Latex vessels with customized compliance for use in arterial flow models

Walker, Richard; Smith, Roy E.; Sherriff, S B; Wood, R. F.

doi:10.1088/0967-3334/20/3/305

Cited by 22 publications

(14 citation statements)

References 26 publications

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“…Thus, the linear relation between flow and pressure drop as observed in this study might not completely represent the in-vivo situation. Earlier studies have modeled the compliance vessel using fluid structure interaction formulation [1] and investigated in experiments the elastic material property [15]. Future in vivo studies using patient-specific artery models that incorporate the compliance characteristic of the artery wall and more complex lesion morphology might provide further insights.…”

Section: Discussionmentioning

confidence: 99%

Numerical and experimental investigations of the flow–pressure relation in multiple sequential stenoses coronary artery

Chin

Thondapu

et al. 2017

Int J Cardiovasc Imaging

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Virtual fractional flow reserve (vFFR) has been evaluated as an adjunct to invasive fractional flow reserve (FFR) in the light of its operational and economic benefits. The accuracy of vFFR and the complexity of hyperemic flow simulation are still not clearly understood. This study investigates the flow–pressure relation in an idealised multiple sequential stenoses coronary artery model via numerical and experimental approaches. Pressure drop is linearly correlated with flow rate irrespective of the number of stenosis. Computational fluid dynamics results are in good agreement with the experimental data, demonstrating reasonable accuracy of vFFR. It was also found that the difference between data obtained with steady and pulsatile flows is negligible, indicating the steady flow may be used instead of pulsatile flow conditions in vFFR computation. This study adds to the current understanding of vFFR and may improve its clinical applicability as an adjunct to invasively determined FFR.

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Section: Discussionmentioning

confidence: 99%

Numerical and experimental investigations of the flow–pressure relation in multiple sequential stenoses coronary artery

Chin

Thondapu

et al. 2017

Int J Cardiovasc Imaging

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“…Because of these parameters creating materials with a similar stress-strain response to aortic tissue may not lead to models that behave similar to the vessel itself. Because of this, the compliance (or stiffness) of arteries has become the attribute which researchers attempt to mimic [10,16]. The manufacturing methods for creating both idealised and realistic AAA models have been previously reported [10,16–21].…”

Section: Introductionmentioning

confidence: 99%

“…Because of this, the compliance (or stiffness) of arteries has become the attribute which researchers attempt to mimic [10,16]. The manufacturing methods for creating both idealised and realistic AAA models have been previously reported [10,16–21]. O’ Brien et al [19] and Doyle et al [20] have verified a lost wax manufacturing technique and reported that the variation in wall thickness for large vessel models manufactured using this technique was between 4–11%.…”

Section: Introductionmentioning

confidence: 99%

“…The ultimate tensile strength of the material and the location of rupture of the models were the primary considerations in that study and as such we did not examine the compliance of the models themselves. Other studies have investigated model compliance but have not characterised the materials used to construct the models [10,16]. Those studies were based on AAA models created by brushing latex onto either a glass or plastic former.…”

Section: Introductionmentioning

confidence: 99%

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Engineering Silicone Rubbers for In Vitro Studies: Creating AAA Models and ILT Analogues With Physiological Properties

Corbett

Doyle

Callanan

et al. 2009

Journal of Biomechanical Engineering

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Background In vitro studies of abdominal aortic aneurysm (AAA) have been widely reported. Frequently mock artery models with intraluminal thrombus (ILT) analogues are used to mimic the AAA in vivo. While the models used may be physiological, their properties are frequently either not reported or investigated. Method of Approach This study is concerned with the testing and characterisation of previously used vessel analogue materials and the development of new materials for the manufacture of AAA models. These materials were used in conjunction with a previously validated injection moulding technique to manufacture AAA models of ideal geometry. To determine the model properties (stiffness (β) and compliance) the diameter change of each AAA model was investigated under incrementally increasing internal pressures and compared to published in vivo studies to determine if the models behaved physiologically. A FEA study was implemented to determine if the pressure – diameter change behaviour of the models could be predicted numerically. ILT analogues were also manufactured and characterised. Ideal models were manufactured with ILT analogue internal to the aneurysm region and the effect of the ILT analogue on the model compliance and stiffness was investigated. Results The wall materials had similar properties to aortic tissue at physiological pressures (Einit 2.22MPa and 1.57MPa (aortic tissue: 1.8MPa)). ILT analogues had similar Young’s modulus to the medial layer of ILT (0.24 and 0.33MPa (ILT: 0.28MPa)). All models had aneurysm sac compliance in the physiological range (2.62 – 8.01×10-4/mmHg (AAA in vivo: 1.8 – 9.4×10-4/mmHg)). The necks of our AAA models had similar stiffness to healthy aortas (20.44 – 29.83 (healthy aortas in vivo: 17.5±5.5)). Good agreement was seen between the diameter changes due to pressurisation in the experimental and FEA wall models with a maximum error of 7.3% at 120mmHg. It was also determined that the inclusion of ILT analogue in the sac of our models could have an effect on the compliance of the model neck. Conclusions Ideal AAA models with physiological properties were manufactured. The behaviour of these models due to pressurisation was predicted using FEA, validating this technique for the future design of realistic, physiological AAA models. Addition of ILT analogues in the aneurysm sac was shown to affect neck behaviour. This could have implications for endovascular AAA repair due to the importance of the neck for stent-graft fixation.

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“…In the past, models have been used in a wide range of applications to verify the mathematical theories of blood flow and the response to various haemodynamic situations [1 ± 3]. Walker et al [4] reported that measurement on latex tubings simulating the femoral artery showed good agreement with the mathematical predictions of pulse wave velocity and also with similar static characteristics to human arteries. We have developed a low-cost, fast and easy technique for manufacturing latex tubings with thin-walled aneurysms which have physical characteristics similar to those of human arteries and aneurysms.…”

Section: Introductionmentioning

confidence: 99%