INCREASED STIFFNESS OF RADIAL ARTERY WALL MATERIAL IN END-STAGE RENAL-DISEASE

The incremental elastic modulus (fine), which is the slope of the rela tionship between stress and strain of arteries, is a marker of vascula r wall material stiffness. Isobaric fine is reduced at the site of the radial artery in patients with essential hypertension and increased a t the site of the common carotid artery in subjects with end-stage ren al disease (ESRD). Whether the changes in fine are influenced by the t opography of the vessels, the composition of the arterial wall, and/or by the presence of ESRD is largely ignored. Radial artery fine was me asured in 19 patients with ESRD and compared with the fine of 89 subje cts with essential hypertension and 20 normotensive control subjects. Transcutaneous measurements of radial artery internal diameter and wal l thickness (echo-tracking device) and digital pulse pressure (Finapre s) were allowed to calculate fine under operational tie, at the mean a rterial pressure of each group) and isobaric (100 mm Hg) conditions, a s well as for a given wall stress. Internal diameter and pulsatile cha nges in diameter were identical in the three groups. Wall thickness an d mean blood pressure were significantly elevated in subjects with hyp ertension but not in ESRD patients. Circumferential wall stress was id entical in the three groups. For the same operational wall stress, and therefore at the operational mean arterial pressure of each group, fi ne (kPa . 10(3)) was increased in patients with ESRD (5.53+/-4.0 versu s 3.3+/-2.4 in control subjects; P<.05) and normal in subjects with es sential hypertension (3.87+/-4.0). Under isobaric conditions, fine was also significantly lower in subjects with hypertension and elevated i n patients with ESRD. Thus, at the site of a medium-sized muscular art ery constantly devoid of atherosclerosis, the stiffness of wall materi al 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.