Vessel growth and collapsible pressure-area relationship

Drzewiecki, G.; Field, S.; Moubarak, Issam; Li, John K.‐J.

doi:10.1152/ajpheart.1997.273.4.h2030

Cited by 56 publications

(33 citation statements)

References 20 publications

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“…Compared with previous studies [1,10,29,30], the advantage of the buckling equation obtained in this study lies in its capability to model nonlinear anisotropic material for thick-walled artery. This model overcomes the limit of thin-wall and linear elastic assumptions.…”

Section: Discussionmentioning

confidence: 95%

Effect of Axial Stretch on Lumen Collapse of Arteries

Fatemifar

Han

2016

Journal of Biomechanical Engineering

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The stability of the arteries under in vivo pressure and axial tension loads is essential to normal arterial function, and lumen collapse due to buckling can hinder the blood flow. The objective of this study was to develop the lumen buckling equation for nonlinear anisotropic thick-walled arteries to determine the effect of axial tension. The theoretical equation was developed using exponential Fung strain function, and the effects of axial tension and residual stress on the critical buckling pressure were illustrated for porcine coronary arteries. The buckling behavior was also simulated using finite-element analysis. Our results demonstrated that lumen collapse of arteries could occur when the transmural pressure is negative and exceeded a critical value. This value depends upon the axial stretch ratio and material properties of the arterial wall. Axial tensions show a biphasic effect on the critical buckling pressure. The lumen aspect ratio of arteries increases nonlinearly with increasing external pressure beyond the critical value as the lumen collapses. These results enhance our understanding of artery lumen collapse behavior.

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Section: Discussionmentioning

confidence: 95%

Effect of Axial Stretch on Lumen Collapse of Arteries

Fatemifar

Han

2016

Journal of Biomechanical Engineering

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“…Unlike expansion, buckling occurs rapidly with modest negative transmural pressures 11,13,16 . This phenomenon means that the slope of the pressure-area curve, which is related to vessel stiffness, abruptly changes at the collapse pressure.…”

Section: Figurementioning

confidence: 99%

The origin of Korotkoff sounds and the accuracy of auscultatory blood pressure measurements

Babbs

2015

Journal of the American Society of Hypertension

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This study explores the hypothesis that the sharper, high frequency Korotkoff sounds come from resonant motion of the arterial wall, which begins after the artery transitions from a buckled state to an expanding state. The motion of one mass, two nonlinear springs, and one damper, driven by transmural pressure under the cuff, are used to model and compute the Korotkoff sounds according to principles of classical Newtonian physics. The natural resonance of this springmass-damper system provides a concise, yet rigorous, explanation for the origin of Korotkoff sounds. Fundamentally, wall stretching in expansion requires more force than wall bending in buckling. At cuff pressures between systolic and diastolic arterial pressure, audible vibrations (> 40 Hz) occur during early expansion of the artery wall beyond its zero pressure radius after the outward moving mass of tissue experiences sudden deceleration, caused by the discontinuity in stiffness between bucked and expanded states. The idealized spring-mass-damper model faithfully reproduces the time domain waveforms of actual Korotkoff sounds in humans. Appearance of arterial sounds occurs at or just above the level of systolic pressure. Disappearance of arterial sounds occurs at or just above the level of diastolic pressure. Muffling of the sounds is explained by increased resistance of the artery to collapse, caused by downstream venous engorgement. A simple analytical model can define the physical origin of Korotkoff sounds, suggesting improved mechanical or electronic filters for their selective detection, and confirming the disappearance of the Korotkoff sounds as the optimal diastolic endpoint.

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“…The residual vector R ⃗ is defined as the difference in FE and circulatory cavity volumes: (6) When the residual, normalized to circulatory cavity volume: (7) has not satisfied a preset criterion δ = 0.01%, LV and RV pressures are perturbed in the next two pressure update steps.…”

Section: Updating the Cavity Pressuresmentioning

confidence: 99%

Coupling of a 3D Finite Element Model of Cardiac Ventricular Mechanics to Lumped Systems Models of the Systemic and Pulmonic Circulation

et al. 2006

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In this study we present a novel, robust method to couple finite element (FE) models of cardiac mechanics to systems models of the circulation (CIRC), independent of cardiac phase. For each time step through a cardiac cycle, left and right ventricular pressures were calculated using ventricular compliances from the FE and CIRC models. These pressures served as boundary conditions in the FE and CIRC models. In succeeding steps, pressures were updated to minimize cavity volume error (FE minus CIRC volume) using Newton iterations. Coupling was achieved when a predefined criterion for the volume error was satisfied. Initial conditions for the multi-scale model were obtained by replacing the FE model with a varying elastance model, which takes into account direct ventricular interactions. Applying the coupling, a novel multi-scale model of the canine cardiovascular system was developed. Global hemodynamics and regional mechanics were calculated for multiple beats in two separate simulations with a left ventricular ischemic region and pulmonary artery constriction, respectively. After the interventions, global hemodynamics changed due to direct and indirect ventricular interactions, in agreement with previously published experimental results. The coupling method allows for simulations of multiple cardiac cycles for normal and pathophysiology, encompassing levels from cell to system.

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Vessel growth and collapsible pressure-area relationship

Cited by 56 publications

References 20 publications

Effect of Axial Stretch on Lumen Collapse of Arteries

Effect of Axial Stretch on Lumen Collapse of Arteries

The origin of Korotkoff sounds and the accuracy of auscultatory blood pressure measurements

Coupling of a 3D Finite Element Model of Cardiac Ventricular Mechanics to Lumped Systems Models of the Systemic and Pulmonic Circulation

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