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Cardiac valve computational fluid dynamics

Jonas Lantz, Lilian Henriksson, Anders Persson, Matts Karlsson, Tino Ebbers
Cardiac hemodynamics can be computed from medical imaging data, and results could potentially aid in cardiac diagnosis and treatment optimization. However, simulations are often based on simplified geometries, ignoring features such as papillary muscles and trabeculae due to their complex shape, limitations in image acquisitions, and challenges in computational modeling. This severely hampers the use of computational fluid dynamics in clinical practice. The overall aim of this study was to develop a novel numerical framework that incorporated these geometrical features...
September 12, 2016: Journal of Biomechanical Engineering
A M Bavo, A M Pouch, J Degroote, J Vierendeels, J H Gorman, R C Gorman, P Segers
BACKGROUND: The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework...
2016: Biomedical Engineering Online
Stefania Scarsoglio, Andrea Saglietto, Fiorenzo Gaita, Luca Ridolfi, Matteo Anselmino
BACKGROUND: Although atrial fibrillation (AF), a common arrhythmia, frequently presents in patients with underlying valvular disease, its hemodynamic contributions are not fully understood. The present work aimed to computationally study how physical conditions imposed by pathologic valvular anatomy act on AF hemodynamics. METHODS: We simulated AF with different severity grades of left-sided valvular diseases and compared the cardiovascular effects that they exert during AF, compared to lone AF...
2016: PeerJ
David C Wendell, Margaret M Samyn, Joseph R Cava, Mary M Krolikowski, John F LaDisa
Advancements in image-based computational modeling are producing increasingly more realistic representations of vasculature and hemodynamics, but so far have not compensated for cardiac motion when imposing inflow boundary conditions. The effect of cardiac motion on aortic flow is important when assessing sequelae in this region including coarctation of the aorta (CoA) or regurgitant fraction. The objective of this investigation was to develop a method to assess and correct for the influence of cardiac motion on blood flow measurements through the aortic valve (AoV) and to determine its impact on patient-specific local hemodynamics quantified by computational fluid dynamics (CFD)...
September 1, 2016: Journal of Biomechanical Engineering
C Chnafa, S Mendez, F Nicoud
Intra-cardiac flow has been explored for decades but there is still no consensus on whether or not healthy left ventricles (LV) may harbour turbulent-like flow despite its potential physiological and clinical relevance. The purpose of this study is to elucidate if a healthy LV could harbour flow instabilities, using image-based computational fluid dynamics (CFD). 35 cardiac cycles were simulated in a patient-specific left heart model obtained from cardiovascular magnetic resonance (CMR). The model includes the valves, atrium, ventricle, papillary muscles and ascending aorta...
April 12, 2016: Annals of Biomedical Engineering
Tomohiro Otani, Abdullah Al-Issa, Amir Pourmorteza, Elliot R McVeigh, Shigeo Wada, Hiroshi Ashikaga
Atrial fibrillation (AF), the most common human arrhythmia, is a marker of an increased risk of embolic stroke. However, recent studies suggest that AF may not be mechanistically responsible for the stroke events. An alternative explanation for the mechanism of intracardiac thrombosis and stroke in patients with AF is structural remodeling of the left atrium (LA). Nevertheless, a mechanistic link between LA structural remodeling and intracardiac thrombosis is unclear, because there is no clinically feasible methodology to evaluate the complex relationship between these two phenomena in individual patients...
March 11, 2016: Annals of Biomedical Engineering
Vittoria Flamini, Abe DeAnda, Boyce E Griffith
It has long been recognized that aortic root elasticity helps to ensure efficient aortic valve closure, but our understanding of the functional importance of the elasticity and geometry of the aortic root continues to e-volve as increasingly detailed in vivo imaging data become available. Herein, we describe a fluid-structure interaction model of the aortic root, including the aortic valve leaflets, the sinsuses of Valsalva, the aortic annulus, and the sinotubular junction, that employs a version of Peskin's immersed boundary (IB) method with a finite element (FE) description of the structural elasticity...
April 2016: Theoretical and Computational Fluid Dynamics
Denis Berdajs, Selim Mosbahi, Zalan Forro, Marco Burki, Ludwig K von Segesser
OBJECTIVES: The aim was to determine 3-dimensional (3D) geometrical deformation of the aortic root (AoR) following the David procedure in order to evaluate local haemodynamical conditions of individual AoR elements. METHODS: In the experimental set-up, the David procedure was performed on 10 domestic pigs. Data were compared with the measurements obtained in 10 native AoRs. In each AoR, six high-resolution ultrasonometric crystals (200 Hz) were implanted, being positioned at each commissure and at the AoR base...
June 2016: European Journal of Cardio-thoracic Surgery
Shelby Kutty, Rahul H Rathod, David A Danford, David S Celermajer
The Fontan operation for single ventricle palliation consists of the creation of a complete cavopulmonary connection, usually by incorporating inferior vena caval flow into a pulmonary arterial circulation already receiving flow from the superior vena cava. In single ventricle palliated in this way, the anatomy is complex, and the pathophysiological complications are frequent; so, cardiac imaging is a key aspect of clinical surveillance. Common problems that echocardiography and MRI may disclose and characterise in the Fontan palliation of single ventricle include obstruction of systemic venous and pulmonary arterial flow, atrioventricular and semilunar valve dysfunction, unintended collateral flow patterns, ventricular dysfunction, aortic arch obstruction, interatrial obstruction, fenestration flow and patch leaks...
February 2016: Heart: Official Journal of the British Cardiac Society
Denis Berdajs, Selim Mosbahi, Zalan Forro, Christof Gerber, Enrico Ferrari, Dominique Charbonnier, Ludwig K von Segesser
OBJECTIVES: The aim was to define the 3-dimensional (3D) geometrical changes of the aortic root and to determine the local shear stress profile of aortic root elements during the cardiac cycle. METHODS: Six sonomicrometric crystals (200 Hz) were implanted into the aortic root of five pigs at the commissures and at the aortic root base (AoB). 3D aortic root deformation including volume, torsion and tilt angle were determined. Geometrical data with measured local flow and pressure conditions was used for computed fluid dynamics modelling of the aortic root...
April 2016: European Journal of Cardio-thoracic Surgery
Denis Berdajs, Selim Mosbahi, Jan Vos, Dominique Charbonnier, Roger Hullin, Ludwig K von Segesser
OBJECTIVES: Repair of the right ventricular outflow tract (RVOT) in paediatric cardiac surgery remains challenging due to the high reoperation rate. Intimal hyperplasia and consequent arteriosclerosis is one of the most important limitation factors for graft durability. Since local shear stress and pressure are predictive elements for intimal hyperplasia and wall degeneration, we sought to determine in an oversized 12-mm RVOT model, with computed fluid dynamics simulation, the local haemodynamical factors that may explain intimal hyperplasia...
August 2015: Interactive Cardiovascular and Thoracic Surgery
Emaddin Kidher, Zhuo Cheng, Omar A Jarral, Declan P O'Regan, Xiao Yun Xu, Thanos Athanasiou
BACKGROUND: The evaluation of any new cardiac valvular prosthesis should go beyond the classical morbidity and mortality rates and involve hemodynamic assessment. As a proof of concept, the objective of this study was to characterise for the first time the hemodynamics and the blood flow profiles at the aortic root in patients implanted with BioValsalva™ composite valve-conduit using comprehensive MRI and computer technologies. METHODS: Four male patients implanted with BioValsalva™ and 2 age-matched normal controls (NC) underwent cardiac magnetic resonance imaging (MRI)...
2014: Journal of Cardiothoracic Surgery
Krishnan B Chandran, Hyunggun Kim
The mitral valve (MV) apparatus consists of the two asymmetric leaflets, the saddle-shaped annulus, the chordae tendineae, and the papillary muscles. MV function over the cardiac cycle involves complex interaction between the MV apparatus components for efficient blood circulation. Common diseases of the MV include valvular stenosis, regurgitation, and prolapse. MV repair is the most popular and most reliable surgical treatment for early MV pathology. One of the unsolved problems in MV repair is to predict the optimal repair strategy for each patient...
June 2015: Annals of Biomedical Engineering
Thilo Noack, Philipp Kiefer, Razvan Ionasec, Ingmar Voigt, Tammaso Mansi, Marcel Vollroth, Michael Hoebartner, Martin Misfeld, Friedrich-Wilhelm Mohr, Joerg Seeburger
The high complexity of the mitral valve (MV) anatomy and function is not yet fully understood. Studying especially the dynamic movement and interaction of MV components to describe MV physiology during the cardiac cycle remains a challenge. Imaging is the key to assessing details of MV disease and to studying the lesion and dysfunction of MV according to Carpentier. With the advances of computational geometrical and biomechanical MV models, improved quantification and characterization of the MV has been realized...
November 2013: Annals of Cardiothoracic Surgery
Brian H Jun, Neelakantan Saikrishnan, Ajit P Yoganathan
A number of clinical, in vitro and computational studies have shown the potential for thromboembolic complications in bileaflet mechanical heart valves (BMHV), primarily due to the complex and unsteady flows in the valve hinges. These studies have focused on quantitative and qualitative parameters such as velocity magnitude, turbulent shear stresses, vortex formation, and platelet activation to identify potential for blood damage. However, experimental characterization of the whole flow fields within the valve hinges has not yet been conducted...
March 2014: Annals of Biomedical Engineering
Juhyun Lee, Mahdi Esmaily Moghadam, Ethan Kung, Hung Cao, Tyler Beebe, Yury Miller, Beth L Roman, Ching-Ling Lien, Neil C Chi, Alison L Marsden, Tzung K Hsiai
Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP) (y1) transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development...
2013: PloS One
Francesco Sturla, Emiliano Votta, Marco Stevanella, Carlo A Conti, Alberto Redaelli
Numerical modeling can provide detailed and quantitative information on aortic root (AR) biomechanics, improving the understanding of AR complex pathophysiology and supporting the development of more effective clinical treatments. From this standpoint, fluid-structure interaction (FSI) models are currently the most exhaustive and potentially realistic computational tools. However, AR FSI modeling is extremely challenging and computationally expensive, due to the explicit simulation of coupled AR fluid dynamics and structural response, while accounting for complex morphological and mechanical features...
December 2013: Medical Engineering & Physics
Trung Bao Le, Fotis Sotiropoulos
We develop a novel large-scale kinematic model for animating the left ventricle (LV) wall and use this model to drive the fluid-structure interaction (FSI) between the ensuing blood flow and a mechanical heart valve prosthesis implanted in the aortic position of an anatomic LV/aorta configuration. The kinematic model is of lumped type and employs a cell-based, FitzHugh-Nagumo framework to simulate the motion of the LV wall in response to an excitation wavefront propagating along the heart wall. The emerging large-scale LV wall motion exhibits complex contractile mechanisms that include contraction (twist) and expansion (untwist)...
July 1, 2013: Journal of Computational Physics
Michael Poullis
Aortic root and valve clots are rare but well described in patients on maximal left ventricular assist device (LVAD) support. We performed a theoretical analysis using computational fluid dynamic analyses in two dimensions to try and ascertain if inflow cannula design/orientation/placement affect aortic root flow dynamics. Two-dimensional computational fluid dynamics using easy CFD-G was performed. The effect of a curved inflow cannula, a straight cannula, and one with a hole in the outer curve was analyzed...
December 2012: Journal of Extra-corporeal Technology
Gil Marom, Hee-Sun Kim, Moshe Rosenfeld, Ehud Raanani, Rami Haj-Ali
A bicuspid aortic valve (BAV) is a congenital cardiac disorder where the valve consists of only two cusps instead of three in a normal tricuspid valve (TAV). Although 97% of BAVs include asymmetric cusps, little or no prior studies investigated the blood flow through physiological three-dimensional BAV and root. This study presents four fully coupled fluid-structure interaction (FSI) models, including native TAV, asymmetric BAV with or without a raphe and an almost symmetric BAV. The FSI simulations are based on coupled structural and fluid dynamics solvers that allow accurate modeling of the pressure load on both the root and the cusps...
2012: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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