Image-Derived Human Left Ventricular Modelling with Fluid-Structure Interaction

2015 ◽  
pp. 321-329 ◽  
Author(s):  
Hao Gao ◽  
Colin Berry ◽  
Xiaoyu Luo
Keyword(s):  
Fluid Structure Interaction ◽  
Left Ventricular ◽  
Fluid Structure ◽  
Structure Interaction

Fluid-Structure Interaction Simulation of Blood Flow Inside a Diseased Left Ventricle With Obstructive Hypertrophic Cardiomyopathy in Early Systole

2009 ◽  
Author(s):  
Ahmad Moghaddaszade-Kermani ◽  
Peter Oshkai ◽  
Afzal Suleman
Keyword(s):  
Blood Flow ◽  
Hypertrophic Cardiomyopathy ◽  
Left Ventricle ◽  
Fluid Structure Interaction ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Systolic Phase

Mitral-Septal contact has been proven to be the cause of obstruction in the left ventricle with hypertrophic cardiomyopathy (HC). This paper presents a study on the fluid mechanics of obstruction using two-way loosely coupled fluid-structure interaction (FSI) methodology. A parametric model for the geometry of the diseased left ventricular cavity, myocardium and mitral valve has been developed, using the dimensions extracted from magnetic resonance images. The three-element Windkessel model [1] was modified for HC and solved to introduce pressure boundary condition to the aortic aperture in the systolic phase. The FSI algorithm starts at the beginning of systolic phase by applying the left ventricular pressure to the internal surface of the myocardium to contract the muscle. The displacements of the myocardium and mitral leaflets were calculated using the nonlinear finite element hyperelastic model [2] and subsequently transferred to the fluid domain. The fluid mesh was moved accordingly and the Navier-Stokes equations were solved in the laminar regime with the new mesh using the finite volume method. In the next time step, the left ventricular pressure was increased to contract the muscle further and the same procedure was repeated for the fluid solution. The results show that blood flow jet applies a drag force to the mitral leaflets which in turn causes the leaflet to deform toward the septum thus creating a narrow passage and possible obstruction.

Fluid-Structure Interaction Modeling and Validation of Idealized Left Ventricular Blood Flow

2020 ◽  
Author(s):  
Megan Laughlin ◽  
Sam Stephens ◽  
Hanna Jensen ◽  
Morten Jensen ◽  
Paul Millett
Keyword(s):  
Blood Flow ◽  
Fluid Structure Interaction ◽  
Flow Analysis ◽  
Left Ventricular ◽  
Maximum Pressure ◽  
Flow Loop ◽  
Fluid Structure ◽  
Pressure Drops ◽  
Structure Interaction ◽  
Custom Made

Abstract Fluid Structure Interaction (FSI) models are an essential tool in understanding the complex coupling of blood flow in the heart. The objective of this study is to establish a method of comparing data obtained from FSI models and benchtop measurements from phantoms to identify sources of flow changes for use in intraventricular flow analysis. Two geometries are considered: 1) a vascular model consisting of a straight channel with an ellipsoidal swell and 2) an idealized left ventricle (LV) model representative “acorn” shape. Two phantoms are created for each of the two geometries: 3D printed rigid phantoms from a resin and custom-made tissue-mimicking phantoms from a medical gel. Benchtop measurements are made using the phantoms within a custom flow loop setup with pulsatile flow. Computational Fluid Dynamics (CFD) simulations are conducted with a Smoothed Particle Hydrodynamics (SPH) model. The two flow channel geometries utilized in the experiments are replicated for the simulations. The cavity walls are defined by ghost particles that are rigidly fixed. Maximum pressure drops were 57 mmHg and 196 mmHg for the rigid swell and rigid LV, respectively, whereas maximum pressure drops were 155 mmHg for the gel swell and 140 mmHg for the gel LV. Calculations from the simulations resulted in a maximum pressure drop of 55 mmHg for the swell and 110 mmHg for the LV. This data serves as a first step in corroborating our methodology to utilize the information obtained from both methods to identify and better understand mutual sources of changes in flow patterns.

Computational Modeling for Fluid–Structure Interaction of Bioprosthetic Heart Valve with Different Suture Density: Comparison with Dynamic Structure Simulation

2017 ◽  
Vol 31 (11) ◽  
pp. 1757007 ◽  
Author(s):  
Z. C. Wang ◽  
Q. Yuan ◽  
H. W. Zhu ◽  
B. S. Shen ◽  
D. Tang
Keyword(s):  
Computational Modeling ◽  
Principal Stress ◽  
Heart Valve ◽  
Fluid Structure Interaction ◽  
Dynamic Structure ◽  
Left Ventricular ◽  
Bioprosthetic Heart Valve ◽  
Fluid Structure ◽  
Maximum Deformation ◽  
Structure Interaction

In this paper, a parametric geometry model based on elliptic and conic surfaces was developed for bioprosthetic heart valve (BHV) simulation. The valve material was modeled by a hyperelastic nonlinear anisotropic solid model. Different suture densities could be substituted by various bonded points between artery vessel and the leaflets as boundary conditions in the computational modeling. Besides these two assumptions that dynamic structure (DS) and fluid–structure interaction (FSI) both shared, the latter need incompressible viscous Newton fluid model to depict bloodstream passing through the BHV. Immersed boundary (IB) method was introduced to solve the FSI simulation. In addition, the DS analysis applied transvalvular pressure on the valve while FSI had left ventricular pressure on fluid inlet as initials. There was inconsistency between the moments of the maximum deformation and the maximum loading in both simulations. Although a similar trend of deformation lagging the load was viewed, the extent of delay in FSI was much smaller compared with that in DS simulation. The deformed profiles in cross-sectional views were shown in one picture to illustrate different dynamic responses caused by distinct assumptions. Percent of open area at the moments when the maximum deformation occurred was defined to show which calculation achieved better approximation for precise hemodynamics. Fixed point was given as boundaries between BHV and artery in the modeling part. Calculations showed that the more the fixed points in this bonded contact, the lower the principal stress was. The maximum shear stress showed a different trend. It had a different trend. Stress concentration in the conjunction area made it high-risk to be teared. Different suture densities had significant impaction in FSI simulations. With that analysis our work achieved a more comprehensive simulation to describe true hemodynamics of a BHV implanted in artery. The artery vessel had particular dynamic response under such assumptions, gradient existed in the maximum principal stress distribution diagram, from inner wall through which blood passing to the outer wall. Results showed a large suture density was suggested in BHV implantation.

Investigation of the Blood Flow and Mitral-Septal Opposition in the Left Ventricle With the Obstructive Hyperthrophic Cardiomyopathy During Systole Using Fluid-Structure Interaction Technique

2010 ◽  
Author(s):  
Ahmad Moghaddaszade Kermani ◽  
Afzal Suleman
Keyword(s):  
Blood Flow ◽  
Mitral Valve ◽  
Left Ventricle ◽  
Fluid Structure Interaction ◽  
Left Ventricular ◽  
Anterior Leaflet ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Narrow Passage ◽  
Aortic Orifice

In this article, fluid-structure interaction methodology was used to analyze the blood flow and Mitral-Septal opposition in the Left ventricle with the Obstructive Hyperthrophic Cardiomyopathy (OHCM). The geometry of the computational model includes the diseased left ventricle with thickened septum and Mitral valve. A semi-ellipsoidal geometry was developed with the dimensions, extracted from MR images of the diseased left ventricle. Also, the geometry of the Mitral valve was created using anatomical data provided in literature [1]. The three element Windkessel model and atrial pressure [2, 3] were used to introduce mass flow and pressure boundary conditions to the aortic orifice and left atrium respectively. Effect of the fibers was taken into account by varying the Young’s modulus of the mitral valve tissue with circumferential and radial coordinates. The fluid-structure interaction algorithm started at the beginning of the systole (when the mitral valve is fully open with zero stress) by applying the left ventricular pressure on the left ventricular wall and aortic mass flow outlet on the aortic orifice. The Navier-Stokes equations were solved with SIMPLE algorithm and finite volume method to calculate the blood flow inside the diseased left ventricle. The calculated pressure was applied to the surface of the mitral valve and the structural model of the tissue was solved using non-linear finite element. The deformation of the mitral valve was transferred to the blood by moving the fluid mesh. In the next time step, the same procedure was repeated with the new mesh. This algorithm was followed up to the end of the systole. The thickened septum creates a narrow passage for the blood flowing out of the left ventricle, thus a jet of blood flow is developed in this narrow passage which applies high shear stress on the anterior leaflet of the mitral valve. The drag force deforms the anterior leaflet toward the septum, obstructing the blood flow rushing toward the aortic orifice.

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