BACKGROUND: Systolic blood flow has been simulated in the abdominal aorta and the superior mesent... more BACKGROUND: Systolic blood flow has been simulated in the abdominal aorta and the superior mesenteric artery. The simulations were carried out using two different computational hemodynamic methods: the finite element method to solve the Navier Stokes equations and the lattice Boltzmann method. RESULTS: We have validated the lattice Boltzmann method for systolic flows by comparing the velocity and pressure profiles of simulated blood flow between methods. We have also analyzed flow-specific ...
www.complex-automata.org A simplified description of the system in terms of relevant scales is dr... more www.complex-automata.org A simplified description of the system in terms of relevant scales is drawn in fig. 1. A model for Smooth Muscle Cell growth (slowest time scale) is coupled to the more rapid blood flow. A diffusion model acting on an intermediate time scale can be used to take into account drug release from an eluting stent. Acknowledgements: COAST is funded by the European Union under EU-FP6-IST-FET Contract 033664. Universiteit van Amsterdam
Vascular stent deployment in peripheral arteries is a medical intervention in which a wire mesh t... more Vascular stent deployment in peripheral arteries is a medical intervention in which a wire mesh tube is inserted into the artery to provide internal support. However, stents positioned in locations such as the femoral artery are subject to cyclic bending, and are therefore at risk of fatigue fracture. A software tool chain, called AimaSimul, is being implemented to support stent modeling, surgical simulation and risk calculation for surgical planning. In particular, the AimaSimul preoperative planning tool allows clinicians, starting from patient-specific medical images, to interactively assess different stent models and deployment options for the risk of breakage. This paper describes the main functionalities of AimaSimul and, in particular, the stent deployment and deformation.
PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text ... more PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon. Simulations of time harmonic blood flow in the Mesenteric artery: comparing finite element and lattice Boltzmann methods
More than 5000 artificial heart valves are implanted each year in the United Kingdom. About three... more More than 5000 artificial heart valves are implanted each year in the United Kingdom. About three quarters are mechanical 1 and about two thirds are implanted in:the aortic position. Echocardiography is universally used to confirm normal fuction or to detect and quantify dysfunction of the valve. Because of shielding it is more difficult to study artificial valves than native valves and the results are harder to interpret because there is no clearcut distinction between normal and abnormal function: all valves are stenotic compared with normal native valves. In addition artificial valves (table 1) have different orifice characteristics, downstream flow profiles, and patterns of physiological regurgitation: experience gained with one type cannot necessarily be applied to another
There are a number of difficulties confronting the regulation of human tissue engineered products... more There are a number of difficulties confronting the regulation of human tissue engineered products, from the scientific, ethical and legal perspectives. Many of these issues are international in scope and any responses must consider the global implications of marketing and monitoring these products. The article argues that as tissue engineered products become more available regulatory authorities should not be pressured into adopting possibly inappropriate measures, but must consider all the factors relevant to human health, including the need for innovative regulatory mechanisms as well as innovative tissue products themselves.
Journal of Thoracic and Cardiovascular Surgery - J THORAC CARDIOVASC SURG, 2003
ObjectivesNominal size remains the standard by which valves are compared, but its relationship wi... more ObjectivesNominal size remains the standard by which valves are compared, but its relationship with orifice area and the patient tissue annulus diameter may differ according to valve design. The aims of this study were to measure the orifice size and compare biologic equivalence in six bileaflet mechanical heart valve designs.
To better understand the flow pattern and the mechanical environment induced by the single leafle... more To better understand the flow pattern and the mechanical environment induced by the single leaflet mechanical heart valves, both experimental and theoretical studies have been conducted. A pulse duplicator was used for driving two mechanical heart valves (Medtronic Hall and Omniscience) and a high speed video camera (500 frames per second) tracked their motion. Several tests, at different heart rates
BACKGROUND: Systolic blood flow has been simulated in the abdominal aorta and the superior mesent... more BACKGROUND: Systolic blood flow has been simulated in the abdominal aorta and the superior mesenteric artery. The simulations were carried out using two different computational hemodynamic methods: the finite element method to solve the Navier Stokes equations and the lattice Boltzmann method. RESULTS: We have validated the lattice Boltzmann method for systolic flows by comparing the velocity and pressure profiles of simulated blood flow between methods. We have also analyzed flow-specific ...
www.complex-automata.org A simplified description of the system in terms of relevant scales is dr... more www.complex-automata.org A simplified description of the system in terms of relevant scales is drawn in fig. 1. A model for Smooth Muscle Cell growth (slowest time scale) is coupled to the more rapid blood flow. A diffusion model acting on an intermediate time scale can be used to take into account drug release from an eluting stent. Acknowledgements: COAST is funded by the European Union under EU-FP6-IST-FET Contract 033664. Universiteit van Amsterdam
Vascular stent deployment in peripheral arteries is a medical intervention in which a wire mesh t... more Vascular stent deployment in peripheral arteries is a medical intervention in which a wire mesh tube is inserted into the artery to provide internal support. However, stents positioned in locations such as the femoral artery are subject to cyclic bending, and are therefore at risk of fatigue fracture. A software tool chain, called AimaSimul, is being implemented to support stent modeling, surgical simulation and risk calculation for surgical planning. In particular, the AimaSimul preoperative planning tool allows clinicians, starting from patient-specific medical images, to interactively assess different stent models and deployment options for the risk of breakage. This paper describes the main functionalities of AimaSimul and, in particular, the stent deployment and deformation.
PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text ... more PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon. Simulations of time harmonic blood flow in the Mesenteric artery: comparing finite element and lattice Boltzmann methods
More than 5000 artificial heart valves are implanted each year in the United Kingdom. About three... more More than 5000 artificial heart valves are implanted each year in the United Kingdom. About three quarters are mechanical 1 and about two thirds are implanted in:the aortic position. Echocardiography is universally used to confirm normal fuction or to detect and quantify dysfunction of the valve. Because of shielding it is more difficult to study artificial valves than native valves and the results are harder to interpret because there is no clearcut distinction between normal and abnormal function: all valves are stenotic compared with normal native valves. In addition artificial valves (table 1) have different orifice characteristics, downstream flow profiles, and patterns of physiological regurgitation: experience gained with one type cannot necessarily be applied to another
There are a number of difficulties confronting the regulation of human tissue engineered products... more There are a number of difficulties confronting the regulation of human tissue engineered products, from the scientific, ethical and legal perspectives. Many of these issues are international in scope and any responses must consider the global implications of marketing and monitoring these products. The article argues that as tissue engineered products become more available regulatory authorities should not be pressured into adopting possibly inappropriate measures, but must consider all the factors relevant to human health, including the need for innovative regulatory mechanisms as well as innovative tissue products themselves.
Journal of Thoracic and Cardiovascular Surgery - J THORAC CARDIOVASC SURG, 2003
ObjectivesNominal size remains the standard by which valves are compared, but its relationship wi... more ObjectivesNominal size remains the standard by which valves are compared, but its relationship with orifice area and the patient tissue annulus diameter may differ according to valve design. The aims of this study were to measure the orifice size and compare biologic equivalence in six bileaflet mechanical heart valve designs.
To better understand the flow pattern and the mechanical environment induced by the single leafle... more To better understand the flow pattern and the mechanical environment induced by the single leaflet mechanical heart valves, both experimental and theoretical studies have been conducted. A pulse duplicator was used for driving two mechanical heart valves (Medtronic Hall and Omniscience) and a high speed video camera (500 frames per second) tracked their motion. Several tests, at different heart rates
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