Biomechanical Assessment of Bicuspid Aortic Valve Phenotypes: A Fluid–Structure Interaction Modelling Approach

The bicuspid aortic valve (BAV) is a congenital malformation of the aortic valve with a variety of structural features. The current research on BAV mainly focuses on the systolic phase, while ignoring the diastolic hemodynamic characteristics and valve mechanics. The purpose of this study is to compare the differences in hemodynamics and mechanical properties of BAV with different phenotypes throughout the cardiac cycle by means of numerical simulation. Based on physiological anatomy, we established an idealized tricuspid aortic valve (TAV) model and six phenotypes of BAV models (including Type 0 a–p, Type 0 lat, Type 1 L–R, Type 1 N-L, Type 1 R-N, and Type 2), and simulated the dynamic changes of the aortic valve during the cardiac cycle using the fluid–structure interaction method. The morphology of the leaflets, hemodynamic parameters, flow patterns, and strain were analyzed. Compared with TAV, the cardiac output and effective orifice area of different BAV phenotypes decreased certain degree, along with the peak velocity and mean pressure difference increased both. Among all BAV models, Type 2 exhibited the worst hemodynamic performance. During the systole, obvious asymmetric flow field was observed in BAV aorta, which was related to the orientation of BAV. Higher strain was generated in diastole for BAV models. The findings of this study suggests specific differences in the hemodynamic characteristics and valve mechanics of different BAV phenotypes, including different severity of stenosis, flow patterns, and leaflet strain, which may be critical for prediction of other subsequent aortic diseases and differential treatment strategy for certain BAV phenotype.

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Patient-Specific Valve Dynamics Using 3D Fluid-Structure Interaction Modeling: Comparison Between Bicuspid and Tricuspid Aortic Valves

Volume 1B: Extremity; Fluid Mechanics; Gait; Growth, Remodeling, and Repair; Heart Valves; Injury Biomechanics; Mechanotransduction and Sub-Cellular Biophysics; MultiScale Biotransport; Muscle, Tendon and Ligament; Musculoskeletal Devices; Multiscale Mechanics; Thermal Medicine; Ocular Biomechanics; Pediatric Hemodynamics; Pericellular Phenomena; Tissue Mechanics; Biotransport Design and Devices; Spine; Stent Device Hemodynamics; Vascular Solid Mechanics; Student Paper and Design Competitions ◽

10.1115/sbc2013-14563 ◽

2013 ◽

Author(s):

V. Govindarajan ◽

J. Mousel ◽

S. C. Vigmostad ◽

H. S. Udaykumar ◽

M. M. Levack ◽

...

Keyword(s):

Aortic Valve ◽

Bicuspid Aortic Valve ◽

Fluid Structure Interaction ◽

Geometric Distortion ◽

Patient Specific ◽

Endothelial Lining ◽

Aortic Valves ◽

Fluid Structure ◽

Structure Interaction ◽

Opening Phase

Aortic valve diseases such as congenital bicuspid aortic valve (BAV) and progressive calcification in tricuspid valves affect the hemodynamics in the aortic arch. In addition to leaflet calcification, BAVs are associated with other ailments such as aortic coarctation, aneurysm and dissection [1]. It has also been observed that progressive calcification is accelerated in the case of BAVs compared to normal tricuspid valves. While it is not yet known whether the geometric distortion in BAVs is the main cause of calcification [2] in these valves, the distortion in the leaflets may give rise to altered stresses during the deformation processes which might play a role in accelerating the calcification process in BAVs. In addition, the altered flow caused by the change in geometry could alter the local fluid stresses during the opening phase, which might affect the endothelial lining of the aortic wall. Analyzing and comparing BAV and tricuspid aortic valves as a fluid-structure interaction problem will help determine the stress distribution on the leaflets during opening phase, and enable the examination of altered flow dynamics in the ascending aorta. In this study, the opening phase of a patient-specific bicuspid aortic valve is analyzed at physiological conditions and compared with the opening phase of a tricuspid aortic valve.

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Fluid structure interaction modelling of aortic valve stenosis: Effects of valve calcification on coronary artery flow and aortic root hemodynamics

Computer Methods and Programs in Biomedicine ◽

10.1016/j.cmpb.2020.105647 ◽

2020 ◽

Vol 196 ◽

pp. 105647

Author(s):

Araz R. Kivi ◽

Nima Sedaghatizadeh ◽

Benjamin S. Cazzolato ◽

Anthony C. Zander ◽

Ross Roberts-Thomson ◽

...

Keyword(s):

Coronary Artery ◽

Aortic Valve ◽

Aortic Valve Stenosis ◽

Aortic Root ◽

Fluid Structure Interaction ◽

Valve Calcification ◽

Fluid Structure ◽

Structure Interaction ◽

Interaction Modelling ◽

Artery Flow

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Patient-specific analysis of bicuspid aortic valve hemodynamics using a fully coupled fluid-structure interaction (FSI) model

10.1101/2021.10.24.21265224 ◽

2021 ◽

Author(s):

TONGRAN QIN ◽

Andres Caballero ◽

Wenbin Mao ◽

Brian Barrett ◽

Norihiko Kamioka ◽

...

Keyword(s):

Aortic Valve ◽

Bicuspid Aortic Valve ◽

Peak Velocity ◽

Fluid Structure Interaction ◽

Ascending Aorta ◽

Patient Specific ◽

Fluid Structure ◽

Structure Interaction ◽

Flow Displacement ◽

Fully Coupled

Bicuspid aortic valve (BAV), the most common congenital heart disease, is prone to develop significant valvular dysfunction and aortic wall abnormalities. Growing evidence has suggested that abnormal BAV hemodynamics could contribute to the disease progression. In order to investigate the BAV hemodynamic, we performed 3D patient-specific fluid-structure interaction (FSI) simulations of BAV with fully coupled flow dynamics and valve motions throughout the cardiac cycle. The results showed that the flow during systole can be characterized by a systolic jet and two counter-rotating recirculation vortices. At peak systole, the jet was usually eccentric, with asymmetric recirculation vortices, and helical flow motion in the ascending aorta. The flow structure at peak systole was quantified using the vorticity, flow reversal ratio and helicity index at four locations from the aortic root to the ascending aorta. The systolic jet was evaluated using the metrics including the peak velocity, normalized flow displacement, and jet angle. It was found that both the peak velocity and normalized flow displacement (rather than jet angle) of the systolic jet showed a strong correlation with the vorticity and helicity index of the flow in the ascending aorta, which suggests that these two metrics can be used for noninvasive evaluation of abnormal flow patterns in BAV patients.

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Systolic fluid–structure interaction model of the congenitally bicuspid aortic valve: assessment of modelling requirements

Computer Methods in Biomechanics & Biomedical Engineering ◽

10.1080/10255842.2014.900663 ◽

2014 ◽

Vol 18 (12) ◽

pp. 1305-1320 ◽

Cited By ~ 5

Author(s):

May Y.S. Kuan ◽

Daniel M. Espino

Keyword(s):

Aortic Valve ◽

Bicuspid Aortic Valve ◽

Fluid Structure Interaction ◽

Interaction Model ◽

Fluid Structure ◽

Structure Interaction

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Modeling of aortic valve stenosis using fluid-structure interaction method

Perfusion ◽

10.1177/0267659121998549 ◽

2021 ◽

pp. 026765912199854

Author(s):

Mohammad Javad Ghasemi Pour ◽

Kamran Hassani ◽

Morteza Khayat ◽

Shahram Etemadi Haghighi

Keyword(s):

Blood Flow ◽

Aortic Valve ◽

Fluid Structure Interaction ◽

Three Dimensional ◽

Fluid Structure ◽

Structure Interaction ◽

Relaxation Phase ◽

Exercise Condition ◽

Time Dependent Domain ◽

Comparison Of The Results

Background and objectives: Fluid structure interaction (FSI) is defined as interaction of the structures with contacting fluids. The aortic valve experiences the interaction with blood flow in systolic phase. In this study, we have tried to predict the hemodynamics of blood flow through a normal and stenotic aortic valve in two relaxation and exercise conditions using a three-dimensional FSI method. Methods: The aorta valve was modeled as a three-dimensional geometry including a normal model and two others with 25% and 50% stenosis. The geometry of the aortic valve was extracted from CT images and the models were generated by MMIMCS software and then they were implemented in ANSYS software. The pulsatile flow rate was used for all cases and the numerical simulations were conducted based on a time-dependent domain. Results: The obtained results including the velocity, pressure, and shear stress contours in different systolic time sequences were explained and discussed. The maximum blood flow velocity in relaxation phase was obtained 1.62 m/s (normal valve), 3.78 m/s (25% stenosed valve), and 4.73 m/s (50% stenosed valve). In exercise condition, the maximum velocities are 2.86, 4.32, and 5.42 m/s respectively. The maximum blood pressure in relaxation phase was calculated 111.45 mmHg (normal), 148.66 mmHg (25% stenosed), and 164.21 mmHg (50% stenosed). However, the calculated values in exercise situation were 129.57, 163.58, and 191.26 mmHg. The validation of the predicted results was also conducted using existing literature. Conclusions: We believe that such model are useful tools for biomechanical experts. The further studies should be done using experimental data and the data are implemented on the boundary conditions for better comparison of the results.

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