Effects of Coronary Artery Lesion Characteristics on Myocardial Ischemia / 医用生物力学

Objective To investigated the effect of stenosis characteristics (vascular elasticity and plaque properties) on myocardial ischemia. Methods An ideal geometric multi-scale coronary stenosis model based on fluid-structure interaction was established, and the fractional flow reserve (FFR) was simulated to evaluate myocardial ischemia. The effects of vascular elastic wall (elastic modulus of 1 MPa) and rigid wall, plaque types (lipid-rich plaque and calcified plaque) and plaque volume on myocardial ischemia were considered separately. Results The FFRCT simulation result of vessels with elastic wall was larger than that with rigid wall under all stenosis situations. The FFRCT of vessels in lipid-rich lesions was higher than that of calcified plaque (P=0.001). The trapezoidal plaque volume was larger than the cosine plaque volume, and the FFRCT of vessels in trapezoidal plaque was smaller than that of cosine plaque (P=0.001). Conclusions Vascular elasticity is a critical factor to simulate vascular hemodynamics. In moderate stenosis, calcified plaques are more likely to induce myocardial ischemia due to the larger luminal deformation and dilation of rich lipid plaque. When the stenosis is constant, the smaller the plaque volume, the higher the FFRCT and the smaller the possibility of myocardial ischemia.

Analysis on Motion Characteristics of Red Blood Cells in Capillaries / 医用生物力学

Objective To study the motion and deformation of red blood cells ( RBCs) with different mechanical properties in capillaries,and make analysis on the associated hemorheological parameters. Methods The RBC was modeled as a hyper elastic membrane using Skalak model. The fluid was solved using a two-order difference scheme with the membrane mechanics treated by the immersed method. The pathological viscosity ratio λ= 5 was considered. Results The steady deformation of RBCs with different membrane stiffness in the capillary was obtained. With membrane stiffness increasing, the cell transformed from axisymmetric shapes to non-axisymmetric shapes. With capillary number increasing, the deformability of RBCs weakened and the flow resistance increased. Conclusions With stiffening of cell membrane, the non-axisymmetric cell shape appears and the flow resistance increases. Therefore, in diseases involved stiffening RBCs, the stiffened RBCs can cause the blockage of capillaries and hypoxia in surrounding tissues.

Fluid-Structure Interaction Simulation of Carotid Plaque / 医用生物力学

Objective To propose a two-way fluid-structure interaction (FSI) method based on real patients with carotid artery stenosis, and analyze the hemodynamic parameters of carotid plaques with different types at the lesion as well as deformation and stress changes of the plaque itself. Methods Three-dimensional ( 3D) modeling was performed based on computed tomography angiography ( CTA) data of patients with moderate carotid artery stenosis. The carotid artery wall model and plaque model were separated, and transient fluid structure coupling calculation was performed. The situation from early stage of carotid atherosclerosis to formation of the plaque was simulated. The plaque types were divided into thickened plaques, lipid plaques, mixed plaques and calcified plaques, among which thickened plaques were regarded as non-plaque conditions for representing the thickening of vascular intima-media. The stenotic carotid arteries with different plaque types were compared and analyzed. Results The plaques with different types had little effect on the overall blood flow, but the wall shear stress of lipid plaques at the lesion was lower than that of other plaques. With thickened plaques as a control, concurrence of the plaque would inhibit artery expansion, and lipid plaques were the most obvious. Calcified plaques had the highest average plaque structure stress, while lipid plaques had the lowest average plaque structure stress. Conclusions The method proposed in this study can analyze fluid area and solid area at the same time. The results can contribute to better understanding the influence of different plaque types on carotid artery diseases.

Finite Element Analysis of Male Urethral Sphincter Loss Synergy / 医用生物力学

Objective To investigate the influence of internal and external sphincter loss synergy on stress distributions and urine flow rates of lower urinary tract organs and tissues. Methods Based on collodion slice, the geometric model of the lower urinary tract was reconstructed, and finite element model of the lower urinary tract with muscle active force was established. Through fluid structure coupling simulation, the changes of tissue stress and urine flow rate were simulated under four conditions: normal contraction of internal and external sphincter, total loss of muscle active force and single loss of muscle active force for internal and external sphincters at the end of urination. Results The urethral stress changes in normal contraction of internal and external sphincter muscles were the same as the clinically measured urethral pressure changes. Compared with normal contraction, when the internal sphincter lost its muscle active force alone, stress of the internal sphincter and the urethra of the prostate was reduced by 33.6% and 13.8%, and flow rate of urine in this position was also reduced. When the external sphincter lost its muscle active force alone, the urethral stress of the external sphincter and external urethra was reduced by 59.5% and 24.03%, respectively. When the internal and external sphincter lost muscle active force, stress of the internal sphincter, the prostate, the external sphincter and the external urethra were reduced by 38.77%, 18.6%, 63.58%, 29.74%, respectively, and flow velocity in the corresponding position was also reduced. Conclusions Internal and external sphincter loss synergy resulted in the difference of tissue stress and urine flow rate. The results can provide the theoretical basis for surgical treatment of urinary incontinence caused by sphincter.

Risk Assessment of Carotid Atherosclerotic Plaque Rupture under Cervical Rotatory Manipulation Based on Fluid-Structure Interaction Finite Element Model / 医用生物力学

Objective To evaluate the rupture risk of carotid atherosclerotic plaque under cervical rotatory manipulation. Methods The fluid-structure interaction (FSI) model of carotid atherosclerotic plaque was established, and tensile deformation of the plaque and lumen under cervical rotatory manipulation was simulated.Mechanical parameters such as the maximum flow shear stress(FSS), the maximum wall shear stress (WSS), the maximum plaque wall stress (PWS), wall tensile stress (WTS) and wall pressure (WP) of the plaque and lumen were recorded. Results Under 16% carotid tensile deformation, the maximum WSS of the plaque was 40.54 Pa. The maximum PWS was 66.16 kPa, which was far smaller than the threshold of plaque rupture.The maximum WTS of fiber cap and the maximum strain were 156.75 kPa and 0.56, which were larger than the fracture strain range. The maximum WTS of the lumen was 1 040.30 kPa, which approached the threshold of medial membrane rupture and might cause vascular injury. Conclusions When the cervical spine rotates to the end range of motion, large carotid artery stretch may cause damage to epidermal tissues of the plaque, leading to abscission. Lesions, ulcers, bleeding and vascular damage may form inside the plaque, which will affect stability of the plaque. Cervical rotatory manipulation should be performed cautiously in patients with cervical diseases who also have carotid atherosclerotic plaques.The finite element assessment of plaques before manipulation may be an effective safety screening method.

Finite element analysis of the effects of periodontal tissue temperature by continuous wave technique / 华西口腔医学杂志

OBJECTIVES@#The safety of root canal filling with 200 °C hot gutta-percha was investigated to study the effect of continuous wave technique combined with high-temperature injectable gutta-percha condensation technique on the surface temperature of periodontal tissue.@*METHODS@#CT technique and Mimics, Geomagic, and Solidworks software were utilized to build the entity models of alveolar bone, dentin and root canal, periodontal ligament, and blood flow, respectively, which were then assembled in Solidworks into a finite element model of tooth with blood flow. By utilizing ABAQUS collaborative simulation platform, fluid-structure coupling was analyzed on the whole process of root canal filling. Consequently, the surface temperature of the periodontal tissue was obtained.@*RESULTS@#In the absence of blood flow, the temperature of the periodontal ligament surface reached 50.048 ℃ during root canal filling with 200 ℃ gutta-percha. Considering blood flow, the temperature of periodontal ligament surface was 39.570 ℃.@*CONCLUSIONS@#The temperature of the periodontal ligament surface increased when the continuous wave root canal was filled with 200 ℃ gutta-percha, and the periodontal tissue was not damaged.

Simulation and Analysis of Capture Characteristics of Circulating Tumor Cells Based on Unidirectional Fluid-Solid Interaction Method / 医用生物力学

Objective To study movement process of circulating tumor cells (CTCs) in the blood and mechanism of CTC capture by CellCollector, and reveal relationship between the detected CTC numbers and the actual CTC concentration in the body. Methods Based on Fluent and EDEM software, the unidirectional fluid-solid interaction method was applied to establish a two-phase flow model, including the hemodynamic model and the CTC transport model, and capture simulations under different CTC concentration conditions were conducted. Results The number of CTCs captured by CellCollector was significantly positively correlated with the CTC concentration in the body. When the CTC concentration was low, CTCs could only be captured in several time intervals, and the capture had a certain contingency; as the concentration increased, the uniformity of CTC capture over time became better, and the total number of captures also increased. Conclusions Through the fitting of simulation results, analytical quantitative relationship between the captured CTC number and the CTC concentration in the body is preliminarily given, which provides theoretical basis and mechanical explanation for the clinical use of CellCollector.

Fluid-Structure Interaction Simulation of Multiple Overlapping Uncovered Stent Intervention in Aortic Dissection / 医用生物力学

Objective To propose a one-way fluid-structure interaction (FSI) method based on an idealized aortic dissection model, so as to analyze the hemodynamics and wall stress in the false lumen (FL) under the influence of multiple overlapping uncovered stents (MOUS). Methods Upon establishment of the numerical model, the models were divided into two categories according to whether the model involved FL perfused branch artery. The characteristics of hemodynamics and wall stress state in the post-operative scenarios were simulated under different surgical strategies. The wall stress state of the FL before and after thrombosis formation was also compared and analyzed. ResultsThe release process of the stents had little influence on wall stress of the FL. The high velocity and high wall shear stress (WSS) area in the FL could not be reduced by using the MOUS alone. If only the proximal entry tear was blocked with a covered stent-graft, the distal end would maintain a region of high flow rate and high WSS. The combination of covered stent-graft and MOUS would result in a region of low flow rate and low WSS, as well as reduced wall pressure and wall stress in the FL. Compared with the model with FL perfused branch arteries, the model without it was more likely to form a region of low flow rate and low WSS after surgery. However, blood pressure in the FL was relatively higher. The formation of thrombus in the FL could greatly reduce wall stress in the area covered by the thrombus. Conclusions The method proposed in this study can simultaneously investigate hemodynamics and wall stress characteristics of the FL, and provide support for studying mechanical mechanism of FL thrombolysis induced by MOUS and the post-operative aortic expansion.

Analysis on Hemodynamic Characteristics of Individualized Carotid Aneurysms / 医用生物力学

Objective To construct an individualized fluid-solid coupling model, calculate and analyze the influence of different blood characteristics on hemodynamics in the aneurysm cavity, and further explore the influence on rupture of the cerebral aneurysm. Methods First, three-dimensional (3D) digital silhouette images were collected to construct an aneurysm model, and the influence of different blood flow characteristics on dynamic parameters of the carotid aneurysm was analyzed by computational fluid dynamic (CFD) method under the same boundary conditions. Finally, particle image velocimetry (PIV) experiment was performed on the simplified carotid aneurysm experimental model to verify reliability of the blood flow calculation method. Results For the fluid-structure coupling model with different blood flow characteristics, within a cardiac cycle, at the same time, obvious differences were found in the low velocity area of tumor cavity, the streamline distributions of tumor cavity, the wall shear stress (WSS) and deformation of the aneurysm wall. Through PIV experiments, it was found that the vortex position in tumor cavity changed with the velocity, which was consistent with flow trend of the simulation analysis results. Conclusions The two kinds of blood characteristics have small differences, but the non-Newtonian fluid is closer to true state of the blood, and the numerical results will be closer to true flow state.

Effects of Perfusion Velocity on Suspended Cells in Microchannels / 医用生物力学

Objective To establish a finite element model of cell perfusion culture, and study the effect of different perfusion speeds on the movement of suspended cells. Methods The two-dimensional (2D) model of cell and microchannels was established using COMSOL Multiphysics and meshed. Three groups were established according to the perfusion speed, namely, u0=0.196 mm/s, u1=0.117 mm/s, u2=0.04 mm/s. The fluid-structure interaction module was used for calculation. Results The flow field distribution in the microchannel was relatively uniform. During the equal period of time, the ratio of cell suspension perfusion speed was u0∶u1∶u2=5∶3∶1, and the ratio of cell displacement in the microchannel was D0∶D1∶D2=4.1∶ 2.9∶1. When the speed was proportional, the displacement of cells also roughly followed the corresponding proportional change. With the increase of perfusion speed, stress concentration in cells during movement would occur. The stress and fluid shear force (FSS) of cells during movement were within the safe value range, and cell destruction would not occur. Conclusions The suspended cells can enter into the microchannel without injury at a certain perfusion speed. Perfusion techniques can be used in cell implantation of in vitro tissue engineering products.

Fluid Structure Interaction of Renal Arteries of Abdominal Aorta Subjected to Single and Double Stenosed Complication

@#Introduction: In this study, Renal artery (RA) stenosis of Single Stenosed (SS) and Double Stenosed (DS) with the condition of Normal Blood Pressure (NBP) and High Blood Pressure (HBP) were investigated using the aid of Fluid Structure Interaction (FSI) approach. Methods: Numerical analysis of 3D model patient’s specific abdominal aorta with RA stenosis was conducted using FSI solver in software ANSYS 18. Results: The results of velocity profile, pressure drop, time average wall shear stress (TAWSS), Oscillatory shear index (OSI) and total deformation of SS and DS with the condition of NBP and HBP were compared in terms of blood flow and structural wall tissue behaviour. The results concluded SS-NBP produced the highest value of velocity profile, TAWSS and OSI parameter compared to the others. Meanwhile, SS-HBP indicates the highest value pressure drop. On the other hand, SS-HBP and DS-HBP have a higher distribution of deformation contour and also maximum VMS compared to SS-NBP and DS-HBP. Conclusion: With the aid of FSI approach, this studied has proven that the existence of SS at RA location has a higher impact on the velocity magnitude, higher pressure drop, higher TAWSS and OSI value compared to the DS case. This is due to a high concentration of pressure acting at the narrow blood vessel of SS compared to DS cases which most of the blood flow will pass to the lower part of abdominal aorta.

Influence of Dimple Depth on Lubricant Thickness in Elastohydrodynamic Lubrication for Metallic Hip Implants Using Fluid Structure Interaction (FSI) Approach

@#Introduction: The lubricant thickness in clearance between bearing surfaces for metallic hip implants are currently incapable of accommodating the motion experienced (high load and low entraining motion) in hip walking cycle. Thus, micro-dimpled surfaces were introduced onto surfaces of metallic acetabular cups to improve lubricant thickness. Micro-dimpled surface is a method of advanced surface improvement to increase the lubricant thickness in various tribological applications, such as hip implants. However, the application of micro-dimpled surfaces in hip implants has not yet been explored adequately. Therefore, this study aims to identify the influence of micro-dimpled depth on lubricant thickness elastohydrodynamically for metallic hip implants using Fluid-Structure Interaction (FSI) approach. Methods: Fluid-Structure Interaction (FSI) approach is an alternative method for analysing characteristics of lubrication in hip implant. Dimples of radius 0.25 mm and various depths of 5μm, 45μm and 100μm were applied on the cup surfaces. The vertical load in z-direction and rotation velocity around y-axes representing the average load and flexion-extension (FE) velocity of hip joint in normal walking were applied on Elastohydrodynamic lubrication (EHL) model. Results: The metallic hip implants with micro-dimpled surfaces provided enhanced lubricant thickness, namely by 6%, compared to non-dimpled surfaces. Furthermore, it was suggested that the shallow depth of micro-dimpled surfaces contributed to the enhancement of lubricant thickness. Conclusion: Micro-dimpled surfaces application was effective to improve tribological performances, especially in increasing lubricant thickness for metallic hip implants.

Analysis of Blood Flow and Vascular Injury in Aneurysm-Carrying Vessels Based on Fluid-Structure Interaction Method / 医用生物力学

Objective To study the blood flow in aneurysm and its influence on mechanical properties of vascular walls for two kinds of common aneurysms, so as to improve the diagnosis and treatment of aneurysms and the prognosis of patients. Methods The interaction between the aneurysm-carrying vessels and blood of two common aneurysms was studied by fluid-structure interaction method. The blood flow velocity, wall deformation, stress distribution and damage form of aneurysm-carrying vessels were analyzed. Results The blood flow in both aneurysms were slow and stable, which resulted in better deposition and adhesion conditions. The junction between the aneurysm and the downstream of the blood vessel was a dangerous place for damage. The spindle aneurysm would undergo shear failure on outer wall of the aneurysm, while the cystic aneurysm would undergo stretching failure on inner wall. Under the effect of the same blood flow, a larger stress appeared on the cystic aneurysm, which was more prone to damage, and the tensile failure would lead to a more serious consequences. Conclusions The junction at the aneurysm and blood vessel is prone to damage, and the cystic aneurysm is more dangerous and harmful.

Analysis of Blood Flow and Vascular Injury in Aneurysm-Carrying Vessels Based on Fluid-Structure Interaction Method / 医用生物力学

Objective To study the blood flow in aneurysm and its influence on mechanical properties of vascular walls for two kinds of common aneurysms, so as to improve the diagnosis and treatment of aneurysms and the prognosis of patients. Methods The interaction between the aneurysm-carrying vessels and blood of two common aneurysms was studied by fluid-structure interaction method. The blood flow velocity, wall deformation, stress distribution and damage form of aneurysm-carrying vessels were analyzed. Results The blood flow in both aneurysms were slow and stable, which resulted in better deposition and adhesion conditions. The junction between the aneurysm and the downstream of the blood vessel was a dangerous place for damage. The spindle aneurysm would undergo shear failure on outer wall of the aneurysm, while the cystic aneurysm would undergo stretching failure on inner wall. Under the effect of the same blood flow, a larger stress appeared on the cystic aneurysm, which was more prone to damage, and the tensile failure would lead to a more serious consequences. Conclusions The junction at the aneurysm and blood vessel is prone to damage, and the cystic aneurysm is more dangerous and harmful.

Finite element analysis of male lower urinary tract based on the collodion slice images / 生物医学工程学杂志

Males typically have high rates of morbidity of primary bladder neck obstruction, while the existing urodynamic examination is invasive and more likely to cause false diagnosis. To build a non-invasive biomechanical detecting system for the male lower urinary tract, a finite element model for male lower urinary tract based on the collodion slice images of normal male lower urinary tract was constructed, and the fluid-structure interaction of the lower urinary tract was simulated based on the real urination environment. The finite element model of the lower urinary tract was validated by comparing the clinical experiment data with the simulation result. The stress, flow rate and deformation of the lower urinary tract were analyzed, and the results showed that the Von Mises stress and the wall shear stress at the membrane sphincter in the normal male lower urinary tract model reached a peak, and there was nearly 1 s delay than in the bladder pressure, which helped to validate the model. This paper lays a foundation for further research on the urodynamic response mechanism of the bladder pressure and flow rate of the lower urinary tract obstruction model, which can provide a theoretical basis for the research of non-invasive biomechanical detecting system.

Investigation of the effects of miniscrew-assisted rapid palatal expansion on airflow in the upper airway of an adult patient with obstructive sleep apnea syndrome using computational fluid-structure interaction analysis / 대한치과교정학회지

OBJECTIVE: The objective of this study was to investigate the effects of miniscrew-assisted rapid palatal expansion (MARPE) on changes in airflow in the upper airway (UA) of an adult patient with obstructive sleep apnea syndrome (OSAS) using computational fluid-structure interaction analysis. METHODS: Three-dimensional UA models fabricated from cone beam computed tomography images obtained before (T0) and after (T1) MARPE in an adult patient with OSAS were used for computational fluid dynamics with fluid-structure interaction analysis. Seven and nine cross-sectional planes (interplane distance of 10 mm) in the nasal cavity (NC) and pharynx, respectively, were set along UA. Changes in the cross-sectional area and changes in airflow velocity and pressure, node displacement, and total resistance at maximum inspiration (MI), rest, and maximum expiration (ME) were investigated at each plane after MARPE. RESULTS: The cross-sectional areas at most planes in NC and the upper half of the pharynx were significantly increased at T1. Moreover, airflow velocity decreased in the anterior NC at MI and ME and in the nasopharynx and oropharynx at MI. The decrease in velocity was greater in NC than in the pharynx. The airflow pressure in the anterior NC and entire pharynx exhibited a decrease at T1. The amount of node displacement in NC and the pharynx was insignificant at both T0 and T1. Absolute values for the total resistance at MI, rest, and ME were lower at T1 than at T0. CONCLUSIONS: MARPE improves airflow and decreases resistance in UA; therefore, it may be an effective treatment modality for adult patients with moderate OSAS.

FSI simulation of patient-specific aortic dissection and its bypass grafting / 医用生物力学

Objective To investigate the effects of different bypass grafting for treating DeBakey Ⅲ aortic dissection. Methods The patient-specific models of DeBakey Ⅲ aortic dissection based on CT images were reconstructed by using Mimics software, and two bridge models of bypassing between ascending aorta and abdominal aorta (AA), and between left subclavian artery and abdominal aorta (LA) were established by computer-aided method, respectively. Then numerical simulations were performed by using fluid-structure interaction (FSI) method to compare hemodynamic differences of these two models. Results After bypass surgery, the mass flow, mean and maximum velocities of the through lumen models were reduced to different degrees. Meanwhile, both the maximum blood pressures and displacements of the vessel walls of AA models were decreased, but those of LA models were increased. In contrast, all the above-mentioned hemodynamic parameters of the blind lumen models were decreased, especially for AA models. Conclusions The AA bypassing is a better treatment for DeBakey Ⅲ aortic dissection of through lumen and blind lumen. The therapeutic effects can be easily explained through simulation results, to ensure the scientific validity and clinical utility of bypassing.

Fluid-structure interaction analysis on hemodynamics of vertebral arteries during physiological activities of cervical spine / 医用生物力学

Objective To further understand the biomechanical relationship between activities of cervical spine and blood flow of vertebral artery (VA) by developing the VA finite element model and calculating the fluid-structure interaction. Methods Based on the normal model of cervical spine and the developed C0-T1 finite element model with bilateral VA, the flexion and extension, right and left lateral bending, right and left axial rotation movement of cervical spine at physiological velocity were simulated. The effects of cervical activities on stress of vertebral arterial wall were observed, and the biomechanical interaction between the vessel wall and fluid was calculated by fluid-structure interaction equation to obtain the hemodynamic parameters. Results The maximum stress was usually concentrated on the both sides of C2 transverse foramen, where the second arc of vertebral arterial wall protruded into the cranial direction during cervical activities. The maximum strain of the vessel wall was most obvious during the extension and lateral bending movement, with strain ratio of 23.04% and 35.5%, respectively. The maximum stress on the vessel was located in the position of contralateral transverse foramen during lateral bending movement, while the maximum strain on the vessel was located in the position of ipsilateral transverse foramen during rotation movement. In aspect of cervical spine range of motion (ROM), the minimum volume flow rate occurred within 30%-40% of the physiological ROM. The volume flow rate-time curve of bilateral VA was similar during flexion and extension movement, when the circulation of flow rate was completed for two times within 0.5 s. The peak and valley of ipsilateral blood flow in volume flow rate-time curve occurred earlier than that of contralateral blood flow during lateral bending movement, while the results of rotation movement were opposite. Conclusions The obtained stress features of bilateral VA vessel and the law of the volume flow rate-time curve validated the experimental results with those in the literature, which could reasonably explain the clinical phenomenon. The established model would provide an ideal platform for researches on vertebral artery-related diseases.

Computational Modeling with Fluid-Structure Interaction of the Severe M1 Stenosis Before and After Stenting / 신경중재치료의학

PURPOSE: Image-based computational models with fluid-structure interaction (FSI) can be used to perform plaque mechanical analysis in intracranial artery stenosis. We described a process in FSI study applied to symptomatic severe intracranial (M1) stenosis before and after stenting. MATERIALS AND METHODS: Reconstructed 3D angiography in STL format was transferred to Magics for smoothing of vessel surface and trimming of branch vessels and to HyperMesh for generating tetra volume mesh from triangular surface-meshed 3D angiogram. Computational analysis of blood flow in the blood vessels was performed using the commercial finite element software ADINA Ver 8.5. The distribution of wall shear stress (WSS), peak velocity and pressure was analyzed before and after intracranial stenting. RESULTS: The wall shear stress distributions from Computational fluid dynamics (CFD) simulation with rigid wall assumption as well as FSI simulation before and after stenting could be compared. The difference of WSS between rigid wall and compliant wall model both in pre- and post-stent case is only minor except at the stenosis region. These WSS values were greatly reduced after stenting to 15~20 Pa at systole and 3~5 Pa at end-diastole in CFD simulation, which are similar in FSI simulations. CONCLUSION: Our study revealed that FSI simulation before and after intracranial stenting was feasible despite of limited vessel wall dimension and could reveal change of WSS as well as flow velocity and wall pressure.

Hemodynamic comparison between elastic and rigid vessels for the central shunt / 医用生物力学

Objective To study the hemodynamics of central shunt (CS) by numerical simulation and investigate the effects of the elastic and rigid vessel wall on distributions of hemodynamic parameters in the vessel. Methods Two idealized CS models were constructed, one with a rigid wall (the rigid model) and the other with an elastic wall (the elastic model). Numerical calculation was conducted by the finite element method, and the elastic model adopted the fluid structure interaction. Results The distribution of flow velocity and pressure in both models were generally the same. About 68.9% of the aortic blood was directed into the pulmonary artery for the rigid model, as compared to 70% for the elastic model. The pressure drops within the shunt for the elastic model and rigid model were about 7.668 8 kPa and 7.222 3 kPa, respectively. The maximum variation in the average cross sections along the shunt was about 2.2% for the elastic model, appearing at the proximal end to side (ETS) anastomosis. The maximum difference of wall shear stress (WSS) between the two models at five key regions of each was about 16.1%. Conclusions Generally, the global flow structure in both the CS models remains unchanged; the elasticity of the vessel wall slightly influenced the flow distributions and pressure drop of the shunt; the effect from elasticity of the vessel wall on average cross sections along the shunt was higher at the proximal ETS anastomosis than that at the distal ETS anastomosis; the hypothesis that the vessel wall is rigid is acceptable in CS numerical simulations for the treatment of tetralogy of Fallot (TOF). However, the coupling of flow dynamics and wall mechanics may lead to a more reliable simulation result in the CS.