Effects of Prolonged Immobilization of the Limb on Radial Artery Mechanical Properties

Abstract

Abstract-Physical training is associated with an increase in arterial distensibility. Whether the effect of training on this variable is evident also for ordinary levels of exercise or no exercise is unknown, however. We have addressed this issue by investigating the effect on radial artery distensibility of prolonged monolateral immobilization of the ipsilateral limb versus the following resumption of normal mobility. We studied 7 normotensive subjects (age, 25.4Ϯ3.0 years; systolic/diastolic blood pressure, 119Ϯ9/68Ϯ6 mm Hg, meanϮSE) in whom 1 limb had been immobilized for 30 days in plaster because of a fracture of the elbow. At both the day after plaster removal and after 45 days of rehabilitation, radial artery distensibility was evaluated by an echo-tracking device (NIUS-02), which allows arterial diameter to be measured noninvasively and continuously over all pressures from diastole to systole (finger monitoring), with the distensibility values being continuously derived from the Langewouters formula. In both instances, the contralateral arm was used as control. Immediately after removal of the plaster, radial artery distensibility was markedly less in the previously immobilized and fractured limb compared with the contralateral limb (0.4Ϯ0.1 versus 0.8Ϯ0.1, 1/mm Hg 10 Ϫ3, PϽ0.05). After rehabilitation, the distensibility of the radial artery was markedly increased in the previously fractured limb (0.65Ϯ0.1 1/mm Hg 10 Ϫ3, PϽ0.05), whereas no change was seen in the contralateral limb. Thus, complete interruption of physical activity is associated with a marked reduction of arterial distensibility, indicating that even an ordinary level of activity plays a major role in modulation of arterial mechanical properties. (Hypertension. 1998;32:584-587.) Key Words: arterial distensibility Ⅲ training Ⅲ exercise Ⅲ vessels Ⅲ circulation E xercise training is associated with several changes in cardiac and arteriolar structure and function. [1][2][3][4][5][6][7][8][9] There is evidence, however, that large and conduit artery mechanical properties are also modified by training and that the modification consists of an increase in distensibility 10 -13 that is particularly evident in the arteries of the limbs most involved in the physical activity.14 Whether arterial mechanical properties are modified also by ordinary levels of physical activity (rather than becoming manifest only during exercise training) has never been investigated. In the present study, we addressed this issue by measuring radial artery diameter and distensibility in subjects in whom 1 arm was immobilized in plaster for 30 days because of an elbow fracture. The examination was performed on the day after removal of the plaster and after 45 days of rehabilitation, in both instances using the contralateral radial artery as control. Methods SubjectsWe studied 7 healthy, right-handed young subjects (5 males, 2 females) aged from 17 to 30 years (25.4Ϯ3.0 years, meanϮSE). The subjects suffered from elbow fracture that had been treated by complete immobilizat...

Short-term unilateral leg immobilization alters peripheral but not central arterial structure and function in healthy young humans

“…The reduction in peripheral arterial compliance noted both in the femoral and popliteal arteries mirrored previous limb fracture and repair studies (Giannattasio et al 1998) and this was rapid (within 12 days). A similar time-course for changes in the immobilized limb was suggested by trends in previous leg immobilization studies (Sugawara et al 2004); however, the current study is the first to also document arterial adaptations in the contralateral limb.…”

“…Unilateral lower limb suspension does not appear to alter vessel responsiveness to nitric oxide (Bleeker et al 2005a(Bleeker et al , b, 2006; however, a trend to enhanced vasodilation in response to a flow-mediated shear stimulus was observed (Bleeker et al 2005a). Arterial compliance, an index of arterial structure, is reduced in immobilized upper limbs as a result of fracture (Giannattasio et al 1998); however, there may be a confounding effect of tissue damage and repair in this model. In a noninjury model (Sugawara et al 2004), femoral artery distension, an index of arterial distensibility, tended to decrease in the immobilized leg after 7 days.…”

Age-related and blood pressure-independent reduction in aortic stiffness after kidney transplantation

“…Second, the reduction in aortic VSMC tone can also play a major role in the functional reduction in aortic stiffness, which could be explained by elimination of the uremic milieu and improvement in endothelial dysfunction [21]. This functional improvement in aortic VSMC tone could lead to the regression of VSMC hypertrophy, and hence a reduction in aortic wall thickness and stiffness in a relatively short period, as it has been shown for the brachial artery [22]. Finally, in a study by Karalliedde et al [23], valsartan, as compared with amlodipine, showed a BP-independent reduction in aortic stiffness in as little as 24 weeks of treatment.…”

Arterial properties of the carotid and femoral artery in endurance-trained and paraplegic subjects

“…On the other hand, the immobilization of an extremity that is not paralyzed allows for a rather monocausal explanation of the effects of muscular inactivity on the structural and functional properties of muscular-type arteries. Giannattasio et al (6) found a reduction in lumen size and elasticity in the radial artery of the immobilized upper limb compared with the mobile limb. In contrast to our study, the shear rate was not assessed, which might have shown a physiological response of the arterial wall to changes in local blood flow in these subjects in contrast to the paraplegic subjects in our study.…”

“…Conducting muscular-type arteries like the common femoral artery (CFA) have seldom been the object of studies, although they are important for the propagation of blood flow (23). In athletes, a larger luminal size of the CFA (11), but not a higher elasticity, has been reported, whereas in the immobilized upper limb compared with the mobile limb a parallel reduction in elasticity and luminal size of the radial artery has been shown (6). However, so far, no study in humans has assessed the local shear rate in relation to or together with arterial structure and elasticity, although local shear rate is one primary determinant of these parameters.…”