Hamada Toshihiko, Murata Tetsuhito, Narita Kosuke, Takahashi Tetsuya, Wada Yuji, Kimura Hideki, Yoshida Haruyoshi
Department of Clinical and Laboratory Science, University of Fukui, Fukui, Japan.
Blood Press. 2008;17(3):134-40. doi: 10.1080/08037050802162839.
Objective. A fall in nocturnal blood pressure (BP) is generally observed in normotensive subjects as well as in those with mild to moderate essential hypertension, regardless of the level of daytime BP. Among elderly hypertensive subjects, extreme-dippers with a marked nocturnal fall in BP as well as non-dippers with nocturnal fall absence are at increased risk for cardiovascular and cerebrovascular complications. However, the relationship between these abnormal diurnal BP variation patterns in normotensive elderly subjects has not been investigated. Methods. We classified 45 healthy late middle-aged and older adults into three groups according to the nocturnal systolic BP fall pattern examined by 24-h ambulatory BP monitoring (dipper, non-dipper and extreme-dipper), and compared the parameters of initial atherosclerosis, endothelial function and autonomic function. As a parameter of atherosclerotic factors, the intima-media thickness (IMT) of the carotid artery was examined, and as a parameter of endothelial function, brachial artery endothelium-dependent flow-mediated dilation (FMD) was ultrasonographyically measured. Autonomic function was assessed by power spectral analysis of heart rate variability (HRV). Results. No difference was observed in the severity of IMT between the three groups. The percent change of FMD in subjects in the extreme-dipper group was significantly lower than that of subjects in the dipper group, indicating that extreme-dippers in healthy elderly subjects may be associated with endothelial dysfunction. Also, HRV due to sympathetic modulation of subjects in the extreme-dipper group was significantly higher than that of subjects in the dipper and non-dipper groups, suggesting the activation of sympathetic tone. Conclusion. In healthy elderly subjects, the extreme-dipper type may reflect a decrease in endothelial function, i.e. initial stage atherosclerosis, rather than the dipper type.
目的。无论日间血压水平如何，正常血压受试者以及轻度至中度原发性高血压患者通常都会出现夜间血压下降。在老年高血压患者中，夜间血压显著下降的极端杓型血压者以及夜间血压无下降的非杓型血压者发生心血管和脑血管并发症的风险增加。然而，正常血压老年受试者中这些异常的昼夜血压变化模式之间的关系尚未得到研究。方法。我们根据24小时动态血压监测所检测的夜间收缩压下降模式（杓型、非杓型和极端杓型）将45名健康的中老年成年人分为三组，并比较了初始动脉粥样硬化、内皮功能和自主神经功能的参数。作为动脉粥样硬化因素的参数，检测了颈动脉内膜中层厚度（IMT），作为内皮功能的参数，超声测量了肱动脉内皮依赖性血流介导的舒张功能（FMD）。通过心率变异性（HRV）的功率谱分析评估自主神经功能。结果。三组之间IMT的严重程度没有差异。极端杓型组受试者FMD的百分比变化显著低于杓型组受试者，这表明健康老年受试者中的极端杓型血压者可能与内皮功能障碍有关。此外，极端杓型组受试者交感神经调节引起的HRV显著高于杓型组和非杓型组受试者，提示交感神经张力激活。结论。在健康老年受试者中，极端杓型类型可能反映内皮功能下降，即动脉粥样硬化的初始阶段，而不是杓型类型。
