Impedance of arterial system simulated by viscoelastic t tubes terminated in windkessels

Liu, Zhaorong; Shen, Feng; Yin, F. C. P.

doi:10.1152/ajpheart.1989.256.4.h1087

Cited by 14 publications

(11 citation statements)

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“…Viscoelastic properties of the blood vessel derived by Liu et al [10] were included in the present analysis. The phase delay between the vessel diameter to the action of arterial pressure were assumed to be function of wave frequency.…”

Section: Methodsmentioning

confidence: 99%

“…Nominally, the impedance spectrum (i.e., modulus and phase angle) oscillates with respect to frequency, and the maxima and minima correspond to multiple zero-crossings of the phase angle at various frequencies [4,14]. Thus, more complex vascular models have been proposed to account for these effects, such as the four-element or five-element windkessel model [4,21], models with various arrays of branching tubes [4,18], and the asymmetric T-tube model [10]. Nevertheless, the wave nature of the arterial system can not be completely manifested.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the transmission line or wave propagation models are very useful in the description of arterial vascular flow and pressure propagation [3,10,13]. However, the effects of veins are often neglected.…”

Section: Introductionmentioning

confidence: 99%

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Effects of vascular properties on the impedance spectra of systemic circulation

Chen

Shau

1996

Journal of the Chinese Institute of Engineers

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A viscoelastic four-tube arteries-micro-vessels-veins model has been built using transmission line network. Hemodynamic data from literature are used in the fluid-circuit analogic model. The predicted input impedance spectra agree reasonably well with the published measurements. Parametric analysis shows that the changes in the vascular properties in different portions of the body cause fluctuations of the maxima or minima of the impedance spectrum. In general, the changes of vascular properties in the lower body affect the first minimum, and the changes in the upper body influence the second minimum. Decreasing capacitances (i.e., increasing arterial stiffness due to aging), reducing the lumen area, or decreasing the length of blood vessels result in an increase of the impedance modulus, and the shift of the first minimum to a higher frequency, which agree well with experiments. The changes of peripheral resistances of all terminations affect the magnitude of impedance modulus maxima only. The current model uses simple physiological data directly; it can be used to simulate the effect of pharmacologic manipulation on the impedace spectra of the patients.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of vascular properties on the impedance spectra of systemic circulation

Chen

Shau

1996

Journal of the Chinese Institute of Engineers

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“…here, E 1 , r 1 , h 1 are the Young's modulus, inner radius and wall thickness of the 1D tube, respectively; k and φ 0 define the wall viscosity; L p is the inductance; R cp is the characteristic impedance; R p is the resistance; and C p is the compliance of the termination [30].…”

Section: Determination Of the Circumferential Stressmentioning

confidence: 99%

A multiscale model for analyzing the synergy of CS and WSS on the endothelium in straight arteries

et al. 2006

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A multiscale model was proposed to calculate the circumferential stress (CS) and wall shear stress (WSS) and analyze the effects of global and local factors on the CS, WSS and their synergy on the arterial endothelium in large straight arteries. A parameter pair [Zs, SP A] (defined as the ratio of CS amplitude to WSS amplitude and the phase angle between CS and WSS for different harmonic components, respectively) was proposed to characterize the synergy of CS and WSS. The results demonstrated that the CS or WSS in the large straight arteries is determined by the global factors, i.e. the preloads and the afterloads, and the local factors, i.e. the local mechanical properties and the zero-stress states of arterial walls, whereas the Zs and SP A are primarily determined by the local factors and the afterloads. Because the arterial input impedance has been shown to reflect the physiological and pathological states of whole downstream arterial beds, the stress amplitude ratio Zs and the stress phase difference SP A might be appropriate indices to reflect the influences of the states of whole downstream arterial beds on the local blood flow-dependent phenomena such as angiogenesis, vascular remodeling and atherosgenesis.

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“…Several experienced modelers have assembled multipart branching structures, such as tapered tube models and transmission line models, to capture many of the circulatory system's intricacies. 4,20,49 The consequences of an increasingly complex model are amplified computation time and a large number of adjustable parameters, both of which can be discouraging to novices in the field of cardiovascular modeling or those who have a more generalized need to investigate cardiovascular system dynamics. In contrast, the Windkessel model, developed by Otto Frank, has inspired numerous representations of the systemic circulation that condense the impedance characteristics of many circulatory elements into a much simpler configuration.…”

Section: Introductionmentioning

confidence: 99%

A LabVIEW™ Model Incorporating an Open-Loop Arterial Impedance and a Closed-Loop Circulatory System

et al. 2005

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While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.

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Impedance of arterial system simulated by viscoelastic t tubes terminated in windkessels

Cited by 14 publications

References 0 publications

Effects of vascular properties on the impedance spectra of systemic circulation

Effects of vascular properties on the impedance spectra of systemic circulation

A multiscale model for analyzing the synergy of CS and WSS on the endothelium in straight arteries

A LabVIEW™ Model Incorporating an Open-Loop Arterial Impedance and a Closed-Loop Circulatory System

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