Using a Novel In Vitro Fontan Model and Condition-Specific Real-Time MRI Data to Examine Hemodynamic Effects of Respiration and Exercise

Tree, Michael; Wei, Zhenglun Alan; Trusty, Phillip M.; Raghav, Vrishank; Fogel, Mark A.; Maher, Kevin; Yoganathan, Ajit P.

doi:10.1007/s10439-017-1943-0

Cited by 16 publications

(9 citation statements)

References 40 publications

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“…On the other hand, with a deformable wall, the particles in the wall boundary layers had a higher probability of being redirected towards the bulk of the flow during contraction of the deforming wall. TCPC pressure drop and power loss are important hemodynamic metrics, as high power loss suggests a less efficient pathway, which has been related to patient exercise intolerance [8][9][10]51]. Pressure drop and power loss were compared between the rigid wall and FSI simulations.…”

Section: Discussionmentioning

confidence: 99%

“…It has been suggested that some of these complications may be attributed to the unfavorable hemodynamics in the connection [6]. For example, there has been evidence showing the possible link between TCPC energy dissipation and patient exercise tolerance [7][8][9][10]. Also, unbalanced distribution of hepatic blood flow between the two sides of the lungs has been associated with the risk of pulmonary arteriovenous malformations [11,12].…”

Section: Introductionmentioning

confidence: 99%

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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: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Tang

Wei

Fogel

et al. 2020

Biology

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“…Thus, it is emphasized that incorporation of respiration is important when local hemodynamic metrics are of interest, including wall shear stress and stagnation volume, due to the high temporal variation of such metrics during the respiratory cycle ( 45 , 53 , 65 ). As a result, inclusion of pulsatile boundary conditions acquired under free-breathing in patient-specific CFD models is recommended ( 11 , 60 , 68 ).…”

Section: Effect Of Respiration On Clinically Used Flow Parametersmentioning

confidence: 99%

The Influence of Respiration on Blood Flow in the Fontan Circulation: Insights for Imaging-Based Clinical Evaluation of the Total Cavopulmonary Connection

Woude

Rijnberg

Hazekamp

et al. 2021

Front. Cardiovasc. Med.

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Congenital heart disease is the most common birth defect and functionally univentricular heart defects represent the most severe end of this spectrum. The Fontan circulation provides an unique solution for single ventricle patients, by connecting both caval veins directly to the pulmonary arteries. As a result, the pulmonary circulation in Fontan palliated patients is characterized by a passive, low-energy circulation that depends on increased systemic venous pressure to drive blood toward the lungs. The absence of a subpulmonary ventricle led to the widely believed concept that respiration, by sucking blood to the pulmonary circulation during inspiration, is of great importance as a driving force for antegrade blood flow in Fontan patients. However, recent studies show that respiration influences pulsatility, but has a limited effect on net forward flow in the Fontan circulation. Importantly, since MRI examination is recommended every 2 years in Fontan patients, clinicians should be aware that most conventional MRI flow sequences do not capture the pulsatility of the blood flow as a result of the respiration. In this review, the unique flow dynamics influenced by the cardiac and respiratory cycle at multiple locations within the Fontan circulation is discussed. The impact of (not) incorporating respiration in different MRI flow sequences on the interpretation of clinical flow parameters will be covered. Finally, the influence of incorporating respiration in advanced computational fluid dynamic modeling will be outlined.

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“…9,30,34 Recently, a promising in vitro model has been introduced that uses a patient-specific, MRI-derived compliant TCPC model based on the patient-specific compliance value and uses condition-specific (breathheld, free breathing and exercise), real-time, phasecontrast MRI-derived flow waveforms as inflow conditions. 92 First results have shown and quantified the effect of respiration and exercise on energy loss and demonstrated that the effect of these parameters was highly patient-specific. Therefore, it is emphasized that future CFD models should use patient-and conditionspecific boundaries.…”

Section: In Vitro 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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Using a Novel In Vitro Fontan Model and Condition-Specific Real-Time MRI Data to Examine Hemodynamic Effects of Respiration and Exercise

Cited by 16 publications

References 40 publications

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

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

The Influence of Respiration on Blood Flow in the Fontan Circulation: Insights for Imaging-Based Clinical Evaluation of the Total Cavopulmonary Connection

Energetics of Blood Flow in Cardiovascular Disease

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