Arterial tree

About: Arterial tree is a research topic. Over the lifetime, 880 publications have been published within this topic receiving 32363 citations. The topic is also known as: arterial tree organ.

Numerical simulation and experimental validation of blood flow in arteries with structured-tree outflow conditions.

Abstract: Blood flow in the large systemic arteries is modeled using one-dimensional equations derived from the axisymmetric Navier–Stokes equations for flow in compliant and tapering vessels. The arterial tree is truncated after the first few generations of large arteries with the remaining small arteries and arterioles providing outflow boundary conditions for the large arteries. By modeling the small arteries and arterioles as a structured tree, a semi-analytical approach based on a linearized version of the governing equations can be used to derive an expression for the root impedance of the structured tree in the frequency domain. In the time domain, this provides the proper outflow boundary condition. The structured tree is a binary asymmetric tree in which the radii of the daughter vessels are scaled linearly with the radius of the parent vessel. Blood flow and pressure in the large vessels are computed as functions of time and axial distance within each of the arteries. Comparison between the simulations and magnetic resonance measurements in the ascending aorta and nine peripheral locations in one individual shows excellent agreement between the two. © 2000 Biomedical Engineering Society.

Stiffness of systemic arteries in patients with myocardial infarction. A noninvasive method to predict severity of coronary atherosclerosis.

Abstract: The static elastic properties of arterial tree (abdominal aorta and common carotid artery) were studied in 19 normal subjects and in 49 patients with myocardial infarction with an ultrasonic phase-locked echo-tracking system that allows continuous transcutaneous measurement of the arterial diameter. The stiffness index beta, which represented the mechanical properties in the arterial wall, was calculated from the relation between systemic blood pressure and the diameter of the artery. Patients with myocardial infarction underwent coronary angiography in their convalescent period to determine involved vessels. In 11 patients, coronary artery was patent; 15 patients had one-vessel disease, 12 had two-vessel disease, and the remaining 11 patients had three-vessel disease. In normal subjects, increasing age was associated with an increase in arterial stiffness. An average value of the stiffness index of the abdominal aorta was 8.58 +/- 3.02 (mean +/- SD) and that of common carotid artery was 9.17 +/- 2.22. In patients with three-vessel disease, these values were significantly higher (22.37 +/- 4.29 in abdominal aorta and 13.17 +/- 4.56 in common carotid artery) than those in normal subjects. Stiffness index of patients with two- or one-vessel disease was also increased but lower than those in patients with three-vessel disease (p less than 0.05). Forty-four of 49 patients with infarction had an arterial stiffness index of abdominal aorta higher than the 95% confidence limits of the normal data (p less than 0.05). Twenty-eight patients were outside the nomogram of common carotid artery (p less than 0.05). The mechanical properties of these elastic arteries provided sufficiently reliable information on changes caused by atherosclerosis.

Alterations with Age in the Viscoelastic Properties of Human Arterial Walls

Abstract: The circumferential incremental Young's modulus was measured in 59 major arteries of both "young" (less than 35 years of age) and "old" (greater than 35 years of age) subjects. Dynamic measurements of wall elasticity and viscosity were made which indicated a high viscosity in the femoral arteries. This was attributed to their high content of muscle. Although the "young" group showed, at any given pressure, an increasing wall stiffness towards the periphery, in "old" arteries, an opposite trend was found. When dimensional changes (radius and wall thickness) in the "old" group were considered it was apparent that at all sites the arterial wall tissue became weaker with age. Nevertheless, as a consequence of these dimensional changes the impedance characteristics of the old arterial tree still retained the nonuniformity (an increase towards the periphery) of the "young" which has considerable haemodynamic advantage.