CFD Modeling of Blood Flow in a Bidirectional Glenn Shunt and a Combined Bidirectional Glenn and Blalock-Taussig Shunt

2021 ◽  
Author(s):  
Chunhui Wang ◽  
Ramesh K. Agarwal
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Patient Specific ◽  
Glenn Shunt ◽  
Bidirectional Glenn ◽  
Bidirectional Glenn Shunt ◽  
Blalock Taussig Shunt

Abstract Cyanosis or “Blue Baby Syndrome,” is an infant disorder which affects the newly born babies whose skins turn blue or purple because of lack of required blood flow between heart and lung due to pulmonary vascular blockage. Many patients may also have stenosis in vessels. If there is not enough blood flow from heart to the lung, lack of oxygen will cause platelet aggregation and coagulation resulting in elevated wall shear stress which may potentially result in death. In order to address the congenital defect and increase blood flow and oxygen saturation levels within the blood pumping system, a biological shunt is usually planted between innominate veins and left and right pulmonary arteries. The well-known examples are Blalock-Taussig shunt (BT shunt) between right ventricle and pulmonary artery and bidirectional Glenn shunt (BGS) between innominate veins and pulmonary arteries. The goal of this paper is to study the hemodynamics of BGS, wherein the blood flow goes through superior vena cava (SVC), innominate and subclavian veins and pulmonary arteries. In another simulation, Blalok-Taussing shunt (BTS) is also included along with the BGS. In BTS, the blood directly flows between innominate and pulmonary artery. The models are created with SolidWorks and Blender software based on real patient aorta model parameters. The commercial CFD software ANSYS is used to simulate the blood flow. CFD simulations are performed for blood flow (1) in patient specific aorta model without BGS and (2) in patient specific model with both BGS and BTS. The results for distribution of pressure, velocity and wall shear stress are obtained and analyzed to evaluate the performance of BGS alone and with both BGS and BTS. The computations are compared with limited available clinical data. This study demonstrates how CFD can be effectively utilized in the design of medical devices such as BGS and BTS and to improve the clinical outcomes in patients.

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.

Investigation of two-way fluid-structure interaction of blood flow in a patient-specific left coronary artery

2021 ◽  
pp. 1-18
Author(s):  
Abdulgaphur Athani ◽  
N.N.N. Ghazali ◽  
Irfan Anjum Badruddin ◽  
Sarfaraz Kamangar ◽  
Ali E. Anqi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Left Coronary Artery ◽  
Fluid Structure Interaction ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Fluid Structure ◽  
Structure Interaction

BACKGROUND: The blood flow in the human artery has been a subject of sincere interest due to its prime importance linked with human health. The hemodynamic study has revealed an essential aspect of blood flow that eventually proved to be paramount to make a correct decision to treat patients suffering from cardiac disease. OBJECTIVE: The current study aims to elucidate the two-way fluid-structure interaction (FSI) analysis of the blood flow and the effect of stenosis on hemodynamic parameters. METHODS: A patient-specific 3D model of the left coronary artery was constructed based on computed tomography (CT) images. The blood is assumed to be incompressible, homogenous, and behaves as Non-Newtonian, while the artery is considered as a nonlinear elastic, anisotropic, and incompressible material. Pulsatile flow conditions were applied at the boundary. Two-way coupled FSI modeling approach was used between fluid and solid domain. The hemodynamic parameters such as the pressure, velocity streamline, and wall shear stress were analyzed in the fluid domain and the solid domain deformation. RESULTS: The simulated results reveal that pressure drop exists in the vicinity of stenosis and a recirculation region after the stenosis. It was noted that stenosis leads to high wall stress. The results also demonstrate an overestimation of wall shear stress and velocity in the rigid wall CFD model compared to the FSI model.

Computational Fluid Dynamics of a Vascular Access Case for Hemodialysis

2000 ◽  
Vol 123 (3) ◽  
pp. 284-292 ◽  
Author(s):  
Bogdan Ene-Iordache ◽  
Lidia Mosconi ◽  
Giuseppe Remuzzi ◽  
Andrea Remuzzi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Radial Artery ◽  
Stress Gradient ◽  
Vascular Lesions ◽  
Patient Specific ◽  
Wall Shear

Vascular accesses (VA) for hemodialysis are usually created by native arteriovenous fistulas (AVF) or synthetic grafts. Maintaining patency of VA continues to be a major problem for patients with end-stage renal disease, since in these vessels thrombosis and intimal hyperplasia often occur. These lesions are frequently associated with disturbed flow that develops near bifurcations or sharp curvatures. We explored the possibility of investigating blood flow dynamics in a patient-specific model of end-to-end native AVF using computational fluid dynamics (CFD). Using digital subtraction angiographies of an AVF, we generated a three-dimensional meshwork for numerical analysis of blood flow. As input condition, a time-dependent blood waveform in the radial artery was derived from centerline velocity obtained during echo-color-Doppler ultrasound examination. The finite element solution was calculated using a fluid-dynamic software package. In the straight, afferent side of the radial artery wall shear stress ranged between 20 and 36 dynes/cm2, while on the inner surface of the bending zone it increased up to 350 dynes/cm2. On the venous side, proximal to the anastomosis, wall shear stress was oscillating between negative and positive values (from −12 dynes/cm2 to 112 dynes/cm2), while distal from the anastomosis, the wall shear stress returned within the physiologic range, ranging from 8 to 22 dynes/cm2. Areas of the vessel wall with very high shear stress gradient were identified on the bending zone of the radial artery and on the venous side, after the arteriovenous shunt. Secondary blood flows were also observed in these regions. CFD gave a detailed description of blood flow field and showed that this approach can be used for patient-specific analysis of blood vessels, to understand better the role of local hemodynamic conditions in the development of vascular lesions.

Blood Flow Manipulation in the Aorta With Coarctation and Arch Narrowing for Pediatric Subjects

2020 ◽  
Vol 88 (2) ◽  
Author(s):  
Yuxi Jia ◽  
Kumaradevan Punithakumar ◽  
Michelle Noga ◽  
Arman Hemmati
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Aortic Arch ◽  
Flow Direction ◽  
Upper Body ◽  
Patient Specific ◽  
Shear Stresses ◽  
Wall Shear

Abstract The characteristics of blood flow in an abnormal pediatric aorta with an aortic coarctation and aortic arch narrowing are examined using direct numerical simulations and patient-specific boundary conditions. The blood flow simulations of a normal pediatric aorta are used for comparison to identify unique flow features resulting from the aorta geometrical anomalies. Despite flow similarities compared to the flow in normal aortic arch, the flow velocity decreases with an increase in pressure, wall shear stress, and vorticity around both anomalies. The presence of wall shear stresses in the trailing indentation region and aorta coarctation opposing the primary flow direction suggests that there exist recirculation zones in the aorta. The discrepancy in relative flowrates through the top and bottom of the aorta outlets, and the pressure drop across the coarctation, implies a high blood pressure in the upper body and a low blood pressure in the lower body. We propose using flow manipulators prior to the aortic arch and coarctation to lower the wall shear stress, while making the recirculation regions both smaller and weaker. The flow manipulators form a guide to divert and correct blood flow in critical regions of the aorta with anomalies.

scholarly journals Computational Fluid Dynamics Characterization of Two Patient-Specific Systemic-to-Pulmonary Shunts before and after Operation

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Neichuan Zhang ◽  
Haiyun Yuan ◽  
Xiangyu Chen ◽  
Jiawei Liu ◽  
Qifei Jian ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pulmonary Artery ◽  
Energy Loss ◽  
Three Dimensional ◽  
Left Pulmonary Artery ◽  
Postoperative Recovery ◽  
Patient Specific ◽  
Wall Shear ◽  
Ct Data

Studying the haemodynamics of the central shunt (CS) and modified Blalock–Taussig shunt (MBTS) benefits the improvement of postoperative recovery for patients with an aorta-pulmonary shunt. Shunt configurations, including CS and MBTS, are virtually reconstructed for infants A and B based on preoperative CT data, and three-dimensional models of A, 11 months after CS, and B, 8 months after MBTS, are reconstructed based on postoperative CT data. A series of parameters including energy loss, wall shear stress, and shunt ratio are computed from simulation to analyse the haemodynamics of CS and MBTS. Our results showed that the shunt ratio of the CS is approximately 30% higher than the MBTS and velocity distribution in the left pulmonary artery (LPA) and right pulmonary artery (RPA) was closer to a natural development in the CS than the MBTS. However, energy loss of the MBTS is lower, and the MBTS can provide more symmetric pulmonary artery (PA) flow than the CS. With the growth of infants A and B, the shunt ratio of infants was decreased, but maximum wall shear stress and the distribution region of high wall shear stress (WSS) were increased, which raises the probability of thrombosis. For infant A, the preoperative abnormal PA structure directly resulted in asymmetric growth of PA after operation, and the LPA/RPA ratio decreased from 0.49 to 0.25. Insufficient reserved length of the MBTS led to traction phenomena with the growth of infant B; on the one hand, it increased the eddy current, and on the other hand, it increased the flow resistance of anastomosis, promoting asymmetric PA flow.

scholarly journals Use of Pericardial Patch Conduit in Bidirectional Glenn Shunt: An Innovative Technique

2020 ◽  
Vol 13 (1) ◽  
pp. 92-94
Author(s):  
Kazi Shariful Islam ◽  
Shahriar Moinuddin ◽  
Ankan Kumar Paul ◽  
Masud Alam
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Stenosis ◽  
Fontan Procedure ◽  
Left Pulmonary Artery ◽  
Intermediate Step ◽  
Glenn Shunt ◽  
Bidirectional Glenn ◽  
Palliative Procedure ◽  
Bidirectional Glenn Shunt ◽  
Right Pulmonary Artery

Bidirectional Glenn Shunt is a palliative procedure in single ventricle or hypoplastic right ventricle, tricuspid atresia and pulmonary stenosis complex where definitive repair is not feasible as well as a intermediate step of Fontan procedure. It is done by anastomosing superior venacava with right pulmonary artery or conduit can be used. We were forced to do the anastomosis between superior venacava and left pulmonary artery using a conduit as anatomy wasn’t favorable. Due to unavailability of any recognized conduits we used autologous pericardium and created a conduit with it to carry out anastomosis. Post-operative results were satisfactory. Cardiovasc. j. 2020; 13(1): 92-94

Sign in / Sign up

Export Citation Format

Share Document