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.

Effect of Flow Pulsatility and Wall Compliance on the Energy Loss in the Total Cavopulmonary Connection

2013 ◽  
Author(s):  
Reza H. Khiabani ◽  
Sulisay Phonekeo ◽  
Harish Srinimukesh ◽  
Elaine Tang ◽  
Mark Fogel ◽  
...  
Keyword(s):  
Energy Loss ◽  
Wall Motion ◽  
Heart Defects ◽  
Superior Vena ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Total Cavopulmonary Connection ◽  
Venous Flow ◽  
The Right ◽  
Cavopulmonary Connection

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. In the current practice, surgical interventions on SVHD patients commonly result in the total cavopulmonary connection (TCPC) [1]. 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 and wall motion may result in complex and unsteady flow patterns in the TCPC. Although vessel wall motion and different degrees of pulsatility have been observed in vivo, non-pulsatile (time-averaged) flow boundary conditions and rigid walls have traditionally been assumed in estimating the TCPC hemodynamic parameters (such as energy loss). Recent studies have shown that these assumptions may result in significant inaccuracies in modeling TCPC hemodynamics [2, 3].

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).

In Vitro Study of Pulmonary Vascular Resistance in Fontan Circulation With Respiration Effects

2012 ◽  
Author(s):  
Marija Vukicevic ◽  
Timothy A. Conover ◽  
Jian Zhou ◽  
Tain-Yen Hsia ◽  
Richard S. Figliola
Keyword(s):  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Heart Defects ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Fontan Operation ◽  
Venous Pressure ◽  
Pulmonary Arteries ◽  
Pulmonary Regurgitation ◽  
Vena Cava

The Fontan operation is the final stage of palliative surgery for children born with single ventricle heart defects. The most common configuration is called total cavopulmonary connection (TCPC), wherein the inferior vena cava and superior vena cava are anastomosed directly to the pulmonary arteries; therefore the pulmonary circulation is driven by venous pressure only. The Fontan procedure, although successful in the early postoperative period, with time can decrease in efficiency or even fail within several years after the operation. The reasons of different clinical outcomes for some of the Fontan patients are not clear enough, even though it is commonly accepted that certain factors such as low pulmonary vascular resistance and proper shape and size of the TCPC construction are crucial for the succesful long term outcomes. Accordingly, one of the major problems is the increase in pulmonary vascular resistance due to altered hemodynamics after the surgery, causing venous hypertension and respiratory-dependent pulmonary regurgitation [1]. The main pulmonary arteries may also see increased resistance due to congenital malformations, surgical scarring, or deliberate surgical banding. Thus, the consequence of the increased pulmonary vascular resistance at both proximal and distal locations with respect to the TCPC junction, and its effect on the systemic pressures and flow rates, is the main objective of this study.

Optimization of an Idealized Y-Graft for the Fontan Procedure Using CFD and a Derivative-Free Optimization Algorithm

2009 ◽  
Author(s):  
Weiguang Yang ◽  
Jeffrey A. Feinstein ◽  
V. Mohan Reddy ◽  
Alison L. Marsden
Keyword(s):  
Heart Defects ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Survival Rates ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Protein Losing Enteropathy ◽  
Second Stage ◽  
Derivative Free Optimization ◽  
Derivative Free

The Fontan procedure is a surgery performed to treat patients with single ventricle congenital heart defects. The Fontan is the final of three surgical stages. The first stage consists of aortic reconstruction, in a Norwood procedure or variant thereof. In the second stage, the Bidirectional Glenn procedure, the superior vena cava (SVC) is disconnected from the heart and redirected into the pulmonary arteries (PAs). In the third and final stage, the inferior vena cava (IVC) is connected to PAs via a straight Gore-Tex tube, forming a T-shaped junction. Although early survival rates following the Fontan procedure can exceed 90%, significant morbidity remains after surgery including venous hemodynamic abnormalities, diminished exercise capacity, thromboembolic complications, protein-losing enteropathy, heart transplant etc. [1].

Effect of Flow Pulsatility on 2nd Stage Fontan Hemodynamics: An In Vitro Investigation

2009 ◽  
Author(s):  
Christopher M. Haggerty ◽  
Lakshmi P. Dasi ◽  
Jessica Kanter ◽  
Ajit P. Yoganathan
Keyword(s):  
Congenital Heart ◽  
Single Ventricle ◽  
Heart Defects ◽  
Superior Vena ◽  
Fontan Procedure ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Second Stage ◽  
In Vitro Investigation

The Fontan procedure [1] is the staged, palliative surgical approach used to treat patients suffering from single ventricle congenital heart defects. The second stage of this procedure involves the connection of the superior vena cava (SVC) to the pulmonary arteries (PAs) in either an end-to-side (known as the Bi-Directional Glenn (BDG)) or side-to-side (or Hemi-Fontan (HF)) fashion. Because of obvious disparities at the connection site, there are understandable differences in the fluid dynamics between the two geometries.

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.

Hemodynamic Impact of Stenting in the Total Cavopulmonary Connection With Lateral Tunnel Stenosis

2012 ◽  
Author(s):  
Elaine Tang ◽  
Doff B. McElhinney ◽  
Ajit P. Yoganathan
Keyword(s):  
Heart Defects ◽  
Superior Vena ◽  
Pulmonary Arteries ◽  
Vena Cava ◽  
Total Cavopulmonary Connection ◽  
Lateral Tunnel ◽  
The Us ◽  
Intravascular Stent ◽  
The Right ◽  
Cavopulmonary Connection

2 per 1000 children in the US are born with functionally single ventricle (SV) heart defects. To restore the separate systemic and pulmonary circulations, a Total Cavopulmonary Connection (TCPC) is carried out through a series of surgical steps, which result in the direct connection of the superior vena cava (SVC) and inferior vena cava (IVC) to the pulmonary arteries without an intervening pulmonary ventricle. One way to complete the TCPC is by placing a synthetic patch in the right atrium, forming an intracardiac lateral tunnel (LT) as the final step. As patients grow, some LT pathways become stenosed. The stenosis can impose extra resistance to flow in addition to the TCPC in the SV circulation. One method of treating LT stenosis is by placement of an intravascular stent.

Two-scale haemodynamic modelling for patients with Fontan circulation

2021 ◽  
Vol 36 (5) ◽  
pp. 267-278
Author(s):  
Tatiana K. Dobroserdova ◽  
Yuri V. Vassilevski ◽  
Sergey S. Simakov ◽  
Timur M. Gamilov ◽  
Andrey A. Svobodov ◽  
...  
Keyword(s):  
Blood Flow ◽  
Heart Defects ◽  
Superior Vena ◽  
Fontan Operation ◽  
Vena Cava ◽  
Fontan Circulation ◽  
Exercise Intolerance ◽  
4D Flow ◽  
Surgical Interventions ◽  
The Right

Abstract Palliation of congenital single ventricle heart defects suggests multi-stage surgical interventions that divert blood flow from the inferior and superior vena cava directly to the right and left pulmonary arteries, skipping the right ventricle. Such system with cavopulmonary anastomoses and single left ventricle is called Fontan circulation, and the region of reconnection is called the total cavopulmonary connection (TCPC). Computational blood flow models allow clinicians to predict the results of the Fontan operation, to choose an optimal configuration of TCPC and thus to reduce negative postoperative consequences. We propose a two-scale (1D3D) haemodynamic model of systemic circulation for a patient who has underwent Fontan surgical operation. We use CT and 4D flow MRI data to personalize the model. The model is tuned to patient’s data and is able to represent measured time-averaged flow rates at the inlets and outlets of TCPC, as well as pressure in TCPC for the patient in horizontal position.We demonstrate that changing to quiescent standing position leads to other patterns of blood flow in regional (TCPC) and global haemodynamics. This confirms clinical data on exercise intolerance of Fontan patients.

Selective parasympathectomy of automatic and conductile tissues of the canine heart

1985 ◽  
Vol 248 (1) ◽  
pp. H61-H68 ◽  
Author(s):  
W. C. Randall ◽  
J. L. Ardell
Keyword(s):  
Vagal Stimulation ◽  
Superior Vena ◽  
Sympathetic Innervation ◽  
Pulmonary Veins ◽  
Vena Cava ◽  
Dorsal Surface ◽  
Atrial Pacing ◽  
Canine Heart ◽  
Surgical Interventions ◽  
The Right

From right thoracotomy (T4-T5), the canine heart was suspended in its pericardium to expose its major venous inputs. Vagal and sympathetic trunks were prepared for electrical stimulation (10-20 Hz, 5.0 ms, 3-5 V) before and after each separate denervation procedure. Vagal stimulation was instituted with and without concurrent atrial pacing. The following surgical interventions were performed. 1) The superior vena cava was cleared of connective and nervous tissues from the pericardial reflection caudally to the level of the right pulmonary artery. 2) The azygos vein was cleared, tied, and sectioned. 3) The right pulmonary veins were isolated and cleared intrapericardially. 4) The dorsal surface of the atria was dissected between the right and left pulmonary veins and painted with phenol. Each step in the procedure elicited successive stepwise deletion of parasympathetic influences on sinoatrial tissues of the canine heart with only minor ablation of sympathetic inputs. 5) Dissection of the triangular fat pad at the junction of the inferior vena cava and inferior left atrium eliminated the remaining parasympathetic efferent input to the heart with dramatic deletion of atrioventricular block during either left or right vagal stimulation, again with preservation of most of the sympathetic innervation. These experiments clearly demonstrate differential and selective inputs of parasympathetic pathways to sinoatrial (SAN) and atrioventricular (AVN) regions of the dog heart but relatively little interference with sympathetic distributions.(ABSTRACT TRUNCATED AT 250 WORDS)

Comprehensive transthoracic cardiac imaging in mice using ultrasound biomicroscopy with anatomical confirmation by magnetic resonance imaging

2004 ◽  
Vol 18 (2) ◽  
pp. 232-244 ◽  
Author(s):  
Yu-Qing Zhou ◽  
F. Stuart Foster ◽  
Brian J. Nieman ◽  
Lorinda Davidson ◽  
X. Josette Chen ◽  
...  
Keyword(s):  
Cardiac Imaging ◽  
Superior Vena ◽  
Main Pulmonary Artery ◽  
Vena Cava ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Ascending Aorta ◽  
High Frequency Ultrasound ◽  
The Right

High-frequency ultrasound biomicroscopy (UBM) has recently emerged as a high-resolution means of phenotyping genetically altered mice and has great potential to evaluate the cardiac morphology and hemodynamics of mouse mutants. However, there is no standard procedure of in vivo transthoracic cardiac imaging using UBM to comprehensively phenotype the adult mice. In this paper, the characteristic mouse thoracic anatomy is elucidated using magnetic resonance (MR) imaging on fixed mice. Besides the left parasternal and apical windows commonly used for transthoracic ultrasound cardiac imaging, a very useful right parasternal window is found. We present strategies for optimal visualization using UBM of key cardiac structures including: 1) the right atrial inflow channels such as the right superior vena cava; 2) the right ventricular inflow tract via the tricuspid orifice; 3) the right ventricular outflow tract to the main pulmonary artery; 4) the left atrial inflow channel, e.g., pulmonary vein; 5) the left ventricular inflow tract via the mitral orifice; 6) the left ventricular outflow tract to the ascending aorta; 7) the left coronary artery; and 8) the aortic arch and associated branches. Two-dimensional ultrasound images of these cardiac regions are correlated to similar sections in the three-dimensional MR data set to verify anatomical details of the in vivo UBM imaging. Dimensions of the left ventricle and ascending aorta are measured by M-mode. Flow velocities are recorded using Doppler at six representative intracardiac locations: right superior vena cava, tricuspid orifice, main pulmonary artery, pulmonary vein, mitral orifice, and ascending aorta. The methodologies and baseline measurements of inbred mice provide a useful guide for investigators applying the high-frequency ultrasound imaging to mouse cardiac phenotyping.

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