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Computational fluid dynamics of coronary flow

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https://www.readbyqxmd.com/read/28542193/an-agent-based-model-of-leukocyte-transendothelial-migration-during-atherogenesis
#1
Rita Bhui, Heather N Hayenga
A vast amount of work has been dedicated to the effects of hemodynamics and cytokines on leukocyte adhesion and trans-endothelial migration (TEM) and subsequent accumulation of leukocyte-derived foam cells in the artery wall. However, a comprehensive mechanobiological model to capture these spatiotemporal events and predict the growth and remodeling of an atherosclerotic artery is still lacking. Here, we present a multiscale model of leukocyte TEM and plaque evolution in the left anterior descending (LAD) coronary artery...
May 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28511838/supra-annular-valve-in-valve-implantation-reduces-blood-stasis-on-the-transcatheter-aortic-valve-leaflets
#2
Koohyar Vahidkhah, Ali N Azadani
Leaflet thrombosis following transcatheter aortic valve replacement (TAVR) and Valve-in-Valve (ViV) procedures has been increasingly recognized. This study aimed to investigate the effect of positioning of the transcatheter aortic valve (TAV) in ViV setting on the flow dynamics aspect of post-ViV thrombosis by quantifying the blood stasis in the intra-annular and supra-annular settings. To that end, two idealized computational models, representing ViV intra-annular and supra-annular positioning of a TAV were developed in a patient-specific geometry...
May 5, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28506646/virtual-resting-pd-pa-from-coronary-angiography-and-blood-flow-modelling-diagnostic-performance-against-fractional-flow-reserve
#3
Michail I Papafaklis, Takashi Muramatsu, Yuki Ishibashi, Christos V Bourantas, Dimitrios I Fotiadis, Emmanouil S Brilakis, Héctor M Garcia-Garcia, Javier Escaned, Patrick W Serruys, Lampros K Michalis
BACKGROUND: Fractional flow reserve (FFR) has been established as a useful diagnostic tool. The distal coronary pressure to aortic pressure (Pd/Pa) ratio at rest is a simpler physiologic index but also requires the use of the pressure wire, whereas recently proposed virtual functional indices derived from coronary imaging require complex blood flow modelling and/or are time-consuming. Our aim was to test the diagnostic performance of virtual resting Pd/Pa using routine angiographic images and a simple flow model...
May 3, 2017: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/28500478/effect-of-stenosis-eccentricity-on-the-functionality-of-coronary-bifurcation-lesions-a-numerical-study
#4
Catherine Pagiatakis, Jean-Claude Tardif, Philippe L L'Allier, Rosaire Mongrain
Interventional cardiologists still rely heavily on angiography for the evaluation of coronary lesion severity, despite its poor correlation with the presence of ischemia. In order to improve the accuracy of the current diagnostic procedures, an understanding of the relative influence of geometric characteristics on the induction of ischemia is required. This idea is especially important for coronary bifurcation lesions (CBLs), whose treatment is complex and is associated with high rates of peri- and post-procedural clinical events...
May 13, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28500311/optimisation-of-a-novel-spiral-inducing-bypass-graft-using-computational-fluid-dynamics
#5
Andres Ruiz-Soler, Foad Kabinejadian, Mark A Slevin, Paulo J Bartolo, Amir Keshmiri
Graft failure is currently a major concern for medical practitioners in treating Peripheral Vascular Disease (PVD) and Coronary Artery Disease (CAD). It is now widely accepted that unfavourable haemodynamic conditions play an essential role in the formation and development of intimal hyperplasia, which is the main cause of graft failure. This paper uses Computational Fluid Dynamics (CFD) to conduct a parametric study to enhance the design and performance of a novel prosthetic graft, which utilises internal ridge(s) to induce spiral flow...
May 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28483152/blood-stasis-on-transcatheter-valve-leaflets-and-implications-for-valve-in-valve-leaflet-thrombosis
#6
Koohyar Vahidkhah, Shahnaz Javani, Mostafa Abbasi, Peyman N Azadani, Anwar Tandar, Danny Dvir, Ali N Azadani
BACKGROUND: Leaflet thrombosis after valve-in-valve (ViV) procedure has been increasingly recognized. This study aimed to investigate the flow dynamics aspect of leaflet thrombosis by quantifying the blood stasis on the noncoronary and coronary leaflets of a surgical aortic valve (SAV) and a transcatheter aortic valve (TAV) in a ViV setting. METHODS: Two computational models, representing a SAV and a TAV in ViV setting, were developed in a patient-specific geometry...
May 5, 2017: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/28457603/healthy-and-diseased-coronary-bifurcation-geometries-influence-near-wall-and-intravascular-flow-a-computational-exploration-of-the-hemodynamic-risk
#7
Claudio Chiastra, Diego Gallo, Paola Tasso, Francesco Iannaccone, Francesco Migliavacca, Jolanda J Wentzel, Umberto Morbiducci
Local hemodynamics has been identified as one main determinant in the onset and progression of atherosclerotic lesions at coronary bifurcations. Starting from the observation that atherosensitive hemodynamic conditions in arterial bifurcation are majorly determined by the underlying anatomy, the aim of the present study is to investigate how peculiar coronary bifurcation anatomical features influence near-wall and intravascular flow patterns. Different bifurcation angles and cardiac curvatures were varied in population-based, idealized models of both stenosed and unstenosed bifurcations, representing the left anterior descending (LAD) coronary artery with its diagonal branch...
April 20, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28407768/a-study-of-noninvasive-fractional-flow-reserve-derived-from-a-simplified-method-based-on-coronary-computed-tomography-angiography-in-suspected-coronary-artery-disease
#8
Changzheng Shi, Dong Zhang, Kunlin Cao, Tao Zhang, Liangping Luo, Xin Liu, Heye Zhang
BACKGROUND: The invasive fractional flow reserve has been considered the gold standard for identifying ischaemia-related stenosis in patients with suspected coronary artery disease. Determining non-invasive FFR based on coronary computed tomographic angiography datasets using computational fluid dynamics tends to be a demanding process. Therefore, the diagnostic performance of a simplified method for the calculation of FFRCTA requires further evaluation. OBJECTIVES: The aim of this study was to investigate the diagnostic performance of FFRCTA calculated based on a simplified method by referring to the invasive FFR in patient-specific coronary arteries and clinical decision-making...
April 14, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28349764/computational-fluid-dynamics-study-of-common-stent-models-inside-idealised-curved-coronary-arteries
#9
Winson X Chen, Eric K W Poon, Nicholas Hutchins, Vikas Thondapu, Peter Barlis, Andrew Ooi
The haemodynamic behaviour of blood inside a coronary artery after stenting is greatly affected by individual stent features as well as complex geometrical properties of the artery including tortuosity and curvature. Regions at higher risk of restenosis, as measured by low wall shear stress (WSS < 0.5 Pa), have not yet been studied in detail in curved stented arteries. In this study, three-dimensional computational modelling and computational fluid dynamics methodologies were used to analyse the haemodynamic characteristics in curved stented arteries using several common stent models...
May 2017: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/28324943/overcoming-spatio-temporal-limitations-using-dynamically-scaled-in-vitro-pc-mri-a-flow-field-comparison-to-true-scale-computer-simulations-of-idealized-stented-and-patient-specific-left-main-bifurcations
#10
Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan
The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226721/overcoming-spatio-temporal-limitations-using-dynamically-scaled-in-vitro-pc-mri-a-flow-field-comparison-to-true-scale-computer-simulations-of-idealized-stented-and-patient-specific-left-main-bifurcations
#11
Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan, Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan, Stuart Norris, Brett Cowan, Pau Medrano-Gracia, Kathleen Gilbert, Mark Webster, Alistair Young, Susann Beier, John Cater, John Ormiston
The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28220273/numerical-and-experimental-investigations-of-the-flow-pressure-relation-in-multiple-sequential-stenoses-coronary-artery
#12
S Li, Cheng Chin, Vikas Thondapu, Eric K W Poon, Jason P Monty, Yingguang Li, Andrew S H Ooi, Shengxian Tu, Peter Barlis
Virtual fractional flow reserve (vFFR) has been evaluated as an adjunct to invasive fractional flow reserve (FFR) in the light of its operational and economic benefits. The accuracy of vFFR and the complexity of hyperemic flow simulation are still not clearly understood. This study investigates the flow-pressure relation in an idealised multiple sequential stenoses coronary artery model via numerical and experimental approaches. Pressure drop is linearly correlated with flow rate irrespective of the number of stenosis...
February 20, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28148771/oscillatory-wall-shear-stress-is-a-dominant-flow-characteristic-affecting-lesion-progression-patterns-and-plaque-vulnerability-in-patients-with-coronary-artery-disease
#13
Lucas H Timmins, David S Molony, Parham Eshtehardi, Michael C McDaniel, John N Oshinski, Don P Giddens, Habib Samady
Although experimental studies suggest that low and oscillatory wall shear stress (WSS) promotes plaque transformation to a more vulnerable phenotype, this relationship has not been examined in human atherosclerosis progression. Thus, the aim of this investigation was to examine the association between oscillatory WSS, in combination with WSS magnitude, and coronary atherosclerosis progression. We hypothesized that regions of low and oscillatory WSS will demonstrate progression towards more vulnerable lesions, while regions exposed to low and non-oscillatory WSS will exhibit progression towards more stable lesions...
February 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28121952/instantaneous-wave-free-ratio-derived-from-coronary-computed-tomography-angiography-in-evaluation-of-ischemia-causing-coronary-stenosis-feasibility-and-initial-clinical-research
#14
Yue Ma, Hui Liu, Yang Hou, Aike Qiao, Yingying Hou, Qingqing Yang, Qiyong Guo
The instantaneous wave-free ratio (iFR) closely related to fractional flow reserve (FFR) is a adenosine-independent physiologic index of coronary stenosis severity. We sought to evaluate whether iFR derived from coronary computed tomographic angiography (iFRCT) can be used as a novel noninvasive method for diagnosis of ischemia-causing coronary stenosis.We retrospectively enrolled 33 patients (47 lesions) with coronary artery disease (CAD) and examined with coronary computed tomographic angiography (CTA), invasive coronary angiography (ICA), and FFR...
January 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28109933/integrating-ct-myocardial-perfusion-and-ct-ffr-in-the-work-up-of-coronary-artery%C3%A2-disease
#15
Adriaan Coenen, Alexia Rossi, Marisa M Lubbers, Akira Kurata, Atsushi K Kono, Raluca G Chelu, Sabrina Segreto, Marcel L Dijkshoorn, Andrew Wragg, Robert-Jan M van Geuns, Francesca Pugliese, Koen Nieman
OBJECTIVES: The aim of this study was to investigate the individual and combined accuracy of dynamic computed tomography (CT) myocardial perfusion imaging (MPI) and computed tomography angiography (CTA) fractional flow reserve (FFR) for the identification of functionally relevant coronary artery disease (CAD). BACKGROUND: Coronary CTA has become an established diagnostic test for ruling out CAD, but it does not allow interpretation of the hemodynamic severity of stenotic lesions...
January 12, 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28108202/evaluation-of-coronary-flow-conditions-in-complex-coronary-artery-bifurcations-stenting-using-computational-fluid-dynamics-impact-of-final-proximal-optimization-technique-on-different-double-stent-techniques
#16
Gianluca Rigatelli, Marco Zuin, Fabio Dell'Avvocata, Dobrin Vassilev, Ramesh Daggubati, Thach Nguyen, Nguyen Van Viet Thang, Nicolas Foin
BACKGROUND/PURPOSE: Computational fluid dynamics (CFD) have been recently adopted in many fields of cardiovascular medicine and in interventional cardiology. Using CFD analysis we compared the use of different PCI procedures, with and without the utilization of a proximal optimization technique (POT), on a complex coronary artery bifurcation. METHODS/MATERIALS: For the analysis, we considered a hypothetic model of a left anterior descending artery-diagonal Medina 1,1,1 bifurcation type with a diameter of the proximal main branch (MB) and the side branch (SB) set at 3...
January 9, 2017: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/27924174/feasibility-study-of-computational-fluid-dynamics-simulation-of-coronary-computed-tomography-angiography-based-on-dual-source-computed-tomography
#17
Jing Lu, Jie Yu, Heshui Shi
BACKGROUND: Adding functional features to morphological features offers a new method for non-invasive assessment of myocardial perfusion. This study aimed to explore technical routes of assessing the left coronary artery pressure gradient, wall shear stress distribution and blood flow velocity distribution, combining three-dimensional coronary model which was based on high resolution dual-source computed tomography (CT) with computational fluid dynamics (CFD) simulation. METHODS: Three cases of no obvious stenosis, mild stenosis and severe stenosis in left anterior descending (LAD) were enrolled...
January 2017: Journal of Clinical Medicine Research
https://www.readbyqxmd.com/read/27901333/fractional-flow-reserve-lessons-from-platform-and-future-perspectives
#18
Gianluca Pontone, Patrizia Carità, Massimo Verdecchia, Dario Buccheri, Daniele Andreini, Andrea I Guaricci, Mark Rabbat, Mauro Pepi
In the treatment of stable coronary artery disease (CAD) the identification of patients who may gain the highest benefit from further invasive treatments is of pivotal importance for the healthcare system. In this setting, it has been established that an ischemia-guided revascularization strategy yields improved clinical outcomes in a cost- effective fashion compared with anatomy-guided revascularization alone. Invasive fractional flow reserve (FFR) is considered the gold standard, especially in the intermediate-range atherosclerotic lesions, for assessing lesion specific ischemia at the time of invasive coronary angiography and has now become the standard of reference for studies assessing the diagnostic performance of the various non-invasive stress tests...
November 30, 2016: Minerva Cardioangiologica
https://www.readbyqxmd.com/read/27863293/the-conical-stent-in-coronary-artery-improves-hemodynamics-compared-with-the-traditional-cylindrical-stent
#19
Yi Yu, Yujie Zhou, Qian Ma, Shuo Jia, Sijing Wu, Yan Sun, Xiaoli Liu, Yingxin Zhao, Yuyang Liu, Dongmei Shi
OBJECTIVES: This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). BACKGROUND: The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter...
January 15, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/27777957/optimal-revascularization-strategy-on-medina-0-1-0-left-main-bifurcation-lesions-in-type-2-diabetes
#20
Xuwei Zheng, Hongyu Peng, Donghui Zhao, Qin Ma, Kun Fu, Guo Chen, Qian Fan, Jinghua Liu
Aim. Diabetes mellitus (DM) is a major risk factor for cardiovascular disease. The implications of a diagnosis of DM are as severe as the diagnosis of coronary artery disease. For many patients with complex coronary artery disease, optimal revascularization strategy selection and optimal medical therapy are equally important. In this study, we compared the hemodynamic results of different stenting techniques for Medina 0,1,0 left main bifurcation lesions. Methods. We use idealized left main bifurcation models and computational fluid dynamics analysis to evaluate hemodynamic parameters which are known to affect the risk of restenosis and thrombosis at stented bifurcation...
2016: Journal of Diabetes Research
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