Mourad J J, Girerd X, Boutouyrie P, Laurent S, Safar M, London G
Department of Internal Medicine, INSERM (U337), Broussais Hospital, Paris, France.
Hypertension. 1997 Dec;30(6):1425-30. doi: 10.1161/01.hyp.30.6.1425.
The incremental elastic modulus (Einc), which is the slope of the relationship between stress and strain of arteries, is a marker of vascular wall material stiffness. Isobaric Einc is reduced at the site of the radial artery in patients with essential hypertension and increased at the site of the common carotid artery in subjects with end-stage renal disease (ESRD). Whether the changes in Einc are influenced by the topography of the vessels, the composition of the arterial wall, and/or by the presence of ESRD is largely ignored. Radial artery Einc was measured in 19 patients with ESRD and compared with the Einc of 89 subjects with essential hypertension and 20 normotensive control subjects. Transcutaneous measurements of radial artery internal diameter and wall thickness (echo-tracking device) and digital pulse pressure (Finapres) were allowed to calculate Einc under operational (ie, at the mean arterial pressure of each group) and isobaric (100 mm Hg) conditions, as well as for a given wall stress. Internal diameter and pulsatile changes in diameter were identical in the three groups. Wall thickness and mean blood pressure were significantly elevated in subjects with hypertension but not in ESRD patients. Circumferential wall stress was identical in the three groups. For the same operational wall stress, and therefore at the operational mean arterial pressure of each group, Einc (kPa x 10[3]) was increased in patients with ESRD (5.53+/-4.0 versus 3.3+/-2.4 in control subjects; P<.05) and normal in subjects with essential hypertension (3.87+/-4.0). Under isobaric conditions, Einc was also significantly lower in subjects with hypertension and elevated in patients with ESRD. Thus, at the site of a medium-sized muscular artery constantly devoid of atherosclerosis, the stiffness of wall material is increased in patients with ESRD. The demonstrated alterations of the arterial wall are independent of the level of blood pressure and tensile stress and should be related to the status ESRD.
增量弹性模量（Einc）是动脉应力与应变关系的斜率，是血管壁材料硬度的标志物。原发性高血压患者桡动脉部位的等压Einc降低，而终末期肾病（ESRD）患者颈总动脉部位的等压Einc升高。Einc的变化是否受血管形态、动脉壁成分和/或ESRD的影响在很大程度上被忽视了。对19例ESRD患者的桡动脉Einc进行了测量，并与89例原发性高血压患者和20例血压正常的对照者的Einc进行了比较。采用经皮测量桡动脉内径和壁厚（回声跟踪装置）以及数字脉压（Finapres），以计算在工作状态（即每组的平均动脉压）和等压（100 mmHg）条件下以及给定壁应力下的Einc。三组的内径和直径的搏动变化相同。高血压患者的壁厚和平均血压显著升高，但ESRD患者则不然。三组的周向壁应力相同。对于相同的工作壁应力，因此在每组的工作平均动脉压下，ESRD患者的Einc（kPa×10[3]）升高（5.53±4.0，而对照组为3.3±2.4；P<0.05），原发性高血压患者的Einc正常（3.87±4.0）。在等压条件下，高血压患者的Einc也显著降低，而ESRD患者的Einc升高。因此，在一个始终无动脉粥样硬化的中等大小肌性动脉部位，ESRD患者的壁材料硬度增加。所证实的动脉壁改变与血压水平和拉伸应力无关，应与ESRD状态有关。
