Hemodynamic effects of stent-graft introducer sheath during thoracic endovascular aortic repair

Qiao, Yonghui; Mao, Le; Wang, Yan; Luan, Jingyang; Chen, Yanlu; Zhu, Ting; Luo, Kun; Fan, Jianren

doi:10.1007/s10237-021-01542-5

Cited by 12 publications

(2 citation statements)

References 33 publications

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“…For the BFS model, the inlet flow rate was uniform because of the non-circular inlet shape, and a zero averaged pressure was used as the outlet boundary condition. The entrance of the FDA nozzle was circular, so a parabolic velocity profile was imposed at the inlet to reduce the length of the inlet straight pipe ( Qiao et al, 2022a ; Qiao et al, 2022b ):

where

is the radial location of the inlet. The outlet boundary condition of the nozzle remains unchanged.…”

Section: Methodologiesmentioning

confidence: 99%

Computational Prediction of Thrombosis in Food and Drug Administration’s Benchmark Nozzle

2022

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Thrombosis seriously threatens human cardiovascular health and the safe operation of medical devices. The Food and Drug Administration’s (FDA) benchmark nozzle model was designed to include the typical structure of medical devices. However, the thrombosis in the FDA nozzle has yet not been investigated. The objective of this study is to predict the thrombus formation process in the idealized medical device by coupling computational fluid dynamics and a macroscopic hemodynamic-based thrombus model. We developed the hemodynamic-based thrombus model by considering the effect of platelet consumption. The thrombus model was quantitatively validated by referring to the latest thrombosis experiment, which was performed in a backward-facing step with human blood flow. The same setup was applied in the FDA nozzle to simulate the thrombus formation process. The thrombus shaped like a ring was firstly observed in the FDA benchmark nozzle. Subsequently, the accuracy of the shear-stress transport turbulence model was confirmed in different turbulent flow conditions. Five scenarios with different Reynolds numbers were carried out. We found that turbulence could change the shape of centrosymmetric thrombus to axisymmetric and high Reynolds number blood flow would delay or even prevent thrombosis. Overall, the present study reports the thrombosis process in the FDA benchmark nozzle using the numerical simulation method, and the primary findings may shed light on the effect of turbulence on thrombosis.

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where

is the radial location of the inlet. The outlet boundary condition of the nozzle remains unchanged.…”

Section: Methodologiesmentioning

confidence: 99%

Computational Prediction of Thrombosis in Food and Drug Administration’s Benchmark Nozzle

2022

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“…An area with high RRT is subjected to both low and oscillating wall shear stresses simultaneously [54]. RRT is a measure of how closely the particles remain in proximity to the wall and can be calculated using the following formula [55]:…”

Section: Hemodynamic Parametersmentioning

confidence: 99%

The Role of Wall Mechanics in the Hemodynamics of a Realistic Abdominal Aortic Aneurysm: A Fluid-Structure Interaction Study

Moradicheghamahi

2024

Journal of Engineering

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Abdominal aortic aneurysm (AAA) can lead to high mortality rates and further complications such as stroke or heart attack due to the risk of rupture and thrombosis. Wall mechanics play a crucial role in the development and progression of aneurysms. This study investigated the effects of wall mechanics on hemodynamic parameters in AAA to understand the risk of rupture and thrombosis. The impact of three aortic wall models (rigid, linear elastic, and hyperelastic) on structural and hemodynamic parameters was examined using CFD and FSI techniques. The blood was modeled using the Carreau non-Newtonian model, and the flow was simulated using the k-ω model. Physiological pulses were used for the velocity at the inlet and the pressure at the outlet. The results demonstrated close similarity between the predictions of the linear elastic and hyperelastic models, in contrast to the somewhat different results of the rigid model. The hyperelastic model predicted higher deformation and von Mises stress levels than the elastic model, although the difference in stress predictions was smaller than the difference in deformation predictions. The rigid model evaluated the time-averaged wall shear stress and oscillatory shear index higher than the other two models in the aneurysmal area but with a lower relative residence time. In general, the hyperelastic model predicted a higher risk of rupture than linear elastic models and a higher risk of thrombus formation than the other two models. The rigid model had the most optimistic prediction.

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A new method for scaling inlet flow waveform in hemodynamic analysis of aortic dissection

Wang,

Armour,

Guo

et al. 2024

Numer Methods Biomed Eng

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Computational fluid dynamics (CFD) simulations have shown great potentials in cardiovascular disease diagnosis and postoperative assessment. Patient‐specific and well‐tuned boundary conditions are key to obtaining accurate and reliable hemodynamic results. However, CFD simulations are usually performed under non‐patient‐specific flow conditions due to the absence of in vivo flow and pressure measurements. This study proposes a new method to overcome this challenge by tuning inlet boundary conditions using data extracted from electrocardiogram (ECG). Five patient‐specific geometric models of type B aortic dissection were reconstructed from computed tomography (CT) images. Other available data included stoke volume (SV), ECG, and 4D‐flow magnetic resonance imaging (MRI). ECG waveforms were processed to extract patient‐specific systole to diastole ratio (SDR). Inlet boundary conditions were defined based on a generic aortic flow waveform tuned using (1) SV only, and (2) with ECG and SV (ECG + SV). 4D‐flow MRI derived inlet boundary conditions were also used in patient‐specific simulations to provide the gold standard for comparison and validation. Simulations using inlet flow waveform tuned with ECG + SV not only successfully reproduced flow distributions in the descending aorta but also provided accurate prediction of time‐averaged wall shear stress (TAWSS) in the primary entry tear (PET) and abdominal regions, as well as maximum pressure difference, ∆Pmax, from the aortic root to the distal false lumen. Compared with simulations with inlet waveform tuned with SV alone, using ECG + SV in the tuning method significantly reduced the error in false lumen ejection fraction at the PET (from 149.1% to 6.2%), reduced errors in TAWSS at the PET (from 54.1% to 5.7%) and in the abdominal region (from 61.3% to 11.1%), and improved ∆Pmax prediction (from 283.1% to 18.8%) However, neither of these inlet waveforms could be used for accurate prediction of TAWSS in the ascending aorta. This study demonstrates the importance of SDR in tailoring inlet flow waveforms for patient‐specific hemodynamic simulations. A well‐tuned flow waveform is essential for ensuring that the simulation results are patient‐specific, thereby enhancing the confidence and fidelity of computational tools in future clinical applications.

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Hemodynamic effects of stent-graft introducer sheath during thoracic endovascular aortic repair

Cited by 12 publications

References 33 publications

Computational Prediction of Thrombosis in Food and Drug Administration’s Benchmark Nozzle

Computational Prediction of Thrombosis in Food and Drug Administration’s Benchmark Nozzle

The Role of Wall Mechanics in the Hemodynamics of a Realistic Abdominal Aortic Aneurysm: A Fluid-Structure Interaction Study

A new method for scaling inlet flow waveform in hemodynamic analysis of aortic dissection

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