Dynamics of Arterial Remodeling in Response to a Sustained Step Change in Blood Flow Using a Constituent-Based Model

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176359 ◽

2007 ◽

Author(s):

Alkiviadis Tsamis ◽

Nikos Stergiopulos

Keyword(s):

Blood Flow ◽

Arterial Wall ◽

Wall Stress ◽

Step Change ◽

Local Blood Flow ◽

Inner Radius ◽

Flow Changes ◽

Baseline Levels ◽

Two Phases

The arterial wall undergoes substantial remodeling whenever the local blood flow changes for more than a few days [1]. An increase in flow causes an increase in inner radius, which occurs in two phases and tends to restore the baseline levels of intimal shear stress [2]. Firstly, an acute dilation of the artery occurs due to relaxation of vascular smooth muscle (VSM) cells [3]. Secondly, a long-term media reconstruction takes place, during which VSM cells migrate and proliferate circumferentially causing an increase in undeformed lumen. Moreover, arterial wall thickens to restore the altered wall stress [4].

Download Full-text

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

Journal of Applied Physiology ◽

10.1152/jappl.2000.89.5.1956 ◽

2000 ◽

Vol 89 (5) ◽

pp. 1956-1963 ◽

Cited By ~ 91

Author(s):

Arno Schmidt-Trucksäss ◽

Andreas Schmid ◽

Christian Brunner ◽

Nicole Scherer ◽

Guido Zäch ◽

...

Keyword(s):

Blood Flow ◽

Shear Rate ◽

Femoral Artery ◽

Arterial Wall ◽

Activity Level ◽

Functional Adaptation ◽

Local Blood Flow ◽

Flow Changes ◽

The Impact

In humans, the relationships of blood flow changes to structure, function, and shear rate of conducting arteries have not been thoroughly examined. Therefore, the purpose of this study was to investigate these parameters of the elastic-type, common carotid artery (CCA) and the muscular-type, common femoral artery (CFA) in long-term highly active and extremely inactive individuals, assuming that the impact of activity-induced blood flow changes on conduit arteries, if any, should be seen in these subjects. We examined 21 highly endurance-trained athletes (A), 10 paraplegic subjects (P), and 20 sedentary subjects (S) by means of noninvasive ultrasound. As a result, the CFA diameter and compliance were highest in A (9.7 ± 0.81 mm; 1.84 ± 0.54 mm2/kPa) and lowest in P (5.9 ± 0.7 mm; 0.54 ± 0.27 mm2/kPa) compared with S (8.3 ± 1.0 mm; 0.92 ± 0.48 mm2/kPa) with P < 0.01 among the groups. Both parameters correlated with each other ( r = 0.62; P < 0.01). Compared with A (378 ± 84 s−1; 37 ± 15 s−1) and S (356 ± 113 s−1; 36 ± 20 s−1), the peak and mean shear rates of the CFA were almost or more than doubled in P (588 ± 120 s−1; 89 ± 26 s−1). In the CCA, only the compliance and peak shear rate showed significant differences among the groups (A: 1.28 ± 0.47 mm2/kPa, 660 ± 138 s−1; S: 1.04 ± 0.27 mm2/kPa, 588 ± 109 s−1; P: 0.65 ± 0.22 mm2/kPa, 490 ± 149 s−1; P < 0.05). In conclusion, the results suggest a structural and functional adaptation in the CFA and a predominantly functional adaptation of the arterial wall properties to differences in the physical activity level and associated exercise-induced blood flow changes in the CCA. The results for humans confirm those from animal experiments. Similar shear rate values of S and P in the CFA support the hypothesis of constant shear stress regulation due to local blood flow changes in humans. On the other hand, the increased shear rate in the CFA in P indicates an at least partially nonphysiological response of the arterial wall in long-term chronic sympathectomy due to a change in local blood flow.

Download Full-text

Alterations in Rubidium-86 Extraction in Normal Mouse Tissues after Irradiation: An Estimate of Long-Term Blood Flow Changes in Kidney, Lung, Liver, Skin and Muscle

Radiation Research ◽

10.2307/3573450 ◽

1973 ◽

Vol 53 (1) ◽

pp. 88 ◽

Cited By ~ 42

Author(s):

Eli Glatstein

Keyword(s):

Blood Flow ◽

Normal Mouse ◽

Mouse Tissues ◽

Flow Changes

Download Full-text

Calculation of the Outcomes of Adaptive and Maladaptive Remodeling of Arteries Subjected to Sustained Hypertension Using a 3D Two-Layered Model

ASME 2012 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2012-80092 ◽

2012 ◽

Author(s):

Alexander Rachev ◽

W. Robert Taylor ◽

Raymond P. Vito

Keyword(s):

Blood Flow ◽

Coronary Artery ◽

Arterial Pressure ◽

Optimal Performance ◽

Mechanical Environment ◽

Layered Model ◽

Adaptive Process ◽

Baseline Levels ◽

General Method

Arteries respond to long-term alterations in arterial pressure and blood flow by changing geometry, structure, and composition. This response is termed as remodeling and plays an important role in normal arterial physiology and in the genesis and progression of certain vascular disorders. In healthy mature arteries, remodeling represents an adaptive process that tends to restore the local mechanical environment of vascular cells to baseline levels and thereby to preserve the optimal performance of the arterial function. The objective of this study is twofold — to develop a general method for calculation the remodeling outputs of an artery considered as a two-layered tube; and to provide results for adaptive and maladaptive remodeling of a coronary artery.

Download Full-text