Mar Philip L, Shibao Cyndya A, Garland Emily M, Black Bonnie K, Biaggioni Italo, Diedrich André, Paranjape Sachin Y, Robertson David, Raj Satish R
*Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN 37232-2102, U.S.A.
Clin Sci (Lond). 2015 Jul;129(2):107-16. doi: 10.1042/CS20140766.
Patients with neurogenic orthostatic hypotension (OH) typically have impaired sympathetic nervous system tone and therefore low levels of upright plasma norepinephrine (NE) (noradrenaline). We report a subset of patients who clinically have typical neurogenic OH but who paradoxically have elevated upright levels of plasma NE. We retrospectively studied 83 OH patients evaluated at the Vanderbilt Autonomic Dysfunction Center between August 2007 and May 2013. Based on standing NE, patients were dichotomized into a hyperadrenergic OH group [hyperOH: upright NE ≥ 3.55 nmol/l (600 pg/ml), n=19] or a non-hyperadrenergic OH group [nOH: upright NE < 3.55 nmol/l (600 pg/ml), n=64]. Medical history and data from autonomic testing, including the Valsalva manoeuvre (VM), were analysed. HyperOH patients had profound orthostatic falls in blood pressure (BP), but less severe than in nOH [change in SBP (systolic blood pressure): -53 ± 31 mmHg compared with -68 ± 33 mmHg, P=0.050; change in DBP (diastolic blood pressure): -18 ± 23 mmHg compared with -30 ± 17 mmHg, P=0.01]. The expected compensatory increase in standing heart rate (HR) was similarly blunted in both hyperOH and nOH groups [84 ± 15 beats per minute (bpm) compared with 82 ± 14 bpm; P=0.6]. HyperOH patients had less severe sympathetic failure as evidenced by smaller falls in DBP during phase 2 of VM and a shorter VM phase 4 BP recovery time (16.5 ± 8.9 s compared with 31.6 ± 16.6 s; P<0.001) than nOH patients. Neurogenic hyperOH patients have severe neurogenic OH, but have less severe adrenergic dysfunction than nOH patients. Further work is required to understand whether hyperOH patients will progress to nOH or whether this represents a different disorder.
神经源性直立性低血压（OH）患者通常交感神经系统张力受损，因此直立位血浆去甲肾上腺素（NE）（去甲肾上腺素）水平较低。我们报告了一组临床上具有典型神经源性OH但直立位血浆NE水平却反常升高的患者。我们回顾性研究了2007年8月至2013年5月在范德比尔特自主神经功能障碍中心评估的83例OH患者。根据站立位NE水平，将患者分为高肾上腺素能OH组[高OH：直立位NE≥3.55 nmol/l（600 pg/ml），n = 19]或非高肾上腺素能OH组[nOH：直立位NE < 3.55 nmol/l（600 pg/ml），n = 64]。分析了病史和自主神经测试数据，包括瓦尔萨尔瓦动作（VM）。高OH患者血压有明显的直立性下降，但比nOH患者轻[收缩压（SBP）变化：-53±31 mmHg，而nOH为-68±33 mmHg，P = 0.050；舒张压（DBP）变化：-18±23 mmHg，而nOH为-30±17 mmHg，P = 0.01]。高OH组和nOH组站立位心率（HR）预期的代偿性增加同样减弱[分别为84±15次/分钟（bpm）和82±14 bpm；P = 0.6]。高OH患者交感神经功能衰竭较轻，表现为VM第2期DBP下降较小以及VM第4期血压恢复时间较短（16.5±8.9秒，而nOH为31.6±16.6秒；P < 0.001）。神经源性高OH患者有严重的神经源性OH，但肾上腺素能功能障碍比nOH患者轻。需要进一步研究以了解高OH患者是否会进展为nOH，或者这是否代表一种不同的疾病。
