tilt table testing, and thoracic F-dopamine positron emission tomographic scanning (F-DA PET) were analyzed from 72 patients with LBnOH [44 with Parkinson disease (PD) and nOH, 28 with pure autonomic failure]. Comparison subjects had PD without OH (N = 44) or PD risk factors without parkinsonism or OH (N = 28) or were healthy volunteers (N = 8). Indices of baroreflex function included the Valsalva maneuver-associated baroreflex areas in Phase II (BRA-II) and IV (BRA-IV), the pressure recovery time (PRT), and baroreflex-cardiovagal and adrenergic sensitivities (BRS-V and BRS-A). The fractional orthostatic increment in plasma norepinephrine (Fx∆NE) provided a neurochemical index of baroreflex-sympathoneural function.
As expected, the LBnOH group had baroreflex-sympathoneural and baroreflex-cardiovagal impairment and low cardiac F-DA-derived radioactivity. Among patients, values for ∆BPs correlated with BRA-II, BRA-IV, BRS-V, and Fx∆NE but not with values for PRT, BRS-A, supine plasma NE, or F-DA-derived radioactivity.
Across individual patients with LBnOH, quantitative indices of baroreflex dysfunctions and peripheral noradrenergic deficiency are inconsistently associated with the magnitude of OH, even under controlled laboratory conditions.
患有路易体病（LBnOH）合并体位性低血压的患者通常存在压力反射失败和外周去甲肾上腺素能缺陷。这些异常中的任何一种或两种都可能决定个体患者 OH 的严重程度。我们回顾性地将主动站立或 90°头高位倾斜 5 分钟期间的收缩压（∆BPs）的体位性下降与几个压力反射和交感去甲肾上腺素能指数相关联。
从 Valsalva 动作、头高位倾斜试验和胸部 F-多巴胺正电子发射断层扫描（F-DA PET）获得的生理、神经化学和交感神经影像学数据来自 72 例 LBnOH 患者（44 例帕金森病（PD）和 nOH，28 例单纯自主衰竭）。对照受试者包括无 OH 的 PD（N=44）或无帕金森病或 OH 的 PD 危险因素（N=28）或健康志愿者（N=8）。压力反射功能指数包括第二阶段（BRA-II）和第四阶段（BRA-IV）的 Valsalva 动作相关压力反射区、压力恢复时间（PRT）以及压力反射-心迷走神经和肾上腺素能敏感性（BRS-V 和 BRS-A）。血浆去甲肾上腺素的体位性增量分数（Fx∆NE）提供了压力反射-交感神经功能的神经化学指数。
正如预期的那样，LBnOH 组存在压力反射-交感神经和压力反射-心迷走神经损伤以及低心脏 F-DA 衍生放射性。在患者中，∆BPs 值与 BRA-II、BRA-IV、BRS-V 和 Fx∆NE 相关，但与 PRT、BRS-A、仰卧位血浆 NE 或 F-DA 衍生放射性无关。
在 LBnOH 的个体患者中，压力反射功能障碍和外周去甲肾上腺素能缺乏的定量指数与 OH 的严重程度不一致，即使在受控的实验室条件下也是如此。
