High-Order Large Eddy Simulation of Flow in Idealized and Patient-Specific Total Cavopulmonary Connections

2011 ◽  
Author(s):  
Kameswararao Anupindi ◽  
Steven Frankel ◽  
Jun Chen ◽  
Dinesh Shetty ◽  
Jeffrey Kennington ◽  
...  
Keyword(s):  
Inferior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Patient Specific ◽  
Complex Congenital Heart Disease ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Left And Right ◽  
Viscous Impeller Pump ◽  
Cavopulmonary Connection

The Fontan procedure is used in pediatric situations in which infants have complex congenital heart disease or a single effective ventricle. This procedure by-passes right heart by connecting the left and right pulmonary arteries (LPA/RPA) to the superior and inferior vena cavae (SVC/IVC). The resulting reconstructed anatomy is called total cavopulmonary connection or TCPC. Knowledge of fluid dynamics in TCPC helps in optimizing the connection itself for reduced resistance as well as aids in designing cavopulmonary assist devices like viscous impeller pump (VIP) [1].

Modeling of Patient-Specific Fontan Physiology From MRI Images for CFD Testing of a Cavopulmonary Assist Device

2011 ◽  
Author(s):  
Jonathan DeGan ◽  
Jeffrey Kennington ◽  
Kameswararao Anupindi ◽  
Dinesh Shetty ◽  
Jun Chen ◽  
...  
Keyword(s):  
Inferior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Patient Specific ◽  
Systemic Blood Flow ◽  
Congenital Condition ◽  
Left And Right ◽  
Fontan Physiology ◽  
Cavopulmonary Connection ◽  
Cavopulmonary Assist Device

Single ventricle heart disease is a congenital condition characterized by the inoperability of one ventricle of an infant’s heart. Those suffering from this condition face a series of palliative surgeries called the Fontan procedure, which bypasses the non-functional ventricle by creating a total cavopulmonary connection, or TCPC. This TCPC forms from the anastomosis of the superior and inferior vena cavae (SVC, IVC) to the left and right pulmonary arteries (LPA, RPA), thus allowing systemic blood flow to bypass the heart and flow passively to the lungs. The Fontan procedure creates this junction with three surgeries separated by months or years.

Design of a Novel Cavopulmonary Assist Device for Fontan Procedures: CFD, PIV, and Hydraulic Testing

2010 ◽  
Author(s):  
Jeffrey R. Kennington ◽  
Steven Frankel ◽  
Jun Chen ◽  
Mark D. Rodefeld ◽  
Guruprasad A. Giridharan
Keyword(s):  
Inferior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Hydraulic Testing ◽  
Assist Device ◽  
Lung Resistance ◽  
Left And Right ◽  
The Right ◽  
Cavopulmonary Connection ◽  
Cavopulmonary Assist Device

Single ventricle heart disease is the leading cause of death for birth defects in children under one years of age [1]. The current surgical procedure requires the use of a shunt for the first stage of the surgery. The following surgeries remove the shunt but cannot be performed on a newborn due to higher lung resistance during the first weeks of life. The overall surgical process, known as the Fontan procedure, results in a reconstructed anatomy where the left and right pulmonary arteries are sutured to the superior and inferior vena cavae (SVC/IVC), hence bypassing the right heart. This anatomy is called a total cavopulmonary connection or TCPC.

Effect of Caval Waveform on Energy Dissipation of Failing Fontan Patients

2009 ◽  
Author(s):  
Onur Dur ◽  
Ergin Kocyildirim ◽  
Curt G. Degroff ◽  
Peter Wearden ◽  
Victor Morell ◽  
...  
Keyword(s):  
Inferior Vena ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Surgical Reconstruction ◽  
Power Losses ◽  
Last Stage ◽  
Cavopulmonary Connection ◽  
Failing Fontan ◽  
Fontan Patients

Last stage of the palliative surgical reconstruction (i.e. Fontan procedure) for the infants with functional single-ventricle is total cavopulmonary connection (TCPC), where the superior vena cavae (SVC) and inferior vena cavae (IVC) are routed directly into the pulmonary arteries. Limited pumping energy available due to the absence of right-ventricle and altered venous characteristics require optimized hemodynamics inside the TCPC pathway, which can be achieved by minimizing the power losses.

Evaluation of Hemodynamic Efficiency in a New “Y-Graft” Design for the Fontan Operation

2007 ◽  
Author(s):  
Adam J. Bernstein ◽  
Alison L. Marsden ◽  
Ryan L. Spilker ◽  
V. Mohan Reddy ◽  
Charles A. Taylor ◽  
...  
Keyword(s):  
Inferior Vena ◽  
Fontan Procedure ◽  
Fontan Operation ◽  
Survival Rates ◽  
Pulmonary Arteries ◽  
Left Heart ◽  
Hypoplastic Left Heart ◽  
Blood Flows ◽  
Left Heart Syndrome ◽  
Cavopulmonary Connection

Hypoplastic left heart syndrome is a congenital heart defect that occurs in 20 per 100,000 live births. Patients are born with severe underdevelopment of the left side of the heart which, if left untreated, is uniformly fatal. A series of operations is performed, including a cavopulmonary (Glenn) shunt and total cavopulmonary connection (Fontan procedure), which connect the superior (SVC) and inferior vena cavae (IVC) respectively in an end-to-side fashion to the left (LPA) and right pulmonary arteries (RPA), resulting in a T-shaped junction. This bypasses the heart on the venous side as blood flows from the IVC and SVC directly into the pulmonary arteries. Early survival rates following the Fontan are as high as 90%. However, these figures drop to 60% survival after 10 years [1], and most patients exhibit diminished exercise capacity.

Investigation of Vessel Growth and its Impact on Hemodynamics in Patients With Lateral Tunnel Total Cavopulmonary Connection

2012 ◽  
Author(s):  
Maria Restrepo ◽  
Lucia Mirabella ◽  
Elaine Tang ◽  
Chris Haggerty ◽  
Mark A. Fogel ◽  
...  
Keyword(s):  
Heart Defects ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Total Cavopulmonary Connection ◽  
Lateral Tunnel ◽  
Vessel Growth ◽  
Original Size ◽  
The Right ◽  
Cavopulmonary Connection

Single ventricle heart defects affect 2 per 1000 live births in the US and are lethal if left untreated. The Fontan procedure used to treat these defects consists of a series of palliative surgeries to create the total cavopulmonary connection (TCPC), which bypasses the right heart. In the last stage of this procedure, the inferior vena cava (IVC) is connected to the pulmonary arteries (PA) using one of the two approaches: the extra-cardiac (EC), where a synthetic graft is used as the conduit; and the lateral tunnel (LT) where part of the atrial wall is used along with a synthetic patch to create the conduit. The LT conduit is thought to grow in size in the long term because it is formed partially with biological tissue, as opposed to the EC conduit that retains its original size because it contains only synthetic material. The growth of the LT has not been yet quantified, especially in respect to the growth of other vessels forming the TCPC. Furthermore, the effect of this growth on the hemodynamics has not been elucidated. The objective of this study is to quantify the TCPC vessels growth in LT patients from serial magnetic resonance (MR) images, and to understand its effect on the connection hemodynamics using computational fluid dynamics (CFD).

Hemodynamics Characteristics of a Four-Way Right-Atrium Bypass Connector

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Elizabeth Mack ◽  
Alexandrina Untaroiu
Keyword(s):  
Superior Vena Cava ◽  
Right Atrium ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Right Ventricular Dysfunction ◽  
Patient Specific ◽  
Optimal Size ◽  
Size Change

Currently, the surgical procedure followed by the majority of cardiac surgeons to address right ventricular dysfunction is the Fontan procedure, which connects the superior vena cava and inferior vena cava (IVC) directly to the left and right pulmonary arteries (LPA and RPA, respectively) bypassing the right atrium. The goal of this study is to develop a patient-specific four-way connector to bypass the dysfunctional right ventricle and augment the pulmonary circulation. The four-way connector was intended to channel the blood flow from the inferior and superior vena cava directly to the RPA and LPA. By creating a connector with proper hemodynamic characteristics, one can control the jet flow interactions between the inferior and superior vena cava and streamline the flow toward the RPA and LPA. The focus for this study was on creating a system that could identify the optimal configuration for the four-way connector for patients from 0 to 20 years of age. A platform was created in ANSYS that utilized the design of experiments (DOE) function to minimize power-loss and blood damage propensity in the connector based on junction geometries. It was confirmed that as the patient's age and artery size change, the optimal size and shape of the connector also changes. However, the corner radius did not decrease at the same rate as the opening diameters. However, it was found that power losses within the connector decrease, and average and maximum blood traversal time through the connector increased for increasing opening radius.

Comparison of Clinical and Simulation Results for the Stanford Y-Graft Fontan Pilot Trial

2012 ◽  
Author(s):  
Weiguang Yang ◽  
Jeffrey A. Feinstein ◽  
V. Mohan Reddy ◽  
Frandics P. Chan ◽  
Alison L. Marsden
Keyword(s):  
Inferior Vena ◽  
Single Ventricle ◽  
Heart Defects ◽  
Fontan Procedure ◽  
Pilot Trial ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Extracardiac Conduit ◽  
Lateral Tunnel ◽  
Third Stage

Without surgical palliation, single ventricle heart defects are uniformly fatal. A three-staged surgical repair is typically performed on these patients, who are otherwise severely cyanotic. In the third stage, the Fontan procedure, the inferior vena cava (IVC) is connected to the pulmonary arteries (PAs) via a lateral tunnel or extracardiac conduit. Following Fontan completion, deoxygenated blood from the upper and lower body is redirected to the PAs, bypassing the heart.

Global Sensitivity Analysis for Patient-Specific Aortic Simulations: The Role of Geometry, Boundary Condition and Large Eddy Simulation Modeling Parameters

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Huijuan Xu ◽  
Davide Baroli ◽  
Alessandro Veneziani
Keyword(s):  
Stochastic Process ◽  
Sensitivity Analysis ◽  
Large Eddy Simulation ◽  
Numerical Simulations ◽  
Global Sensitivity Analysis ◽  
Patient Specific ◽  
Global Sensitivity ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Inflow Conditions

Abstract Numerical simulations for computational hemodynamics in clinical settings require a combination of many ingredients, mathematical models, solvers and patient-specific data. The sensitivity of the solutions to these factors may be critical, particularly when we have a partial or noisy knowledge of data. Uncertainty quantification is crucial to assess the reliability of the results. We present here an extensive sensitivity analysis in aortic flow simulations, to quantify the dependence of clinically relevant quantities to the patient-specific geometry and the inflow boundary conditions. Geometry and inflow conditions are generally believed to have a major impact on numerical simulations. We resort to a global sensitivity analysis, (i.e., not restricted to a linearization around a working point), based on polynomial chaos expansion (PCE) and the associated Sobol' indices. We regard the geometry and the inflow conditions as the realization of a parametric stochastic process. To construct a physically consistent stochastic process for the geometry, we use a set of longitudinal-in-time images of a patient with an abdominal aortic aneurysm (AAA) to parametrize geometrical variations. Aortic flow is highly disturbed during systole. This leads to high computational costs, even amplified in a sensitivity analysis -when many simulations are needed. To mitigate this, we consider here a large Eddy simulation (LES) model. Our model depends in particular on a user-defined parameter called filter radius. We borrowed the tools of the global sensitivity analysis to assess the sensitivity of the solution to this parameter too. The targeted quantities of interest (QoI) include: the total kinetic energy (TKE), the time-average wall shear stress (TAWSS), and the oscillatory shear index (OSI). The results show that these indexes are mostly sensitive to the geometry. Also, we find that the sensitivity may be different during different instants of the heartbeat and in different regions of the domain of interest. This analysis helps to assess the reliability of in silico tools for clinical applications.

Analysis of Aeroacoustic Generated From a Rotating Tire With a Longitudinal Groove Using Large-Eddy Simulation

2021 ◽  
Author(s):  
Kengo Asada ◽  
Kimie Ito ◽  
Satoshi Sekimoto ◽  
Kozo Fujii ◽  
Masataka Koishi ◽  
...  
Keyword(s):  
Side Surface ◽  
Large Eddy Simulations ◽  
Groove Width ◽  
Lateral Side ◽  
Noise Sources ◽  
Sound Sources ◽  
Longitudinal Groove ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Left And Right

Abstract Flow fields obtained by large-eddy simulations around a rotating tire with the longitudinal groove are investigated to clarify the relationships between the shape parameters of the grooves and the directivity of aeroacoustic noise and to clarify noise sources. To obtain acoustic field around the rotating tire, the large-eddy simulations using the sixth-order compact finite difference scheme and the tridiagonal filter are performed. The four computational cases including the case without groove are considered in the present study. The proper orthogonal decomposition (POD) analysis revealed the distribution of bipolar modes that spread from the tire to the left and right. This result indicates two symmetrical sound sources near the front of the tire side surface regardless of the presence or absence of the groove shape. It is also found that the presence of grooves in the tire weakens the amplitude of the POD mode that spreads to the left and right. This fact is consistent with the fact that the sound pressure level on the lateral side of the tire weakens as the groove width widens. Based on the observation of the instantaneous field and these analyzes, the following is found. The noise-induced by the flow around the tire considered in the present study is emitted when the turbulent flow generated in front of the tire collides with the tire and flows along the tire’s side surface. Besides, when the tire has a groove, a part of the flow that collides with the tire flows into the groove so that the flow rate flowing on the side surface of the tire decreases and the noise itself also decreases. Therefore, the wider the tire’s groove width, the less noise is emitted from the tire’s lateral side.

Virtual Design for the Fontan Procedure: From Idealized to Patient Specific Models Using CFD and Derivative-Free Optimization

2010 ◽  
Author(s):  
Weiguang Yang ◽  
Guillaume Troianowski ◽  
Alexandre Birolleau ◽  
Irene Vignon-Clementel ◽  
Jeffrey A. Feinstein ◽  
...  
Keyword(s):  
Single Ventricle ◽  
Heart Defects ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Patient Specific ◽  
Virtual Design ◽  
Modeling Tools ◽  
Patient Specific Modeling

Single ventricle congenital heart defects are among the most challenging for pediatric cardiologists to treat. Children born with these defects are cyanotic, and these conditions are nearly uniformly fatal without treatment. A series of surgeries is performed to palliate single ventricle defects. The first stage consists of aortic reconstruction in a Norwood procedure. In the second stage, the Bidirectional Glenn procedure, the superior vena cava (SVC) is disconnected from the heart and redirected into the pulmonary arteries (PA’s). In the third and final stage, the Fontan procedure, the inferior vena cava (IVC) is connected to the PA’s via a straight Gore-Tex tube, forming a T-shaped junction with or without offset. Patient specific modeling tools provide a means to evaluate new designs with the goal of lowering long-term morbidity and improving patients’ quality of life.

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