Physics of Pulsatile Flow

Zamir, M.; Budwig, Ralph

doi:10.1115/1.1451229

Cited by 72 publications

(103 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This finding is significant to vessel function since 40 mmHg is below the hypertensive systolic pressure of approximately 47 mmHg previously measured in eNOSnull mice exposed to two weeks of severe hypoxia (Fagan et al 1999). A vessel that cannot stretch in response to a pulsatile pressure wave presents an increased resistance to flow (Zamir 2000). Therefore, these changes in circumferential stretch in eNOS-null mouse PAs in response to severe hypoxia may directly affect right ventricular energy requirements and contribute to right ventricular failure.…”

Section: Static Behaviormentioning

confidence: 87%

The Mechanobiology of Pulmonary Vascular Remodeling in the Congenital Absence of eNOS

Kobs

Chesler

2006

Biomech Model Mechanobiol

View full text Add to dashboard Cite

Primary pulmonary hypertension is a rare but deadly disease. Lungs extracted from PPH patients are deficient in endothelial nitric oxide synthase (eNOS), making the eNOS-null mouse a potentially useful model of the disease. To better understand the progression of pulmonary vascular remodeling in the congenital absence of eNOS, we induced pulmonary hypertension in eNOS-null mice using hypobaric hypoxia, and then quantified large artery structure and function in contralateral vessels. In particular, to assess structure we quantified diameter, wall thickness, and collagen, elastin and smooth muscle cell content; to quantify function we performed pressure-diameter tests. After remodeling, the pulmonary arteries had increased wall, collagen and elastin thicknesses compared to controls (P<0.05). The remodeled pulmonary arteries also had increased elastic moduli at low and high strains compared to controls (P<0.05). The increases in moduli at low and high strain correlated with increases in elastin and collagen thickness, respectively (P<0.05). These results provide insight into the mechanobiology of pulmonary vascular remodeling in the congenital absence of eNOS, and the coupled nature of these changes.

show abstract

Section: Static Behaviormentioning

confidence: 87%

The Mechanobiology of Pulmonary Vascular Remodeling in the Congenital Absence of eNOS

Kobs

Chesler

2006

Biomech Model Mechanobiol

View full text Add to dashboard Cite

show abstract

“…Equations (2), (5) and (6) admit axially traveling fluid flow waves as solutions (e.g., ZAMIR, 2000). Let us consider a wave traveling in the positive z direction: Vol.…”

Section: Introductionmentioning

confidence: 99%

Oscillating Flow of a Compressible Fluid through Deformable Pipes and Pipe Networks: Wave Propagation Phenomena

Bernabé

2009

Pure appl. geophys.

View full text Add to dashboard Cite

Similarly to blood pulse propagation in the artery system, oscillating flow can propagate as a wave in fluid-saturated pipes, networks of pipes or, by extension, in porous media, if the fluid is compressible and/or the pipes are elastically deformable. First, propagation of flow waves generated in a semi-infinite pipe by harmonic pressure oscillations at the pipe entrance is analyzed. The dispersion equation is derived, allowing determination of the phase velocity and quality factor as functions of frequency. Wave reflections at the end of a finite-length pipe and ensuing interferences between forward and backward traveling waves are then examined. Because of fluid storage in the pipe, the amplitude of the AC volumetric fluxes entering and exiting the pipe at its upstream and downstream ends are not equal. Thus, two different, upstream and downstream, frequencydependent, AC hydraulic conductivities are introduced. Superposed on the classic viscous-inertial flow transition (controlled by the value of the pipe radius), these complex-valued parameters show another transition between an interference-free regime at low frequencies and a strong interference regime above a critical frequency that roughly scales as the pipe length. Because of attenuation, the flow wave interferences tend to gradually weaken with increasing frequencies. Finally, the single pipe model is used to investigate fluid flow waves through pipe networks with results very similar to those described above. The flow waves analyzed here are akin to the Biot's slow P waves and their propagation properties could affect seismic soundings in some geological settings.

show abstract

“…Dashed lines represent what the gradients would be under the idealized conditions of Poiseuille flow density I since the former provides a measure of the total cross-sectional area available to the flow within the vasa vasorum tree. In the same way, density III provides a yet more meaningful measure than densities I and II since the former actually provides a direct, though approximate, measure of the flow rate based on Murray's cube law (Zamir 2000). The comparisons in Fig.…”

Section: Discussionmentioning

confidence: 94%

“…Under the idealized conditions of Poiseuille flow, the pressure drop is related to the diameter d and length l of the vessel and the flow rate q through it, as well as the viscosity m of the fluid, and is given by (Zamir 2000)…”

Section: Pressure Gradientsmentioning

confidence: 99%

Vasa vasorum growth in the coronary arteries of newborn pigs

2004

View full text Add to dashboard Cite

Experimental studies have shown that a "plexus" of vasa vasorum already exists in fetal arteries. In this study we examine the further development of vasa vasorum in the newborn. Hearts from 1- and 6-month-old pigs were harvested and infused with Microfil via the aortic ostia of the coronary arteries at physiological pressure (100 mmHg). Coronary arteries (RCA, LAD, and LCX) were then isolated and scanned intact with micro-CT (20 microm cubic voxel size). Using Analyze 5.0 software we digitally isolated individual vasa vasorum trees (eight from 1-month-old and eight from 6-month-old pigs) and measured geometrical data such as interbranch segmental diameters, lengths, and branching angles as well as mother-daughter branch relationships for all segments of each vasa vasorum tree structure. Also, we determined the volume of vessel wall perfused by individual vasa vasorum trees. Our results show that the vasa vasorum architecture in newborn pigs is already tree-like, and this structure as well as the volume of vessel wall perfused by it expand in concert with the growth of the host coronary artery. We give quantitative details of this growth of vasa vasorum in terms of its branching architecture and hemodynamic capacity, based on direct measurements from 3D images of this microvasculature.

show abstract

Physics of Pulsatile Flow

Cited by 72 publications

References 0 publications

The Mechanobiology of Pulmonary Vascular Remodeling in the Congenital Absence of eNOS

The Mechanobiology of Pulmonary Vascular Remodeling in the Congenital Absence of eNOS

Oscillating Flow of a Compressible Fluid through Deformable Pipes and Pipe Networks: Wave Propagation Phenomena

Vasa vasorum growth in the coronary arteries of newborn pigs

Contact Info

Product

Resources

About