The Advantages of Viscous Dissipation Rate over Simplified Power Loss as a Fontan Hemodynamic Metric

Wei, Zhenglun Alan; Tree, Michael; Trusty, Phillip M.; Wu, Wenjun; Singh-Gryzbon, Shelly

doi:10.1007/s10439-017-1950-1

Cited by 35 publications

(12 citation statements)

References 34 publications

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“…Homogeneous material properties were assigned at the vessel wall. This study's primary hemodynamic metrics are power loss and hepatic flow distributions: their definitions adhere to previous studies [23,[45][46][47][48]].…”

Section: Hemodynamic Assessmentmentioning

confidence: 99%

Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection

Tang

Wei

Fogel

et al. 2020

Biology

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Total cavopulmonary connection (TCPC) hemodynamics has been hypothesized to be associated with long-term complications in single ventricle heart defect patients. Rigid wall assumption has been commonly used when evaluating TCPC hemodynamics using computational fluid dynamics (CFD) simulation. Previous study has evaluated impact of wall compliance on extra-cardiac TCPC hemodynamics using fluid-structure interaction (FSI) simulation. However, the impact of ignoring wall compliance on the presumably more compliant intra-atrial TCPC hemodynamics is not fully understood. To narrow this knowledge gap, this study aims to investigate impact of wall compliance on an intra-atrial TCPC hemodynamics. A patient-specific model of an intra-atrial TCPC is simulated with an FSI model. Patient-specific 3D TCPC anatomies were reconstructed from transverse cardiovascular magnetic resonance images. Patient-specific vessel flow rate from phase-contrast magnetic resonance imaging (MRI) at the Fontan pathway and the superior vena cava under resting condition were prescribed at the inlets. From the FSI simulation, the degree of wall deformation was compared with in vivo wall deformation from phase-contrast MRI data as validation of the FSI model. Then, TCPC flow structure, power loss and hepatic flow distribution (HFD) were compared between rigid wall and FSI simulation. There were differences in instantaneous pressure drop, power loss and HFD between rigid wall and FSI simulations, but no difference in the time-averaged quantities. The findings of this study support the use of a rigid wall assumption on evaluation of time-averaged intra-atrial TCPC hemodynamic metric under resting breath-held condition.

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Section: Hemodynamic Assessmentmentioning

confidence: 99%

Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection

Tang

Wei

Fogel

et al. 2020

Biology

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“…A polyhedral mesh of approximately D IVC /20 mm elements was used in order to achieve mesh independent results, where D IVC is the diameter of the IVC. 19 All simulations were performed using ANSYS Fluent (Release 17.1) which is a finite volume pressurebased NavierStokes solver. Blood was modeled as a single-phase Newtonian fluid (μ=0.04 g/ (cm•s), ρ=1.06 g/cm3).…”

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

“…Blood was modeled as a single-phase Newtonian fluid (μ=0.04 g/ (cm•s), ρ=1.06 g/cm3). The appropriate patient specific blood flow waveforms extracted from PC-MRI were used as boundary conditions for each TCPC inlet and outlet 19,20 . Twenty cardiac cycles were simulated to overcome transition effects and achieve period stability, using the final cycle for data analysis.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

The first cohort of prospective Fontan surgical planning patients with follow-up data: How accurate is surgical planning?

Trusty

Wei

Slesnick

et al. 2019

The Journal of Thoracic and Cardiovascular Surgery

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Objective: Fontan surgical planning is an image-based, collaborative effort which is hypothesized to result in improved patient outcomes. A common motivation for Fontan surgical planning is the progression (or concern for progression) of pulmonary arteriovenous malformations (PAVMs). The purpose of this study is to evaluate the accuracy of surgical planning predictions, specifically hepatic flow distribution (HFD, a known factor in PAVM progression), and identify methodological improvements needed to increase prediction accuracy. Methods: Twelve single ventricle patients who were enrolled in a surgical planning protocol for Fontan surgery with pre-and post-operative cardiac imaging are included in this study. Computational fluid dynamics were used to compare HFD in both the surgical planning prediction and actual post-operative conditions. Results: Overall, HFD prediction error was 17±13%. This error was similar between surgery types (15±18% and 18±10% for revisions vs Fontan completions respectively, p=0.73), but was

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“…The capability of the catheterization method to accurately capture the highly dynamic and 3D flow and pressure fields is limited. In a recent in vivo study, 69 averaged pressures and velocities were used at the inlet and outlet sections, which have been shown to overestimate energy loss with 18%, 94 and are inherently associated with measurement errors because the position and size of the catheter inside the vessel will influence measured pressure and velocity values. For example, when a swirling, helical flow pattern is present, the central pressure measurement may not reflect the true pressure.…”

Section: Catheterization Studiesmentioning

confidence: 99%

Energetics of Blood Flow in Cardiovascular Disease

Rijnberg¹,

Hazekamp²,

Wentzel

et al. 2018

Circulation

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Visualization and quantification of the adverse effects of distorted blood flow are important emerging fields in cardiology. Abnormal blood flow patterns can be seen in various cardiovascular diseases and are associated with increased energy loss. These adverse energetics can be measured and quantified using 3-dimensional blood flow data, derived from computational fluid dynamics and 4-dimensional flow magnetic resonance imaging, and provide new, promising hemodynamic markers. In patients with palliated single-ventricular heart defects, the Fontan circulation passively directs systemic venous return to the pulmonary circulation in the absence of a functional subpulmonary ventricle. Therefore, the Fontan circulation is highly dependent on favorable flow and energetics, and minimal energy loss is of great importance. A focus on reducing energy loss led to the introduction of the total cavopulmonary connection (TCPC) as an alternative to the classical Fontan connection. Subsequently, many studies have investigated energy loss in the TCPC, and energy-saving geometric factors have been implemented in clinical care. Great advances have been made in computational fluid dynamics modeling and can now be done in 3-dimensional patient-specific models with increasingly accurate boundary conditions. Furthermore, the implementation of 4-dimensional flow magnetic resonance imaging is promising and can be of complementary value to these models. Recently, correlations between energy loss in the TCPC and cardiac parameters and exercise intolerance have been reported. Furthermore, efficiency of blood flow through the TCPC is highly variable, and inefficient blood flow is of clinical importance by reducing cardiac output and increasing central venous pressure, thereby increasing the risk of experiencing the well-known Fontan complications. Energy loss in the TCPC will be an important new hemodynamic parameter in addition to other well-known risk factors such as pulmonary vascular resistance and can possibly be improved by patient-specific surgical design. This article describes the theoretical background of mechanical energy of blood flow in the cardiovascular system and the methods of calculating energy loss, and it gives an overview of geometric factors associated with energy efficiency in the TCPC and its implications on clinical outcome. Furthermore, the role of 4-dimensional flow magnetic resonance imaging and areas of future research are discussed.

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The Advantages of Viscous Dissipation Rate over Simplified Power Loss as a Fontan Hemodynamic Metric

Cited by 35 publications

References 34 publications

Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection

Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection

The first cohort of prospective Fontan surgical planning patients with follow-up data: How accurate is surgical planning?

Energetics of Blood Flow in Cardiovascular Disease

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