Re-examination of the mechanical anisotropy of porcine thoracic aorta by uniaxial tensile tests

Chen, Qiang; Wang, Yan; Li, Zhi Yong

doi:10.1186/s12938-016-0279-6

Cited by 14 publications

(8 citation statements)

References 41 publications

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“…The aorta is anisotropic, compliant and distensible, with the ability to stretch more in the circumferential direction than the longitudinal direction. 15 These intrinsic properties of the aorta result in a physiologically important function, allowing for the prevention of pathologic increases in systolic blood pressure, afterload and pulse pressure. This is accomplished through a buffer-reservoir type effect during systole and also by attenuating pressure decay during diastole.…”

Section: Methodsmentioning

confidence: 99%

Resuscitative endovascular balloon occlusion of the aorta: rupture risk and implications for blind inflation

Wasicek

Teeter

Brenner

et al. 2018

Trauma Surg Acute Care Open

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BackgroundResuscitative endovascular balloon occlusion of the aorta (REBOA) is a torso hemorrhage control technique. To expedite deployment, inflation is frequently performed as a blind technique with minimal imaging, which carries a theoretical risk of aortic injury. The objective of this study was to examine the relationship between balloon inflation, deformation and the risk of aortic rupture.MethodsCompliant balloon catheters were incrementally inflated in segments of cadaveric swine aorta. Serial longitudinal and circumferential measurements were recorded, along with the incidence of aortic rupture.ResultsFourteen cadaveric swine aorta segments were tested with mean (±SD) baseline aortic diameter (mm) of 14.2±3.4. Rupture occurred in three aortas. The mean baseline diameters (mm) of the aortic segments that were ruptured were significantly smaller than those that did not rupture (8.9±1.2 vs 15.6±1.9; P<0.001). The maximal circumferential stretch ratios were significantly higher in the aorta segments that ruptured compared with those that did not (1.9±0.1 vs 1.5±0.1; P<0.001). The maximal amount of balloon longitudinal deformation was 80 mm (116% longer than the intended working length).ConclusionsInflation of aortic balloon catheters carries an inherent risk of aortic injury, which may be minimized through an understanding of the intrinsic characteristics of the aorta and compliant balloons. Smaller diameter aortic segments undergoing overinflation, particularly beyond a circumferential stretch ratio of 1.8, are at risk of aortic rupture.Level of evidenceLevel II.

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Section: Methodsmentioning

confidence: 99%

Resuscitative endovascular balloon occlusion of the aorta: rupture risk and implications for blind inflation

Wasicek

Teeter

Brenner

et al. 2018

Trauma Surg Acute Care Open

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“…13 14 Because of the destructive nature of some contact-based, elasticity test methods, like tensile testing, ex vivo porcine liver has been used by other authors to determine the elasticity of liver parenchyma and blood vessels. [15][16][17] However, porcine organs have been reported to be up to twice as hard as live human liver. [18][19][20] Most studies that use ex vivo test specimens fail to mention if specimens were hydrated or prewarmed before testing, conditions well known to affect the hardness and elastic response of both organic soft tissues and synthetic elastomers.…”

Section: Open Accessmentioning

confidence: 99%

Synthesis and characterisation of a cancerous liver for presurgical planning and training applications

Arm

Shahidi

Clarke

et al. 2022

BMJ Open Gastroenterol

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ObjectivesOncology surgeons use animals and cadavers in training because of a lack of alternatives. The aim of this work was to develop a design methodology to create synthetic liver models familiar to surgeons, and to help plan, teach and rehearse patient-specific cancerous liver resection surgery.DesignSynthetic gels were selected and processed to recreate accurate anthropomorphic qualities. Organic and synthetic materials were mechanically tested with the same equipment and standards to determine physical properties like hardness, elastic modulus and viscoelasticity. Collected data were compared with published data on the human liver. Patient-specific CT data were segmented and reconstructed and additive manufactured models were made of the liver vasculature, parenchyma and lesion. Using toolmaking and dissolvable scaffolds, models were transformed into tactile duplicates that could mimic liver tissue behaviour.ResultsPorcine liver tissue hardness was found to be 23 H00 (±0.1) and synthetic liver was 10 H00 (±2.3), while human parenchyma was reported as 15.06 H00 (±2.64). Average elastic Young’s modulus of human liver was reported as 0.012 MPa, and synthetic liver was 0.012 MPa, but warmed porcine parenchyma was 0.28 MPa. The final liver model demonstrated a time-dependant viscoelastic response to cyclic loading.ConclusionSynthetic liver was better than porcine liver at recreating the mechanical properties of living human liver. Warmed porcine liver was more brittle, less extensible and stiffer than both human and synthetic tissues. Qualitative surgical assessment of the model by a consultant liver surgeon showed vasculature was explorable and that bimanual palpation, organ delivery, transposition and organ slumping were analogous to human liver behaviour.

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“…Furthermore, a Fung-type strainenergy function was used to fit the mean curves, which requires further study on layer-specific mechanical tests and micro-structured constitutive models (Weisbeker et al 2015). Moreover, at the low stretch ratio of the stress-stretch curve, the smooth muscle and the elastin play a dominate role, and the contribution result from the unfolding of the crimpled elastin/collagen and the rotation of cross-linked elastin/collagen (Gasser et al, 2006;Chen et al, 2016). At the high stretch ratio, the mechanical properties mainly rely on the tension of the after-straightened elastin/collagen.…”

Section: Limitationsmentioning

confidence: 99%

Circumferential variation in mechanical characteristics of porcine descending aorta

Chen¹,

Gao²,

Liu³

et al. 2018

Biocell

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2018)Circumferential variation in mechanical characteristics of porcine descendingAbstract: Arterial characterization of healthy descending thoracic aorta (DTA) is indispensable in determining stress distributions across wall thickness and different regions that may be responsible for aorta inhomogeneous dilation, rupture, and dissection when aneurysm occurs. Few studies have shown the inhomogeneity of DTA along the aorta tree considering changes in circumferential direction. The present study aims to clarify the circumferential regional characterization of DTA. Porcine DTA tissues were tested according to region and orientation using uniaxial tension.For axial test, results show that the difference in circumferential direction was mainly in collagen fiber modulus, where the anterior collagen fiber modulus was significantly lower than the posterior quadrant. For circumferential test, the difference in circumferential direction was mainly in the recruitment parameter, where the circumferential stiffness is significantly higher in the posterior region at physiological maximum stress. The proximal posterior quadrant and left quadrant showed significantly lower axial collagen fiber stiffness than the right and anterior quadrants, which may be a factor in aneurysm development. Furthermore, the constitutive parameters for similar detailed regions can be used by biomedical engineers to investigate improved therapies and thoroughly understand the initial stage of aneurysm development. The regional collagen fiber modulus can help improve our understanding of the mechanisms of arterial dilation and aortic dissection.

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Re-examination of the mechanical anisotropy of porcine thoracic aorta by uniaxial tensile tests

Cited by 14 publications

References 41 publications

Resuscitative endovascular balloon occlusion of the aorta: rupture risk and implications for blind inflation

Resuscitative endovascular balloon occlusion of the aorta: rupture risk and implications for blind inflation

Synthesis and characterisation of a cancerous liver for presurgical planning and training applications

Circumferential variation in mechanical characteristics of porcine descending aorta

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