Weber M A, Neutel J M, Smith D H, Graettinger W F
Hypertension Center, Veterans Affairs Medical Center, Long Beach 90822.
Circulation. 1994 Nov;90(5):2291-8. doi: 10.1161/01.cir.90.5.2291.
Between 20% and 30% of patients with clinically diagnosed hypertension have normal blood pressure (BP) values during automated ambulatory 24-hour BP monitoring. It has not been clear, however, whether these patients can be regarded as normotensive or whether they should be treated in the same way as confirmed hypertensive patients.
Ambulatory BP monitoring was performed in 88 normal control subjects and 171 hypertensive patients (office diastolic BP > or = 90 mm Hg on three visits; never treated or off treatment for more than 6 months). Hypertensive patients were classified as nonconfirmed or white coat (n = 58) if their 24-hour diastolic averages were < 85 mm Hg and at least 15 mm Hg lower than their office values. For comparisons, white coat patients were pair-matched with normal subjects by 24-hour diastolic averages and sex, and by similar age and weight; there were 40 such pairs. White coat patients were likewise pair-matched with confirmed hypertensive patients by identical office BPs (51 pairs). Participants were studied by individualized treadmill testing, Doppler echocardiography, and assays of resting plasma catecholamines, upright plasma renin and aldosterone, and lipid, glucose, and insulin concentrations. Because of the matching, compared with normal subjects, patients with white coat hypertension and normal subjects had identical 24-hour BP averages. The white coat patients exhibited slightly greater variability among individual readings (obtained each 15 minutes) throughout the day [P < .05]), but there were no differences in hemodynamic responses to exercise. Plasma norepinephrine (P < .05), renin and aldosterone (P < .01 for each), and insulin and low-density lipoprotein cholesterol levels (P < .01 for each) were higher in the white coat group, as were left ventricular septal wall (P < .05) and muscle mass (P = .07) echocardiographic measurements. When compared with the confirmed hypertensive patients, the white coat patients had higher renin (P < .01) but were otherwise similar. Within the white coat group, plasma norepinephrine correlated with total cholesterol and triglycerides (P < .05 for each), and aldosterone correlated with left ventricular mass (P < .01); there were no significant correlations within the normal control subject or confirmed hypertension groups.
Patients with white coat hypertension differ in metabolic, neuroendocrine, and cardiac findings from normal control subjects and have greater BP variability. These changes appear to be mediated by heightened activity of the sympathetic and renin-angiotensin systems. Although these characteristics could reflect an alerting reaction in the clinic due to awareness of their diagnosis, the white coat hypertensive patients also have evidence for additional, more-sustained differences from normal subjects. Thus, this condition appears to be a true variant of hypertension.
在临床诊断为高血压的患者中，有20%至30%的患者在自动动态24小时血压监测期间血压值正常。然而，尚不清楚这些患者是否可被视为血压正常，或者他们是否应与确诊的高血压患者接受相同的治疗。
对88名正常对照受试者和171名高血压患者进行了动态血压监测（三次就诊时诊室舒张压≥90 mmHg；从未接受治疗或停药超过6个月）。如果高血压患者的24小时舒张压平均值<85 mmHg且至少比其诊室值低15 mmHg，则将其分类为未确诊或白大衣高血压患者（n = 58）。为了进行比较，根据24小时舒张压平均值和性别，以及相似的年龄和体重，将白大衣高血压患者与正常受试者进行配对匹配；共有40对。同样根据相同的诊室血压将白大衣高血压患者与确诊的高血压患者进行配对匹配（51对）。通过个体化的跑步机测试、多普勒超声心动图以及静息血浆儿茶酚胺、直立位血浆肾素和醛固酮以及血脂、血糖和胰岛素浓度的检测对参与者进行研究。由于匹配，与正常受试者相比，白大衣高血压患者和正常受试者的24小时血压平均值相同。白大衣高血压患者在全天各次读数（每15分钟获取一次）之间的变异性略大[P < 0.05]），但运动时的血流动力学反应没有差异。白大衣高血压组的血浆去甲肾上腺素（P < 0.05）、肾素和醛固酮（各P < 0.01）以及胰岛素和低密度脂蛋白胆固醇水平（各P < 0.01）较高，左心室间隔壁（P < 0.05）和肌肉质量（P = 0.07）的超声心动图测量值也较高。与确诊的高血压患者相比，白大衣高血压患者的肾素水平较高（P < 0.01），但其他方面相似。在白大衣高血压组内，血浆去甲肾上腺素与总胆固醇和甘油三酯相关（各P < 0.05），醛固酮与左心室质量相关（P < 0.01）；在正常对照受试者组或确诊高血压组内没有显著相关性。
白大衣高血压患者在代谢、神经内分泌和心脏方面的表现与正常对照受试者不同，且血压变异性更大。这些变化似乎是由交感神经和肾素 - 血管紧张素系统的活性增强介导的。尽管这些特征可能反映了患者在诊所因知晓诊断而产生的警觉反应，但白大衣高血压患者也有证据表明与正常受试者存在其他更持续的差异。因此，这种情况似乎是高血压的一种真正变体。
