Image-based computational hemodynamics analysis of systolic obstruction in hypertrophic cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is a pathological condition characterized by an abnormal thickening of the myocardium. When it affects the medio-basal portion of the septum, it is named Hypertrophic Obstructive Cardiomyopathy because it induces a flow obstruction in the left ventricle outflow tract, which may compromise the cardiac function and possibly lead to cardiac death. In this work, we investigate the hemodynamics of different HCM patients by means of computational hemodynamics, aiming at quantifying the effects of this pathology on blood flow and pressure gradients and thus providing clinical indications that may help diagnosis and the design of surgical treatment (septal myectomy). To this aim, we employ an enhanced version of an image-based computational pipeline proposed in a previous work, integrating fluid dynamics simulations with geometrical and functional data reconstructed from standard cine-MRI acquisitions. Blood flow is modelled as an incompressible Newtonian fluid, The corresponding Navier-Stokes equations are solved in a moving domain obtained from cine-MRI, whereas the valve leaflets are accounted for by a resistive method.

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Image-Based Computational Hemodynamics Analysis of Systolic Obstruction in Hypertrophic Cardiomyopathy

Frontiers in Physiology ◽

10.3389/fphys.2021.787082 ◽

2022 ◽

Vol 12 ◽

Author(s):

Ivan Fumagalli ◽

Piermario Vitullo ◽

Christian Vergara ◽

Marco Fedele ◽

Antonio F. Corno ◽

...

Keyword(s):

Blood Flow ◽

Hypertrophic Cardiomyopathy ◽

Pathological Condition ◽

Ventricular Outflow Tract ◽

Hypertrophic Obstructive Cardiomyopathy ◽

Left Ventricular ◽

Patient Specific ◽

Cine Mri ◽

Septal Myectomy ◽

Blood Flow Dynamics

Hypertrophic Cardiomyopathy (HCM) is a pathological condition characterized by an abnormal thickening of the myocardium. When affecting the medio-basal portion of the septum, it is named Hypertrophic Obstructive Cardiomyopathy (HOCM) because it induces a flow obstruction in the left ventricular outflow tract. In any type of HCM, the myocardial function can become compromised, possibly resulting in cardiac death. In this study, we investigated with computational analysis the hemodynamics of patients with different types of HCM. The aim was quantifying the effects of this pathology on the intraventricular blood flow and pressure gradients, and providing information potentially useful to guide the indication and the modality of the surgical treatment (septal myectomy). We employed an image-based computational approach, integrating fluid dynamics simulations with geometric and functional data, reconstructed from standard cardiac cine-MRI acquisitions. We showed that with our approach we can better understand the patho-physiological behavior of intraventricular blood flow dynamics due to the abnormal morphological and functional aspect of the left ventricle. The main results of our investigation are: (a) a detailed patient-specific analysis of the blood velocity, pressure and stress distribution associated to HCM; (b) a computation-based classification of patients affected by HCM that can complement the current clinical guidelines for the diagnosis and treatment of HOCM.

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Short-term outcomes of surgical atrial ablation and septal myectomy

Patologiya krovoobrashcheniya i kardiokhirurgiya ◽

10.21688/1681-3472-2021-3-51-60 ◽

2021 ◽

Vol 25 (3) ◽

pp. 51

Author(s):

A. S. Zalesov ◽

A. V. Bogachev-Prokophiev ◽

A. V. Afanasyev ◽

R. M. Sharifulin ◽

A. V. Sapegin ◽

...

Keyword(s):

Atrial Fibrillation ◽

Hypertrophic Cardiomyopathy ◽

Sinus Node ◽

Hypertrophic Obstructive Cardiomyopathy ◽

Radiofrequency Energy ◽

Short Term ◽

Surgical Ablation ◽

Septal Myectomy ◽

Atrial Ablation ◽

Obstructive Hypertrophic Cardiomyopathy

Background. Hypertrophic cardiomyopathy is one of the most common types of cardiomyopathy. The appearance of atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy is associated with significant clinical worsening. Outcomes of surgical ablation and septal myectomy in these patients are limited. Aim. This retrospective study aimed to evaluate short-term outcomes of concomitant surgical ablation and septal myectomy in patients with obstructive hypertrophic cardiomyopathy and atrial fibrillation. Methods. Fifty-five patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent concomitant surgical ablation and septal myectomy between 2014 and 2019 were analysed. Patients with paroxysmal atrial fibrillation predominantly underwent left atrial ablation, and those with nonparoxysmal atrial fibrillation predominantly underwent the Maze IV procedure. Surgical ablation was performed using cryoablation alone (83.6%) or in combination with radiofrequency energy (16.4%). Results. Hospital mortality was 1.8%. Incidence of major adverse events was 3.6%. Sinus node dysfunction and atrioventricular block occurred in 7.3% and 1.8% of patients, respectively. Bleeding requiring revision occurred in 2 (3.6%) patients. Forty-nine (89.1%) patients had stable sinus rhythm and five (9.1%) were on dual-chamber pacemaker stimulation at the time of discharge. Conclusion. Concomitant septal myectomy and surgical ablation are feasible and safe in patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation.Received 5 April 2021. Revised 16 May 2021. Accepted 17 May 2021.Funding: The study did not have sponsorship.Conflict of interest: The authors declare no conflicts of interests.Contribution of the authors Conception and study design: A.S. Zalesov, A.V. Bogachev-Prokophiev Data collection and analysis: A.S. Zalesov, S.A. Budagaev, A.V. Sapegin Statistical analysis: A.S. Zalesov, A.V. Afanasyev, R.M. Sharifulin Drafting the article: A.S. Zalesov Critical revision of the article: A.V. Bogachev-Prokophiev, S.I. Zheleznev, I.I. Demin Final approval of the version to be published: A.S. Zalesov, A.V. Bogachev-Prokophiev, A.V. Afanasyev, R.M. Sharifulin, A.V. Sapegin, S.A. Budagaev, S.I. Zheleznev, I.I. Demin

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Numerical investigation of a small water turbine used for the power supply of underwater vehicles

Advances in Mechanical Engineering ◽

10.1177/1687814018783654 ◽

2018 ◽

Vol 10 (6) ◽

pp. 168781401878365 ◽

Cited By ~ 3

Author(s):

Zhaoyong Mao ◽

Jingang Bai

Keyword(s):

Stokes Equations ◽

Underwater Vehicles ◽

Geometric Parameters ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Sliding Mesh ◽

Small Water ◽

Water Turbine ◽

Computational Fluid Dynamics Simulations ◽

Dynamics Simulations

The development of underwater vehicles is facing the problem of sustainable energy supply. This study introduces a small water turbine, the Lenz turbine, for energy generation from the ocean currents which will provide energy for the underwater vehicles. Computational fluid dynamics simulations of the effect of geometric parameters, including the blade radius, chord length, and pitch angle, on the performance of the turbine are conducted. The Reynolds-Averaged Navier–Stokes equations are numerically solved with a sliding mesh method. Thirteen sets of tests in total are performed at different values of tip-speed ratios. The tests are divided into three groups to study the effect of the three parameters mentioned above, separately. The obtained power coefficients, coefficient of torque, and the dynamic torque on a blade are then compared in each group of tests. Pressure contours and velocity contours are given to explain the reason how the geometric parameters affect the rotor performance.

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Modelling and Analysis of Complex Viscous Fluid in Thin Elastic Tubes

Complexity ◽

10.1155/2020/9256845 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Yufang Gao ◽

Zongguo Zhang

Keyword(s):

Cardiovascular Disease ◽

Blood Flow ◽

Viscous Fluid ◽

Boussinesq Equation ◽

Stokes Equations ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Viscous Term ◽

Thin Tube ◽

Elastic Tubes

Cardiovascular disease is a major threat to human health. The study on the pathogenesis and prevention of cardiovascular disease has received special attention. In this paper, we have contributed to the derivation of a mathematical model for the nonlinear waves in an artery. From the Navier–Stokes equations and continuity equation, the vorticity equation satisfied by the blood flow is established. And based on the multiscale analysis and perturbation method, a new model of the Boussinesq equation with viscous term is derived to describe the propagation of a viscous fluid through a thin tube. In order to be more consistent with the flow of the fluid, the time-fractional Boussinesq equation with viscous term is deduced by employing the semi-inverse method and the fractional variational principle. Moreover, the approximate analytical solution of the fractional equation is obtained, and the effect of viscosity on the amplitude and width of the wave is studied. Finally, the effects of the fractional order parameters and vessel radius on blood flow volume are discussed and analyzed.

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A new approach to the assessment of outcomes of alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

Patologiya krovoobrashcheniya i kardiokhirurgiya ◽

10.21688/1681-3472-2013-3-46-49 ◽

2015 ◽

Vol 17 (2) ◽

pp. 46

Author(s):

A. G. Osiev ◽

Ye. I. Kretov ◽

V. P. Kurbatov ◽

S. P. Mironenko ◽

R. A. Naydenov ◽

...

Keyword(s):

Hypertrophic Cardiomyopathy ◽

Interventricular Septum ◽

Hypertrophic Obstructive Cardiomyopathy ◽

Left Ventricular ◽

Alcohol Septal Ablation ◽

New Approach ◽

Surgical Interventions ◽

Septal Myectomy ◽

Left Ventricular Output ◽

Cardiac Disorders

Hypertrophic cardiomyopathy is a heterogeneous disease characterized by myocardial hypertrophy, without any other systemic or cardiac disorders and with predominant involvement of the interventricular septum. Approximately 25% of patients have a dynamic obstruction of the left ventricular output tract due its constriction and abnormal systolic anterior motion of the mitral valve. Therapeutic strategy for patients with hypertrophic obstructive cardiomyopathy, who remain symptomatic despite drug therapy, includes surgery (septal myectomy) and non-surgical interventions, such as alcohol septal ablation. In the present study the possibility of cardiac MRI with contrast enhancement in the evaluation of the results of endovascular treatment hypertrophic cardiomyopathy and evidence for the benefits of this method in 25 patients with an obstructive form of hypertrophic cardiomyopathy after alcohol septal ablation are discussed.

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Study of the Dynamic and Thermal Behaviors of an Air Flow in a T-Bifurcation

Journal of Heat Transfer ◽

10.1115/1.4040481 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 1

Author(s):

Ali Riahi ◽

Julien Pelle ◽

Lilia Chouchene ◽

Souad Harmand ◽

Sadok Ben Jabrallah

Keyword(s):

Heat Transfer ◽

Stokes Equations ◽

Initial Conditions ◽

Research Work ◽

Internal Surface ◽

Numerical Approach ◽

Navier Stokes ◽

Flow Ratio ◽

Sst Turbulence Model ◽

Dynamics Simulations

This paper presents a numerical and experimental study of a turbulent flow of air in a T-bifurcation. This configuration corresponds to a stator containing radial vents oriented vertically to the rotor–stator air gap in electrical machines. Our analysis focuses on the local convective heat transfer over the internal surface of the vents under a turbulent mass flow rate. To model the cooling installation in this region, computational fluid dynamics simulations and an experiment using particle image velocimetry (PIV) are performed. The resulting flow generally produces recirculation zones in various channels. The effect of the flow ratio and diameter of the bifurcation on the dynamic and thermal behavior of the flow is also examined. In this study, we apply a numerical approach based on the k–ω shear stress transport (SST) turbulence model (using the commercial software, “comsolmultiphysics”) to numerically solve the Navier–Stokes equations and energy equation of the system under consideration. We describe the different hypotheses necessary to formulate the equations governing the problem, initial conditions, and boundary condition. The velocity in the bifurcation calculated using the simulation is compared with that obtained by the experiment and it reveals a good agreement. The effect of the branch diameter of the bifurcation and flow ratio on the heat transfer is specifically analyzed in this research work.

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A Parallel Domain Decomposition Algorithm for Simulating Blood Flow with Incompressible Navier-Stokes Equations with Resistive Boundary Condition

Communications in Computational Physics ◽

10.4208/cicp.060510.150511s ◽

2012 ◽

Vol 11 (4) ◽

pp. 1279-1299

Author(s):

Yuqi Wu ◽

Xiao-Chuan Cai

Keyword(s):

Boundary Condition ◽

Blood Flow ◽

Domain Decomposition ◽

Stokes Equations ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Outflow Boundary Condition ◽

Outflow Boundary ◽

Domain Decomposition Algorithm ◽

Fully Coupled

AbstractWe introduce and study a parallel domain decomposition algorithm for the simulation of blood flow in compliant arteries using a fully-coupled system of nonlinear partial differential equations consisting of a linear elasticity equation and the incompressible Navier-Stokes equations with a resistive outflow boundary condition. The system is discretized with a finite element method on unstructured moving meshes and solved by a Newton-Krylov algorithm preconditioned with an overlapping restricted additive Schwarz method. The resistive outflow boundary condition plays an interesting role in the accuracy of the blood flow simulation and we provide a numerical comparison of its accuracy with the standard pressure type boundary condition. We also discuss the parallel performance of the implicit domain decomposition method for solving the fully coupled nonlinear system on a supercomputer with a few hundred processors.

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Structured tree outflow condition for blood flow in larger systemic arteries

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1999.276.1.h257 ◽

1999 ◽

Vol 276 (1) ◽

pp. H257-H268 ◽

Cited By ~ 125

Author(s):

Mette S. Olufsen

Keyword(s):

Boundary Condition ◽

Blood Flow ◽

Stokes Equations ◽

Navier Stokes ◽

Phase Lag ◽

Tree Model ◽

Arterial Tree ◽

Windkessel Model ◽

Navier Stokes Equations ◽

Systemic Arteries

A central problem in modeling blood flow and pressure in the larger systemic arteries is determining a physiologically based boundary condition so that the arterial tree can be truncated after a few generations. We have used a structured tree attached to the terminal branches of the truncated arterial tree in which the root impedance is estimated using a semianalytical approach based on a linearization of the viscous axisymmetric Navier-Stokes equations. This provides a dynamic boundary condition that maintains the phase lag between blood flow and pressure as well as the high-frequency oscillations present in the impedance spectra. Furthermore, it accommodates the wave propagation effects for the entire systemic arterial tree. The result is a model that is physiologically adequate as well as computationally feasible. For validation, we have compared the structured tree model with a pure resistance and a windkessel model as well as with measured data.

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A multiscale model of thrombus development

Journal of The Royal Society Interface ◽

10.1098/rsif.2007.1202 ◽

2007 ◽

Vol 5 (24) ◽

pp. 705-722 ◽

Cited By ~ 112

Author(s):

Zhiliang Xu ◽

Nan Chen ◽

Malgorzata M Kamocka ◽

Elliot D Rosen ◽

Mark Alber

Keyword(s):

Blood Flow ◽

Stokes Equations ◽

Blood Flow Rate ◽

Multiscale Model ◽

Navier Stokes ◽

Cellular Potts Model ◽

Navier Stokes Equations ◽

Activated Platelets ◽

Preliminary Experimental Data ◽

The One

A two-dimensional multiscale model is introduced for studying formation of a thrombus (clot) in a blood vessel. It involves components for modelling viscous, incompressible blood plasma; non-activated and activated platelets; blood cells; activating chemicals; fibrinogen; and vessel walls and their interactions. The macroscale dynamics of the blood flow is described by the continuum Navier–Stokes equations. The microscale interactions between the activated platelets, the platelets and fibrinogen and the platelets and vessel wall are described through an extended stochastic discrete cellular Potts model. The model is tested for robustness with respect to fluctuations of basic parameters. Simulation results demonstrate the development of an inhomogeneous internal structure of the thrombus, which is confirmed by the preliminary experimental data. We also make predictions about different stages in thrombus development, which can be tested experimentally and suggest specific experiments. Lastly, we demonstrate that the dependence of the thrombus size on the blood flow rate in simulations is close to the one observed experimentally.

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STENOSIS EFFECTS ON THE FLUID MECHANICS OF THE COMMON CAROTID ARTERY BIFURCATION FOR UNSTEADY FLOWS

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519415400084 ◽

2015 ◽

Vol 15 (02) ◽

pp. 1540008 ◽

Cited By ~ 2

Author(s):

N. ANTONOVA ◽

D. XU ◽

I. VELCHEVA ◽

E. KALIVIOTIS ◽

P. TOSHEVA

Keyword(s):

Blood Flow ◽

Carotid Artery ◽

Common Carotid Artery ◽

Stokes Equations ◽

Unsteady Flows ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Computational Fluid Dynamics Cfd ◽

The Common ◽

Detailed Picture

The time-varying blood flow in the common carotid artery (CCA) bifurcation is numerically studied on the basis of Navier-Stokes equations for four different cases, including cases with stenoses at different sites in the vicinity of the bifurcation. The cases studied were: (a) without stenoses, (b) with one stenosis upstream the bifurcation, (c) with two opposite stenoses upstream the bifurcation and (d) with an additional stenosis on the apex of the bifurcation. The mesh was generated via a geometry reconstruction and imported into a computational fluid dynamics (CFD) solver. The numerical results of the blood flow in the CCA bifurcation gave a detailed picture of the axial velocity and presented as velocity and vorticity magnitudes. More specifically, it was observed that the appearance of stenotic regions upstream the bifurcation affect both the velocity and vorticity characteristics, whereas a stenoses on the apex of the bifurcation seems to have a small effect on the vorticity characteristics downstream the flow.

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