Biomechanical Properties of Human Ascending Thoracic Aortic Aneurysms

Azadani, Ali N.; Chitsaz, Sam; Mannion, Alex; Mookhoek, Aart; Wisneski, Andrew D.; Guccione, Julius M.; Hope, Michael D.; Ge, Liang; Tseng, Elaine E.

doi:10.1016/j.athoracsur.2013.03.094

Cited by 85 publications

(65 citation statements)

References 23 publications

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“…Planar biaxial testing is a common approach to characterizing soft biological tissues [9,19,21,26,27] and the specimen fixation with clamps used in the present work allowed higher stress levels than reported earlier to be reached. Consequently, porcine aorta biomechanics could be characterized well beyond the physiological stress range (axial FPK stress, up to 420 kPa; circumferential FPK stress, up to 400 kPa; see electronic supplement) so the data presented could also be used to simulate supraphysiological loading states.…”

Section: Planar Biaxial Testing Up To High Stretchesmentioning

confidence: 82%

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Structure-based constitutive model can accurately predict planar biaxial properties of aortic wall tissue

et al. 2015

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Section: Planar Biaxial Testing Up To High Stretchesmentioning

confidence: 82%

“…local fiber and continuum deformations match. In addition to microstructural data, in vitro aortic tissue testing provides mechanical input information for model parameter identification, where biaxial testing [9,19,21,26,27] is specifically capable of closely reflecting the in vivo mechanical environment of vascular tissue.…”

Section: Introductionmentioning

confidence: 99%

Structure-based constitutive model can accurately predict planar biaxial properties of aortic wall tissue

et al. 2015

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“…Tissue from the ascending aorta has been tested in a variety of configurations (reviewed by Avanzini et al [17]), with uniaxial and equibiaxial stretch tensile tests being the most common. In-plane uniaxial [18][19][20] and biaxial tension tests [21][22][23][24] provide information on tensile failure in the plane of the medial lamella ðr hh ; r zz Þ; and the biaxial tests can provide some additional information on in-plane shear ðr hz Þ. Although the dominant stresses in these tests may be the primary stresses during vessel rupture, they are not those driving dissection.…”

Section: Introductionmentioning

confidence: 99%

Failure of the Porcine Ascending Aorta: Multidirectional Experiments and a Unifying Microstructural Model

Witzenburg

Dhume

Shah

et al. 2017

Journal of Biomechanical Engineering

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The ascending thoracic aorta is poorly understood mechanically, especially its risk of dissection. To make better predictions of dissection risk, more information about the multidimensional failure behavior of the tissue is needed, and this information must be incorporated into an appropriate theoretical/computational model. Toward the creation of such a model, uniaxial, equibiaxial, peel, and shear lap tests were performed on healthy porcine ascending aorta samples. Uniaxial and equibiaxial tests showed anisotropy with greater stiffness and strength in the circumferential direction. Shear lap tests showed catastrophic failure at shear stresses (150-200 kPa) much lower than uniaxial tests (750-2500 kPa), consistent with the low peel tension ($60 mN/mm). A novel multiscale computational model, including both prefailure and failure mechanics of the aorta, was developed. The microstructural part of the model included contributions from a collagenreinforced elastin sheet and interlamellar connections representing fibrillin and smooth muscle. Components were represented as nonlinear fibers that failed at a critical stretch. Multiscale simulations of the different experiments were performed, and the model, appropriately specified, agreed well with all experimental data, representing a uniquely complete structure-based description of aorta mechanics. In addition, our experiments and model demonstrate the very low strength of the aorta in radial shear, suggesting an important possible mechanism for aortic dissection.

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“…31,49,60 The impact of material properties for these computational analyses may be considerable. 60 Also an assumption raised by several authors 2,11,26,62 is that the stiffness of tissues from ATAAs may be positively correlated with the strength. So obtaining non-invasively the patient-specific material properties may represent a very important interest.…”

Section: Discussionmentioning

confidence: 97%

“…19,29,41 Obtaining the local thickness is still challenging, despite the importance of this parameter for AAAs and ATAAs. 37,44,49 The current study is focused on identifying, noninvasively and in vivo, the patient specific material properties of ATAAs, which represent essential biomechanical determinants for ATAA strength 2,11,26 and for ATAA growth. 31,32,49,60 Several inverse approaches have already been developed to estimate mechanical properties of soft tissues in the human body.…”

Section: Introductionmentioning

confidence: 99%

Predictive Models with Patient Specific Material Properties for the Biomechanical Behavior of Ascending Thoracic Aneurysms

et al. 2015

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The aim of this study is to identify the patient-specific material properties of ascending thoracic aortic aneurysms (ATAA) using preoperative dynamic gated computed tomography (CT) scans. The identification is based on the simultaneous minimization of two cost functions, which define the difference between model predictions and gated CT measurements of the aneurysm volume at respectively systole and cardiac mid-cycle. The method is applied on five patients who underwent surgical repair of their ATAA at the University Hospital Center of St. Etienne. For these patients, the aneurysms were collected and tested mechanically using an in vitro bench. For the sake of validation, the mechanical properties found using the in vivo approach and the in vitro bench were compared. We eventually performed finite-element stress analyses based on each set of material properties. Rupture risk indexes were estimated and compared, showing promising results of the patient-specific identification method based on gated CT.

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Biomechanical Properties of Human Ascending Thoracic Aortic Aneurysms

Cited by 85 publications

References 23 publications

Structure-based constitutive model can accurately predict planar biaxial properties of aortic wall tissue

Structure-based constitutive model can accurately predict planar biaxial properties of aortic wall tissue

Failure of the Porcine Ascending Aorta: Multidirectional Experiments and a Unifying Microstructural Model

Predictive Models with Patient Specific Material Properties for the Biomechanical Behavior of Ascending Thoracic Aneurysms

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