Kario Kazuomi, Mitsuhashi Takeshi, Shimada Kazuyuki
Department of Cardiology, Jichi Medical School, Kawachi, Tochigi, Japan.
Am J Hypertens. 2002 Jun;15(6):531-7. doi: 10.1016/s0895-7061(02)02266-5.
Abnormal patterns of diurnal blood pressure (BP) variation have been reported to be related to advanced target organ damage and poor cardiovascular prognosis. However, the neurohumoral characteristics of patients with such variation have not been fully investigated. We measured BP and plasma levels of neurohumoral factors (norepinephrine [NE], epinephrine, renin, and arginine vasopressin [VP]) during the 70 degree head-up tilt test (10 min supine and 15 min tilting) in 120 older subjects (mean age 71 years) who had sustained hypertension as determined by ambulatory BP monitoring. They who were subclassified according to the nocturnal systolic BP fall as follows: 28 extreme dippers with >20% nocturnal BP fall; 78 dippers with >0% but <20% fall; and 14 nondippers with <0% fall. Plasma renin activity (r = 0.22, P = .02) and VP level (r = 0.36, P < .0001) after tilting were positively associated with the nocturnal systolic BP fall. Plasma NE levels were significantly higher in nondippers than in dippers in both the supine and tilting positions (supine 519 v 315 pg/mL, P = .001; tilting 803 v 550 ng/mL, P < .01), whereas the increase of NE induced by tilting was comparable in the two groups. Plasma renin activity in both the supine and tilting positions was comparable in the three groups, but the increase of this activity caused by tilting was less marked in the nondippers than in the extreme dippers (0.05 v 0.26 ng/mL/min, P = .02) and dippers (0.21 ng/mL/min, P = .07). Plasma VP was markedly increased after tilting in the extreme dippers compared with dippers (3.8 v 2.6 pg/mL, P < .001) and nondippers (v 2.0 pg/mL, P < .001), whereas the levels in the supine position were comparable in the three groups (2.0 pg/mL for extreme dippers, 1.9 pg/mL for dippers, 1.6 pg/mL for nondippers). In conclusion, diurnal BP variation in elderly hypertensive individuals was significantly associated with neurohumoral factors regulating circulating blood volume. Increased VP after tilting in extreme dippers might counteract reduced circulating blood volume, whereas nondippers appear to have alpha- and beta-adrenergic subsensitivity that may be induced by their chronic exposure to high NE levels.
据报道，异常的昼夜血压（BP）变化模式与靶器官损害进展及不良心血管预后相关。然而，此类变化患者的神经体液特征尚未得到充分研究。我们对120名老年受试者（平均年龄71岁）进行了70度头高位倾斜试验（仰卧10分钟，倾斜15分钟），这些受试者经动态血压监测确诊为持续性高血压。根据夜间收缩压下降情况将他们分为以下几类：28名极端杓型血压者，夜间血压下降>20%；78名杓型血压者，夜间血压下降>0%但<20%；14名非杓型血压者，夜间血压下降<0%。倾斜后血浆肾素活性（r = 0.22，P = 0.02）和血管加压素（VP）水平（r = 0.36，P < 0.0001）与夜间收缩压下降呈正相关。在仰卧位和倾斜位时，非杓型血压者的血浆去甲肾上腺素（NE）水平均显著高于杓型血压者（仰卧位：519对315 pg/mL，P = 0.001；倾斜位：803对550 ng/mL，P < 0.01），而倾斜诱导的NE增加在两组中相当。三组在仰卧位和倾斜位时的血浆肾素活性相当，但倾斜引起的该活性增加在非杓型血压者中比极端杓型血压者（0.05对0.26 ng/mL/分钟，P = 0.02）和杓型血压者（0.21 ng/mL/分钟，P = 0.07）更不明显。与杓型血压者（3.8对2.6 pg/mL，P < 0.001）和非杓型血压者（对2.0 pg/mL，P < 0.001）相比，极端杓型血压者倾斜后血浆VP显著升高，而三组仰卧位时的水平相当（极端杓型血压者为2.0 pg/mL，杓型血压者为1.9 pg/mL，非杓型血压者为1.6 pg/mL）。总之，老年高血压患者的昼夜血压变化与调节循环血容量的神经体液因素显著相关。极端杓型血压者倾斜后VP增加可能抵消循环血容量减少，而非杓型血压者似乎存在α和β肾上腺素能亚敏感性，这可能是由于长期暴露于高NE水平所致。
