Haemodynamic Variations of Flow to Renal Arteries in Custom-Made and Pivot Branch Fenestrated Endografting

Ou, Jing; Tang, Abraham Yik-Sau; Chiu, Tor-Wo; Chow, K. W.; Chan, Yiu-Che; Cheng, Stephen W.K.

doi:10.1016/j.ejvs.2016.10.022

Cited by 10 publications

(9 citation statements)

References 27 publications

(25 reference statements)

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“…In the vast majority of CFD studies, the EVAR devices are simulated with an unwrinkled fabric surface that serves as a smooth boundary wall for the blood flow. 20,22,34,35 Yet by disregarding the wrinkles on the surface of the graft, possible flow disturbances can be overlooked. Herein, it was successfully demonstrated that the output of the FEA simulation can be used as input for a CFD investigation.…”

Section: Discussionmentioning

confidence: 99%

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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Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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“…Compared to previous ideal model used to study branched stent configurations 17,33,38 , the models used in this study were derived from clinical cases, which examined and added the current knowledge with "real-world" data. Moreover, the models in this study provided important insights on the velocity and the WSS distribution of the BSG.…”

Section: Discussionmentioning

confidence: 99%

Hemodynamic Parameters Predict the In-Stent Thrombosis After the Multibranched Endovascular Repair for Complex Abdominal Aortic Aneurysms: A Preliminary Study on Branched Stent-Graft Thrombosis.

Liu

Yang

et al. 2020

Preprint

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Backgrounds: Branched vessel occlusion is frequently reported in the endovascular repair for aortic pathology. This study aimed to evaluate the hemodynamic indicators associated with the in-stent thrombosis (IST) of the branched stent-graft (BSG) after the endovascular aortic repair (EVAR) for complex abdominal aortic aneurysm.Methods: A retrospective evaluation was performed based on the computed tomography (CT) scan and clinical data of three patients who underwent multibranched endovascular repair. The reconstruction of patient-specific 3-dimension models and hemodynamic analysis for IST were performed. The hemodynamic related parameters including time-averaged wall shear stress (TAWSS), oscillatory shear stress index (OSI) and relative residence time (RRT) were compared between the individual data.Results: The velocity, TAWSS, OSI and RRT were radically changed in the area of IST. The IST of the BSG were located at the hemodynamic alteration regions near the bending curve where the decreased flow velocity (<0.6 m/s), TAWSS (<0.8 Pa) and elevated OSI (>0.3), and RRT (>5 s) were constantly observed. Conclusions: The hemodynamic perturbations in the BSG predispose the IST, which could be predicted by a series changes of the flow parameters. Early hemodynamic analysis might be useful for identifying and remediating the IST after the multibranched endovascular repair.Trial registration: This study was retrospectively registered and approved by the institutional ethical review board.

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“…This failure of correlation even remains true when hemodynamic outcomes are improved with caudal orientation of renal stents. 20 Thus, despite much suspicion that forced anatomic changes may bear some culpability for the deterioration of renal function often seen after aneurysm repair, contemporary imaging techniques have failed to provide proof. We believe a functional indicator, such as renal volume, which links anatomic change to important perfusion-related outcomes, provides a surrogate measure of stent performance, and may be a better indicator of the four-dimensional behaviour of the stents.…”

Section: Discussionmentioning

confidence: 99%

Accuracy of implementing principles of fusion imaging in the follow up and surveillance of complex aneurysm repair

et al. 2018

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Fusion imaging is standard for the endovascular treatment of complex aortic aneurysms, but its role in follow up has not been explored. A critical issue is renal function deterioration over time. Renal volume has been used as a marker of renal impairment; however, it is not reproducible and remains a complex and resource-intensive procedure. The aim of this study is to determine the accuracy of a fusion-based software to automatically calculate the renal volume changes during follow up. In this study, computerized tomography (CT) scans of 16 patients who underwent complex aortic endovascular repair were analysed. Preoperative, 1-month and 1-year follow-up CT scans have been analysed using a conventional approach of semi-automatic segmentation, and a second approach with automatic segmentation. For each kidney and at each time point the percentage of change in renal volume was calculated using both techniques. After review, volume assessment was feasible for all CT scans. For the left kidney, the intraclass correlation coefficient (ICC) was 0.794 and 0.877 at 1 month and 1 year, respectively. For the right side, the ICC was 0.817 at 1 month and 0.966 at 1 year. The automated technique reliably detected a decrease in renal volume for the eight patients with occluded renal arteries during follow up. This is the first report of a fusion-based algorithm to detect changes in renal volume during postoperative surveillance using an automated process. Using this technique, the standardized assessment of renal volume could be implemented with greater ease and reproducibility and serve as a warning of potential renal impairment.

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Haemodynamic Variations of Flow to Renal Arteries in Custom-Made and Pivot Branch Fenestrated Endografting

Abstract: Navigating the renal stents towards caudal orientation can achieve better haemodynamic outcomes in both fenestrated devices. Custom-made fenestrated stent grafts are the preferred choice for elective patients. Further clinical evidence is required to validate the computational simulations.

Cited by 10 publications

References 27 publications

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

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

Hemodynamic Parameters Predict the In-Stent Thrombosis After the Multibranched Endovascular Repair for Complex Abdominal Aortic Aneurysms: A Preliminary Study on Branched Stent-Graft Thrombosis.

Accuracy of implementing principles of fusion imaging in the follow up and surveillance of complex aneurysm repair

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