Patient-specific in silico endovascular repair of abdominal aortic aneurysms: application and validation

Lin

Thierfelder

et al. 2020

Self Cite

Endovascular aortic repair (EVAR) is a challenging intervention whose longterm success strongly depends on the appropriate stent-graft (SG) selection and sizing. Most off-the-shelf SGs are straight and cylindrical. Especially in challenging vessel morphologies, the morphology of off-the-shelf SGs is not able to meet the patient-specific demands. Advanced manufacturing technologies facilitate the development of highly customized SGs. Customized SGs that have the same morphology as the luminal vessel surface could considerably improve the quality of the EVAR outcome with reduced likelihoods of EVAR related complications such as endoleaks type I and SG migration. In this contribution, we use an in silico EVAR methodology that approximates the deployed state of the elastically deformable SG in a hyperelastic, anisotropic vessel. The in silico EVAR results of off-the-shelf SGs and customized SGs are compared qualitatively and quantitatively in terms of mechanical and geometrical parameters such as stent stresses, contact tractions, SG fixation forces and the SG-vessel attachment. In a numerical proof of concept, eight different vessel morphologies, such as a conical vessel, a barrel shaped vessel and a curved vessel, are used to demonstrate the added value of customized SGs compared to off-the-shelf SGs. The numerical investigation has shown large benefits of the highly customized SGs compared to off-the-shelf SGs with respect to a better SG-vessel attachment and a considerable increase in SG fixation forces of up to 50% which indicate decreased likelihoods of EVAR related complications. Hence, this numerical proof of concept motivates further research and development of highly customized SGs for the use in challenging vessel morphologies. K E Y W O R D Sabdominal aortic aneurysm, customized stent-graft, endovascular repair, personalized medicine

Section: Methodsmentioning

confidence: 99%

Section: Limitationsmentioning

confidence: 99%

Section: Limitationsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Customized stent‐grafts for endovascular aneurysm repair with challenging necks: A numerical proof of concept

Lin

Thierfelder

et al. 2020

Self Cite

“…The calculation of the centerline

{scriptC}_{De}

of the SG in the deployed state is not discussed in this contribution. The interested reader can find detailed information on this topic in Hemmler et al 17 . We only evaluate the geometrical shape of the stent since the geometrical shape of the graft is dominated by its buckling pattern and does not represent the effects that shall be investigated in this section.…”

Section: Methodsmentioning

confidence: 99%

In silico study of vessel and stent‐graft parameters on the potential success of endovascular aneurysm repair

Lutz

Reeps

et al. 2019

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The variety of stent‐graft (SG) design variables (eg, SG type and degree of SG oversizing) and the complexity of decision making whether a patient is suitable for endovascular aneurysm repair (EVAR) raise the need for the development of predictive tools to assist clinicians in the preinterventional planning phase. Recently, some in silico EVAR methods have been developed to predict the deployed SG configuration. However, only few studies investigated how to assess the in silico EVAR outcome with respect to EVAR complication likelihoods (eg, endoleaks and SG migration). Based on a large literature study, in this contribution, 20 mechanical and geometrical parameters (eg, SG drag force and SG fixation force) are defined to evaluate the quality of the in silico EVAR outcome. For a cohort of n = 146 realizations of parameterized vessel and SG geometries, the in silico EVAR results are studied with respect to these mechanical and geometrical parameters. All degrees of SG oversizing in the range between 5% and 40% are investigated continuously by a computationally efficient parameter continuation approach. The in silico investigations have shown that the mechanical and geometrical parameters are able to indicate candidates at high risk of postinterventional complications. Hence, this study provides the basis for the development of a simulation‐based metric to assess the potential success of EVAR based on engineering parameters.

Patient‐specific computational modeling of endovascular aneurysm repair: State of the art and future directions

Avril

Gee

et al. 2021

Self Cite

Endovascular aortic repair (EVAR) has become the preferred intervention option for aortic aneurysms and dissections. This is because EVAR is much less invasive than the alternative open surgery repair. While in‐hospital mortality rates are smaller for EVAR than open repair (1%–2% vs. 3%–5%), the early benefits of EVAR are lost after 3 years due to larger rates of complications in the EVAR group. Clinicians follow instructions for use (IFU) when possible, but are left with personal experience on how to best proceed and what choices to make with respect to stent‐graft (SG) model choice, sizing, procedural options, and their implications on long‐term outcomes. Computational modeling of SG deployment in EVAR and tissue remodeling after intervention offers an alternative way of testing SG designs in silico, in a personalized way before intervention, to ultimately select the strategies leading to better outcomes. Further, computational modeling can be used in the optimal design of SGs in cases of complex geometries. In this review, we address some of the difficulties and successes associated with computational modeling of EVAR procedures. There is still work to be done in all areas of EVAR in silico modeling, including model validation, before models can be applied in the clinic, but much progress has already been made. Critical to clinical implementation are current efforts focusing on developing fast algorithms that can achieve (near) real‐time solutions, as well as ways of dealing with inherent uncertainties related to patient aortic wall degradation on an individualized basis. We are optimistic that EVAR modeling in the clinic will soon become a reality to help clinicians optimize EVAR interventions and ultimately reduce EVAR‐associated complications.