Analysis of flow patterns on branched endografts for aortic arch aneurysms

Chiu, Tor-Wo; Tang, Abraham Yik-Sau; Cheng, Stephen W.K.; Chow, K. W.

doi:10.1016/j.imu.2018.10.008

Cited by 10 publications

(11 citation statements)

References 40 publications

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“…The other components of the main SG and the BSs were let free. 7 5. Simulation assessment Positions of stent rings obtained from the post-operative CT scan were chosen as reference positions to validate our deployment simulation.…”

Section: Simulation Methodology Of Stent-grafts Deploymentmentioning

confidence: 99%

Predictive Numerical Simulations of Double Branch Stent-Graft Deployment in an Aortic Arch Aneurysm

Derycke

Perrin²,

Cochennec

et al. 2019

Ann Biomed Eng

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and key terms:Total endovascular repair of the aortic arch represents a promising option for patients ineligible to open surgery. Custom-made design of stent-grafts (SG), such as the Terumo Aortic® RelayBranch device (DB), requires complex preoperative measures. Accurate SG deployment is required to avoid intraoperative or postoperative complications, which is extremely challenging in the aortic arch. In that context, our aim is to develop a computational tool able to predict SG deployment in such highly complex situations. A patient-specific case is performed with complete deployment of the DB and its bridging stents in an aneurysmal aortic arch. Deviations of our simulation predictions from actual stent positions are estimated based on post-operative scan and a sensitivity analysis is performed to assess the effects of material parameters. Results show a very good agreement between simulations and postoperative scan, with especially a torsion effect, which is successfully reproduced by our simulation. Relative diameter, transverse and longitudinal deviations are of 3.2±4.0%, 2.6±2.9mm and 5.2±3.5mm respectively. Our numerical simulations show their ability to successfully predict the DB deployment in complex anatomy. The results emphasize the potential of computational simulations to assist practitioners in planning and performing complex and secure interventions.

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Section: Simulation Methodology Of Stent-grafts Deploymentmentioning

confidence: 99%

Predictive Numerical Simulations of Double Branch Stent-Graft Deployment in an Aortic Arch Aneurysm

Derycke

Perrin²,

Cochennec

et al. 2019

Ann Biomed Eng

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“…configurations deployed in the three aortic arch branches. 20 Results showed that an antegrade curved LSA stent graft generates less resistance to flow than a retrograde configuration, allowing a 79% LSA flow rate increase. These outcomes demonstrate that the orientation of a branched stent…”

mentioning

confidence: 96%

Haemodynamics of Different Configurations of a Left Subclavian Artery Stent Graft for Thoracic Endovascular Aortic Repair

Tricarico

Tran‐Son‐Tay

Laquian

et al. 2020

European Journal of Vascular and Endovascular Surgery

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WHAT THIS PAPER ADDS Technologies allowing endografting in the aortic arch are in active clinical trials with various configurations of branch stent graft design. A systematic computational fluid dynamic analysis was carried out to quantitatively evaluate the haemodynamic characteristics of stenting within the left subclavian artery (LSA). The results showed that a shorter extension of the LSA branch stent graft into the aortic lumen up to 5 mm has a smaller risk of potential thrombus generation; a longer extension could lead to thrombus formation impacting outcomes. These findings may help optimise the deployment and design of the stent graft system for treating aortic pathologies involving arch branches. Objective: Branched stent grafts represent a viable option for left subclavian artery (LSA) revascularisation in patients treated by thoracic endovascular aortic repair (TEVAR) for Zone 2 lesions. This study investigated the haemodynamic performance of different LSA branched stent graft configurations as potential determinants of thrombotic and stroke risks. Methods: A three dimensional aortic arch geometry extracted from post-operative computed tomography images of a TEVAR patient using a single LSA branched aortic endograft was modified in silico to obtain ten potential LSA branched stent graft configurations: five down facing (0e5 e 10 mm aortic protrusion with 10e12 mm internal diameter), four curved (30e60 with antegrade/retrograde orientation), and one LSA orifice misalignment. The 0 mm down facing stent graft was considered base configuration. Computational fluid dynamic analyses were performed to identify differences in pressure, energy, and wall shear stress (WSS) based parameters. Results: Total pressure drop and energy loss variations among configurations were not greater than 5 mmHg (6% of mean arterial pressure) and 5.7 mW (0.7% of cardiac power), respectively. Protrusions up to 5 mm created clinically insignificant flow disturbances. However, stent graft protrusions further into the aortic lumen created more complex haemodynamics, characterised by larger energy loss and more prominent flow recirculation. Protrusion greater than 5 mm into the lumen was associated with larger areas of elevated maximum WSS (>20 Pa) along the outer surface of the branched stent graft. Conclusion: Arterial haemodynamic characteristics are affected by LSA branched stent graft configurations, with pressure drops and energy losses likely to be clinically insignificant. The length of the stent graft protrusion into the aortic lumen generated the largest haemodynamic variations in the aortic system. Protrusions up to 5 mm have smaller risk of potential thrombus generation. Conversely, larger protrusions into the aortic lumen showed more disturbed haemodynamics, suggesting a greater risk of potential thrombus formation, which may be clinically important over time.

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“…The blood flow was assumed to be laminar, in keeping with other studies in the field. 6 , 12 , 37 Additionally, the flow was assumed to be incompressible and the blood non-Newtonian with density = 1060 kg/m 8 and dynamic viscosity described by the Carreau-Yasuda model: where denotes the scalar shear rate. The shear viscosity at low shear rates, = 0.16, the shear viscosity at large shear rates, = 0.0035 and material coefficients and were equal to 8.2 s and 0.2128 respectively, following common values found in the literature.…”

Section: Methodsmentioning

confidence: 99%

Section: Cfdmentioning

confidence: 99%

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Efficiently Simulating an Endograft Deployment: A Methodology for Detailed CFD Analyses

et al. 2020

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Numerical models of endografts for the simulation of endovascular aneurysm repair are increasingly important in the improvement of device designs and patient outcomes. Nevertheless, current finite element analysis (FEA) models of complete endograft devices come at a high computational cost, requiring days of runtime, therefore restricting their applicability. In the current study, an efficient FEA model of the Anaconda™ endograft (Terumo Aortic, UK) was developed, able to yield results in just over 4 h, an order of magnitude less than similar models found in the literature. The model was used to replicate a physical device that was deployed in a 3D printed aorta and comparison of the two shapes illustrated a less than 5 mm placement error of the model in the regions of interest, consistent with other more computationally intensive models in the literature. Furthermore, the final goal of the study was to utilize the deployed fabric model in a hemodynamic analysis that would incorporate realistic fabric folds, a feature that is almost always omitted in similar simulations. By successfully exporting the deployed graft geometry into a flow analysis, it was illustrated that the inclusion of fabric wrinkles enabled clinically significant flow patterns such as flow stagnation and recirculation to be detected, paving the way for this modelling methodology to be used in future for stent design optimisation.

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Analysis of flow patterns on branched endografts for aortic arch aneurysms

Cited by 10 publications

References 40 publications

Predictive Numerical Simulations of Double Branch Stent-Graft Deployment in an Aortic Arch Aneurysm

Predictive Numerical Simulations of Double Branch Stent-Graft Deployment in an Aortic Arch Aneurysm

Haemodynamics of Different Configurations of a Left Subclavian Artery Stent Graft for Thoracic Endovascular Aortic Repair

Efficiently Simulating an Endograft Deployment: A Methodology for Detailed CFD Analyses

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