451
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Niu L, Meng L, Xu L, Liu J, Wang Q, Xiao Y, Qian M, Zheng H. Stress phase angle depicts differences in arterial stiffness: phantom and in vivo study. Phys Med Biol 2015; 60:4281-94. [DOI: 10.1088/0031-9155/60/11/4281] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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452
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Nouri M, Jalali F, Karimi G, Zarrabi K. Image-based computational simulation of sub-endothelial LDL accumulation in a human right coronary artery. Comput Biol Med 2015; 62:206-21. [PMID: 25957745 DOI: 10.1016/j.compbiomed.2015.04.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 11/29/2022]
Abstract
Accumulation of low density lipoproteins (LDL) in the vessel wall is suggested as the initiator of atherosclerosis and coronary stenosis. This process is associated with the performance of endothelium layer that regulates entering of macromolecules to the vessel wall. Therefore, the present study aims to investigate sub-endothelial accumulation of LDL molecules in a coronary tree and predict atherosclerosis prone sites. Non-Newtonian blood flow is simulated for normal and hypertensive conditions through the lumen of a right coronary artery reconstructed from computed tomography (CT) images. A three-pore model is implemented as the endothelium boundary condition and hence, plasma flow and LDL transport are simulated within the arterial wall. Based on the pore model, endothelium pathways divide into normal junctions, vesicles and leaky junctions. Most of LDL molecules pass through the leaky junctions that arise at locations with low wall shear stress (WSS). Results indicate that increase in the number of leaky junctions at branch points with low WSS can lead to both elevated levels of sub-endothelial LDL accumulation and atherosclerosis risk. Findings reveal that at the branch points with disturbed flow, sub-endothelial concentration of LDL for the hypertensive condition is higher than the normal condition, however for the rest of regions with uniform geometry and unidirectional flow, this is reversed. Comparisons of non-Newtonian and Newtonian flows show mean increases of 34% and 13% in the sub-endothelial concentrations of Newtonian flows during the normal and hypertensive conditions, respectively.
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Affiliation(s)
- Mohammad Nouri
- Department of Chemical Engineering, University of Tehran, Tehran, Iran
| | - Farhang Jalali
- Department of Chemical Engineering, University of Tehran, Tehran, Iran.
| | | | - Khalil Zarrabi
- Department of Cardiac Surgery, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
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453
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Dunn J, Thabet S, Jo H. Flow-Dependent Epigenetic DNA Methylation in Endothelial Gene Expression and Atherosclerosis. Arterioscler Thromb Vasc Biol 2015; 35:1562-9. [PMID: 25953647 DOI: 10.1161/atvbaha.115.305042] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/27/2015] [Indexed: 12/31/2022]
Abstract
Epigenetic mechanisms that regulate endothelial cell gene expression are now emerging. DNA methylation is the most stable epigenetic mark that confers persisting changes in gene expression. Not only is DNA methylation important in rendering cell identity by regulating cell type-specific gene expression throughout differentiation, but it is becoming clear that DNA methylation also plays a key role in maintaining endothelial cell homeostasis and in vascular disease development. Disturbed blood flow causes atherosclerosis, whereas stable flow protects against it by differentially regulating gene expression in endothelial cells. Recently, we and others have shown that flow-dependent gene expression and atherosclerosis development are regulated by mechanisms dependent on DNA methyltransferases (1 and 3A). Disturbed blood flow upregulates DNA methyltransferase expression both in vitro and in vivo, which leads to genome-wide DNA methylation alterations and global gene expression changes in a DNA methyltransferase-dependent manner. These studies revealed several mechanosensitive genes, such as HoxA5, Klf3, and Klf4, whose promoters were hypermethylated by disturbed blood flow, but rescued by DNA methyltransferases inhibitors such as 5Aza-2-deoxycytidine. These findings provide new insight into the mechanism by which flow controls epigenomic DNA methylation patterns, which in turn alters endothelial gene expression, regulates vascular biology, and modulates atherosclerosis development.
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Affiliation(s)
- Jessilyn Dunn
- From the Wallace H. Coulter Department of Biomedical Engineering (J.D., S.T., H.J.) and Division of Cardiology, Georgia Institute of Technology and Emory University, Atlanta
| | - Salim Thabet
- From the Wallace H. Coulter Department of Biomedical Engineering (J.D., S.T., H.J.) and Division of Cardiology, Georgia Institute of Technology and Emory University, Atlanta
| | - Hanjoong Jo
- From the Wallace H. Coulter Department of Biomedical Engineering (J.D., S.T., H.J.) and Division of Cardiology, Georgia Institute of Technology and Emory University, Atlanta.
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454
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Andreou I, Antoniadis AP, Shishido K, Papafaklis MI, Koskinas KC, Chatzizisis YS, Coskun AU, Edelman ER, Feldman CL, Stone PH. How do we prevent the vulnerable atherosclerotic plaque from rupturing? Insights from in vivo assessments of plaque, vascular remodeling, and local endothelial shear stress. J Cardiovasc Pharmacol Ther 2015; 20:261-275. [PMID: 25336461 DOI: 10.1177/1074248414555005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/14/2014] [Indexed: 01/13/2023]
Abstract
Coronary atherosclerosis progresses both as slow, gradual enlargement of focal plaque and also as a more dynamic process with periodic abrupt changes in plaque geometry, size, and morphology. Systemic vasculoprotective therapies such as statins, angiotensin-converting enzyme inhibitors, and antiplatelet agents are the cornerstone of prevention of plaque rupture and new adverse clinical outcomes, but such systemic therapies are insufficient to prevent the majority of new cardiac events. Invasive imaging methods have been able to identify both the anatomic features of high-risk plaque and the ongoing pathobiological stimuli responsible for progressive plaque inflammation and instability and may provide sufficient information to formulate preventive local mechanical strategies (eg, preemptive percutaneous coronary interventions) to avert cardiac events. Local endothelial shear stress (ESS) triggers vascular phenomena that synergistically exacerbate atherosclerosis toward an unstable phenotype. Specifically, low ESS augments lipid uptake and catabolism, induces plaque inflammation and oxidation, downregulates the production, upregulates the degradation of extracellular matrix, and increases cellular apoptosis ultimately leading to thin-cap fibroatheromas and/or endothelial erosions. Increases in blood thrombogenicity that result from either high or low ESS also contribute to plaque destabilization. An understanding of the actively evolving vascular phenomena, as well as the development of in vivo imaging methodologies to identify the presence and severity of the different processes, may enable early identification of a coronary plaque destined to acquire a high-risk state and allow for highly selective, focal preventive interventions to avert the adverse natural history of that particular plaque. In this review, we focus on the role of ESS in the pathobiologic processes responsible for plaque destabilization, leading either to accelerated plaque growth or to acute coronary events, and emphasize the potential to utilize in vivo risk stratification of individual coronary plaques to optimize prevention strategies to preclude new cardiac events.
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Affiliation(s)
- Ioannis Andreou
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Antonios P Antoniadis
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Koki Shishido
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Michail I Papafaklis
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Konstantinos C Koskinas
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Yiannis S Chatzizisis
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Ahmet U Coskun
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Elazer R Edelman
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Charles L Feldman
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Peter H Stone
- The Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
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455
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Impact of top end anastomosis design on patency and flow stability in coronary artery bypass grafting. Heart Vessels 2015; 31:643-8. [DOI: 10.1007/s00380-015-0680-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 03/06/2015] [Indexed: 11/25/2022]
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456
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Merkle VM, Martin D, Hutchinson M, Tran PL, Behrens A, Hossainy S, Bluestein D, Wu X, Slepian MJ. Hemocompatibility of Poly(vinyl alcohol)-Gelatin Core-Shell Electrospun Nanofibers: A Scaffold for Modulating Platelet Deposition and Activation. ACS APPLIED MATERIALS & INTERFACES 2015; 7:8302-12. [PMID: 25815434 PMCID: PMC4545287 DOI: 10.1021/acsami.5b01671] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this study, we evaluate coaxial electrospun nanofibers with gelatin in the shell and poly(vinyl alcohol) (PVA) in the core as a potential vascular material by determining fiber surface roughness, as well as human platelet deposition and activation under varying conditions. PVA scaffolds had the highest surface roughness (Ra=65.5±6.8 nm) but the lowest platelet deposition (34.2±5.8 platelets) in comparison to gelatin nanofibers (Ra=36.8±3.0 nm and 168.9±29.8 platelets) and coaxial nanofibers (1 Gel:1 PVA coaxial, Ra=24.0±1.5 nm and 150.2±17.4 platelets. 3 Gel:1 PVA coaxial, Ra=37.1±2.8 nm and 167.8±15.4 platelets). Therefore, the chemical structure of the gelatin nanofibers dominated surface roughness in platelet deposition. Due to their increased stiffness, the coaxial nanofibers had the highest platelet activation rate, rate of thrombin formation, in comparison to gelatin and PVA fibers. Our studies indicate that mechanical stiffness is a dominating factor for platelet deposition and activation, followed by biochemical signals, and lastly surface roughness. Overall, these coaxial nanofibers are an appealing material for vascular applications by supporting cellular growth while minimizing platelet deposition and activation.
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Affiliation(s)
- Valerie M. Merkle
- Biomedical Engineering Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona U.S.A
| | - Daniel Martin
- Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona U.S.A
| | - Marcus Hutchinson
- Department of Molecular and Cellular Biology, The University of Arizona, Tucson, Arizona U.S.A
| | - Phat L. Tran
- Sarver Heart Center, Department of Medicine, The University of Arizona, Tucson, Arizona, U.S.A
| | - Alana Behrens
- Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona U.S.A
| | - Samir Hossainy
- Sarver Heart Center, Department of Medicine, The University of Arizona, Tucson, Arizona, U.S.A
| | - Danny Bluestein
- Aerospace & Mechanical Engineering Department, The University of Arizona, Tucson, Arizona, U.S.A
| | - Xiaoyi Wu
- Biomedical Engineering Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona U.S.A
- Corresponding author at: Aerospace and Mechanical Engineering Department, The University of Arizona, Tucson AZ 85721, USA. Tel.: 1-520-626-5854 Fax: 1-00-520-621-8191,
| | - Marvin J. Slepian
- Biomedical Engineering Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona U.S.A
- Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona U.S.A
- Sarver Heart Center, Department of Medicine, The University of Arizona, Tucson, Arizona, U.S.A
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York U.S.A
- Corresponding author at: Sarver Heart Center, College of Medicine, The University of Arizona, Tucson AZ 85721, USA. Tel.: +1 520 626 8543,
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457
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Weddell JC, Kwack J, Imoukhuede PI, Masud A. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models. PLoS One 2015; 10:e0124575. [PMID: 25897758 PMCID: PMC4405589 DOI: 10.1371/journal.pone.0124575] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 03/14/2015] [Indexed: 11/19/2022] Open
Abstract
Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF) constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS) is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.
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Affiliation(s)
- Jared C. Weddell
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
- * E-mail:
| | - JaeHyuk Kwack
- Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
| | - P. I. Imoukhuede
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
| | - Arif Masud
- Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
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458
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Zhang JM, Luo T, Tan SY, Lomarda AM, Wong ASL, Keng FYJ, Allen JC, Huo Y, Su B, Zhao X, Wan M, Kassab GS, Tan RS, Zhong L. Hemodynamic analysis of patient-specific coronary artery tree. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015; 31:e02708. [PMID: 25630671 DOI: 10.1002/cnm.2708] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 12/04/2014] [Accepted: 12/05/2014] [Indexed: 05/28/2023]
Abstract
Local hemodynamic parameters, such as wall shear stress (WSS), oscillatory shear index and relative resident time (RRT), have been linked to coronary plaque initiation and progression. In this study, a left coronary artery tree model was reconstructed from computed tomography angiography images of a patient with multiple stenoses. The geometry of the coronary artery tree model was virtually restored by eliminating the lesions, essentially re-creating the virtually healthy artery anatomy. Using numerical simulations, flow characteristics and hemodynamic parameter distributions in the stenosed and virtually healthy models were investigated. In the virtually healthy artery model, disturbed flows were found at four locations, prone to initialization of plaque formation. Low WSS and high RRT were exhibited in three of the four locations, and high WSS and low RRT were exhibited in the fourth. These findings suggest that coronary plaque is more likely to form in locations with disturbed flow conditions characterized by low WSS and high RRT or high WSS and low RRT. In addition, clinical index of fractional flow reserve was found to significantly correlate with blood flow rate, rather than anatomic parameters, such as diameter stenosis, which implied the importance of hemodynamic environment in stenosis formation.
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Affiliation(s)
- Jun-Mei Zhang
- National Heart Center Singapore, 5 Hospital Drive, 169609, Singapore; Duke-NUS Graduate Medical School, Singapore, 8 College Road, 169857, Singapore
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459
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Meirson T, Orion E, Avrahami I. Numerical analysis of Venous External Scaffolding Technology for Saphenous Vein Grafts. J Biomech 2015; 48:2090-5. [PMID: 25869720 DOI: 10.1016/j.jbiomech.2015.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 11/28/2022]
Abstract
This paper presents a method for analyzing and comparing numerically Saphenous Vein Grafts (SVGs) following Coronary Artery Bypass Graft surgery (CABG). The method analyses the flow dynamics inside vein grafts with and without supporting using Venous External Scaffolding Technology (VEST). The numerical method uses patients׳ specific computational fluid dynamics (CFD) methods to characterize the relevant hemodynamic parameters of patients׳ SVGs. The method was used to compare the hemodynamics of six patient׳s specific model and flow conditions of stented and non-stented SVGs, 12 months post-transplantation. The flow parameters used to characterize the grafts׳ hemodynamics include Time Averaged Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI) and Relative Residence Time (RRT). The effect of stenting was clearly demonstrated by the chosen parameters. SVGs under constriction of VEST were associated with similar spatial average of TAWSS (10.73 vs 10.29 dyn/cm(2)), yet had fewer lesions with low TAWSS, lower OSI (0.041 vs 0.08) and RRT (0.12 vs 0.24), and more uniform flow with less flow discrepancies. In conclusion, the suggested method and parameters well demonstrated the advantage of VEST support. Stenting vein grafts with VEST improved hemodynamic factors which are correlated to graft failure following CABG procedure.
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Affiliation(s)
- T Meirson
- Department of Medical Engineering, Afeka Academic College of Engineering, Tel Aviv, Israel.
| | - E Orion
- Vascular Graft Solutions Ltd., Tel Aviv 6971921, Israel
| | - I Avrahami
- Department of Mechanical Engineering & Mechatronics, Ariel University, Israel
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460
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Bourantas CV, Räber L, Zaugg S, Sakellarios A, Taniwaki M, Heg D, Moschovitis A, Radu M, Papafaklis MI, Kalatzis F, Naka KK, Fotiadis DI, Michalis LK, Serruys PW, Garcia Garcia HM, Windecker S. Impact of local endothelial shear stress on neointima and plaque following stent implantation in patients with ST-elevation myocardial infarction: A subgroup-analysis of the COMFORTABLE AMI-IBIS 4 trial. Int J Cardiol 2015; 186:178-185. [PMID: 25828109 DOI: 10.1016/j.ijcard.2015.03.160] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 03/02/2015] [Accepted: 03/15/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Numerous studies have demonstrated an association between endothelial shear stress (ESS) and neointimal formation after stent implantation. However, the role of ESS on the composition of neointima and underlying plaque remains unclear. METHODS Patients recruited in the Comfortable AMI-IBIS 4 study implanted with bare metal stents (BMS) or biolimus eluting stents (BES) that had biplane coronary angiography at 13 month follow-up were included in the analysis. The intravascular ultrasound virtual-histology (IVUS-VH) and the angiographic data were used to reconstruct the luminal surface, and the stent in the stented segments. Blood flow simulation was performed in the stent surface, which was assumed to represent the luminal surface at baseline, to assess the association between ESS and neointima thickness. The predominant ESS was estimated in 3-mm segments and was correlated with the amount of neointima, neointimal tissue composition, and with the changes in the underlying plaque burden and composition. RESULTS Forty three patients (18 implanted with BMS and 25 with BES) were studied. In both stent groups negative correlations were noted between ESS and neointima thickness in BMS (P < 0.001) and BES (P = 0.002). In BMS there was a negative correlation between predominant ESS and the percentage of the neointimal necrotic core component (P = 0.015). In BES group, the limited neointima formation did not allow evaluation of the effect of ESS on its tissue characteristics. ESS did not affect vessel wall remodeling and the plaque burden and composition behind BMS (P > 0.10) and BES (P > 0.45). CONCLUSIONS ESS determines neointimal formation in both BMS and BES and affects the composition of the neointima in BMS. Conversely, ESS does not impact the plaque behind struts irrespective of stent type throughout 13 months of follow-up.
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Affiliation(s)
- Christos V Bourantas
- Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, The Netherlands; University College of London, London, United Kingdom
| | - Lorenz Räber
- Department of Interventional Cardiology, Bern University Hospital, Bern, Switzerland
| | - Serge Zaugg
- Clinical Trials Unit, Bern University, Bern, Switzerland
| | - Antonis Sakellarios
- Department of Materials Science and Engineering, University of Ioannina, Ioannina, Greece
| | - Masanori Taniwaki
- Department of Interventional Cardiology, Bern University Hospital, Bern, Switzerland
| | - Dik Heg
- Clinical Trials Unit, Bern University, Bern, Switzerland; Institute of Social and Preventive Medicine, Bern University, Bern, Switzerland
| | - Aris Moschovitis
- Department of Interventional Cardiology, Bern University Hospital, Bern, Switzerland
| | - Maria Radu
- The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Michail I Papafaklis
- Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
| | - Fanis Kalatzis
- Department of Materials Science and Engineering, University of Ioannina, Ioannina, Greece
| | - Katerina K Naka
- Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
| | - Dimitrios I Fotiadis
- Department of Materials Science and Engineering, University of Ioannina, Ioannina, Greece
| | - Lampros K Michalis
- Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
| | - Patrick W Serruys
- Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, The Netherlands
| | - Hector M Garcia Garcia
- Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, The Netherlands
| | - Stephan Windecker
- Department of Interventional Cardiology, Bern University Hospital, Bern, Switzerland.
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461
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Renker M, Baumann S, Rier J, Ebersberger U, Fuller SR, Batalis NI, Schoepf UJ, Chiaramida SA. Imaging coronary artery disease and the myocardial ischemic cascade: clinical principles and scope. Radiol Clin North Am 2015; 53:261-9. [PMID: 25726992 DOI: 10.1016/j.rcl.2014.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
On a subcellular level, atherogenesis is characterized by the translocation of proatherogenic lipoproteins into the arterial wall. An inflammatory response involving complex repair mechanisms subsequently causes maladaptive vascular changes resulting in coronary stenosis or occlusion. The chronology of the underlying processes occurring from atherosclerosis to myocardial ischemia affect the selection and interpretation of diagnostic testing. An understanding of the ischemic cascade, atherosclerosis, coronary remodeling, plaque morphology, and their relationship to clinical syndromes is essential in determining which diagnostic modalities are useful in clinical practice.
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Affiliation(s)
- Matthias Renker
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA; Department of Medicine I, Cardiology and Angiology, Giessen University Hospital, Klinistrasse 33, Giessen 35392, Germany
| | - Stefan Baumann
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA; 1st Department of Medicine University Medical Centre Mannheim (UMM), Theodor-Kutzer-Ufer 1-3, Mannheim 68167, Germany
| | - Jeremy Rier
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA
| | - Ullrich Ebersberger
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA; Department of Cardiology, Heart Centre Munich-Bogenhausen, Munich Municipal Hospital Group, Englschalkinger Strasse 77, Munich 81925, Germany
| | - Stephen R Fuller
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA
| | - Nicholas I Batalis
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, HD281, 165 Ashley Avenue, Charleston, SC 29425, USA
| | - U Joseph Schoepf
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA.
| | - Salvatore A Chiaramida
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425, USA
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462
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Sui B, Gao P, Lin Y, Jing L, Sun S, Qin H. Hemodynamic parameters distribution of upstream, stenosis center, and downstream sides of plaques in carotid artery with different stenosis: a MRI and CFD study. Acta Radiol 2015; 56:347-54. [PMID: 24676083 DOI: 10.1177/0284185114526713] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Histopathological studies have shown significant differences in plaque components and surface conditions between upstream and downstream of the stenosis. It can be deduced that the flow status near the plaques is different from the flow status at the upstream side, stenosis center, or downstream side of the plaque. PURPOSE To study the hemodynamic parameter distribution in different locations near atherosclerotic plaques in the carotid arteries with different stenosis degrees. MATERIAL AND METHODS Eleven patients were recruited in this study. CE-MRA was performed to obtain the carotid three-dimensional surface data and the stenosis degrees were calculated. The hemodynamic parameters including wall shear stress (WSS), pressure, and velocity near the plaques were obtained by computational fluid dynamic (CFD) method. Local hemodynamics parameters were analyzed and compared between different stenosis degree groups, and between upstream, stenosis center, and downstream sides of plaques. Relative ratio of velocity, WSS, and pressure values in different locations was calculated and compared. RESULTS Fourteen carotid arteries (with 4 mild, 6 moderate, and 4 severe stenosis) were analyzed. Significant differences were found in Pressure max (P = 0.025), Pressure mean (P = 0.020), and Pressure min (P = 0.026) between three stenosis groups. It showed significant differences in Vmin (P < 0.001) and WSSmin (P < 0.001) between three different locations. It showed upstream to downstream ratio of WSSmax (P = 0.034) and WSSmean value (P = 0.042) was significantly different between mild and moderate/severe groups. Significant differences were found in upstream to stenosis center ratio of Pressure max value (P = 0.018), Pressure mean value (P = 0.029), and Pressure min value (P = 0.026), as well as in stenosis center to downstream ratio of Pressure min value (P = 0.042). CONCLUSION Velocity, WSS, pressure, and relative ratio of these parameters have certain trends in distribution around the plaques in the carotid arteries.
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Affiliation(s)
- Binbin Sui
- Radiology Department, Beijing Neurosurgical Institute, Affiliated Beijing Tiantan Hospital, Capital Medical University, Beijing, PR China
| | - Peiyi Gao
- Radiology Department, Beijing Neurosurgical Institute, Affiliated Beijing Tiantan Hospital, Capital Medical University, Beijing, PR China
| | - Yan Lin
- Radiology Department, Beijing Neurosurgical Institute, Affiliated Beijing Tiantan Hospital, Capital Medical University, Beijing, PR China
| | - Lina Jing
- Radiology Department, Beijing Neurosurgical Institute, Affiliated Beijing Tiantan Hospital, Capital Medical University, Beijing, PR China
| | - Shengjun Sun
- Radiology Department, Beijing Neurosurgical Institute, Affiliated Beijing Tiantan Hospital, Capital Medical University, Beijing, PR China
| | - Haiqiang Qin
- Neurology Department, Affiliated Beijing Tiantan Hospital, Capital Medical University, Beijing, PR China
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463
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Park JB, Koo BK. Noninvasive hemodynamic assessment using coronary computed tomography angiography: the present and future. Interv Cardiol 2015. [DOI: 10.2217/ica.14.65] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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464
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Frattolin J, Zarandi MM, Pagiatakis C, Bertrand OF, Mongrain R. Numerical study of stenotic side branch hemodynamics in true bifurcation lesions. Comput Biol Med 2015; 57:130-8. [DOI: 10.1016/j.compbiomed.2014.11.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/19/2014] [Accepted: 11/28/2014] [Indexed: 11/15/2022]
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465
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FU YULIN, QIAO AIKE, JIN LONG. THE INFLUENCE OF HEMODYNAMICS ON THE ULCERATION PLAQUES OF CAROTID ARTERY STENOSIS. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415500086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The further rupture of atherosclerotic ulceration plaque is one of the main triggers of the carotid ischemic stroke. However, the abnormal hemodynamics is not well addressed yet. A lesion-based computational fluid dynamic (CFD) analysis is proposed to investigate the complex hemodynamic change of the ulceration plaque that prevails in patients. The 3D models including eight groups of ulcerations (six groups with single ulceration and two groups with two consecutive ulcerations), were reconstructed based on the computer tomography (CT) images, and the tetrahedral grid was taken to mesh the models with the appropriate numbers. After setting the boundary conditions, numerical simulation was carried out to analyze the pulsatile blood flow in the models. The complex flow in the vicinity of the ulcerations directly leads to a significant effect on the distribution of the wall shear stress (WSS). WSS is respectively from 3.29 to 35.41 Pa at the upstream, from 11.90 to 41.85 Pa at the downstream ulceration, and 18.60 and 30.60 Pa in the area between the two consecutive ulcerations. The rupture from these regions could cause the further rupture of ulceration plaques, particularly at the downstream ulceration and the area between the two consecutive ulcerations. The twisting and the curling of the flow at the ulcerations can lead to thrombosis which may break free later and go through the downstream stenosis by the effect of the flow. The different degrees of WSS in downstream and upstream ulcerations will damage the ulceration on the plaque because of pulling and stretching forces at the ulcerations. Furthermore, high wall shear stress gradient (WSSG) also increases the risk of the further rupture. Our study gives a better understanding in the further rupture mechanism of ulceration plaques and provides the information of the location of thrombosis after aggravated rupturing, which can be referred by surgeons to improve the surgical planning.
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Affiliation(s)
- YULIN FU
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
| | - AIKE QIAO
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
| | - LONG JIN
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P. R. China
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466
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Leung TW, Wang L, Soo YOY, Ip VHL, Chan AYY, Au LWC, Fan FSY, Lau AYL, Leung H, Abrigo J, Wong A, Mok VCT, Ng PW, Tsoi TH, Li SH, Man CBL, Fong WC, Wong KS, Yu SCH. Evolution of intracranial atherosclerotic disease under modern medical therapy. Ann Neurol 2015; 77:478-86. [PMID: 25557926 DOI: 10.1002/ana.24340] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/26/2014] [Accepted: 12/07/2014] [Indexed: 01/05/2023]
Affiliation(s)
- Thomas W. Leung
- Division of Neurology, Department of Medicine and Therapeutics
| | - Lily Wang
- Division of Neurology, Department of Medicine and Therapeutics
| | | | | | - Anne Y. Y. Chan
- Division of Neurology, Department of Medicine and Therapeutics
| | - Lisa W. C. Au
- Division of Neurology, Department of Medicine and Therapeutics
| | | | - Alex Y. L. Lau
- Division of Neurology, Department of Medicine and Therapeutics
| | - Howan Leung
- Division of Neurology, Department of Medicine and Therapeutics
| | - Jill Abrigo
- Department of Diagnostic and Interventional Radiology; Prince of Wales Hospital, Chinese University of Hong Kong
| | - Adrian Wong
- Division of Neurology, Department of Medicine and Therapeutics
| | | | - Ping Wing Ng
- Department of Medicine and Geriatrics; United Christian Hospital
| | - Tak Hong Tsoi
- Department of Medicine; Pamela Youde Nethersole Eastern Hospital
| | - Siu Hung Li
- Department of Medicine; North District Hospital
| | | | - Wing Chi Fong
- Department of Medicine; Queen Elizabeth Hospital; Hong Kong
| | - Ka Sing Wong
- Division of Neurology, Department of Medicine and Therapeutics
| | - Simon C. H. Yu
- Department of Diagnostic and Interventional Radiology; Prince of Wales Hospital, Chinese University of Hong Kong
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467
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Tang D, Li ZY, Gijsen F, Giddens DP. Cardiovascular diseases and vulnerable plaques: data, modeling, predictions and clinical applications. Biomed Eng Online 2015; 14 Suppl 1:S1. [PMID: 25602945 PMCID: PMC4306097 DOI: 10.1186/1475-925x-14-s1-s1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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468
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Molony DS, Timmins LH, Hung OY, Rasoul-Arzrumly E, Samady H, Giddens DP. An assessment of intra-patient variability on observed relationships between wall shear stress and plaque progression in coronary arteries. Biomed Eng Online 2015; 14 Suppl 1:S2. [PMID: 25603192 PMCID: PMC4306111 DOI: 10.1186/1475-925x-14-s1-s2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Wall shear stress (WSS) has been associated with sites of plaque localization and with changes in plaque composition in human coronary arteries. Different values have been suggested for categorizing WSS as low, physiologic or high; however, uncertainties in flow rates, both across subjects and within a given individual, can affect the classification of WSS and thus influence the observed relationships between local hemodynamics and plaque changes over time. This study examines the effects of uncertainties in flow rate boundary conditions upon WSS values and investigates the influence of this variability on the observed associations of WSS with changes in VH-IVUS derived plaque components. METHODS Three patients with coronary artery disease underwent baseline and 12 month follow-up angiography and virtual histology-intravascular ultrasound (VH-IVUS) measurements. Coronary artery models were reconstructed from the data and models with and without side-branches were created. Patient-specific Doppler ultrasound (DUS) data were employed as inflow boundary conditions and computational fluid dynamics was used to calculate the WSS in each model. Further, the influence of representative coronary artery flow waveforms upon WSS values was investigated and the concept of treating WSS using relative, rather than actual, values was explored. RESULTS Models that included side-branch outflows and subject-specific DUS velocities were considered to be the reference cases. Hemodynamic differences were caused by the exclusion of side-branches and by imposing alternative velocity waveforms. One patient with fewer side-branches and a scaled generic waveform had little deviation from the reference case, while another patient with several side-branches excluded showed much larger departures from the reference situation. Differences between models and the respective reference cases were reduced when data were analyzed using relative, rather than actual, WSS. CONCLUSIONS When considering individual subjects, large variations in patient-specific flow rates and exclusion of multiple side-branches in computational models can cause significant differences in observed associations between plaque evolution and ranges of computed WSS. These differences may contribute to the large variability typically found among subjects in pooled populations. Relative WSS may be more useful than actual WSS as a correlative variable when there is a large degree of uncertainty in flow rate data.
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469
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Liu B, Zheng J, Bach R, Tang D. Influence of model boundary conditions on blood flow patterns in a patient specific stenotic right coronary artery. Biomed Eng Online 2015; 14 Suppl 1:S6. [PMID: 25602370 PMCID: PMC4306119 DOI: 10.1186/1475-925x-14-s1-s6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background In literature, the effect of the inflow boundary condition was investigated by examining the impact of the waveform and the shape of the spatial profile of the inlet velocity on the cardiac hemodynamics. However, not much work has been reported on comparing the effect of the different combinations of the inlet/outlet boundary conditions on the quantification of the pressure field and flow distribution patterns in stenotic right coronary arteries. Method Non-Newtonian models were used to simulate blood flow in a patient-specific stenotic right coronary artery and investigate the influence of different boundary conditions on the phasic variation and the spatial distribution patterns of blood flow. The 3D geometry of a diseased artery segment was reconstructed from a series of IVUS slices. Five different combinations of the inlet and the outlet boundary conditions were tested and compared. Results The temporal distribution patterns and the magnitudes of the velocity, the wall shear stress (WSS), the pressure, the pressure drop (PD), and the spatial gradient of wall pressure (WPG) were different when boundary conditions were imposed using different pressure/velocity combinations at inlet/outlet. The maximum velocity magnitude in a cardiac cycle at the center of the inlet from models with imposed inlet pressure conditions was about 29% lower than that from models using fully developed inlet velocity data. Due to the fact that models with imposed pressure conditions led to blunt velocity profile, the maximum wall shear stress at inlet in a cardiac cycle from models with imposed inlet pressure conditions was about 29% higher than that from models with imposed inlet velocity boundary conditions. When the inlet boundary was imposed by a velocity waveform, the models with different outlet boundary conditions resulted in different temporal distribution patterns and magnitudes of the phasic variation of pressure. On the other hand, the type of different boundary conditions imposed at the inlet and the outlet did not have significant effect on the spatial distribution patterns of the PD, the WPG and the WSS on the lumen surface, regarding the locations of the maximum and the minimum of each quantity. Conclusions The observations from this study indicated that the ways how pressure and velocity boundary conditions are imposed in computational models have considerable impact on flow velocity and shear stress predictions. Accuracy of in vivo measurements of blood pressure and velocity is of great importance for reliable model predictions.
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470
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Sakellarios AI, Bizopoulos P, Stefanou K, Athanasiou LS, Papafaklis MI, Bourantas CV, Naka KK, Michalis LK, Fotiadis DI. A proof-of-concept study for predicting the region of atherosclerotic plaque development based on plaque growth modeling in carotid arteries. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2015:6552-6555. [PMID: 26737794 DOI: 10.1109/embc.2015.7319894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work, we present a computational model for plaque growth utilizing magnetic resonance data of a patient's carotid artery. More specifically, we model blood flow utilizing the Navier-Stokes equations, as well as LDL and HDL transport using the convection-diffusion equation in the arterial lumen. The accumulated LDL in the arterial wall is oxidized considering the protective effect of HDL. Macrophages recruitment and foam cells formation are the final step of the proposed multi-level modeling approach of the plaque growth. The simulated results of our model are compared with the follow-up MRI findings in 12 months regarding the change to the arterial wall thickness. WSS and LDL may indicate potential regions of plaque growth (R(2)=0.35), but the contribution of foam cells formation, macrophages and oxidized LDL increased the prediction significantly (R(2)=0.75).
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471
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Mekonnen G, Corban MT, Hung OY, Eshtehardi P, Eapen DJ, Al-Kassem H, Rasoul-Arzrumly E, Gogas BD, McDaniel MC, Pielak T, Thorball CW, Sperling L, Quyyumi AA, Samady H. Plasma soluble urokinase-type plasminogen activator receptor level is independently associated with coronary microvascular function in patients with non-obstructive coronary artery disease. Atherosclerosis 2014; 239:55-60. [PMID: 25574858 DOI: 10.1016/j.atherosclerosis.2014.12.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 12/02/2014] [Accepted: 12/15/2014] [Indexed: 12/27/2022]
Abstract
BACKGROUND Soluble urokinase-type plasminogen activator receptor (suPAR) is a novel biomarker released from leukocytes and endothelial cells that has been associated with atherosclerotic cardiovascular disease. We hypothesized that plasma suPAR level is an independent predictor of coronary microvascular function. METHODS Coronary blood flow velocity and plasma suPAR levels were evaluated in patients with non-obstructive coronary artery disease. Coronary flow reserve (CFR) was calculated as the ratio of hyperemic to basal average peak blood flow velocity and coronary microvascular dysfunction was defined as CFR ≤ 2.0 in the setting of a fractional flow reserve value of ≥0.75. Plasma suPAR levels were measured using ELISA technique. The association between suPAR and CFR was investigated using univariate and multivariate regression analyses. RESULTS In 66 patients, 47% were men, 26% had diabetes, 68% had hypertension and 76% had dyslipidemia. Mean age was 55 ± 12 years and median suPAR level 2.82 (2.08-3.40) ng/mL. Plasma suPAR levels correlated with age (r = 0.31, p = 0.01), body mass index (r = 0.25, p = 0.04) and high-sensitivity C-reactive protein (hs-CRP) (r = 0.33, p = 0.009). While median suPAR level was not significantly different in patients with different cardiovascular risk factors, patients on statin therapy had significantly higher suPAR level (p = 0.03). SuPAR correlated negatively with CFR and, after multivariate adjustment for established cardiovascular risk factors, medications profiles and hs-CRP, suPAR remained an independent predictor of CFR (B = -0.30, p = 0.04), indicating an independent association between suPAR level and coronary microvascular function. CONCLUSIONS In this cross-sectional study, plasma suPAR level was an independent predictor of coronary microvascular function. Larger prospective clinical trials are warranted to investigate the prognostic value of this novel biomarker and the role of immune dysregulation in coronary microvascular disease.
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Affiliation(s)
- Girum Mekonnen
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Michel T Corban
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Olivia Y Hung
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Parham Eshtehardi
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Danny J Eapen
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Hatem Al-Kassem
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Emad Rasoul-Arzrumly
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Bill D Gogas
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael C McDaniel
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Tomasz Pielak
- Clinical Research Center, Copenhagen University Hospital, Hvidovre, Denmark
| | | | - Laurence Sperling
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Arshed A Quyyumi
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Habib Samady
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
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472
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Corban MT, Hung OY, Timmins LH, Samady H. Reply: Myocardial bridging. J Am Coll Cardiol 2014; 64:2179-81. [PMID: 25457409 DOI: 10.1016/j.jacc.2014.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 09/08/2014] [Indexed: 02/08/2023]
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473
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Madssen E, Moholdt T, Videm V, Wisløff U, Hegbom K, Wiseth R. Coronary atheroma regression and plaque characteristics assessed by grayscale and radiofrequency intravascular ultrasound after aerobic exercise. Am J Cardiol 2014; 114:1504-11. [PMID: 25248813 DOI: 10.1016/j.amjcard.2014.08.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/15/2014] [Accepted: 08/15/2014] [Indexed: 12/14/2022]
Abstract
The aim of the present study was to investigate effects of aerobic interval training (AIT) versus moderate continuous training (MCT) on coronary atherosclerosis in patients with significant coronary artery disease on optimal medical treatment. Thirty-six patients were randomized to AIT (intervals at ≈ 90% of peak heart rate) or MCT (continuous exercise at ≈ 70% of peak heart rate) 3 times a week for 12 weeks after intracoronary stent implantation. Grayscale and radiofrequency intravascular ultrasounds (IVUS) were performed at baseline and follow-up. The primary end point was the change in plaque burden, and the secondary end points were change in necrotic core and plaque vulnerability. Separate lesions were classified using radiofrequency IVUS criteria. We demonstrated that necrotic core was reduced in both groups in defined coronary segments (AIT -3.2%, MCT -2.7%, p <0.05) and in separate lesions (median change -2.3% and -0.15 mm(3), p <0.05). Plaque burden was reduced by 10.7% in separate lesions independent of intervention group (p = 0.06). No significant differences in IVUS parameters were found between exercise groups. A minority of separate lesions were transformed in terms of plaque vulnerability during follow-up with large individual differences between and within patients. In conclusion, changes in coronary artery plaque structure or morphology did not differ between patients who underwent AIT or MCT. The combination of regular aerobic exercise and optimal medical treatment for 12 weeks induced a moderate regression of necrotic core and plaque burden in IVUS-defined coronary lesions.
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474
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The study on hemodynamic effect of varied support models of BJUT-II VAD on coronary artery: a primary CFD study. ASAIO J 2014; 60:643-51. [PMID: 25373559 DOI: 10.1097/mat.0000000000000137] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BJUT-II VAD (Beijing University of Technology ventricular assist device II) is a novel left ventricular assist device. Because of the special connection between the pump and native heart, the hemodynamic effects of BJUT-II VAD on coronary artery are still unclear. Hence, numerical simulations have been conducted to clarify changes in hemodynamic effects of different support modes. A patient-specific left coronary arterial geometric model is reconstructed based on the computed tomography (CT) data. Three support modes, "constant speed mode," "co-pulse mode," and "counter pulse mode," are used in this study. The wall shear stress (WSS), wall shear stress gradient (WSSG), cycle-averaged wall shear stress (avWSS), oscillatory shear index (OSI), and the flow pattern are calculated to evaluate the hemodynamic states of coronary artery. The computational results demonstrate that the hemodynamic states of coronary artery are directly affected by the support modes. The co-pulse modes could achieve the highest blood perfusion (constant speed: 153 ml/min vs. co-pulse: 775 ml/min vs. counter pulse: 140 ml/min) and the highest avWSS (constant speed: 18.1 Pa vs. co-pulse: 42.6 Pa vs. counter pulse: 22.6 Pa). In addition, both the WSS and WSSG at the time of peak blood velocity under the constant speed mode are lower than those under other two support modes. In contrast, the counter pulse mode generates the highest OSI value (constant speed: 0.365 vs. co-pulse: 0.379 vs. counter pulse: 0.426). BJUT-II VAD under co-pulse mode may have benefits for improving coronary perfusion and preventing the development of atherosclerosis; however, the constant speed mode may have benefit for preventing the development of plaque vulnerability.
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475
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Feng C, Hua T, Xu Y, Liu XY, Huang J. Arterial remodeling of basilar atherosclerosis in isolated pontine infarction. Neurol Sci 2014; 36:547-51. [PMID: 25367406 DOI: 10.1007/s10072-014-1994-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/28/2014] [Indexed: 11/29/2022]
Abstract
Isolated pontine infarctions are usually classified as paramedian pontine infarction (PPI) and lacunar pontine infarction (LPI). Although they have different shapes and locations, some recent studies proved that they might both be associated with basilar artery atherosclerosis in pathogenesis. This study aimed to explore the difference of basilar artery remodeling between two subtypes of pontine infarctions. Patients with PPI or LPI were scanned by High-resolution MRI (HR-MRI). The MR images of patients with basilar artery atherosclerosis were further analyzed to measure the vessel, lumen and wall areas at different segments of basilar arteries. Stenosis rate and remodeling index were calculated according to which arterial remodeling was divided into positive, intermediate and negative remodeling. Vascular risk factors and remodeling-related features were compared between PPI and LPI, and also between patients with and without positive remodeling. 34 patients with PPI and 21 patients with LPI had basilar artery atherosclerosis identified by HR-MRI. Positive remodeling was dominant in LPI group while in PPI group, three subtypes of remodeling were equal. Patients with positive remodeling had higher levels of low-density lipoprotein and homocysteine. Positive remodeling of basilar artery might reflect the low stability of basilar atherosclerotic plaques, which was more closely associated with LPI than PPI.
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Affiliation(s)
- Chao Feng
- Department of Neurology, Shanghai Tenth People's Hospital of Tongji University, Middle Yanchang Rd. 301#, Zhabei District, Shanghai, China
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476
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Vergallo R, Papafaklis MI, Yonetsu T, Bourantas CV, Andreou I, Wang Z, Fujimoto JG, McNulty I, Lee H, Biasucci LM, Crea F, Feldman CL, Michalis LK, Stone PH, Jang IK. Endothelial shear stress and coronary plaque characteristics in humans: combined frequency-domain optical coherence tomography and computational fluid dynamics study. Circ Cardiovasc Imaging 2014; 7:905-911. [PMID: 25190591 DOI: 10.1161/circimaging.114.001932] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 09/03/2014] [Indexed: 01/24/2023]
Abstract
BACKGROUND Despite the exposure of the entire vasculature to the atherogenic effects of systemic risk factors, atherosclerotic plaques preferentially develop at sites with disturbed flow. This study aimed at exploring in vivo the relationship between local endothelial shear stress (ESS) and coronary plaque characteristics in humans using computational fluid dynamics and frequency-domain optical coherence tomography. METHODS AND RESULTS Three-dimensional coronary artery reconstruction was performed in 21 patients (24 arteries) presenting with acute coronary syndrome using frequency-domain optical coherence tomography and coronary angiography. Each coronary artery was divided into sequential 3-mm segments and analyzed for the assessment of local ESS and plaque characteristics. A total of 146 nonculprit segments were evaluated. Compared with segments with higher ESS [≥1 Pascal (Pa)], those with low ESS (<1 Pa) showed higher prevalence of lipid-rich plaques (37.5% versus 20.0%; P=0.019) and thin-cap fibroatheroma (12.5% versus 2.0%; P=0.037). Overall, lipid plaques in segments with low ESS had thinner fibrous cap (115 μm [63-166] versus 170 μm [107-219]; P=0.004) and higher macrophage density (normalized standard deviation: 8.4% [4.8-12.6] versus 6.2% [4.2-8.8]; P=0.017). Segments with low ESS showed more superficial calcifications (minimum calcification depth: 93 μm [50-140] versus 152 μm [105-258]; P=0.049) and tended to have higher prevalence of spotty calcifications (26.0% versus 12.0%; P=0.076). CONCLUSIONS Coronary regions exposed to low ESS are associated with larger lipid burden, thinner fibrous cap, and higher prevalence of thin-cap fibroatheroma in humans. Frequency-domain optical coherence tomography-based assessment of ESS and wall characteristics may be useful in identifying vulnerable coronary regions. CLINICAL TRIAL REGISTRATION URL http://www.clinicaltrials.gov. Unique identifier: NCT01110538.
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Affiliation(s)
- Rocco Vergallo
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Michail I Papafaklis
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Taishi Yonetsu
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Christos V Bourantas
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Ioannis Andreou
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Zhao Wang
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - James G Fujimoto
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Iris McNulty
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Hang Lee
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Luigi M Biasucci
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Filippo Crea
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Charles L Feldman
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Lampros K Michalis
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Peter H Stone
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
| | - Ik-Kyung Jang
- From the Department of Medicine, Cardiology Division (R.V., T.Y., I.M., I.-K.J.) and Department of Medicine, Biostatistics Center (H.L.), Massachusetts General Hospital, and Department of Medicine, Cardiovascular Division, Brigham & Women's Hospital (M.I.P., I.A., C.L.F., P.H.S.), Harvard Medical School, Boston, MA; Department of Interventional Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (C.V.B.); Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (Z.W., J.G.F.); Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy (L.M.B., F.C.); and Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece (L.K.M.)
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477
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Co-localization of Disturbed Flow Patterns and Occlusive Cardiac Allograft Vasculopathy Lesion Formation in Heart Transplant Patients. Cardiovasc Eng Technol 2014; 6:25-35. [DOI: 10.1007/s13239-014-0198-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
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478
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Focal association between wall shear stress and clinical coronary artery disease progression. Ann Biomed Eng 2014; 43:94-106. [PMID: 25316593 DOI: 10.1007/s10439-014-1155-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 10/07/2014] [Indexed: 10/24/2022]
Abstract
Wall shear stress (WSS) has been investigated as a potential prospective marker to identify rapidly progressing coronary artery disease (CAD) and potential for lesions to acquire vulnerable characteristics. Previous investigations, however, are limited by a lack of understanding of the focal association between WSS and CAD progression (i.e., data are notably spatially averaged). Thus, the aim of this investigation was to examine the focal association between WSS and coronary atherosclerosis progression, and compare these results to those determined by spatial averaging. Five patients with CAD underwent baseline and 6-month follow-up angiographic and virtual histology-intravascular ultrasound imaging to quantify CAD progression. Patient-specific computational fluid dynamics models were constructed to compute baseline WSS values, which were either averaged around the entire artery circumference or examined in focal regions (sectors). Analysis of data within each sector (n = 3871) indicated that circumferentially averaged and sector WSS values were statistically different (p < 0.05) and exhibited poor agreement (concordance correlation coefficient = 0.69). Furthermore, differences were observed between the analysis techniques when examining the association of WSS and CAD progression. This investigation highlights the importance of examining spatially heterogeneous variables at a focal level to reduce the affect of data reduction and warrants implementation in a larger clinical study to determine the predictive power in prospectively identifying rapidly progressing and/or vulnerable coronary plaques.
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479
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Sennoga CA, Seddon JM, Frueh JA, Zhang D, Haskard DO, Eckersley RJ, Tang MX. Dynamics of targeted microbubble adhesion under pulsatile compared with steady flow. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:2445-2457. [PMID: 25023113 DOI: 10.1016/j.ultrasmedbio.2014.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 03/05/2014] [Accepted: 03/10/2014] [Indexed: 06/03/2023]
Abstract
Hemodynamic flow variations at low fluid shear stress are thought to play a critical role in local atherosclerotic plaque initiation and development and to affect plaque instability. Targeted microbubbles are being developed as intravascular agents for identifying atherosclerotic lesions using ultrasound. How variations in local hydrodynamic flow influence the adhesiveness of targeted microbubbles is not well understood. We postulated that rates of targeted microbubble binding and accumulation differ when subjected to steady flow (SF) as compared with oscillatory or pulsatile flow (PF), because PF imposes non-uniform blood rheology and periodic acceleration and deceleration of blood velocity, when compared with SF. We assessed the binding rates of targeted microbubbles in seven randomly assigned PF and seven matched SF replicate runs at low (<1 Pa) and intermediate (≥1 and <2.5 Pa) wall shear stress (WSS) by drawing 4.8 × 10(6) microbubbles mL(-1) over streptavidin-coated substrates, immobilized within a parallel plate flow chamber at a calculated density of 81 binding sites μm(-2). Selective binding and accumulation of targeted microbubbles was recorded in a single field of view using real-time video microscopy. Microbubble accumulation was modeled to obtain flow-mediated microbubble binding kinetics (amplitude, A, and rate constant, k). PF elicited higher microbubble accumulation rates, in comparison to SF. The rates of microbubble accumulation differed significantly between PF and SF (p < 0.05) at intermediate WSS but not at low WSS (p > 0.05). The rate of microbubble accumulation decreased as WSS increased.
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Affiliation(s)
- Charles A Sennoga
- Department of Bioengineering, Imperial College London, London, United Kingdom; Imaging Sciences Department, Imperial College London, London, United Kingdom.
| | - John M Seddon
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Jennifer A Frueh
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Dong Zhang
- Key Laboratory of Modern Acoustics of Ministry of Education, Institute of Acoustics, Nanjing University, Nanjing, China
| | - Dorian O Haskard
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Robert J Eckersley
- Division of Imaging Sciences, Biomedical Engineering Department, King's College London, London, United Kingdom
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, United Kingdom
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480
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IVUS-based FSI models for human coronary plaque progression study: components, correlation and predictive analysis. Ann Biomed Eng 2014; 43:107-21. [PMID: 25245219 DOI: 10.1007/s10439-014-1118-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 09/06/2014] [Indexed: 10/24/2022]
Abstract
Atherosclerotic plaque progression is believed to be associated with mechanical stress conditions. Patient follow-up in vivo intravascular ultrasound coronary plaque data were acquired to construct fluid-structure interaction (FSI) models with cyclic bending to obtain flow wall shear stress (WSS), plaque wall stress (PWS) and strain (PWSn) data and investigate correlations between plaque progression measured by wall thickness increase (WTI), cap thickness increase (CTI), lipid depth increase (LDI) and risk factors including wall thickness (WT), WSS, PWS, and PWSn. Quarter average values (n = 178-1016) of morphological and mechanical factors from all slices were obtained for analysis. A predictive method was introduced to assess prediction accuracy of risk factors and identify the optimal predictor(s) for plaque progression. A combination of WT and PWS was identified as the best predictor for plaque progression measured by WTI. Plaque WT had best overall correlation with WTI (r = -0.7363, p < 1E-10), cap thickness (r = 0.4541, p < 1E-10), CTI (r = -0.4217, p < 1E-8), LD (r = 0.4160, p < 1E-10), and LDI (r = -0.4491, p < 1E-10), followed by PWS (with WTI: (r = -0.3208, p < 1E-10); cap thickness: (r = 0.4541, p < 1E-10); CTI: (r = -0.1719, p = 0.0190); LD: (r = -0.2206, p < 1E-10); LDI: r = 0.1775, p < 0.0001). WSS had mixed correlation results.
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481
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Kwak BR, Bäck M, Bochaton-Piallat ML, Caligiuri G, Daemen MJAP, Davies PF, Hoefer IE, Holvoet P, Jo H, Krams R, Lehoux S, Monaco C, Steffens S, Virmani R, Weber C, Wentzel JJ, Evans PC. Biomechanical factors in atherosclerosis: mechanisms and clinical implications. Eur Heart J 2014; 35:3013-20, 3020a-3020d. [PMID: 25230814 DOI: 10.1093/eurheartj/ehu353] [Citation(s) in RCA: 343] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Blood vessels are exposed to multiple mechanical forces that are exerted on the vessel wall (radial, circumferential and longitudinal forces) or on the endothelial surface (shear stress). The stresses and strains experienced by arteries influence the initiation of atherosclerotic lesions, which develop at regions of arteries that are exposed to complex blood flow. In addition, plaque progression and eventually plaque rupture is influenced by a complex interaction between biological and mechanical factors-mechanical forces regulate the cellular and molecular composition of plaques and, conversely, the composition of plaques determines their ability to withstand mechanical load. A deeper understanding of these interactions is essential for designing new therapeutic strategies to prevent lesion development and promote plaque stabilization. Moreover, integrating clinical imaging techniques with finite element modelling techniques allows for detailed examination of local morphological and biomechanical characteristics of atherosclerotic lesions that may be of help in prediction of future events. In this ESC Position Paper on biomechanical factors in atherosclerosis, we summarize the current 'state of the art' on the interface between mechanical forces and atherosclerotic plaque biology and identify potential clinical applications and key questions for future research.
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Affiliation(s)
- Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, CMU, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland
| | | | | | | | | | | | - Imo E Hoefer
- University Medical Center Urecht, Utrecht, The Netherlands
| | | | | | | | | | | | | | | | | | | | - Paul C Evans
- Department of Cardiovascular Science, Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
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482
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Sun Z, Xu L. Computational fluid dynamics in coronary artery disease. Comput Med Imaging Graph 2014; 38:651-63. [PMID: 25262321 DOI: 10.1016/j.compmedimag.2014.09.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/22/2014] [Accepted: 09/03/2014] [Indexed: 01/01/2023]
Abstract
Computational fluid dynamics (CFD) is a widely used method in mechanical engineering to solve complex problems by analysing fluid flow, heat transfer, and associated phenomena by using computer simulations. In recent years, CFD has been increasingly used in biomedical research of coronary artery disease because of its high performance hardware and software. CFD techniques have been applied to study cardiovascular haemodynamics through simulation tools to predict the behaviour of circulatory blood flow in the human body. CFD simulation based on 3D luminal reconstructions can be used to analyse the local flow fields and flow profiling due to changes of coronary artery geometry, thus, identifying risk factors for development and progression of coronary artery disease. This review aims to provide an overview of the CFD applications in coronary artery disease, including biomechanics of atherosclerotic plaques, plaque progression and rupture; regional haemodynamics relative to plaque location and composition. A critical appraisal is given to a more recently developed application, fractional flow reserve based on CFD computation with regard to its diagnostic accuracy in the detection of haemodynamically significant coronary artery disease.
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Affiliation(s)
- Zhonghua Sun
- Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth, Western Australia 6845, Australia.
| | - Lei Xu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
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483
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Rubenstein DA, Yin W. Hypergravity and Hypobaric Hypoxic Conditions Promote Endothelial Cell and Platelet Activation. High Alt Med Biol 2014; 15:396-405. [DOI: 10.1089/ham.2013.1139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- David A. Rubenstein
- Work completed at School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma
- Present address: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York
| | - Wei Yin
- Work completed at School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma
- Present address: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York
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484
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Schrauwen JTC, Koeze DJ, Wentzel JJ, van de Vosse FN, van der Steen AFW, Gijsen FJH. Fast and Accurate Pressure-Drop Prediction in Straightened Atherosclerotic Coronary Arteries. Ann Biomed Eng 2014; 43:59-67. [DOI: 10.1007/s10439-014-1090-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/05/2014] [Indexed: 11/24/2022]
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485
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King SB. Getting outside of our comfort zone. JACC Cardiovasc Interv 2014; 7:825-6. [PMID: 25060029 DOI: 10.1016/j.jcin.2014.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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486
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Koyama S, Itatani K, Yamamoto T, Miyazaki S, Kitamura T, Taketani T, Ono M, Miyaji K. Optimal bypass graft design for left anterior descending and diagonal territory in multivessel coronary disease. Interact Cardiovasc Thorac Surg 2014; 19:406-13. [PMID: 24893870 DOI: 10.1093/icvts/ivu182] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Coronary artery bypass grafting for multivessel disease requires an appropriate graft design to avoid the competition of flow between the graft and the native vessel in order to achieve a sufficient coronary flow and durable graft patency. METHODS Three-dimensional computational models of the left coronary artery were created based on the angiographic data. Three stenosis patterns of 75 and 90% combinations were created in the left anterior descending artery (LAD), the diagonal branch (Dx) and the circumflex artery (LCx). The left internal thoracic artery (LITA) was anastomosed to the LAD, and separate saphenous vein grafts (SVGs) were anastomosed to the Dx and the LCx in the 'Independent' model. The 'Sequential' model included sequential SVG anastomoses to the Dx and the LCx with a left internal thoracic artery-left anterior descending artery bypass, and Y-composite arterial grafts to LAD and Dx were created in the 'Composite' model. RESULTS The 'Independent' model had high reverse flow from the Dx to the LAD in systole, resulting in decreased LITA flow when Dx stenosis was mild. The 'Sequential' model also had reverse flow in diastole, resulting in additional LAD flow. The 'Composite' model distributed increased flow to the Dx when Dx stenosis was severe, resulting in decreased flow to the LAD. CONCLUSIONS Systematic flow evaluation is beneficial for determining the optimal bypass graft arrangement in patients with multivessel disease. Individual SVG anastomoses to the Dx and the LCx are not desirable when Dx stenosis is not severe and a Y-composite arterial graft to the LAD and the Dx is not desirable when Dx stenosis is severe.
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Affiliation(s)
- Sachi Koyama
- Department of Cardiovascular Surgery, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan Department of Cardiac Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Keiichi Itatani
- Department of Cardiovascular Surgery, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan Department of Hemodynamic Analysis, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Tadashi Yamamoto
- Department of Cardiology, Hokkaido Cardiovascular Hospital, Hokkaido, Japan
| | - Shohei Miyazaki
- Department of Hemodynamic Analysis, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Tadashi Kitamura
- Department of Cardiovascular Surgery, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Tuyoshi Taketani
- Department of Cardiovascular Surgery, Mitsui Memorial Hospital, Chiyoda, Tokyo, Japan
| | - Minoru Ono
- Department of Cardiac Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Kagami Miyaji
- Department of Cardiovascular Surgery, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
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487
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Numerical simulation and clinical implications of stenosis in coronary blood flow. BIOMED RESEARCH INTERNATIONAL 2014; 2014:514729. [PMID: 24987691 PMCID: PMC4058689 DOI: 10.1155/2014/514729] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/29/2014] [Indexed: 01/11/2023]
Abstract
Fractional flow reserve (FFR) is the gold standard to guide coronary interventions. However it can only be obtained via invasive angiography. The objective of this study is to propose a noninvasive method to determine FFRCT by combining computed tomography angiographic (CTA) images and computational fluid dynamics (CFD) technique. Utilizing the method, this study explored the effects of diameter stenosis (DS), stenosis length, and location on FFRCT. The baseline left anterior descending (LAD) model was reconstructed from CTA of a healthy porcine heart. A series of models were created by adding an idealized stenosis (with DS from 45% to 75%, stenosis length from 4 mm to 16 mm, and at 4 locations separately). Through numerical simulations, it was found that FFRCT decreased (from 0.89 to 0.74), when DS increased (from 45% to 75%). Similarly, FFRCT decreased with the increase of stenosis length and the stenosis located at proximal position had lower FFRCT than that at distal position. These findings are consistent with clinical observations. Applying the same method on two patients' CTA images yielded FFRCT close to the FFR values obtained via invasive angiography. The proposed noninvasive computation of FFRCT is promising for clinical diagnosis of CAD.
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488
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Zhang JM, Zhong L, Su B, Wan M, Yap JS, Tham JPL, Chua LP, Ghista DN, Tan RS. Perspective on CFD studies of coronary artery disease lesions and hemodynamics: a review. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:659-680. [PMID: 24459034 DOI: 10.1002/cnm.2625] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 10/30/2013] [Accepted: 11/04/2013] [Indexed: 06/03/2023]
Abstract
Coronary artery disease (CAD) is the most common cardiovascular disease. Early diagnosis of CAD's physiological significance is of utmost importance for guiding individualized risk-tailored treatment strategies. In this paper, we first review the state-of-the-art clinical diagnostic indices to quantify the severity of CAD and the associated invasive and noninvasive imaging technologies in order to quantify the anatomical parameters of diameter stenosis, area stenosis, and hemodynamic indices of coronary flow reserve and fractional flow reserve. With the development of computational technologies and CFD methods, tremendous progress has been made in applying image-based CFD simulation techniques to elucidate the effects of hemodynamics in vascular pathophysiology toward the initialization and progression of CAD. So then, we review the advancements of CFD technologies in patient-specific modeling, involving the development of geometry reconstruction, boundary conditions, and fluid-structure interaction. Next, we review the applications of CFD to stenotic sites, in order to compute their hemodynamic parameters and study the relationship between the hemodynamic conditions and the clinical indices, to thereby assess the amount of viable myocardium and candidacy for percutaneous coronary intervention. Finally, we review the strengths and limitations of current researches of applying CFD to CAD studies.
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Affiliation(s)
- Jun-Mei Zhang
- National Heart Center Singapore, Mistri Wing 17, 3rd Hospital Avenue, 168752, Singapore
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489
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Fujimoto M, Takao H, Suzuki T, Shobayashi Y, Mayor F, Tateshima S, Yamamoto M, Murayama Y, Viñuela F. Temporal correlation between wall shear stress and in-stent stenosis after Wingspan stent in swine model. AJNR Am J Neuroradiol 2014; 35:994-8. [PMID: 24231853 DOI: 10.3174/ajnr.a3773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE A recent randomized clinical trial on intracranial atherosclerosis was discontinued because of the higher frequency of stroke and death in the angioplasty and stent placement group than in the medical treatment group. An in-depth understanding of the relationship between biologic responses and flow dynamics is still required to identify the current limitations of intracranial stent placement. MATERIALS AND METHODS Five Wingspan stents were deployed in tapered swine ascending pharyngeal arteries. Temporal wall shear stress distributions and in-stent stenosis were evaluated at days 0, 7, 14, and 28 after stent placement. The physiologic role of wall shear stress was analyzed regarding its correlation with in-stent stenosis. RESULTS In-stent stenosis reached a peak of nearly 40% at day 14 and decreased mainly at the distal stent segment until day 28. The wall shear stress demonstrated a characteristic pattern with time on the basis of the in-stent stenosis change. The wall shear stress gradient increased from the proximal to distal segment until day 14. At day 28, the trend was reversed dramatically, decreasing from the proximal to the distal segment. A significant correlation between the in-stent stenosis growth until day 14 and low wall shear stress values just after stent placement was detected. In-stent stenosis regression between days 14 and 28 was also associated with the high wall shear stress values at day 14. CONCLUSIONS These data suggest that the physiologic wall shear stress can control the biphasic in-stent stenosis change in tapered arteries.
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Affiliation(s)
- M Fujimoto
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California
| | - H Takao
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CaliforniaDepartment of Neurosurgery (H.T., T.S., Y.M.), Jikei University School of Medicine, Tokyo, Japan
| | - T Suzuki
- Department of Neurosurgery (H.T., T.S., Y.M.), Jikei University School of Medicine, Tokyo, JapanDepartment of Mechanical Engineering (T.S., M.Y.), Graduate School of Engineering, Tokyo University of Science, Tokyo, Japan
| | - Y Shobayashi
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California
| | - F Mayor
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California
| | - S Tateshima
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California
| | - M Yamamoto
- Department of Mechanical Engineering (T.S., M.Y.), Graduate School of Engineering, Tokyo University of Science, Tokyo, Japan
| | - Y Murayama
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CaliforniaDepartment of Neurosurgery (H.T., T.S., Y.M.), Jikei University School of Medicine, Tokyo, Japan
| | - F Viñuela
- From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California
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490
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Maurovich-Horvat P, Ferencik M, Voros S, Merkely B, Hoffmann U. Comprehensive plaque assessment by coronary CT angiography. Nat Rev Cardiol 2014; 11:390-402. [PMID: 24755916 DOI: 10.1038/nrcardio.2014.60] [Citation(s) in RCA: 279] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Most acute coronary syndromes are caused by sudden luminal thrombosis due to atherosclerotic plaque rupture or erosion. Preventing such an event seems to be the only effective strategy to reduce mortality and morbidity of coronary heart disease. Coronary lesions prone to rupture have a distinct morphology compared with stable plaques, and provide a unique opportunity for noninvasive imaging to identify vulnerable plaques before they lead to clinical events. The submillimeter spatial resolution and excellent image quality of modern computed tomography (CT) scanners allow coronary atherosclerotic lesions to be detected, characterized, and quantified. Large plaque volume, low CT attenuation, napkin-ring sign, positive remodelling, and spotty calcification are all associated with a high risk of acute cardiovascular events in patients. Computation fluid dynamics allow the calculation of lesion-specific endothelial shear stress and fractional flow reserve, which add functional information to plaque assessment using CT. The combination of morphologic and functional characteristics of coronary plaques might enable noninvasive detection of vulnerable plaques in the future.
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Affiliation(s)
- Pál Maurovich-Horvat
- MTA-SE Lendület Cardiovascular Imaging Research Group, Heart and Vascular Centre, Semmelweis University, 68 Varosmajor ut, 1025 Budapest, Hungary
| | - Maros Ferencik
- Cardiac MR PET CT Program, Division of Cardiology and Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge Street, Suite 400, Boston, MA 02114. USA
| | - Szilard Voros
- Stony Brook University, 101 Nicolls Road, Stony Brook, NY 11794 USA
| | - Béla Merkely
- MTA-SE Lendület Cardiovascular Imaging Research Group, Heart and Vascular Centre, Semmelweis University, 68 Varosmajor ut, 1025 Budapest, Hungary
| | - Udo Hoffmann
- Cardiac MR PET CT Program, Division of Cardiology and Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge Street, Suite 400, Boston, MA 02114. USA
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491
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Human coronary plaque wall thickness correlated positively with flow shear stress and negatively with plaque wall stress: an IVUS-based fluid-structure interaction multi-patient study. Biomed Eng Online 2014; 13:32. [PMID: 24669780 PMCID: PMC3977946 DOI: 10.1186/1475-925x-13-32] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/07/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Atherosclerotic plaque progression and rupture are believed to be associated with mechanical stress conditions. In this paper, patient-specific in vivo intravascular ultrasound (IVUS) coronary plaque image data were used to construct computational models with fluid-structure interaction (FSI) and cyclic bending to investigate correlations between plaque wall thickness and both flow shear stress and plaque wall stress conditions. METHODS IVUS data were acquired from 10 patients after voluntary informed consent. The X-ray angiogram was obtained prior to the pullback of the IVUS catheter to determine the location of the coronary artery stenosis, vessel curvature and cardiac motion. Cyclic bending was specified in the model representing the effect by heart contraction. 3D anisotropic FSI models were constructed and solved to obtain flow shear stress (FSS) and plaque wall stress (PWS) values. FSS and PWS values were obtained for statistical analysis. Correlations with p < 0.05 were deemed significant. RESULTS Nine out of the 10 patients showed positive correlation between wall thickness and flow shear stress. The mean Pearson correlation r-value was 0.278 ± 0.181. Similarly, 9 out of the 10 patients showed negative correlation between wall thickness and plaque wall stress. The mean Pearson correlation r-value was -0.530 ± 0.210. CONCLUSION Our results showed that plaque vessel wall thickness correlated positively with FSS and negatively with PWS. The patient-specific IVUS-based modeling approach has the potential to be used to investigate and identify possible mechanisms governing plaque progression and rupture and assist in diagnosis and intervention procedures. This represents a new direction of research. Further investigations using more patient follow-up data are warranted.
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492
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van Wyk S, Prahl Wittberg L, Fuchs L. Atherosclerotic indicators for blood-like fluids in 90-degree arterial-like bifurcations. Comput Biol Med 2014; 50:56-69. [PMID: 24835086 DOI: 10.1016/j.compbiomed.2014.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 02/26/2014] [Accepted: 03/15/2014] [Indexed: 10/25/2022]
Abstract
The identification of regions prone to atherogenesis in the arterial network is compounded by the complex, slow interaction of mechanical and biomechanical processes. In recent times simplifications to the analysis of the near wall hemodynamics have been sought-after to identify plaque prone regions. Mean parameters have been defined to analyze the common fluid mechanical hypotheses considering the role of wall shear stress (WSS) variations in the pathological changes to the endothelium. In this study well known WSS indicators are applied to varying flow conditions of blood-like fluids in a 90-degree arterial bifurcation. The conventional indicators identify two distinct, focal regions that correlate with a known plaque prone location near arterial bifurcations. The results however demonstrate that the interpretation of the indicators can be difficult under varying flow conditions unless complementary parameters are considered simultaneously. A new indicator is also suggested that extracts the peaks of the temporal WSS gradients (PTWSSGs) and is shown to co-incide well with plaque prone regions. The PTWSSG could be used as a complimentary atherogenic indicator in bifurcating arteries, thereby expanding cardiovascular disease studies to the consideration of alternative fluid mechanical hypotheses. The inclusion of a non-Newtonian model is important in predicting the WSS and temporal WSS gradient distributions near the bifurcation due to the separation bubble induced fluctuations in the shear. Atherogenic indicators could be misleading if non-Newtonian effects are excluded.
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Affiliation(s)
- Stevin van Wyk
- Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, Stockholm SE-100 44, Sweden
| | - Lisa Prahl Wittberg
- Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, Stockholm SE-100 44, Sweden.
| | - Laszlo Fuchs
- Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, Stockholm SE-100 44, Sweden
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493
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Corban MT, Hung OY, Eshtehardi P, Rasoul-Arzrumly E, McDaniel M, Mekonnen G, Timmins LH, Lutz J, Guyton RA, Samady H. Myocardial bridging: contemporary understanding of pathophysiology with implications for diagnostic and therapeutic strategies. J Am Coll Cardiol 2014; 63:2346-2355. [PMID: 24583304 DOI: 10.1016/j.jacc.2014.01.049] [Citation(s) in RCA: 199] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/24/2014] [Accepted: 01/28/2014] [Indexed: 12/30/2022]
Abstract
Patients with myocardial bridging are often asymptomatic, but this anomaly may be associated with exertional angina, acute coronary syndromes, cardiac arrhythmias, syncope, or even sudden cardiac death. This review presents our understanding of the pathophysiology of myocardial bridging and describes prevailing diagnostic modalities and therapeutic options for this challenging clinical entity.
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Affiliation(s)
- Michel T Corban
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Olivia Y Hung
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Parham Eshtehardi
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Emad Rasoul-Arzrumly
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Michael McDaniel
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Girum Mekonnen
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Lucas H Timmins
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA
| | - Jerre Lutz
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Robert A Guyton
- Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, GA
| | - Habib Samady
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA
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494
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Corban MT, Eshtehardi P, Suo J, McDaniel MC, Timmins LH, Rassoul-Arzrumly E, Maynard C, Mekonnen G, King S, Quyyumi AA, Giddens DP, Samady H. Combination of plaque burden, wall shear stress, and plaque phenotype has incremental value for prediction of coronary atherosclerotic plaque progression and vulnerability. Atherosclerosis 2014; 232:271-6. [DOI: 10.1016/j.atherosclerosis.2013.11.049] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 01/17/2023]
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495
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Tang D, Kamm RD, Yang C, Zheng J, Canton G, Bach R, Huang X, Hatsukami TS, Zhu J, Ma G, Maehara A, Mintz GS, Yuan C. Image-based modeling for better understanding and assessment of atherosclerotic plaque progression and vulnerability: data, modeling, validation, uncertainty and predictions. J Biomech 2014; 47:834-46. [PMID: 24480706 DOI: 10.1016/j.jbiomech.2014.01.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 01/30/2023]
Abstract
Medical imaging and image-based modeling have made considerable progress in recent years in identifying atherosclerotic plaque morphological and mechanical risk factors which may be used in developing improved patient screening strategies. However, a clear understanding is needed about what we have achieved and what is really needed to translate research to actual clinical practices and bring benefits to public health. Lack of in vivo data and clinical events to serve as gold standard to validate model predictions is a severe limitation. While this perspective paper provides a review of the key steps and findings of our group in image-based models for human carotid and coronary plaques and a limited review of related work by other groups, we also focus on grand challenges and uncertainties facing the researchers in the field to develop more accurate and predictive patient screening tools.
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Affiliation(s)
- Dalin Tang
- School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, China; Worcester Polytechnic Institute, Worcester, MA 01609, USA.
| | - Roger D Kamm
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chun Yang
- Worcester Polytechnic Institute, Worcester, MA 01609, USA; China Information Tech. Designing & Consulting Institute Co., Ltd., Beijing 100048, China
| | - Jie Zheng
- Mallinkcrodt Inst. of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Gador Canton
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Richard Bach
- Cardiovascular Division, Washington University, St. Louis, MO 63110, USA
| | - Xueying Huang
- School of Mathematical Sciences, Xiamen University, Xiamen, Fujian 361005, China
| | - Thomas S Hatsukami
- Division of Vascular Surgery, University of Washington, Seattle, WA, 98195, USA
| | - Jian Zhu
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing 210009, China
| | - Genshan Ma
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing 210009, China
| | | | - Gary S Mintz
- The Cardiovascular Research Foundation, NY, NY, USA
| | - Chun Yuan
- Deparment of Radiology, University of Washington, Seattle, WA 98195, USA
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496
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Tousoulis D, Papageorgiou N, Synetos A, Stefanadis C. Assessing vulnerable plaque: is shear stress enough? Int J Cardiol 2014; 172:e135-e138. [PMID: 24485228 DOI: 10.1016/j.ijcard.2013.12.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/22/2013] [Indexed: 11/22/2022]
Affiliation(s)
- Dimitris Tousoulis
- 1st Cardiology Department, Athens University Medical School, Hippokration Hospital, Greece.
| | - Nikolaos Papageorgiou
- 1st Cardiology Department, Athens University Medical School, Hippokration Hospital, Greece
| | - Andreas Synetos
- 1st Cardiology Department, Athens University Medical School, Hippokration Hospital, Greece
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497
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Rikhtegar F, Wyss C, Stok KS, Poulikakos D, Müller R, Kurtcuoglu V. Hemodynamics in coronary arteries with overlapping stents. J Biomech 2014; 47:505-11. [DOI: 10.1016/j.jbiomech.2013.10.048] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 09/17/2013] [Accepted: 10/26/2013] [Indexed: 01/20/2023]
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498
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Huang X, Yang C, Zheng J, Bach R, Muccigrosso D, Woodard PK, Tang D. Higher critical plaque wall stress in patients who died of coronary artery disease compared with those who died of other causes: a 3D FSI study based on ex vivo MRI of coronary plaques. J Biomech 2013; 47:432-7. [PMID: 24345380 DOI: 10.1016/j.jbiomech.2013.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/08/2013] [Accepted: 11/06/2013] [Indexed: 12/16/2022]
Abstract
Mechanical forces play an important role in the rupture of vulnerable plaques. This process is often associated with cardiovascular syndromes, such as heart attack and stroke. In this study, magnetic resonance imaging (MRI)-based models were used to investigate the association between plaque wall stress (PWS) and coronary artery disease (CAD). Ex vivo MRI data of coronary plaques from 12 patients were used to construct 12 three-dimensional (3D) fluid-structure interaction (FSI) computational models. Six of the patients had died from CAD and six had died from non-CAD causes. PWS was assessed using all nodal points on the lumen surface of each plaque. The maximum PWS from all possible vulnerable sites of each plaque was defined as the 3D critical plaque wall stress (CPWS). Mean 3D CPWS in the CAD group was 94.3% higher than that in the non-CAD group (265.6 vs. 136.7 kPa, P=0.0029). There was no statistically significant difference in global maximum plaque wall stress (GMPWS) between the two groups (P=0.347). There was also no statistically significant difference in plaque burden between the CAD group (84.4±5%) and the non-CAD group (82.0±8%, P=0.552). The results indicate that plaques from patients who died from CAD were associated with higher CPWS compared with those from patients who died from non-CAD causes. With further validation, analysis of CPWS may prove to be an important component in assessment of plaque vulnerability.
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Affiliation(s)
- Xueying Huang
- School of Mathematical Sciences, Xiamen University, 422 South Siming Road, Xiamen, Fujian 361005, China; Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA.
| | - Chun Yang
- Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA; China United Network Communications Co., Ltd., Beijing 100048, China
| | - Jie Zheng
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Richard Bach
- Cardiovascular Division, Washington University, St. Louis, MO 63110, USA
| | - David Muccigrosso
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Pamela K Woodard
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Dalin Tang
- Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA
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499
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Koskinas KC, Chatzizisis YS, Papafaklis MI, Coskun AU, Baker AB, Jarolim P, Antoniadis A, Edelman ER, Stone PH, Feldman CL. Synergistic effect of local endothelial shear stress and systemic hypercholesterolemia on coronary atherosclerotic plaque progression and composition in pigs. Int J Cardiol 2013; 169:394-401. [PMID: 24148915 PMCID: PMC4191915 DOI: 10.1016/j.ijcard.2013.10.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 10/05/2013] [Indexed: 01/06/2023]
Abstract
BACKGROUND Systemic risk factors and local hemodynamic factors both contribute to coronary atherosclerosis, but their possibly synergistic inter-relationship remains unknown. The purpose of this natural history study was to investigate the combined in-vivo effect of varying levels of systemic hypercholesterolemia and local endothelial shear stress (ESS) on subsequent plaque progression and histological composition. METHODS Diabetic, hyperlipidemic swine with higher systemic total cholesterol (TC) (n=4) and relatively lower TC levels (n=5) underwent three-vessel intravascular ultrasound (IVUS) at 3-5 consecutive time-points in-vivo. ESS was calculated serially using computational fluid dynamics. 3-D reconstructed coronary arteries were divided into 3mm-long segments (n=595), which were stratified according to higher vs. relatively lower TC and low (<1.2Pa) vs. higher local ESS (≥1.2Pa). Arteries were harvested at 9months, and a subset of segments (n=114) underwent histopathologic analyses. RESULTS Change of plaque volume (ΔPV) by IVUS over time was most pronounced in low-ESS segments from higher-TC animals. Notably, higher-ESS segments from higher-TC animals had greater ΔPV compared to low-ESS segments from lower-TC animals (p<0.001). The time-averaged ESS in segments that resulted in significant plaque increased with increasing TC levels (slope: 0.24Pa/100mg/dl; r=0.80; p<0.01). At follow-up, low-ESS segments from higher-TC animals had the highest mRNA levels of lipoprotein receptors and inflammatory mediators and, consequently, the greatest lipid accumulation and inflammation. CONCLUSIONS This study redefines the principle concept that "low" ESS promotes coronary plaque growth and vulnerability by demonstrating that: (i.) the pro-atherogenic threshold of low ESS is not uniform, but cholesterol-dependent; and (ii.) the atherogenic effects of local low ESS are amplified, and the athero-protective effects of higher ESS may be outweighed, by increasing cholesterol levels. Intense hypercholesterolemia and very low ESS are synergistic in favoring rapid atheroma progression and high-risk composition.
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Affiliation(s)
- Konstantinos C. Koskinas
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Yiannis S. Chatzizisis
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Michail I. Papafaklis
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Ahmet U. Coskun
- Mechanical and Industrial Engineering, Northeastern University, Boston, MA
| | - Aaron B. Baker
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Petr Jarolim
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Antonios Antoniadis
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Elazer R. Edelman
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Peter H. Stone
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Charles L. Feldman
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
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500
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Timmins LH, Suever JD, Eshtehardi P, McDaniel MC, Oshinski JN, Samady H, Giddens DP. Framework to co-register longitudinal virtual histology-intravascular ultrasound data in the circumferential direction. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:1989-1996. [PMID: 23797242 DOI: 10.1109/tmi.2013.2269275] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Considerable efforts have been directed at identifying prognostic markers for rapidly progressing coronary atherosclerotic lesions that may advance into a high-risk (vulnerable) state. Intravascular ultrasound (IVUS) has become a valuable clinical tool to study the natural history of coronary artery disease (CAD). While prospectively IVUS studies have provided tremendous insight on CAD progression, and its association with independent markers (e.g., wall shear stress), they are limited by the inability to examine the focal association between spatially heterogeneous variables (in both circumferential and axial directions). Herein, we present a framework to automatically co-register longitudinal (in-time) virtual histology-intravascular ultrasound (VH-IVUS) imaging data in the circumferential direction (i.e., rotate follow-up image so circumferential basis coincides with corresponding baseline image). Multivariate normalized cross correlation was performed on paired images (n = 636) from five patients using three independent VH-IVUS defined parameters: artery thickness, VH-IVUS defined plaque constituents, and VH-IVUS perivascular imaging data. Results exhibited high correlation between co-registration rotation angles determined automatically versus manually by an expert reader ( r(2) = 0.90). Furthermore, no significant difference between automatic and manual co-registration angles was observed ( 91.31 ±1.04(°) and 91.07 ±1.04(°), respectively; p = 0.48) and Bland-Altman analysis yielded excellent agreement ( bias = 0.24(°), 95% CI +/- 16.33(°)). In conclusion, we have developed, verified, and validated an algorithm that automatically co-registers VH-IVUS imaging data that will allow for the focal examination of CAD progression.
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