Development of Anatomically Correct Mock-Ups of the Aorta for Piv Investigations

Yip, Ronnie; Mongrain, Rosaire; Ranga, Adrian; Brunette, Jean; Cartier, Raymond

doi:10.24908/pceea.v0i0.3984

Cited by 9 publications

(11 citation statements)

References 8 publications

(10 reference statements)

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“…There are several clinical trials focused on the wavepropagation phenomenon [35] and experimental studies of flow fields in low α regimes through compliant models [36] - [38], but there are few ex-vivo experimental studies that take into account the effects of aortic compliance on the flow fields in a near-physiological regime.…”

Section: A Literature Reviewmentioning

confidence: 99%

Experimental Investigation Of The Effect Of Compliance Properties On The Flow In An Analogous Ex-Vivo Heart Perfusion System

Bessa¹,

Hadfield²,

Chung³

et al. 2021

Progress in Canadian Mechanical Engineering. Volume 4

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The heart transplant waiting list far exceeds supply. This shortage is generally attributed to the high number of discarded hearts and to the narrow six-hour time window currently available through the standard preservation method: static cold storage (SCS). An alternative method called exvivo heart perfusion (EVHP) maintains a human donor heart beating outside the body for the time preceding transplantation surgery. By keeping the heart working in a physiologically consistent way and monitoring its functions, the organ's health can be assessed and the transplant time window can be extended. In order to improve and optimize the EVHP system, the present work aims to further investigate the relationship between pulsatile flow and compliance by assessing the effect of different compliant tubes on the upstream and downstream pressure and flow fields. Hence, silicone tubes of variable compliance, length, and geometrical shape were developed for this studyalthough only one sample has been tested so far, in addition to an experimental setup containing a hydraulic circuit analogous to the left flow loop of the EVHP system. The flow fields downstream of the compliant section are assessed using laser Doppler velocimetry (LDV). Findings will include novel visualizations of these flow fields as well as comparisons of pressure waveforms from an assortment of compliance conditions.

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Section: A Literature Reviewmentioning

confidence: 99%

Experimental Investigation Of The Effect Of Compliance Properties On The Flow In An Analogous Ex-Vivo Heart Perfusion System

Bessa¹,

Hadfield²,

Chung³

et al. 2021

Progress in Canadian Mechanical Engineering. Volume 4

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show abstract

“…There have been several clinical investigations into wave propagation effects in-vivo [47], and experimental investigations into flow fields through compliant phantoms in low α regimes [48][49][50], but, to the authors' knowledge, there has been little experimental investigation into controlled changes in aortic compliance within a physiological range in an ex-vivo environment. There has been a great deal of research into understanding velocity distributions through compliant phantoms using PIV or particle tracking velocimetry (PTV) in cardiovascular flow regimes [38,48,49,51], including the effect of certain pathophysiology such as stenosis [52,53], in compliant pulsatile flow regimes through the use of stereo-PIV and time-resolved PIV. However, to the authors' knowledge, there remains limited understanding of the effect of physiologically relevant aortic compliant response on downstream velocity fields and pump performance.…”

Section: Plos Onementioning

confidence: 99%

“…The compliant response of the aorta has a significant impact on wave propagation effects in-vivo and therefore is widely recognized as being a clinically important marker for overall cardiovascular health [ 43 – 46 ]. There have been several clinical investigations into wave propagation effects in-vivo [ 47 ], and experimental investigations into flow fields through compliant phantoms in low α regimes [ 48 – 50 ], but, to the authors’ knowledge, there has been little experimental investigation into controlled changes in aortic compliance within a physiological range in an ex-vivo environment. There has been a great deal of research into understanding velocity distributions through compliant phantoms using PIV or particle tracking velocimetry (PTV) in cardiovascular flow regimes [ 38 , 48 , 49 , 51 ], including the effect of certain pathophysiology such as stenosis [ 52 , 53 ], in compliant pulsatile flow regimes through the use of stereo-PIV and time-resolved PIV.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation into the effect of compliance of a mock aorta on cardiac performance

et al. 2020

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Demand for heart transplants far exceeds supply of donated organs. This is attributed to the high percentage of donor hearts that are discarded and to the narrow six-hour time window currently available for transplantation. Ex-vivo heart perfusion (EVHP) provides the opportunity for resuscitation of damaged organs and extended transplantation time window by enabling functional assessment of the hearts in a near-physiologic state. Present work investigates the fluid mechanics of the ex-vivo flow loop and corresponding impact on cardiac performance. A mechanical flow loop is developed that is analogous to the region of the EVHP system that mimics in-vivo systemic circulation, including the body's largest and most compliant artery, the aorta. This investigation is focused on determining the effect of mock aortic tubing compliance on pump performance. A custom-made silicone mock aorta was developed to simulate a range of in-vivo conditions and a physiological flow was generated using a commercial ventricular assist device (VAD). Monitored parameters, including pressure, tube distension and downstream velocity, acquired using time-resolved particle imaging velocimetry (PIV), were applied to an unsteady Bernoulli analysis of the flow in a novel way to evaluate pump performance as a proxy for cardiac workload. When compared to the rigid case, the compliant mock aorta case demonstrated healthier physiologic pressure waveforms, steadier downstream flow and reduced energetic demands on the pump. These results provide experimental verification of Windkessel theory and support the need for a compliant mock aorta in the EVHP system.

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“…Furthermore, Clough et al (2012) reported the presence of helical flows at different locations in the false lumen by examining images acquired with phasecontrast magnetic resonance imaging (PC-MRI) and related these helical flows to the aortic expansion rate. More recently, a few research groups are employing laser diagnostic methods to explore the haemodynamics in higher spatial and temporal resolution, using primarily particle image velocimetry (PIV) (Yip et al, 2004;Salameh et al, 2017Salameh et al, , 2019Moravia et al, 2019) and stereo-particle image velocimetry (s-PIV) (Fernandes et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

A combined experimental and computational study of the flow characteristics in a Type B aortic dissection: Effect of primary and secondary tear size

Zadrazil

Corzo

Voulgaropoulos

et al. 2020

Chemical Engineering Research and Design

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Aortic dissection is related to the separation of the tunica intima from the aortic wall, which can cause blood to flow through the newly formed lumen, thereby further damaging the torn vessel. This type of pathology is the most common catastrophic event that affects the aorta and is associated with complications such as malperfusion. In this work, an idealised, simplified geometric model of Type B aortic dissection is investigated experimentally using particle image velocimetry (PIV) and numerically using computational fluid dynamic (CFD) simulations. The flow characteristics through the true and false lumina are investigated parametrically over a range of tear sizes. Specifically, four different tear sizes and size ratios are considered, each representing a different dissection case or stage, and the experimental and numerical results of the flow-rate profiles through the two lumina in each case, along with the phase-averaged velocity vector maps at mid-acceleration, mid-deceleration, relaminarisation and peak systole, and their corresponding velocity profiles are compared. The experimental and numerical results are in good qualitative as well as quantitative agreement. The flow characteristics found here provide insight into the importance of the re-entry tear. We observe that an increase in the re-entry tear size increases considerably the flow rate in the false lumen, decreases significantly the wall shear stress (WSS) and decreases the pressure difference between the false and the true lumen. On the contrary, an increase in the entry tear, increases the flow rate through the false lumen, increases slightly the WSS and increases the pressure difference between the false and the true lumen. These are crucial findings that can help interpret medical diagnosis and accelerate prevention and treatment, especially in high-risk patients.

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Development of Anatomically Correct Mock-Ups of the Aorta for Piv Investigations

Cited by 9 publications

References 8 publications

Experimental Investigation Of The Effect Of Compliance Properties On The Flow In An Analogous Ex-Vivo Heart Perfusion System

Experimental Investigation Of The Effect Of Compliance Properties On The Flow In An Analogous Ex-Vivo Heart Perfusion System

Experimental investigation into the effect of compliance of a mock aorta on cardiac performance

A combined experimental and computational study of the flow characteristics in a Type B aortic dissection: Effect of primary and secondary tear size

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