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.

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.

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)

Modified total cavopulmonary shunt as a staged Fontan operation

2017 ◽  
Vol 26 (9) ◽  
pp. 701-703
Author(s):  
Hidetsugu Asai ◽  
Tsuyoshi Tachibana ◽  
Yasushige Shingu ◽  
Hiroki Kato ◽  
Satoru Wakasa ◽  
...  
Keyword(s):  
Inferior Vena Cava ◽  
Right Ventricular ◽  
Superior Vena Cava ◽  
Inferior Vena ◽  
Superior Vena ◽  
Fontan Operation ◽  
Vena Cava ◽  
Left Superior Vena Cava ◽  
The Right ◽  
Cavopulmonary Shunt

The left superior vena cava became occluded in an infant with hypoplastic left heart syndrome. After a bidirectional Glenn procedure, he presented with severe oxygen desaturation and right ventricular dysfunction; the left superior vena cava drained into the inferior vena cava through collateral veins. As salvage therapy, we created a modified total cavopulmonary shunt using only autologous tissue in which the right hepatic vein and inferior vena cava drained into the pulmonary artery via a lateral tunnel in the right atrium. Immediately after surgery, his oxygen saturation increased and right ventricular function improved.

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.

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.

scholarly journals Hematemesis, a Rare Presentation for Downhill Esophageal Varices

2021 ◽  
pp. 359-364
Author(s):  
Jeremy Van ◽  
Shubha Singh
Keyword(s):  
Blood Flow ◽  
Esophageal Varices ◽  
Inferior Vena ◽  
Superior Vena ◽  
Vena Cava ◽  
Disease Process ◽  
Rare Presentation ◽  
Retrograde Blood Flow ◽  
Flow Through ◽  
The Right

Downhill esophageal varices (DEV) are a rare form of esophageal varices associated with superior vena cava obstruction. Obstruction leads to retrograde blood flow through collateral venous channels, including the esophageal venous plexus, to redirect blood flow to the right atrium via the inferior vena cava. This leads to the formation of DEV. It is a rare phenomenon to have gastrointestinal bleeding, especially hematemesis, on a patient’s first presentation with this disease process. We describe such a case here involving a patient with DEV secondary to metastatic renal cell carcinoma presenting with hematemesis.

Hemodynamics of the Fontan Connection: An In-Vitro Study

1995 ◽  
Vol 117 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Young H. Kim ◽  
P. G. Walker ◽  
A. A. Fontaine ◽  
S. Panchal ◽  
A. E. Ensley ◽  
...  
Keyword(s):  
Pressure Loss ◽  
Superior Vena ◽  
Fontan Operation ◽  
Vena Cava ◽  
In Vitro Study ◽  
Magnetic Resonance Images ◽  
Flow Loop ◽  
Pressure Losses ◽  
The Right

The Fontan operation is one in which the right heart is bypassed leaving the left ventricle to drive the blood through both the capillaries and the lungs, making it important to design an operation which is hemodynamically efficient. The object here was to relate the pressure in Fontan connections to its geometry with the aim of increasing the hemodynamically efficiency. From CT or magnetic resonance images, glass models were made of realistic atrio-pulmonary (AP) and cavo-pulmonary (CP) connections in which the right atrium and/or ventricle are bypassed. The glass models were connected to a steady flow loop and flow visualization, pressure and 3 component LDA measurements made. In the AP model the large atrium and curvature of the conduit created swirling patterns, the magnitude of which was similar to the axial velocity. This led to an inefficient flow and a subsequent large pressure loss (780 Pa). In contrast, the CP connection with a small intra-atrial chamber had reduced swirling and a significantly smaller pressure loss (400 Pa at 8 l.min) and was therefore a more efficient connection. There were, however, still pressure losses and it was found that these occurred where there was a large bending of the flow, such as from the superior vena cava to the MPA and from the MPA to the right pulmonary artery.

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].

Experimentally Modeling Patient-Specific Fontan Circulations Including Respiration Effects Using a Mock Circulatory System

2011 ◽  
Author(s):  
John A. Chiulli ◽  
Timothy A. Conover ◽  
Sharmad S. Joshi ◽  
Richard S. Figliola ◽  
Tain-Yen Hsia
Keyword(s):  
Hepatic Vein ◽  
Heart Defects ◽  
Fontan Operation ◽  
Vena Cava ◽  
Circulatory System ◽  
Fontan Circulation ◽  
Flow Reversal ◽  
Patient Specific ◽  
Pulmonary Vascular Disease ◽  
Mock Circulatory System

The Fontan circulation is the result of a series of operations performed on children born with univentricular circulations (1). These congenital heart defects are uniformly fatal if left alone. After birth, an operation is performed to assure that the child receives enough blood flow to the lungs, but not too much in order to avoid pulmonary vascular disease. Once the child reaches 2–4 years of age, the child’s blood vessels are sufficiently large for the Fontan operation. The Fontan operation connects the great systemic veins directly to the pulmonary arteries, bypassing the right ventricle entirely. One method of the Fontan procedure, which is known as the total cavopulmonary connection (TCPC), achieves venous return to the pulmonary circulation without a ventricular power source. The load on the heart is reduced, and these patients can lead a normal life into adulthood; although late complications continue to prevent normal lifespan. One unique feature of the Fontan circulation is reliance of the inferior vena cava (IVC) flow on respiration, and flow reversal in the IVC and hepatic vein during expiratory phase of breathing (2). Hsia et al. (3) suggest that reducing flow reversal in the hepatic vein will improve the outcome of the Fontan operation. The goal of this study is to model experimentally the Fontan circulation for a variety of different patients using an adjustable mock circulatory system, which for the first time includes the influence of respiration.

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