Investigation of Pulsatile Hemodynamics in Patient-Specific Fontan Templates With Fenestration

2011 ◽  
Author(s):  
Onur Dur ◽  
Greggory Housler ◽  
Ergin Kocyildirim ◽  
Haifa Hong ◽  
Jinfen Liu ◽  
...  
Keyword(s):  
Superior Vena ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Surgical Techniques ◽  
Surgical Reconstruction ◽  
Patient Specific ◽  
Fontan Patient ◽  
Third Stage ◽  
Patients Experience ◽  
Fontan Patients

The third stage for palliative surgical reconstruction for children with functional single-ventricle (SV) physiology is the completion of the total cavopulmonary connection (TCPC), where the superior vena cava (SVC) and inferior vena cava (IVC) are routed directly into the pulmonary arteries. Approximately 5000 newborns in the US each year join to the existing SV (or Fontan) patient population, along with increasing numbers of adult Fontan patients surviving longer due to the advances in surgical techniques and post-op management. Although most post-operative Fontan patients experience an acceptable quality of life, their lifespan is shorter than normal with a significant number of these patients developing late hemodynamic complications (failing Fontan) and requiring heart transplantation. Donor shortage and the high-risk nature of transplantation for these complex and often very ill patients demand alternative therapeutic options [1].

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

2017 ◽  
Author(s):  
Elizabeth Mack ◽  
Alexandrina Untaroiu
Keyword(s):  
Blood Flow ◽  
Superior Vena Cava ◽  
Right Atrium ◽  
Superior Vena ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Design Parameters ◽  
Patient Specific ◽  
Optimal Size ◽  
The Right

Currently, the surgical procedure followed by the majority of cardiac surgeons to address right ventricular dysfunction is the Fontan procedure, which connects the superior and inferior vena cava directly to the left and right pulmonary arteries bypassing the right atrium. However, this is not the most efficient configuration from a hemodynamics perspective. The goal of this study is to develop a patient-specific 4-way connector to bypass the dysfunctional right ventricle and augment the pulmonary circulation. The 4-way connector is intended to channel the blood flow from the inferior and superior vena cava directly to the right and left pulmonary arteries. 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 towards the right and left pulmonary arteries. In this study the focus is on creating a system that can identify the optimal configuration for the 4-way connector for patients from 0–20 years of age. A platform is created in ANSYS that utilizes the DOE function to minimize power-loss and blood damage propensity in the connector based on junction geometries. A CFD model is created to simulate the blood flow through the connector. Then the geometry of the bypass connector is parameterized for DOE process. The selected design parameters include inlet and outlet diameters, radius at the intersection, and length of the connector pathways. The chosen range for each geometric parameter is based on the relative size of the patient’s arteries found in the literature. 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. This means that creating different sized connectors is not just a matter of scaling the original connector to match the desired opening diameter. 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. This information could be used to create a more specific relationship between the opening radius and the flow characteristics. So in order to create patient specific connectors, either a new more complicated trend needs to be found or an optimization program would need to be run on each patient’s specific geometry when they need a new connector.

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.

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.

Optimization of a Y-Graft Design for Improved Hepatic Flow Distribution in the Fontan Circulation

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Weiguang Yang ◽  
Jeffrey A. Feinstein ◽  
Shawn C. Shadden ◽  
Irene E. Vignon-Clementel ◽  
Alison L. Marsden
Keyword(s):  
Heart Diseases ◽  
Heart Defects ◽  
Superior Vena ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Flow Distribution ◽  
Patient Specific ◽  
Pulmonary Flow ◽  
Hemodynamic Performance ◽  
Branch Size

Single ventricle heart defects are among the most serious congenital heart diseases, and are uniformly fatal if left untreated. Typically, a three-staged surgical course, consisting of the Norwood, Glenn, and Fontan surgeries is performed, after which the superior vena cava (SVC) and inferior vena cava (IVC) are directly connected to the pulmonary arteries (PA). In an attempt to improve hemodynamic performance and hepatic flow distribution (HFD) of Fontan patients, a novel Y-shaped graft has recently been proposed to replace the traditional tube-shaped extracardiac grafts. Previous studies have demonstrated that the Y-graft is a promising design with the potential to reduce energy loss and improve HFD. However these studies also found suboptimal Y-graft performance in some patient models. The goal of this work is to determine whether performance can be improved in these models through further design optimization. Geometric and hemodynamic factors that influence the HFD have not been sufficiently investigated in previous work, particularly for the Y-graft. In this work, we couple Lagrangian particle tracking to an optimal design framework to study the effects of boundary conditions and geometry on HFD. Specifically, we investigate the potential of using a Y-graft design with unequal branch diameters to improve hepatic distribution under a highly uneven RPA/LPA flow split. As expected, the resulting optimal Y-graft geometry largely depends on the pulmonary flow split for a particular patient. The unequal branch design is demonstrated to be unnecessary under most conditions, as it is possible to achieve the same or better performance with equal-sized branches. Two patient-specific examples show that optimization-derived Y-grafts effectively improve the HFD, compared to initial nonoptimized designs using equal branch diameters. An instance of constrained optimization shows that energy efficiency slightly increases with increasing branch size for the Y-graft, but that a smaller branch size is preferred when a proximal anastomosis is needed to achieve optimal HFD.

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.

Hemodynamics of neonatal double lumen cannula malposition

Perfusion ◽  
2019 ◽  
Vol 35 (4) ◽  
pp. 306-315
Author(s):  
Muhammad Jamil ◽  
Mohammad Rezaeimoghaddam ◽  
Bilgesu Cakmak ◽  
Yahya Yildiz ◽  
Reza Rasooli ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Inferior Vena Cava ◽  
Residence Time ◽  
Inferior Vena ◽  
Superior Vena ◽  
Vena Cava ◽  
Right Atrial ◽  
Patient Specific ◽  
Blood Damage

Objective: Malposition of dual lumen cannula is a frequent and challenging complication in neonates and plays a significant role in shaping the in vitro device hemodynamics. This study aims to analyze the effect of the dual lumen cannula malposition on right-atrial hemodynamics in neonatal patients using an experimentally validated computational fluid dynamics model. Methods: A computer model was developed for clinically approved dual lumen cannula (13Fr Origen Biomedical, Austin, Texas, USA) oriented inside the atrium of a 3-kg neonate with normal venous return. Atrial hemodynamics and dual lumen cannula malposition were systematically simulated for two rotations (antero-atrial and atrio-septal) and four translations (two intravascular movements along inferior vena cava and two dislodged configurations in the atrium). A multi-domain compartmentalized mesh was prepared to allow the site-specific evaluation of important hemodynamic parameters. Transport of each blood stream, blood damage levels, and recirculation times are quantified and compared to dual lumen cannula in proper position. Results: High recirculation levels (39 ± 4%) in malpositioned cases resulted in poor oxygen saturation where maximum recirculation of up to 42% was observed. Apparently, Origen dual lumen cannula showed poor inferior vena cava blood–capturing efficiency (48 ± 8%) but high superior vena cava blood–capturing efficiency (86 ± 10%). Dual lumen cannula malposition resulted in corresponding changes in residence time (1.7 ± 0.5 seconds through the tricuspid). No significant differences in blood damage were observed among the simulated cases compared to normal orientation. Compared to the correct dual lumen cannula position, both rotational and translational displacements of the dual lumen cannula resulted in significant hemodynamic differences. Conclusion: Rotational or translational movement of dual lumen cannula is the determining factor for atrial hemodynamics, venous capturing efficiency, blood residence time, and oxygenated blood delivery. Results obtained through computational fluid dynamics methodology can provide valuable foresight in assessing the performance of the dual lumen cannula in patient-specific configurations.

NUMERICAL STUDY OF BIDIRECTIONAL GLENN WITH UNILATERAL PULMONARY ARTERY STENOSIS

2014 ◽  
Vol 14 (04) ◽  
pp. 1450056 ◽  
Author(s):  
XI ZHAO ◽  
YOUJUN LIU ◽  
JINLI DING ◽  
FAN BAI ◽  
XIAOCHEN REN ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pulmonary Artery ◽  
Superior Vena Cava ◽  
Superior Vena ◽  
Vena Cava ◽  
Artery Stenosis ◽  
Patient Specific ◽  
Pulmonary Artery Stenosis ◽  
Bidirectional Glenn

Purpose: Hypoplastic left heart syndrome (HLHS) is a congenital heart disease and is usually associated with pulmonary artery stenosis. The superior vena cava-to-pulmonary artery (bidirectional Glenn) shunt is used primarily as a staging procedure to the total cava-to-pulmonary connection for single-ventricle complex. When HLHS coexists with pulmonary artery stenosis, the surgeons then face a multiple problem. This leads to high demand of optimized structure of Glenn surgery. The objective of this article is to investigate the influence of various anastomotic structures and the direction of superior vena cava (SVC) in Glenn on hemodynamics under pulse inflow conditions and try to find an optimal structure of SVC in Glenn surgery with unilateral pulmonary artery stenosis.Method: First, 3D patient-specific models were constructed from medical images of a HLHS patient before any surgery by using the commercial software Mimics, and another software Free-form was used to deform the reconstructed models in the computer. Four 3D patient-specific Glenn models were constructed: model-1 (normal Glenn), model-2 (lean the SVC back to the stenotic pulmonary artery), model-3 (lean the SVC towards the stenotic pulmonary artery), model-4 (add patch at junction of the SVC toward stenosis at pulmonary artery). Second, a lumped parameter model (LPM) was established to predict boundary conditions for computational fluid dynamics (CFD). In addition, numerical simulations were conducted using CFD through the finite volume method. Finally, hemodynamic parameters were obtained and evaluated.Results: It was showed that model-4 have relatively balanced vena cava blood perfusion into the left pulmonary artery (LPA) and right pulmonary artery (RPA), this may be due to less helical flow and the patch at junction of the SVC. Near stenosis of pulmonary artery, model-4 performed with the higher wall shear stress (WSS), which would benefit endothelial cell function and gene expression. In addition, results showed that model-4 performed with the lower oscillatory shear index (OSI) and wall shear stress gradient (WSSG), which would decrease the opportunity of vascular intimal hyperplasia.Conclusion: It is benefited that surgeons adds patch at junction of the SVC towards stenosis at pulmonary artery. These results can impact the surgical design and planning of the Glenn surgery with unilateral pulmonary artery stenosis.

scholarly journals In search of “hepatic factor:” Lack of evidence for ALK1 ligands BMP9 and BMP10

2020 ◽  
Author(s):  
Teresa L. Capasso ◽  
Sara M. Trucco ◽  
Morgan Hindes ◽  
Tristin Schwartze ◽  
Jamie L. Bloch ◽  
...  
Keyword(s):  
Single Ventricle ◽  
Venous Return ◽  
Superior Vena ◽  
Plasma Concentrations ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Systemic Circulation ◽  
Pulmonary Vasculature ◽  
Morphogenetic Protein ◽  
Bone Morphogenetic Protein 9

AbstractIn children with single ventricle physiology, the Glenn procedure is performed to redirect venous return from the superior vena cava directly to the pulmonary arteries and route venous return from the inferior vena cava exclusively to the systemic circulation. Although this surgery successfully palliates the hemodynamic stress experienced by the single ventricle, patients frequently develop pulmonary arteriovenous malformations (PAVMs). Interestingly, PAVMs may regress upon rerouting of hepatic venous effluent to the pulmonary vasculature, suggesting the presence of a circulating “hepatic factor” that is required to prevent PAVMs. Here, we test the hypothesis that hepatic factor is bone morphogenetic protein 9 (BMP9) and/or BMP10. These circulating ligands are produced by the liver and activate endothelial endoglin (ENG)/ALK1 signaling, and mutations in ENG and ALK1 cause hereditary hemorrhagic telangiectasia, a genetic disease associated with AVM development. However, we found no within-subject variation in BMP9, BMP10, or BMP9/10 plasma concentrations when sampled from five cardiovascular sites, failing to support the idea that the Glenn would limit access of these ligands to the lung vasculature. Unexpectedly, however, we found a significant decrease in all three ligand concentrations in Glenn cases versus controls. Our findings suggest that BMP9/BMP10/ENG/ALK1 signaling may be decreased in the Glenn vasculature but fail to implicate these ligands as hepatic factor.

Effect of Flow Pulsatility on Modeling the Total Cavopulmonary Hemodynamics: A Numerical Investigation

2012 ◽  
Author(s):  
Reza H. Khiabani ◽  
Maria Restrepo ◽  
Elaine Tang ◽  
Diane De Zélicourt ◽  
Mark Fogel ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Heart Defects ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Venous Flow ◽  
Surgical Interventions ◽  
The Right

Single Ventricle Heart Defects (SVHD) are present in 2 per 1000 live births in the US. SVHD are characterized by cyanotic mixing between the de-oxygenated blood from the systemic circulation return and the oxygenated blood from the pulmonary arteries. Palliative surgical repairs (Fontan procedure) are performed to bypass the right ventricle in these patients. In current practice, the surgical interventions commonly result in the total cavopulmonary connection (TCPC). In this configuration the systemic venous returns (inferior vena cava, IVC, and superior vena cava, SVC) are directly routed to the right and left pulmonary arteries (RPA and LPA), bypassing the right heart. The resulting anatomy has complex and unsteady hemodynamics characterized by flow mixing and flow separation. Pulsation of the inlet venous flow during a cardiac cycle results in complex and unsteady flow patterns in the TCPC. Although various degrees of pulsatility have been observed in vivo, non-pulsatile (time-averaged) flow boundary conditions have traditionally been assumed in modeling TCPC hemodynamics, and only recently have pulsatile conditions been incorporated without completely characterizing their effect or importance. In this study, 3D numerical simulations were performed to predict TCPC hemodynamics with both pulsatile and non-pulsatile boundary conditions and to investigate the accuracy of applying non-pulsatile boundary conditions. Flow structures, energy dissipation rate and pressure drop were compared under rest and estimated exercise conditions. The results show that TCPC hemodynamics can be strongly influenced by the presence of pulsatile flow. However, there exists a minimum pulsatility threshold, identified by defining a weighted pulsatility index (wPI), above which the influence is significant.

scholarly journals Haemangioendothelioma: a disease with surgical options from robotic surgery to open superior vena cava replacement

2019 ◽  
Vol 29 (3) ◽  
pp. 449-452
Author(s):  
Tugba Cosgun ◽  
Erkan Kaba ◽  
Kemal Ayalp ◽  
Ipek Coban Elbegi ◽  
Alper Toker
Keyword(s):  
Superior Vena Cava ◽  
Superior Vena ◽  
Vena Cava ◽  
Surgical Techniques ◽  
Malignant Tumour ◽  
Vena Cava Replacement ◽  
Treatment Techniques ◽  
Vascular Origin ◽  
Surgical Options ◽  
Epithelioid Haemangioendothelioma

Abstract Epithelioid haemangioendothelioma is a malignant tumour of vascular origin that can occur in the mediastinum. Operative treatment techniques may vary depending on the localization. Our goal was to focus on different surgical techniques, ranging from simple stapling of the vascular structure to replacement of the superior vena cava.

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