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Computational fluid dynamics of coronary flow

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https://www.readbyqxmd.com/read/27901333/fractional-flow-reserve-lessons-from-platform-and-future-perspectives
#1
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
#2
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...
November 8, 2016: 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
#3
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
https://www.readbyqxmd.com/read/27669700/behaviour-of-two-typical-stents-towards-a-new-stent-evolution
#4
M Simão, J M Ferreira, J Mora-Rodriguez, J Fragata, H M Ramos
This study explores the analysis of a new stent geometry from two typical stents used to treat the coronary artery disease. Two different finite element methods are applied with different boundary conditions to investigate the stenosis region. Computational fluid dynamics (CFD) models including fluid-structure interaction are used to assess the haemodynamic impact of two types of coronary stents implantation: (1) type 1-based on a strut-link stent geometry and (2) type 2-a continuous helical stent. Using data from a recent clinical stenosis, flow disturbances and consequent shear stress alterations introduced by the stent treatment are investigated...
September 26, 2016: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/27612619/influence-of-stenosis-on-hemodynamic-parameters-in-the-realistic-left-coronary-artery-under-hyperemic-conditions
#5
Sarfaraz Kamangar, Irfan Anjum Badruddin, A Badarudin, N Nik-Ghazali, Kalimuthu Govindaraju, N J Salman Ahmed, T M Yunus Khan
The current study investigates the hyperemic flow effects on heamodynamics parameters such as velocity, wall shear stress in 3D coronary artery models with and without stenosis. The hyperemic flow is used to evaluate the functional significance of stenosis in the current era. Patients CT scan data of having healthy and coronary artery disease was chosen for the reconstruction of 3D coronary artery models. The diseased 3D models of coronary artery shows a narrowing of >50% lumen area. Computational fluid dynamics was performed to simulate the hyperemic flow condition...
September 9, 2016: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/27575305/computed-tomography-fractional-flow-reserve-can-identify-culprit-lesions-in-aortoiliac-occlusive-disease-using-minimally-invasive-techniques
#6
Erin P Ward, Daniele Shiavazzi, Divya Sood, Allison Marsden, John Lane, Erik Owens, Andrew Barleben
BACKGROUND: Currently, the gold standard diagnostic examination for significant aortoiliac lesions is angiography. Fractional flow reserve (FFR) has a growing body of literature in coronary artery disease as a minimally invasive diagnostic procedure. Improvements in numerical hemodynamics have allowed for an accurate and minimally invasive approach to estimating FFR, utilizing cross-sectional imaging. We aim to demonstrate a similar approach to aortoiliac occlusive disease (AIOD). METHODS: A retrospective review evaluated 7 patients with claudication and cross-sectional imaging showing AIOD...
August 26, 2016: Annals of Vascular Surgery
https://www.readbyqxmd.com/read/27542073/computational-study-of-the-risk-of-restenosis-in-coronary-bypasses
#7
Bruno Guerciotti, Christian Vergara, Sonia Ippolito, Alfio Quarteroni, Carlo Antona, Roberto Scrofani
Coronary artery disease, caused by the buildup of atherosclerotic plaques in the coronary vessel wall, is one of the leading causes of death in the world. For high-risk patients, coronary artery bypass graft is the preferred treatment. Despite overall excellent patency rates, bypasses may fail due to restenosis. In this context, the purpose of this work was to perform a parametric computational study of the fluid dynamics in patient-specific geometries with the aim of investigating a possible relationship between coronary stenosis degree and risk of graft failure...
August 19, 2016: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/27541354/the-effect-of-blood-pressure-on-non-invasive-fractional-flow-reserve-derived-from-coronary-computed-tomography-angiography
#8
Akira Kurata, Adriaan Coenen, Marisa M Lubbers, Koen Nieman, Teruhito Kido, Tomoyuki Kido, Natsumi Yamashita, Kouki Watanabe, Gabriel P Krestin, Teruhito Mochizuki
OBJECTIVES: The aim of this study is to assess the effect of blood pressure (BP) on coronary computed tomography angiography (CTA) derived computational fractional flow reserve (CTA-FFR). MATERIALS AND METHODS: Twenty-one patients who underwent coronary CTA and invasive FFR were retrospectively identified. Ischemia was defined as invasive FFR ≤0.80. Using a work-in-progress computational fluid dynamics algorithm, CTA-FFR was computed with BP measured before CTA, and simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg respectively...
August 19, 2016: European Radiology
https://www.readbyqxmd.com/read/27522378/a-patient-specific-virtual-stenotic-model-of-the-coronary-artery-to-analyze-the-relationship-between-fractional-flow-reserve-and-wall-shear-stress
#9
Kyung Eun Lee, Gook Tae Kim, Jeong Sang Lee, Ju-Hyun Chung, Eun-Seok Shin, Eun Bo Shim
OBJECTIVE: As the stenotic severity of a patient increases, fractional flow reserve (FFR) decreases, whereas the maximum wall shear stress (WSSmax) increases. However, the way in which these values can change according to stenotic severity has not previously been investigated. The aim of this study is to devise a virtual stenosis model to investigate variations in the coronary hemodynamic parameters of patients according to stenotic severity. METHODS: To simulate coronary hemodynamics, a three-dimensional (3D) coronary artery model of computational fluid dynamics is coupled with a lumped parameter model of the coronary micro-vasculature and venous system...
November 1, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27502209/assessing-computational-fractional-flow-reserve-from-optical-coherence-tomography-in-patients-with-intermediate-coronary-stenosis-in-the-left-anterior-descending-artery
#10
Jinyong Ha, Jung-Sun Kim, Jaeyeong Lim, Gihoon Kim, Seungwan Lee, Joon Sang Lee, Dong-Ho Shin, Byeong-Keuk Kim, Young-Guk Ko, Donghoon Choi, Yangsoo Jang, Myeong-Ki Hong
BACKGROUND: Intravascular optical coherence tomography (OCT) imaging provides limited information on the functional assessment of coronary stenosis. We evaluated a new approach to OCT image-based computation modeling, which can be used to estimate the fractional flow reserve (FFR) in patients with intermediate coronary stenosis. METHODS AND RESULTS: Ninety-two patients with intermediate diameter stenosis in the left anterior descending artery underwent both FFR measurement with pressure wires and OCT examination...
August 2016: Circulation. Cardiovascular Interventions
https://www.readbyqxmd.com/read/27495804/coronary-fractional-flow-reserve-measurements-of-a-stenosed-side-branch-a-computational-study-investigating-the-influence-of-the-bifurcation-angle
#11
Claudio Chiastra, Francesco Iannaccone, Maik J Grundeken, Frank J H Gijsen, Patrick Segers, Matthieu De Beule, Patrick W Serruys, Joanna J Wykrzykowska, Antonius F W van der Steen, Jolanda J Wentzel
BACKGROUND: Coronary hemodynamics and physiology specific for bifurcation lesions was not well understood. To investigate the influence of the bifurcation angle on the intracoronary hemodynamics of side branch (SB) lesions computational fluid dynamics simulations were performed. METHODS: A parametric model representing a left anterior descending-first diagonal coronary bifurcation lesion was created according to the literature. Diameters obeyed fractal branching laws...
2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/27490317/watertight-modeling-and-segmentation-of-bifurcated-coronary-arteries-for-blood-flow-simulation-using-ct-imaging
#12
Haoyin Zhou, Peng Sun, Seongmin Ha, Devon Lundine, Guanglei Xiong
Image-based simulation of blood flow using computational fluid dynamics has been shown to play an important role in the diagnosis of ischemic coronary artery disease. Accurate extraction of complex coronary artery structures in a watertight geometry is a prerequisite, but manual segmentation is both tedious and subjective. Several semi- and fully automated coronary artery extraction approaches have been developed but have faced several challenges. Conventional voxel-based methods allow for watertight segmentation but are slow and difficult to incorporate expert knowledge...
October 2016: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
https://www.readbyqxmd.com/read/27484320/longer-coronary-anastomosis-provides-lower-energy-loss-in-coronary-artery-bypass-grafting
#13
Hiroyuki Tsukui, Manabu Shinke, Young Kwang Park, Kenji Yamazaki
Distal anastomosis technique affects graft patency and long-term outcomes in coronary artery bypass grafting, however, there is no standard for the appropriate length of distal anastomosis. The purpose of this study is to evaluate whether longer distal anastomosis provides higher quality of distal anastomosis and better hemodynamic patterns. Off pump CABG training simulator, YOUCAN (EBM Corporation, Japan), was used for distal anastomosis model. Two lengths of distal anastomosis model (10 versus 4 mm) were prepared by end-to-side anastomosis technique...
August 2, 2016: Heart and Vessels
https://www.readbyqxmd.com/read/27467730/haemodynamic-assessment-of-human-coronary-arteries-is-affected-by-degree-of-freedom-of-artery-movement
#14
Ashkan Javadzadegan, Andy S C Yong, Michael Chang, Martin K C Ng, Masud Behnia, Leonard Kritharides
: Abnormal haemodynamic parameters are associated with atheroma plaque progression and instability in coronary arteries. Flow recirculation, shear stress and pressure gradient are understood to be important pathogenic mediators in coronary disease. The effect of freedom of coronary artery movement on these parameters is still unknown. Fluid-structure interaction (FSI) simulations were carried out in 25 coronary artery models derived from authentic human coronaries in order to investigate the effect of degree of freedom of movement of the coronary arteries on flow recirculation, wall shear stress (WSS) and wall pressure gradient (WPG)...
July 28, 2016: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/27382296/noninvasive-ffr-derived-from-coronary-ct-angiography-in-the-management-of-coronary-artery-disease-technology-and-clinical-update
#15
REVIEW
Rine Nakanishi, Mathew J Budoff
After a decade of clinical use of coronary computed tomographic angiography (CCTA) to evaluate the anatomic severity of coronary artery disease, new methods of deriving functional information from CCTA have been developed. These methods utilize the anatomic information provided by CCTA in conjunction with computational fluid dynamics to calculate fractional flow reserve (FFR) values from CCTA image data sets. Computed tomography-derived FFR (CT-FFR) enables the identification of lesion-specific drop noninvasively...
2016: Vascular Health and Risk Management
https://www.readbyqxmd.com/read/27372207/quantifying-the-effect-of-side-branches-in-endothelial-shear-stress-estimates
#16
Andreas A Giannopoulos, Yiannis S Chatzizisis, Pal Maurovich-Horvat, Antonios P Antoniadis, Udo Hoffmann, Michael L Steigner, Frank J Rybicki, Dimitrios Mitsouras
BACKGROUND AND AIMS: Low and high endothelial shear stress (ESS) is associated with coronary atherosclerosis progression and high-risk plaque features. Coronary ESS is currently assessed via computational fluid dynamic (CFD) simulation of coronary blood flow in the lumen geometry determined from invasive imaging such as intravascular ultrasound and optical coherence tomography. This process typically omits side branches of the target vessel in the CFD model as invasive imaging of those vessels is not usually clinically-indicated...
August 2016: Atherosclerosis
https://www.readbyqxmd.com/read/27310014/the-impact-of-the-geometric-characteristics-on-the-hemodynamics-in-the-stenotic-coronary-artery
#17
Changnong Peng, Xiaoqing Wang, Zhanchao Xian, Xin Liu, Wenhua Huang, Pengcheng Xu, Jinyang Wang
The alterations of the hemodynamics in the coronary arteries, which result from patient-specific geometric significances are complex. The effect of the stenosis on the blood flow alteration had been wildly reported, but the combinational contribution from geometric factors required a comprehensive investigation to provide patient-specific information for diagnosis and assisting in the decision on the further treatment strategies. In the present study, we investigated the correlation between hemodynamic parameters and individual geometric factors in the patient-specific coronary arteries...
2016: PloS One
https://www.readbyqxmd.com/read/27302372/transversally-enriched-pipe-element-method-tepem-an-effective-numerical-approach-for-blood-flow-modeling
#18
Luis Alvarez Mansilla, Pablo J Blanco, Carlos A Bulant, Enzo A Dari, Alessandro Veneziani, R A Feijoo
In this work we present a novel approach tailored to approximate the Navier-Stokes equations to simulate fluid flow in three-dimensional tubular domains of arbitrary cross-sectional shape. The proposed methodology is aimed at filling the gap between (cheap) one-dimensional and (expensive) three-dimensional models, featuring descriptive capabilities comparable to the full and accurate 3D description of the problem at a low computational cost. In addition, this methodology can easily be tuned or even adapted to address local features demanding more accuracy...
June 15, 2016: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/27255115/-computed-tomography-in-patients-with-chronic-stable-angina-fractional-flow-reserve-measurement
#19
M Renker, U J Schoepf, T Becher, N Krampulz, W Kim, A Rolf, H Möllmann, C W Hamm, T Henzler, M Borggrefe, I Akin, S Baumann
Coronary computed tomography angiography (cCTA) has been established for the non-invasive diagnosis of coronary artery disease (CAD). Previous studies demonstrated the high diagnostic accuracy of cCTA, particularly for ruling out CAD. As a known limitation of cCTA a large number of visually significant coronary stenoses are found to be hemodynamically not relevant by invasive fractional flow reserve (FFR). CT-based FFR (CT-FFR) builds on recent advances in computational fluid dynamics and image simulation techniques...
June 2, 2016: Herz
https://www.readbyqxmd.com/read/27187726/simplified-models-of-non-invasive-fractional-flow-reserve-based-on-ct-images
#20
Jun-Mei Zhang, Liang Zhong, Tong Luo, Aileen Mae Lomarda, Yunlong Huo, Jonathan Yap, Soo Teik Lim, Ru San Tan, Aaron Sung Lung Wong, Jack Wei Chieh Tan, Khung Keong Yeo, Jiang Ming Fam, Felix Yung Jih Keng, Min Wan, Boyang Su, Xiaodan Zhao, John Carson Allen, Ghassan S Kassab, Terrance Siang Jin Chua, Swee Yaw Tan
Invasive fractional flow reserve (FFR) is the gold standard to assess the functional coronary stenosis. The non-invasive assessment of diameter stenosis (DS) using coronary computed tomography angiography (CTA) has high false positive rate in contrast to FFR. Combining CTA with computational fluid dynamics (CFD), recent studies have shown promising predictions of FFRCT for superior assessment of lesion severity over CTA alone. The CFD models tend to be computationally expensive, however, and require several hours for completing analysis...
2016: PloS One
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