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Harte N, Obrist D, Caversaccio M, Lajoinie G, Wimmer W. Transverse flow under oscillating stimulation in helical square ducts with cochlea-like geometrical curvature and torsion. EUROPEAN JOURNAL OF MECHANICS. B, FLUIDS 2024; 107:165-174. [PMID: 39220585 PMCID: PMC11327769 DOI: 10.1016/j.euromechflu.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/24/2024] [Accepted: 07/01/2024] [Indexed: 09/04/2024]
Abstract
The cochlea, situated within the inner ear, is a spiral-shaped, liquid-filled organ responsible for hearing. The physiological significance of its shape remains uncertain. Previous research has scarcely addressed the occurrence of transverse flow within the cochlea, particularly in relation to its unique shape. This study aims to investigate the impact of the geometric features of the cochlea on fluid dynamics by characterizing transverse flow induced by harmonically oscillating axial flow in square ducts with curvature and torsion resembling human cochlear anatomy. We examined four geometries to investigate curvature and torsion effects on axial and transverse flow components. Twelve frequencies from 0.125 Hz to 256 Hz were studied, covering infrasound and low-frequency hearing, with mean inlet velocity amplitudes representing levels expected for normal conversation or louder situations. Our simulations show that torsion contributes significantly to transverse flow in unsteady conditions, and that its contribution increases with increasing oscillation frequency. Curvature alone has a small effect on transverse flow strength, which decreases rapidly with increasing frequency. Strikingly, the combined effect of curvature and torsion on transverse flow is greater than expected from a simple superposition of the two effects, especially when the relative contribution of curvature alone becomes negligible. These findings may be relevant to understanding physiological processes in the cochlea, including metabolite transport and wall shear stress. Further studies are needed to investigate possible implications for cochlear mechanics.
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Affiliation(s)
- N.C. Harte
- Department of Otorhinolaryngology, TUM School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - D. Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - M. Caversaccio
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head and Neck Surgery, Bern University Hospital, Bern, Switzerland
| | - G.P.R. Lajoinie
- Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics, Technical Medical (TechMed) Center, University of Twente, Enschede, The Netherlands
| | - W. Wimmer
- Department of Otorhinolaryngology, TUM School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Otorhinolaryngology, Head and Neck Surgery, Bern University Hospital, Bern, Switzerland
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2
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Ruiz-Muñoz A, Guala A, Dux-Santoy L, Teixidó-Turà G, Valente F, Garrido-Oliver J, Galian-Gay L, Gutiérrez L, Fernandez-Galera R, Casas-Masnou G, González-Alujas T, Cuéllar-Calabria H, Carrasco-Poves A, Morales-Galán A, Johnson KM, Wieben O, Ferreira-González I, Evangelista A, Rodriguez-Palomares J. False lumen hemodynamics and partial thrombosis in chronic aortic dissection of the descending aorta. Eur Radiol 2024; 34:5190-5200. [PMID: 38183450 DOI: 10.1007/s00330-023-10513-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/17/2023] [Accepted: 11/08/2023] [Indexed: 01/08/2024]
Abstract
OBJECTIVES Partial thrombosis of the false lumen (FL) in patients with chronic aortic dissection (AD) of the descending aorta has been associated with poor outcomes. Meanwhile, the fluid dynamic and biomechanical characteristics associated with partial thrombosis remain to be elucidated. This retrospective, single-center study tested the association between FL fluid dynamics and biomechanics and the presence and extent of FL thrombus. METHODS Patients with chronic non-thrombosed or partially thrombosed FLs in the descending aorta after an aortic dissection underwent computed tomography angiography, cardiovascular magnetic resonance (CMR) angiography, and a 4D flow CMR study. A comprehensive quantitative analysis was performed to test the association between FL thrombus presence and extent (percentage of FL with thrombus) and FL anatomy (diameter, entry tear location and size), fluid dynamics (inflow, rotational flow, wall shear stress, kinetic energy, and flow acceleration and stasis), and biomechanics (pulse wave velocity). RESULTS Sixty-eight patients were included. In multivariate logistic regression FL kinetic energy (p = 0.038) discriminated the 33 patients with partial FL thrombosis from the 35 patients with no thrombosis. Similarly, in separated multivariate linear correlations kinetic energy (p = 0.006) and FL inflow (p = 0.002) were independently related to the extent of the thrombus. FL vortexes, flow acceleration and stasis, wall shear stress, and pulse wave velocity showed limited associations with thrombus presence and extent. CONCLUSION In patients with chronic descending aorta dissection, false lumen kinetic energy is related to the presence and extent of false lumen thrombus. CLINICAL RELEVANCE STATEMENT In patients with chronic aortic dissection of the descending aorta, false lumen hemodynamic parameters are closely linked with the presence and extent of false lumen thrombosis, and these non-invasive measures might be important in patient management. KEY POINTS • Partial false lumen thrombosis has been associated with aortic growth in patients with chronic descending aortic dissection; therefore, the identification of prothrombotic flow conditions is desirable. • The presence of partial false lumen thrombosis as well as its extent was related with false lumen kinetic energy. • The assessment of false lumen hemodynamics may be important in the management of patients with chronic aortic dissection of the descending aorta.
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Affiliation(s)
- Aroa Ruiz-Muñoz
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- CIBER-CV, Instituto de Salud Carlos III, Madrid, Spain
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
- Department of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Andrea Guala
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain.
- CIBER-CV, Instituto de Salud Carlos III, Madrid, Spain.
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain.
| | | | - Gisela Teixidó-Turà
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- CIBER-CV, Instituto de Salud Carlos III, Madrid, Spain
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Filipa Valente
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | | | - Laura Galian-Gay
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Laura Gutiérrez
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Rubén Fernandez-Galera
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Guillem Casas-Masnou
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Teresa González-Alujas
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Hug Cuéllar-Calabria
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Department of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Department of Radiology, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | | | | | - Kevin M Johnson
- Departments of Medical Physics & Radiology, University of Wisconsin, Madison, WI, USA
| | - Oliver Wieben
- Departments of Medical Physics & Radiology, University of Wisconsin, Madison, WI, USA
| | - Ignacio Ferreira-González
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
- Department of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
- CIBERESP, Instituto de Salud Carlos III, Madrid, Spain
| | - Arturo Evangelista
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- CIBER-CV, Instituto de Salud Carlos III, Madrid, Spain
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain
- Department of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Instituto del Corazón, Quirónsalud-Teknon, Barcelona, Spain
| | - Jose Rodriguez-Palomares
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain.
- CIBER-CV, Instituto de Salud Carlos III, Madrid, Spain.
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain.
- Department of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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Qin T, Mao W, Caballero A, Kamioka N, Lerakis S, Lain S, Elefteriades J, Liang L, Sun W. Patient-specific analysis of bicuspid aortic valve hemodynamics using a fully coupled fluid-structure interaction model. Comput Biol Med 2024; 172:108191. [PMID: 38457932 DOI: 10.1016/j.compbiomed.2024.108191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/10/2024] [Accepted: 02/18/2024] [Indexed: 03/10/2024]
Abstract
Bicuspid aortic valve (BAV), the most common congenital heart disease, is prone to develop significant valvular dysfunction and aortic wall abnormalities such as ascending aortic aneurysm. Growing evidence has suggested that abnormal BAV hemodynamics could contribute to disease progression. In order to investigate BAV hemodynamics, we performed 3D patient-specific fluid-structure interaction (FSI) simulations with fully coupled blood flow dynamics and valve motion throughout the cardiac cycle. Results showed that the hemodynamics during systole can be characterized by a systolic jet and two counter-rotating recirculation vortices. At peak systole, the jet was usually eccentric, with asymmetric recirculation vortices and helical flow motion in the ascending aorta. The flow structure at peak systole was quantified using the vorticity, flow rate reversal ratio and local normalized helicity (LNH) at four locations from the aortic root to the ascending aorta. The systolic jet was evaluated with the peak velocity, normalized flow displacement, and jet angle. It was found that peak velocity and normalized flow displacement (rather than jet angle) gave a strong correlation with the vorticity and LNH in the ascending aorta, which suggests that these two metrics could be used for clinical noninvasive evaluation of abnormal blood flow patterns in BAV patients.
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Affiliation(s)
- Tongran Qin
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; Sutra Medical Inc, Lake Forest, CA, USA
| | - Wenbin Mao
- Mechanical Engineering, University of South Florida, FL, USA
| | - Andrés Caballero
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; PAI+ Research Group, Mechanical Engineering Department, Universidad Autónoma de Occidente, Cali, Colombia
| | | | - Stamatios Lerakis
- Emory University, School of Medicine, Atlanta, GA, USA; Division of Cardiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Santiago Lain
- PAI+ Research Group, Mechanical Engineering Department, Universidad Autónoma de Occidente, Cali, Colombia
| | - John Elefteriades
- Aortic Institute, School of Medicine, Yale University, New Haven, CT, USA
| | - Liang Liang
- Department of Computer Science, University of Miami, Coral Gables, FL, USA
| | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; Sutra Medical Inc, Lake Forest, CA, USA.
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Garg P, Markl M, Sathananthan J, Sellers SL, Meduri C, Cavalcante J. Restoration of flow in the aorta: a novel therapeutic target in aortic valve intervention. Nat Rev Cardiol 2024; 21:264-273. [PMID: 37880496 DOI: 10.1038/s41569-023-00943-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/25/2023] [Indexed: 10/27/2023]
Abstract
Aortic blood flow patterns are closely linked to the morphology and function of the left ventricle, aortic valve and aorta. These flow patterns demonstrate the exceptional adaptability of the cardiovascular system to maintain blood circulation under a broad range of haemodynamic workloads and can be altered in various pathophysiological states. For instance, normal ascending aortic systolic flow is predominantly laminar, whereas abnormal aortic systolic flow is associated with increased eccentricity, vorticity and flow reversal. These flow abnormalities result in reduced aortic conduit function and increased energy loss in the cardiovascular system. Emerging evidence details the association of these flow patterns with loss of aortic compliance, which leads to adverse left ventricular remodelling, poor tissue perfusion, and an increased risk of morbidity and death. In this Perspective article, we review the evidence for the link between aortic flow-related abnormalities and cardiovascular disease and how these changes in aortic flow patterns are emerging as a therapeutic target for aortic valve intervention in first-in-human studies.
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Affiliation(s)
- Pankaj Garg
- University of East Anglia, Norwich Medical School, Norwich, UK.
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, UK.
| | - Michael Markl
- Departments of Radiology & Biomedical Engineering, Northwestern University, Feinberg School of Medicine & McCormick School of Engineering, Chicago, IL, USA
| | | | - Stephanie L Sellers
- Cardiovascular Translational Lab, St. Paul's Hospital, University of British Columbia Centre for Heart Lung Innovation, Vancouver, British Columbia, Canada
| | - Chris Meduri
- Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
| | - João Cavalcante
- Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, MN, USA
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Hazan Shenberger S, Avrahami I. The Effect of Mechanical Circulatory Support on Blood Flow in the Ascending Aorta: A Combined Experimental and Computational Study. Bioengineering (Basel) 2024; 11:238. [PMID: 38534512 DOI: 10.3390/bioengineering11030238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/11/2024] [Accepted: 02/22/2024] [Indexed: 03/28/2024] Open
Abstract
Percutaneous mechanical circulatory support (MCS) devices are designed for short-term treatment in cases of acute decompensated heart failure as a bridge to transplant or recovery. Some of the known complications of MCS treatments are related to their hemodynamics in the aorta. The current study investigates the effect of MCS on the aortic flow. The study uses combined experimental and numerical methods to delineate complex flow structures. Particle image velocimetry (PIV) is used to capture the vortical and turbulent flow characteristics in a glass model of the human aorta. Computational fluid dynamics (CFD) analyses are used to complete the 3D flow in the aorta. Three specific MCS configurations are examined: a suction pump with a counterclockwise (CCW) rotating impeller, a suction pump with a clockwise (CW) rotating impeller, and a discharge pump with a straight jet. These models were examined under varying flow rates (1-2.5 L/min). The results show that the pump configuration strongly influences the flow in the thoracic aorta. The rotating impeller of the suction pump induces a dominant swirling flow in the aorta. The swirling flow distributes the incoming jet and reduces the turbulent intensity near the aortic valve and in the aorta. In addition, at high flow rates, the local vortices formed near the pump are washed downstream toward the aortic arch. Specifically, an MCS device with a CCW rotating impeller induces a non-physiological CCW helical flow in the descending aorta (which is opposite to the natural helical flow), while CW swirl combines better with the natural helical flow.
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Affiliation(s)
- Sapir Hazan Shenberger
- Department of Mechanical Engineering and Mechatronics, Ariel University, Ariel 40700, Israel
| | - Idit Avrahami
- Department of Mechanical Engineering and Mechatronics, Ariel University, Ariel 40700, Israel
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6
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Zeugin T, Coulter FB, Gülan U, Studart AR, Holzner M. In vitro investigation of the blood flow downstream of a 3D-printed aortic valve. Sci Rep 2024; 14:1572. [PMID: 38238358 PMCID: PMC10796383 DOI: 10.1038/s41598-024-51676-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/08/2024] [Indexed: 01/22/2024] Open
Abstract
The hemodynamics in the aorta as well as the durability of aortic valve prostheses vary greatly between different types of devices. Although placement and sizing of surgical aortic valve prostheses are excellent, the valve geometry of common devices cannot be customized to fit the patient's anatomy perfectly. Similarly, transcatheter aortic valve implantation (TAVI) devices are not customizable and may be orientated unfavorably during implantation. Imperfect fit of an aortic valve prosthesis may result in suboptimal performance and in some cases the need for additional surgery. Leveraging the advent of precision, multi-material 3D-printing, a bioinspired silicone aortic valve was developed. The manufacturing technique makes it fully customizable and significantly cheaper to develop and produce than common prostheses. In this study, we assess the hemodynamic performance of such a 3D-printed aortic valve and compare it to two TAVI devices as well as to a severely stenosed valve. We investigate the blood flow distal to the valve in an anatomically accurate, compliant aorta model via three-dimensional particle tracking velocimetry measurements. Our results demonstrate that the 3D-printed aortic valve induces flow patterns and topology compatible with the TAVI valves and showing similarity to healthy aortic blood flow. Compared to the stenosis, the 3D-printed aortic valve reduces turbulent kinetic energy levels and irreversible energy losses by over 75%, reaching values compatible with healthy subjects and conventional TAVIs. Our study substantiates that the 3D-printed heart valve displays a hemodynamic performance similar to established devices and underscores its potential for driving innovation towards patient specific valve prostheses.
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Affiliation(s)
- Till Zeugin
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, Swiss Federal Institute of Technology ETH Zürich, Zürich, Switzerland.
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland.
| | - Fergal B Coulter
- Complex Materials, Swiss Federal Institute of Technology ETH Zürich, Zürich, Switzerland
| | | | - André R Studart
- Complex Materials, Swiss Federal Institute of Technology ETH Zürich, Zürich, Switzerland
| | - Markus Holzner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Swiss Federal Institute for Water Science and Technology EAWAG, Dübendorf, Switzerland
- Institute of Hydraulic Engineering and River Research (IWA), University of Natural Resources and Life Sciences, Vienna, Austria
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Kara R, Vergara C. Assessing turbulent effects in ascending aorta in presence of bicuspid aortic valve. Comput Methods Biomech Biomed Engin 2023:1-13. [PMID: 37950490 DOI: 10.1080/10255842.2023.2279938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
Aortic valves with bicuspids have two rather than three leaflets, which is a congenital heart condition. About 0.5-2% of people have a bicuspid aortic valve. Blood flow through the aorta is commonly believed to be laminar, although aortic valve disorders can cause turbulent transitions. Understanding the impact of turbulence is crucial for foreseeing how the disease will progress. The study's objective was use large eddy simulation to provide a thorough analysis of the turbulence in bicuspid aortic valve dysfunction. Using a large eddy simulation, the blood flow patterns of the bicuspid and tricuspid aortic valves were compared, and significant discrepancies were found. The velocity field in flow in bicuspid configurations was asymmetrically distributed toward the ascending aorta. In tricuspid aortic valve (TAV) the flow, on the other hand, was symmetrical within the same aortic segment. Moreover, we looked into standard deviation, Q-criterion, viscosity ratio and wall shear stresses for each cases to understand transition to turbulence. Our findings indicate that in the bicuspid aortic valve (BAV) case, the fluid-dynamic abnormalities increase. The global turbulent kinetic energy and time-averaged wall shear stress for the TAV and BAV scenarios were also examined. We discovered that the global turbulent kinetic energy was higher in the BAV case compared to TAV, in addition to the increased wall shear stress induced by the BAV in the ascending aorta.
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Affiliation(s)
- Rukiye Kara
- Department of Mathematics, Mimar Sinan Fine Arts University, Istanbul, Turkey
| | - Christian Vergara
- LABS - Dipartimento di Chimica, Materiali e Ingegneria Chimica" Giulio Natta" - Politecnico di Milano, Milan, Italy
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Takahashi Y, Kamiya K, Nagai T, Tsuneta S, Oyama-Manabe N, Hamaya T, Kazui S, Yasui Y, Saiin K, Naito S, Mizuguchi Y, Takenaka S, Tada A, Ishizaka S, Kobayashi Y, Omote K, Sato T, Shingu Y, Kudo K, Wakasa S, Anzai T. Differences in blood flow dynamics between balloon- and self-expandable valves in patients with aortic stenosis undergoing transcatheter aortic valve replacement. J Cardiovasc Magn Reson 2023; 25:60. [PMID: 37880721 PMCID: PMC10601149 DOI: 10.1186/s12968-023-00970-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/26/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND The differences in pre- and early post-procedural blood flow dynamics between the two major types of bioprosthetic valves, the balloon-expandable valve (BEV) and self-expandable valve (SEV), in patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR), have not been investigated. We aimed to investigate the differences in blood flow dynamics between the BEV and SEV using four-dimensional flow cardiovascular magnetic resonance (4D flow CMR). METHODS We prospectively examined 98 consecutive patients with severe AS who underwent TAVR between May 2018 and November 2021 (58 BEV and 40 SEV) after excluding those without CMR because of a contraindication, inadequate imaging from the analyses, or patients' refusal. CMR was performed in all participants before (median interval, 22 [interquartile range (IQR) 4-39] days) and after (median interval, 6 [IQR 3-6] days) TAVR. We compared the changes in blood flow patterns, wall shear stress (WSS), and energy loss (EL) in the ascending aorta (AAo) between the BEV and SEV using 4D flow CMR. RESULTS The absolute reductions in helical flow and flow eccentricity were significantly higher in the SEV group compared in the BEV group after TAVR (BEV: - 0.22 ± 0.86 vs. SEV: - 0.85 ± 0.80, P < 0.001 and BEV: - 0.11 ± 0.79 vs. SEV: - 0.50 ± 0.88, P = 0.037, respectively); there were no significant differences in vortical flow between the groups. The absolute reduction of average WSS was significantly higher in the SEV group compared to the BEV group after TAVR (BEV: - 0.6 [- 2.1 to 0.5] Pa vs. SEV: - 1.8 [- 3.5 to - 0.8] Pa, P = 0.006). The systolic EL in the AAo significantly decreased after TAVR in both the groups, while the absolute reduction was comparable between the groups. CONCLUSIONS Helical flow, flow eccentricity, and average WSS in the AAo were significantly decreased after SEV implantation compared to BEV implantation, providing functional insights for valve selection in patients with AS undergoing TAVR. Our findings offer valuable insights into blood flow dynamics, aiding in the selection of valves for patients with AS undergoing TAVR. Further larger-scale studies are warranted to confirm the prognostic significance of hemodynamic changes in these patients.
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Affiliation(s)
- Yuki Takahashi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kiwamu Kamiya
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshiyuki Nagai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
| | - Satonori Tsuneta
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Noriko Oyama-Manabe
- Department of Radiology, Jichi Medical University Saitama Medical Center, 1-847 Amanuma-Cho, Omiya-Ku, Saitama-City, Saitama, 330-8503, Japan
| | - Takeshi Hamaya
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Sho Kazui
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yutaro Yasui
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kohei Saiin
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Seiichiro Naito
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yoshifumi Mizuguchi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Sakae Takenaka
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Atsushi Tada
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Suguru Ishizaka
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yuta Kobayashi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kazunori Omote
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takuma Sato
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yasushige Shingu
- Department of Cardiovascular Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kohsuke Kudo
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Satoru Wakasa
- Department of Cardiovascular Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshihisa Anzai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
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Hülsmann J, Fraune T, Dodawatta B, Reuter F, Beutner M, Beck V, Hackert-Oschätzchen M, Ohl CD, Bettenbrock K, Janiga G, Wippermann J, Wacker M. Integrated biophysical matching of bacterial nanocellulose coronary artery bypass grafts towards bioinspired artery typical functions. Sci Rep 2023; 13:18274. [PMID: 37880281 PMCID: PMC10600183 DOI: 10.1038/s41598-023-45451-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 10/19/2023] [Indexed: 10/27/2023] Open
Abstract
Revascularization via coronary artery bypass grafting (CABG) to treat cardiovascular disease is established as one of the most important lifesaving surgical techniques worldwide. But the shortage in functionally self-adaptive autologous arteries leads to circumstances where the clinical reality must deal with fighting pathologies coming from the mismatching biophysical functionality of more available venous grafts. Synthetic biomaterial-based CABG grafts did not make it to the market yet, what is mostly due to technical hurdles in matching biophysical properties to the complex demands of the CABG niche. But bacterial Nanocellulose (BNC) Hydrogels derived by growing biofilms hold a naturally integrative character in function-giving properties by its freedom in designing form and intrinsic fiber architecture. In this study we use this integral to combine impacts on the luminal fiber matrix, biomechanical properties and the reciprocal stimulation of microtopography and induced flow patterns, to investigate biomimetic and artificial designs on their bio-functional effects. Therefore, we produced tubular BNC-hydrogels at distinctive designs, characterized the structural and biomechanical properties and subjected them to in vitro endothelial colonization in bioreactor assisted perfusion cultivation. Results showed clearly improved functional properties and gave an indication of successfully realized stimulation by artery-typical helical flow patterns.
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Affiliation(s)
- Jörn Hülsmann
- Department for Cardiac Surgery, Medical Faculty, Otto von Guericke University, Magdeburg, Germany.
| | - Theresa Fraune
- Department for Cardiac Surgery, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Baratha Dodawatta
- Laboratory of Fluid Dynamics and Technical Flows, Otto von Guericke University, Magdeburg, Germany
| | - Fabian Reuter
- Department Soft Matter, Otto von Guericke University, Magdeburg, Germany
| | - Martin Beutner
- Chair of Manufacturing Technology with Focus Machining, Institute of Manufacturing Technology and Quality Management, Otto von Guericke University, Magdeburg, Germany
| | - Viktoria Beck
- Department for Cardiac Surgery, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Matthias Hackert-Oschätzchen
- Chair of Manufacturing Technology with Focus Machining, Institute of Manufacturing Technology and Quality Management, Otto von Guericke University, Magdeburg, Germany
| | - Claus Dieter Ohl
- Department Soft Matter, Otto von Guericke University, Magdeburg, Germany
| | - Katja Bettenbrock
- Max Plank Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Gabor Janiga
- Laboratory of Fluid Dynamics and Technical Flows, Otto von Guericke University, Magdeburg, Germany
| | - Jens Wippermann
- Department for Cardiac Surgery, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Max Wacker
- Department for Cardiac Surgery, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
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10
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Ong CW, Wee IJY, Toma M, Cui F, Xu XY, Richards AM, Leo HL, Choong AMTL. Haemodynamic changes in visceral hybrid repairs of type III and type V thoracoabdominal aortic aneurysms. Sci Rep 2023; 13:13760. [PMID: 37612440 PMCID: PMC10447573 DOI: 10.1038/s41598-023-40323-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 08/08/2023] [Indexed: 08/25/2023] Open
Abstract
The visceral hybrid procedure combining retrograde visceral bypass grafting and completion endovascular stent grafting is a feasible alternative to conventional open surgical or wholly endovascular repairs of thoracoabdominal aneurysms (TAAA). However, the wide variability in visceral hybrid configurations means that a priori prediction of surgical outcome based on haemodynamic flow profiles such as velocity pattern and wall shear stress post repair remain challenging. We sought to appraise the clinical relevance of computational fluid dynamics (CFD) analyses in the setting of visceral hybrid TAAA repairs. Two patients, one with a type III and the other with a type V TAAA, underwent successful elective and emergency visceral hybrid repairs, respectively. Flow patterns and haemodynamic parameters were analysed using reconstructed pre- and post-operative CT scans. Both type III and type V TAAAs showed highly disturbed flow patterns with varying helicity values preoperatively within their respective aneurysms. Low time-averaged wall shear stress (TAWSS) and high endothelial cell action potential (ECAP) and relative residence time (RRT) associated with thrombogenic susceptibility was observed in the posterior aspect of both TAAAs preoperatively. Despite differing bypass configurations in the elective and emergency repairs, both treatment options appear to improve haemodynamic performance compared to preoperative study. However, we observed reduced TAWSS in the right iliac artery (portending a theoretical risk of future graft and possibly limb thrombosis), after the elective type III visceral hybrid repair, but not the emergency type V repair. We surmise that this difference may be attributed to the higher neo-bifurcation of the aortic stent graft in the type III as compared to the type V repair. Our results demonstrate that CFD can be used in complicated visceral hybrid repair to yield potentially actionable predictive insights with implications on surveillance and enhanced post-operative management, even in patients with complicated geometrical bypass configurations.
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Affiliation(s)
- Chi Wei Ong
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Ian J Y Wee
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Milan Toma
- Department of Osteopathic Manipulative Medicine, College of Osteopathic Medicine, New York Institute of Technology, New York, USA
| | - Fangsen Cui
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Arthur Mark Richards
- Cardiovascular Research Institute, National University of Singapore, Singapore, Singapore
- Christchurch Heart Institute, University of Otago, New Zealand, New Zealand
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Andrew M T L Choong
- Division of Vascular and Endovascular Surgery, Department of Cardiac, Thoracic and Vascular Surgery, National University Heart Centre, Singapore, Singapore.
- Asian Aortic & Vascular Centre, Singapore, Singapore.
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11
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Calò K, Capellini K, De Nisco G, Mazzi V, Gasparotti E, Gallo D, Celi S, Morbiducci U. Impact of wall displacements on the large-scale flow coherence in ascending aorta. J Biomech 2023; 154:111620. [PMID: 37178494 DOI: 10.1016/j.jbiomech.2023.111620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023]
Abstract
In the context of aortic hemodynamics, uncertainties affecting blood flow simulations hamper their translational potential as supportive technology in clinics. Computational fluid dynamics (CFD) simulations under rigid-walls assumption are largely adopted, even though the aorta contributes markedly to the systemic compliance and is characterized by a complex motion. To account for personalized wall displacements in aortic hemodynamics simulations, the moving-boundary method (MBM) has been recently proposed as a computationally convenient strategy, although its implementation requires dynamic imaging acquisitions not always available in clinics. In this study we aim to clarify the real need for introducing aortic wall displacements in CFD simulations to accurately capture the large-scale flow structures in the healthy human ascending aorta (AAo). To do that, the impact of wall displacements is analyzed using subject-specific models where two CFD simulations are performed imposing (1) rigid walls, and (2) personalized wall displacements adopting a MBM, integrating dynamic CT imaging and a mesh morphing technique based on radial basis functions. The impact of wall displacements on AAo hemodynamics is analyzed in terms of large-scale flow patterns of physiological significance, namely axial blood flow coherence (quantified applying the Complex Networks theory), secondary flows, helical flow and wall shear stress (WSS). From the comparison with rigid-wall simulations, it emerges that wall displacements have a minor impact on the AAo large-scale axial flow, but they can affect secondary flows and WSS directional changes. Overall, helical flow topology is moderately affected by aortic wall displacements, whereas helicity intensity remains almost unchanged. We conclude that CFD simulations with rigid-wall assumption can be a valid approach to study large-scale aortic flows of physiological significance.
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Affiliation(s)
- Karol Calò
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Turin, Italy
| | - Katia Capellini
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Giuseppe De Nisco
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Turin, Italy
| | - Valentina Mazzi
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Turin, Italy
| | - Emanuele Gasparotti
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Diego Gallo
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Turin, Italy
| | - Simona Celi
- BioCardioLab, Bioengineering Unit - Heart Hospital, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Turin, Italy.
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12
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Li D, Wang J, Zeng W, Zeng X, Liu Z, Cao H, Yuan D, Zheng T. The loss of helical flow in the thoracic aorta might be an identifying marker for the risk of acute type B aortic dissection. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107331. [PMID: 36621070 DOI: 10.1016/j.cmpb.2022.107331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/06/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE The occurrence of acute type B aortic dissection (TBAD) remained unclear. This study aimed to investigate the association between flow features and hemodynamic parameters in aortas that demonstrated the risk of TBAD occurrence. METHODS The geometries of 15 hyperacute TBAD and 12 control patients (with healthy aorta) were reconstructed from computed tomography angiography images. Pre-TBAD models were then obtained by eliminating the dissection flaps. Flow features and hemodynamic parameters, including wall shear stress-related parameters and helicities, were compared between pre-TBAD and control models using computational fluid dynamics. RESULTS There were no significant differences in baseline characteristics and anatomical parameters between the two groups. Significant contralateral helical blood flow was present in the healthy thoracic aorta, while almost no helical flow was observed in the pre-TBAD group. In addition, the mean normal transverse wall shear stress (NtransWSS) was significantly higher in the pre-TBAD group (aortic arch 0.49±0.09 vs. 0.40±0.05, P = 0.04; descending aorta: 0.46±0.05 vs. 0.33±0.02, P<0.01). Moreover, a significantly negative correlation was found between helicity and NtransWSS in the descending aorta. Moreover, the location of primary tears in 12 pre-TABD subjects matched well with regions of high NtransWSS. CONCLUSIONS Loss of helical flow in the aortic arch and descending aorta may be a major flow feature in patients with underlying TBAD, resulting in increased flow disturbance and wall lesions.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Jiarong Wang
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China
| | - Wen Zeng
- Division of radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangguo Zeng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Haoyao Cao
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Ding Yuan
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China; Med-X center for informatics, Sichuan University, Chengdu, China.
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China; Med-X center for informatics, Sichuan University, Chengdu, China.
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13
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Cunnane CV, Houston JG, Moran DT, Broderick SP, Ross RA, Walsh MT. Spiral Laminar Flow is Associated with a Reduction in Disturbed Shear in Patient-Specific Models of an Arteriovenous Fistula. Cardiovasc Eng Technol 2023; 14:152-165. [PMID: 36151366 DOI: 10.1007/s13239-022-00644-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 09/03/2022] [Indexed: 11/02/2022]
Abstract
PURPOSE Areas of disturbed shear that arise following arteriovenous fistula (AVF) creation are believed to contribute to the development of intimal hyperplasia (IH). The presence of helical flow can suppress areas of disturbed shear, which may protect the vasculature from IH. Therefore, the aim of this study is to determine if helical flow, specifically spiral laminar flow (SLF), is present in patient-specific AVF models and is associated with a reduction in exposure to disturbed shear. METHODS Four AVF were imaged using MRI within the first two weeks following fistula creation. Patient-specific boundary conditions were obtained using phase-contrast MRI and applied at the inlet and outlets of each model. Computational fluid dynamics was used to analyse the hemodynamics in each model and compare the helical content of the flow to the distribution of disturbed shear. RESULTS BC-1 and RC-2 are characterised by the presence of SLF, which coincides with the lowest distribution of disturbed shear. Contrastingly, SLF is absent from BC-2 and RC-1 and experience the largest amount of disturbed shear. Interestingly, BC-2 and RC-1 developed an anastomosis stenosis, while BC-1 and RC-2 remained stenosis free. CONCLUSION These findings are in agreement with previous clinical studies and further highlight the clinical potential of SLF as a prognostic marker for a healthy AVF, as its presence correlates with an overall reduction in exposure to disturbed shear and a decrease in the incidence of AVF dysfunction, albeit in a small sample size.
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Affiliation(s)
- Connor V Cunnane
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, Faculty of Science and Engineering, University of Limerick, Limerick, Ireland
| | - J Graeme Houston
- Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Daniel T Moran
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, Faculty of Science and Engineering, University of Limerick, Limerick, Ireland
| | - Stephen P Broderick
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, Faculty of Science and Engineering, University of Limerick, Limerick, Ireland
| | - Rose A Ross
- NHS Tayside Vascular Department, Ninewells Hospital, Dundee, UK
| | - Michael T Walsh
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland.
- School of Engineering, Faculty of Science and Engineering, University of Limerick, Limerick, Ireland.
- Health Research Institute, University of Limerick, Limerick, Ireland.
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14
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Sahni A, McIntyre EE, Pal JD, Mukherjee D. Quantitative Assessment of Aortic Hemodynamics for Varying Left Ventricular Assist Device Outflow Graft Angles and Flow Pulsation. Ann Biomed Eng 2023; 51:1226-1243. [PMID: 36705866 DOI: 10.1007/s10439-022-03127-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/25/2022] [Indexed: 01/28/2023]
Abstract
Left ventricular assist devices (LVADs) comprise a primary treatment choice for advanced heart failure patients. Treatment with LVAD is commonly associated with complications like stroke and gastro-intestinal (GI) bleeding, which adversely impacts treatment outcomes, and causes fatalities. The etiology and mechanisms of these complications can be linked to the fact that LVAD outflow jet leads to an altered state of hemodynamics in the aorta as compared to baseline flow driven by aortic jet during ventricular systole. Here, we present a framework for quantitative assessment of aortic hemodynamics in LVAD flows realistic human vasculature, with a focus on quantifying the differences between flow driven by LVAD jet and the physiological aortic jet when no LVAD is present. We model hemodynamics in the aortic arch proximal to the LVAD outflow graft, as well as in the abdominal aorta away from the LVAD region. We characterize hemodynamics using quantitative descriptors of flow velocity, stasis, helicity, vorticity and mixing, and wall shear stress. These are used on a set of 27 LVAD scenarios obtained by parametrically varying LVAD outflow graft anastomosis angles, and LVAD flow pulse modulation. Computed descriptors for each of these scenarios are compared against the baseline flow, and a detailed quantitative characterization of the altered state of hemodynamics due to LVAD operation (when compared to baseline aortic flow) is compiled. These are interpreted using a conceptual model for LVAD flow that distinguishes between flow originating from the LVAD outflow jet (and its impingement on the aorta wall), and flow originating from aortic jet during aortic valve opening in normal physiological state.
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Affiliation(s)
- Akshita Sahni
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, USA
| | - Erin E McIntyre
- Division of Cardiothoracic Surgery, University of Colorado, Anschutz Medical Campus, Aurora, USA
| | - Jay D Pal
- Department of Surgery, University of Washington, Seattle, USA
| | - Debanjan Mukherjee
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, USA.
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15
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Dyverfeldt P, Trenti C, Ziegler M, Bjarnegård N, Lindenberger M. Helical flow in tortuous aortas and its relationship to turbulence: A whole-aorta 4D flow MRI study. Front Cardiovasc Med 2023; 10:1124604. [PMID: 37034318 PMCID: PMC10073741 DOI: 10.3389/fcvm.2023.1124604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/06/2023] [Indexed: 04/11/2023] Open
Abstract
Background Increased vascular tortuosity is a hallmark of ageing of the vascular system, including the aorta. However, the impact of tortuosity on aortic blood flow is unknown. We hypothesized that increased tortuosity would be associated with increased blood flow helicity and with decreased degree of blood flow turbulence as measured by the turbulent kinetic energy (TKE). Methods 4D Flow MR images covering the entire aorta from the aortic valve to the iliac bifurcation were acquired in 23 normal volunteers aged 18-30 years ("Young") and 23 normal volunteers aged 66-76 years ("Old") without aortic disease. The aorta was segmented and divided into four regions: the ascending, descending, suprarenal abdominal and infrarenal abdominal aorta. Tortuosity, helicity, TKE, flow velocity, and Reynolds number were computed for the whole aorta and for each section. Results Tortuosity and helicity were higher whereas TKE, velocity, and Reynolds number were lower in Old than in Young, for all aortic regions (p < 0.05) except for helicity in the descending aorta. Tortuosity correlated positively with helicity and negatively with TKE for all aortic regions (Spearman rho=±0.45-±0.72, p < =0.002) except for TKE in the ascending aorta. Further, helicity correlated with TKE in the descending, suprarenal abdominal and infrarenal abdominal aorta (Spearman rho=-0.56--0.77). Conclusion Tortuosity increases with age and blood flow in tortuous aortas is more helical. Increasing helicity, in turn, is associated with decreasing TKE.
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Affiliation(s)
- Petter Dyverfeldt
- Cardiovascular Sciences; Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Correspondence: Petter Dyverfeldt
| | - Chiara Trenti
- Cardiovascular Sciences; Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Magnus Ziegler
- Cardiovascular Sciences; Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Niclas Bjarnegård
- Cardiovascular Sciences; Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Marcus Lindenberger
- Cardiovascular Sciences; Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Department of Cardiology in Linköping, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
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16
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Deshmukh K, Gupta S, Mitra K, Bit A. Numerical and Experimental Analysis of Shear Stress Influence on Cellular Viability in Serpentine Vascular Channels. MICROMACHINES 2022; 13:mi13101766. [PMID: 36296119 PMCID: PMC9611698 DOI: 10.3390/mi13101766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/19/2022] [Accepted: 10/14/2022] [Indexed: 05/29/2023]
Abstract
3D bioprinting has emerged as a tool for developing in vitro tissue models for studying disease progression and drug development. The objective of the current study was to evaluate the influence of flow driven shear stress on the viability of cultured cells inside the luminal wall of a serpentine network. Fluid-structure interaction was modeled using COMSOL Multiphysics for representing the elasticity of the serpentine wall. Experimental analysis of the serpentine model was performed on the basis of a desirable inlet flow boundary condition for which the most homogeneously distributed wall shear stress had been obtained from numerical study. A blend of Gelatin-methacryloyl (GelMA) and PEGDA200 PhotoInk was used as a bioink for printing the serpentine network, while facilitating cell growth within the pores of the gelatin substrate. Human umbilical vein endothelial cells were seeded into the channels of the network to simulate the blood vessels. A Live-Dead assay was performed over a period of 14 days to observe the cellular viability in the printed vascular channels. It was observed that cell viability increases when the seeded cells were exposed to the evenly distributed shear stresses at an input flow rate of 4.62 mm/min of the culture media, similar to that predicted in the numerical model with the same inlet boundary condition. It leads to recruitment of a large number of focal adhesion point nodes on cellular membrane, emphasizing the influence of such phenomena on promoting cellular morphologies.
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Affiliation(s)
- Khemraj Deshmukh
- Department of Biomedical Engineering, National Institute of Technology, Raipur 492010, India
| | - Saurabh Gupta
- Department of Biomedical Engineering, National Institute of Technology, Raipur 492010, India
| | - Kunal Mitra
- Biomedical Engineering, Florida Tech, Melbourne, FL 32901, USA
| | - Arindam Bit
- Department of Biomedical Engineering, National Institute of Technology, Raipur 492010, India
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17
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On non-Kolmogorov turbulence in blood flow and its possible role in mechanobiological stimulation. Sci Rep 2022; 12:13166. [PMID: 35915207 PMCID: PMC9343407 DOI: 10.1038/s41598-022-16079-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/04/2022] [Indexed: 01/09/2023] Open
Abstract
The study of turbulence in physiologic blood flow is important due to its strong relevance to endothelial mechanobiology and vascular disease. Recently, Saqr et al. (Sci Rep 10, 15,492, 2020) discovered non-Kolmogorov turbulence in physiologic blood flow in vivo, traced its origins to the Navier–Stokes equation and demonstrated some of its properties using chaos and hydrodynamic-stability theories. The present work extends these findings and investigates some inherent characteristics of non-Kolmogorov turbulence in monoharmonic and multiharmonic pulsatile flow under ideal physiologic conditions. The purpose of this work is to propose a conjecture for the origins for picoNewton forces that are known to regulate endothelial cells’ functions. The new conjecture relates these forces to physiologic momentum-viscous interactions in the near-wall region of the flow. Here, we used high-resolution large eddy simulation (HRLES) to study pulsatile incompressible flow in a straight pipe of \documentclass[12pt]{minimal}
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\begin{document}$$L/D=20$$\end{document}L/D=20. The simulations presented Newtonian and Carreau–Yasuda fluid flows, at \documentclass[12pt]{minimal}
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\begin{document}$$R{e}_{m}\approx 250$$\end{document}Rem≈250, each represented by one, two and three boundary harmonics. Comparison was established based on maintaining constant time-averaged mass flow rate in all simulations. First, we report the effect of primary harmonics on the global power budget using primitive variables in phase space. Second, we describe the non-Kolmogorov turbulence in frequency domain. Third, we investigate the near-wall coherent structures in time and space domains. Finally, we propose a new conjecture for the role of turbulence in endothelial cells’ mechanobiology. The proposed conjecture correlates near-wall turbulence to a force field of picoNewton scale, suggesting possible relevance to endothelial cells mechanobiology.
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18
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Shen C, Gharleghi R, Li DD, Beier S. Helical Flow in Healthy and Diseased Patient-specific Coronary Bifurcations. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:3977-3980. [PMID: 36086059 DOI: 10.1109/embc48229.2022.9871374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Helical flow (HF) exists in healthy and diseased coronary bifurcations and was found to have a protective atherosclerotic vascular effect in other vessels. However, the role of HF in patient-specific human coronary arteries still needs further study, and is therefore the objective of this study in both healthy and diseased bifurcations. Computational studies were conducted on 16 patient-specific coronary bifurcations, including eight healthy and eight identical cases with idealized narrowing to represent disease. In general, higher HF intensity may have a favorable effect as it corelated to the reduction of the percentage vessel area exposed to adverse time averaged wall shear stress (TAWSS%) in both healthy and diseased models. The HF intensity and distribution of each model varies due to the complex shape of patient-specific models. The presence of disease appears to have an important impact on the downstream HF patterns and the TAWSS distributions. Clinical Relevance- By understanding the relationship between HF and hemodynamics, HF may be used as a predictor for the formation and progression of atherosclerotic plaque in coronary arteries instead of near-wall WSS measures, which can be determined with higher accuracy in vivo.
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19
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Ebel S, Kühn A, Aggarwal A, Köhler B, Behrendt B, Gohmann R, Riekena B, Lücke C, Ziegert J, Vogtmann C, Preim B, Kropf S, Jung B, Denecke T, Grothoff M, Gutberlet M. Quantitative normal values of helical flow, flow jets and wall shear stress of healthy volunteers in the ascending aorta. Eur Radiol 2022; 32:8597-8607. [PMID: 35612663 DOI: 10.1007/s00330-022-08866-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/08/2022] [Accepted: 05/08/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVES 4D flow MRI enables quantitative assessment of helical flow. We sought to generate normal values and elucidate changes of helical flow (duration, volume, length, velocities and rotational direction) and flow jet (displacement, flow angle) as well as wall shear stress (WSS). METHODS We assessed the temporal helical existence (THEX), maximum helical volume (HVmax), accumulated helical volume (HVacc), accumulated helical volume length (HVLacc), maximum forward velocity (maxVfor), maximum circumferential velocity (maxVcirc), rotational direction (RD) and maximum wall shear stress (WSS) as reported elsewhere using the software tool Bloodline in 86 healthy volunteers (46 females, mean age 41 ± 13 years). RESULTS WSS decreased by 42.1% and maxVfor by 55.7% across age. There was no link between age and gender regarding the other parameters. CONCLUSION This study provides age-dependent normal values regarding WSS and maxVfor and age- and gender-independent normal values regarding THEX, HVmax, HVacc, HVLacc, RD and maxVcirc. KEY POINTS • 4D flow provides numerous new parameters; therefore, normal values are mandatory. • Wall shear stress decreases over age. • Maximum helical forward velocity decreases over age.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany.
- Department of Diagnostic and Interventional Radiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany.
| | - Alexander Kühn
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Abhinav Aggarwal
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
- Department of Radiology, Mata Chanan Devi Hospital of New Delhi, New Delhi, India
| | - Benjamin Köhler
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Benjamin Behrendt
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Robin Gohmann
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Boris Riekena
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Christian Lücke
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Juliane Ziegert
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Charlotte Vogtmann
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Bernhard Preim
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Siegfried Kropf
- Department for Biometry and Medical Informatics, University of Magdeburg, Magdeburg, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Bern, Switzerland
| | - Timm Denecke
- Department of Diagnostic and Interventional Radiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
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20
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Zhang Y, Zhang R, Thomas N, Ullah AH, Eichholz B, Estevadeordal J, Suzen YB. Experimental and computational study of pulsatile flow characteristics in Romanesque and gothic aortic arch models. Med Eng Phys 2022; 102:103784. [DOI: 10.1016/j.medengphy.2022.103784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 10/19/2022]
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21
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Haemodynamic Analysis of Branched Endografts for Complex Aortic Arch Repair. Bioengineering (Basel) 2022; 9:bioengineering9020045. [PMID: 35200399 PMCID: PMC8868591 DOI: 10.3390/bioengineering9020045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
This study aims to investigate the haemodynamic response induced by implantation of a double-branched endograft used in thoracic endovascular aortic repair (TEVAR) of the aortic arch. Anatomically realistic models were reconstructed from CT images obtained from patients who underwent TEVAR using the RelayPlus double-branched endograft implanted in the aortic arch. Two cases (Patient 1, Patient 2) were included here, both patients presented with type A aortic dissection before TEVAR. To examine the influence of inner tunnel branch diameters on localised flow patterns, three tunnel branch diameters were tested using the geometric model reconstructed for Patient 1. Pulsatile blood flow through the models was simulated by numerically solving the Navier–Stokes equations along with a transitional flow model. The physiological boundary conditions were imposed at the model inlet and outlets, while the wall was assumed to be rigid. Our simulation results showed that the double-branched endograft allowed for the sufficient perfusion of blood to the supra-aortic branches and restored flow patterns expected in normal aortas. The diameter of tunnel branches in the device plays a crucial role in the development of flow downstream of the branches and thus must be selected carefully based on the overall geometry of the vessel. Given the importance of wall shear stress in vascular remodelling and thrombus formation, longitudinal studies should be performed in the future in order to elucidate the role of tunnel branch diameters in long-term patency of the supra-aortic branches following TEVAR with the double-branched endograft.
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22
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Raptis A, Tasso P, Batzalexis K, Gallo D, Xenos M, Morbiducci U, Giannoukas A. Remodeling effects of carotid artery stenting versus endarterectomy with patch angioplasty in terms of morphology and hemodynamics. Comput Biol Med 2022; 140:105072. [PMID: 34856465 DOI: 10.1016/j.compbiomed.2021.105072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 11/23/2021] [Indexed: 11/03/2022]
Abstract
BACKGROUND Carotid endarterectomy (CEA) remains the first-line treatment option of symptomatic and asymptomatic carotid stenosis, while stenting (CAS) is reserved for selected patients at high surgical risk. Here, we compare the vascular remodeling process in CEA- and CAS-treated patients with respect to morphological and hemodynamic features, because of their possible engagement in carotid atherosclerosis. METHODS Twelve (12) patients were included, half with patched CEA and half with CAS. Pre- and post-operative 3D image-based models of the carotid bifurcation were anatomically characterized in terms of flare, tortuosity, and curvature. Individual computational fluid dynamics simulations allowed to quantify the postoperative hemodynamic milieu in terms of (1) wall shear stress and (2) helical flow. RESULTS Carotid flare increased in all cases, but a more marked increase emerged after CEA compared to CAS. Tortuosity and curvature increased after CEA but decreased after CAS. CEA patients presented with significantly higher postoperative tortuosity than CAS patients. CEA was associated with a worse (non-statistically significant) score in all flow disturbance indicators vs. CAS. CONCLUSION The increased flare and tortuosity of the carotid bifurcation after CEA vs. CAS is a marked difference in the vascular remodeling process between the two modalities. CAS seems to induce a less pro-restenosis hemodynamic environment compared to CEA. The emerged differences stimulate further analysis on a larger cohort with long-term outcomes, to shed light on the clinical impact of the observations.
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Affiliation(s)
- Anastasios Raptis
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece
| | - Paola Tasso
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Konstantinos Batzalexis
- Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Diego Gallo
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Michalis Xenos
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece; Department of Mathematics, University of Ioannina, Ioannina, Greece
| | - Umberto Morbiducci
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Athanasios Giannoukas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece; Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa, Greece.
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Gil-Sala D, Guala A, Garcia Reyes ME, Azancot MA, Dux-Santoy L, Allegue Allegue N, Teixido Turà G, Goncalves Martins G, Ruiz Muñoz A, Constenla García I, Evangelista A, Tello Díaz C, Ferreira González I, Rodríguez-Palomares JF, Bellmunt S. Geometric, Biomechanic and Haemodynamic Aortic Abnormalities Assessed by 4D Flow Cardiovascular Magnetic Resonance in Patients Treated by TEVAR Following Blunt Traumatic Thoracic Aortic Injury. Eur J Vasc Endovasc Surg 2021; 62:797-807. [PMID: 34511317 DOI: 10.1016/j.ejvs.2021.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 06/29/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Thoracic endovascular aortic repair (TEVAR) is widely used for the treatment of patients with blunt traumatic thoracic aortic injury (BTAI). However, aortic haemodynamic and biomechanical implications of this intervention are poorly investigated. This study aimed to assess whether patients treated by TEVAR following BTAI have thoracic aortic abnormalities in geometry, stiffness, and haemodynamics. METHODS Patients with BTAI treated by TEVAR at Vall d'Hebron Hospital between 1999 and 2019 were compared with propensity score matched healthy volunteers (HVs). All subjects underwent cardiovascular magnetic resonance (CMR) comprising a 4D flow CMR sequence. Spatially resolved aortic diameter, length, volume, and curvature were assessed. Pulse wave velocity, distensibility, and longitudinal strain (all measurements of aortic stiffness) were determined regionally. Moreover, advanced haemodynamic descriptors were quantified: systolic flow reversal ratio (SFRR), quantifying backward flow during systole, and in plane rotational flow (IRF), measuring in plane strength of helical flow. RESULTS Twenty-six BTAI patients treated by TEVAR were included and matched with 26 HVs. They did not differ in terms of age, sex, and body surface area. Patients with TEVAR had a larger and longer ascending aorta (AAo) and marked abnormalities in local curvature. Aortic stiffness was greater in the aortic segments proximal and distal to TEVAR compared with controls. Moreover, TEVAR patients presented strongly altered flow dynamics compared with controls: a reduced IRF from the distal AAo to the proximal descending aorta and an increased SFRR in the whole thoracic aorta. These differences persisted adjusting for cardiovascular risk factors and were independent of time elapsed since TEVAR implantation. CONCLUSION At long term follow up, previously healthy patients who underwent TEVAR implantation following BTAI had increased diameter, length and volume of the ascending aorta, and increased aortic stiffness and abnormal flow patterns in the whole thoracic aorta compared with matched controls. Further studies should address whether these alterations have clinical implications.
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Affiliation(s)
- Daniel Gil-Sala
- Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Departament de Cirurgia. Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Andrea Guala
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain; CIBER-CV, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Marvin E Garcia Reyes
- Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Barcelona, Spain.
| | - Maria A Azancot
- Department of Nephrology, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | | | | | - Gisela Teixido Turà
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain; CIBER-CV, Instituto de Salud Carlos III (ISCIII), Madrid, Spain; Department of Cardiology, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Gabriela Goncalves Martins
- Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Departament de Cirurgia. Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Aroa Ruiz Muñoz
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain; CIBER-CV, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Ivan Constenla García
- Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Arturo Evangelista
- Departament de Cirurgia. Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain; Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain; CIBER-CV, Instituto de Salud Carlos III (ISCIII), Madrid, Spain; Department of Cardiology, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Instituto del Corazón. Quirónsalud-Teknon. Barcelona, Spain
| | - Cristina Tello Díaz
- Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Ignacio Ferreira González
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Barcelona, Spain; CIBER-ESP, Instituto de Salud Carlos III, Madrid, Spain; Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jose F Rodríguez-Palomares
- Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain; CIBER-CV, Instituto de Salud Carlos III (ISCIII), Madrid, Spain; Department of Cardiology, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Sergi Bellmunt
- Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Departament de Cirurgia. Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
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Mandell JG, Loke YH, Mass PN, Cleveland V, Delaney M, Opfermann J, Aslan S, Krieger A, Hibino N, Olivieri LJ. Altered hemodynamics by 4D flow cardiovascular magnetic resonance predict exercise intolerance in repaired coarctation of the aorta: an in vitro study. J Cardiovasc Magn Reson 2021; 23:99. [PMID: 34482836 PMCID: PMC8420072 DOI: 10.1186/s12968-021-00796-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/14/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Coarctation of the aorta (CoA) is associated with decreased exercise capacity despite successful repair. Altered flow patterns have been identified due to abnormal aortic arch geometry. Our previous work demonstrated aorta size mismatch to be associated with exercise intolerance in this population. In this study, we studied aortic flow patterns during simulations of exercise in repaired CoA using 4D flow cardiovascular magnetic resonance (CMR) using aortic replicas connected to an in vitro flow pump and correlated findings with exercise stress test results to identify biomarkers of exercise intolerance. METHODS Patients with CoA repair were retrospectively analyzed after CMR and exercise stress test. Each aorta was manually segmented and 3D printed. Pressure gradient measurements from ascending aorta (AAo) to descending aorta (DAo) and 4D flow CMR were performed during simulations of rest and exercise using a mock circulatory flow loop. Changes in wall shear stress (WSS) and secondary flow formation (vorticity and helicity) from rest to exercise were quantified, as well as estimated DAo Reynolds number. Parameters were correlated with percent predicted peak oxygen consumption (VO2max) and aorta size mismatch (DAAo/DDAo). RESULTS Fifteen patients were identified (VO2max 47 to 126% predicted). Pressure gradient did not correlate with VO2max at rest or exercise. VO2max correlated positively with the change in peak vorticity (R = 0.55, p = 0.03), peak helicity (R = 0.54, p = 0.04), peak WSS in the AAo (R = 0.68, p = 0.005) and negatively with peak WSS in the DAo (R = - 0.57, p = 0.03) from rest to exercise. DAAo/DDAo correlated strongly with change in vorticity (R = - 0.38, p = 0.01), helicity (R = - 0.66, p = 0.007), and WSS in the AAo (R = - 0.73, p = 0.002) and DAo (R = 0.58, p = 0.02). Estimated DAo Reynolds number negatively correlated with VO2max for exercise (R = - 0.59, p = 0.02), but not rest (R = - 0.28, p = 0.31). Visualization of streamline patterns demonstrated more secondary flow formation in aortic arches with better exercise capacity, larger DAo, and lower Reynolds number. CONCLUSIONS There are important associations between secondary flow characteristics and exercise capacity in repaired CoA that are not captured by traditional pressure gradient, likely due to increased turbulence and inefficient flow. These 4D flow CMR parameters are a target of investigation to identify optimal aortic arch geometry and improve long term clinical outcomes after CoA repair.
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Affiliation(s)
- Jason G Mandell
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA.
| | - Yue-Hin Loke
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Paige N Mass
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Vincent Cleveland
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Marc Delaney
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Justin Opfermann
- Department of Mechanical Engineering, Johns Hopkins University, Latrobe Hall 223, 3400 North Charles St, Baltimore, MD, 21218, USA
| | - Seda Aslan
- Department of Mechanical Engineering, Johns Hopkins University, Latrobe Hall 223, 3400 North Charles St, Baltimore, MD, 21218, USA
| | - Axel Krieger
- Department of Mechanical Engineering, Johns Hopkins University, Latrobe Hall 223, 3400 North Charles St, Baltimore, MD, 21218, USA
| | - Narutoshi Hibino
- Section of Cardiac Surgery, Department of Surgery, University of Chicago, 5841 S Maryland Avenue, Chicago, IL, 60637, USA
- Section of Cardiac Surgery, Department of Surgery, Advocate Children's Hospital, 4440 West 95th Street, Oak Lawn, IL, 60453, USA
| | - Laura J Olivieri
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
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25
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Conti M, Romarowski RM, Ferrarini A, Stochino M, Auricchio F, Morganti S, Segesser LKV, Ferrari E. Patient-specific computational fluid dynamics analysis of transcatheter aortic root replacement with chimney coronary grafts. Interact Cardiovasc Thorac Surg 2021; 32:408-416. [PMID: 33351896 DOI: 10.1093/icvts/ivaa288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/16/2020] [Accepted: 10/18/2020] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Transcatheter aortic root repair (TARR) consists of the simultaneous endovascular replacement of the aortic valve, the root and the proximal ascending aorta. The aim of the study is to set-up a computational model of TARR to explore the impact of the endovascular procedure on the coronary circulation supported by chimney grafts. METHODS Computed tomography of a patient with dilated ascending aorta was segmented to obtain a 3-dimensional representation of the proximal thoracic aorta, including aortic root and supra-aortic branches. Computed assisted design tools were used to modify the geometry to create the post-procedural TARR configuration featuring the main aortic endograft integrated with 2 chimney grafts for coronary circulation. Computational Fluid Dynamics simulations were run in both pre- and post-procedural configurations using a pulsatile inflow and lumped parameter models at the outflows to simulate peripheral aortic and coronary circulation. Differences in coronary flow and pressure along the cardiac cycle were evaluated. RESULTS After the virtual implant of the TARR device with coronary grafts, the flow became more organized and less recirculation was seen in the ascending aorta. Coronary perfusion was guaranteed with negligible flow differences between pre- and post-procedural configurations. However, despite being well perfused by chimney grafts, the procedure induces an increase of the pressure drop between the coronary ostia and the ascending aorta of 8 mmHg. CONCLUSIONS The proposed numerical simulations, in the specific case under investigation, suggest that the TARR technique maintains coronary perfusion through the chimney grafts. This study calls for experimental validation and further analyses of the impact of TARR on cardiac afterload, decrease of aortic compliance and local pressure drop induced by the coronary chimney grafts.
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Affiliation(s)
- Michele Conti
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Rodrigo M Romarowski
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Anna Ferrarini
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Matteo Stochino
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Ferdinando Auricchio
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Simone Morganti
- Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Pavia, Italy
| | | | - Enrico Ferrari
- Cardiac Surgery Unit, University of Zurich, Zurich, Switzerland.,Cardiac Surgery Unit, Cardiocentro Ticino, Lugano, Switzerland
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Abstract
Aortic valve stenosis has become the most common valvular heart disease on account of aging population and increasing life expectancy. Echocardiography is the primary diagnosis tool for this, but it still has many flaws. Therefore, advanced cardiovascular multimodal imaging techniques are continuously being developed in order to overcome these limitations. Cardiac magnetic resonance imaging (CMR) allows a comprehensive morphological and functional evaluation of the aortic valve and provides important data for the diagnosis and risk stratification in patients with aortic stenosis. CMR can functionally assess the aortic flow using two-dimensional and time-resolved three-dimensional velocity-encoded phase-contrast techniques. Furthermore, by late gadolinium enhancement and T1-mapping, CMR can reveal the presence of both irreversible replacement and diffuse interstitial myocardial fibrosis. Moreover, its role in guiding aortic valve replacement procedures is beginning to take shape. Recent studies have rendered the importance of active and passive biomechanics in risk stratification and prognosis prediction in patients with aortic stenosis, but more work is required is just in its infancy, but data are promising. In addition, cardiac computed tomography is particularly useful for the diagnosis of aortic valve stenosis, and in preprocedural evaluation of the aorta, while positron emission tomography can be also used to assess valvular inflammation and active calcification. The purpose of this review is to provide a comprehensive overview of current available data regarding advanced cardiovascular multimodal imaging in aortic stenosis.
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Komoriyama H, Kamiya K, Nagai T, Oyama-Manabe N, Tsuneta S, Kobayashi Y, Kato Y, Sarashina M, Omote K, Konishi T, Sato T, Tsujinaga S, Iwano H, Shingu Y, Wakasa S, Anzai T. Blood flow dynamics with four-dimensional flow cardiovascular magnetic resonance in patients with aortic stenosis before and after transcatheter aortic valve replacement. J Cardiovasc Magn Reson 2021; 23:81. [PMID: 34176516 PMCID: PMC8237445 DOI: 10.1186/s12968-021-00771-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 05/04/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pre- and post-procedural hemodynamic changes which could affect adverse outcomes in aortic stenosis (AS) patients who undergo transcatheter aortic valve replacement (TAVR) have not been well investigated. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) enables accurate analysis of blood flow dynamics such as flow velocity, flow pattern, wall shear stress (WSS), and energy loss (EL). We sought to examine the changes in blood flow dynamics of patients with severe AS who underwent TAVR. METHODS We examined 32 consecutive severe AS patients who underwent TAVR between May 2018 and June 2019 (17 men, 82 ± 5 years, median left ventricular ejection fraction 61%, 6 self-expanding valve), after excluding those without CMR because of a contraindication or inadequate imaging from the analyses. We analyzed blood flow patterns, WSS and EL in the ascending aorta (AAo), and those changes before and after TAVR using 4D flow CMR. RESULTS After TAVR, semi-quantified helical flow in the AAo was significantly decreased (1.4 ± 0.6 vs. 1.9 ± 0.8, P = 0.002), whereas vortical flow and eccentricity showed no significant changes. WSS along the ascending aortic circumference was significantly decreased in the left (P = 0.038) and left anterior (P = 0.033) wall at the basal level, right posterior (P = 0.011) and left (P = 0.010) wall at the middle level, and right (P = 0.012), left posterior (P = 0.019) and left anterior (P = 0.028) wall at the upper level. EL in the AAo was significantly decreased (15.6 [10.8-25.1 vs. 25.8 [18.6-36.2]] mW, P = 0.012). Furthermore, a significant negative correlation was observed between EL and effective orifice area index after TAVR (r = - 0.38, P = 0.034). CONCLUSIONS In severe AS patients undergoing TAVR, 4D flow CMR demonstrates that TAVR improves blood flow dynamics, especially when a larger effective orifice area index is obtained.
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Affiliation(s)
- Hirokazu Komoriyama
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kiwamu Kamiya
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshiyuki Nagai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan.
| | - Noriko Oyama-Manabe
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Satonori Tsuneta
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Yuta Kobayashi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yoshiya Kato
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Miwa Sarashina
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kazunori Omote
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takao Konishi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takuma Sato
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Shingo Tsujinaga
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Hiroyuki Iwano
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yasushige Shingu
- Department of Cardiovascular and Thoracic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Satoru Wakasa
- Department of Cardiovascular and Thoracic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshihisa Anzai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
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28
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Ashraf F, Ambreen T, Park CW, Kim DI. Comparative evaluation of ballet-type and conventional stent graft configurations for endovascular aneurysm repair: A CFD analysis. Clin Hemorheol Microcirc 2021; 78:1-27. [PMID: 33459700 PMCID: PMC8293652 DOI: 10.3233/ch-200996] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE: Cross limb stent graft (SG) configuration technique for endovascular aneurysm repair (EVAR) is employed for splayed aortic bifurcations to avoid device kinking and smoothen cannulation. The present study investigates three types of stent graft (SG) configurations for endovascular aneurysm repair (EVAR) in abdominal aortic aneurysm. A computational fluid dynamic analysis was performed on the pulsatile non-Newtonian flow characteristics in three ideally modeled geometries of abdominal aortic (AA) SG configurations. METHODS: The three planar and crosslimb SG configurations were ideally modeled, namely, top-down nonballet-type, top-down ballet-type, and bottom-up nonballet-type configurations. In top-down SG configuration, most of the device is deployed in the main body in the vicinity of renal artery and the limbs are extended to the iliac artery. While in the bottom-up configuration, some of the SG device is deployed in the main body, the limbs are deployed in aortic bifurcation, and the extra stent graft of the main body is extended to the proximal aorta until the below of the renal artery. The effects of non-Newtonian pulsatile flow on the wall stresses and flow patterns of the three models were investigated and compared. Moreover, the average wall shear stress (AWSS), oscillatory shear stress index (OSI), absolute helicity, pressure distribution, graft displacement and flow visualization plots were analyzed. RESULTS: The top-down ballet-type showed less branch blockage effect than the top-down nonballet-type models. Furthermore, the top-down ballet-type configuration showed an increased tendency to sustain high WSS and higher helicity characteristics than that of the bottom-up and top-down non-ballet type configurations. However, displacement forces of the top-down ballet-type configuration were 40% and 9.6% higher than those of the bottom-up and top-down nonballet-type configurations, respectively. CONCLUSIONS: Some complications such as graft tearing, thrombus formation, limb disconnection during long term follow up periods might be relevant to hemodynamic characteristics according to the configurations of EVAR. Hence, the reported data required to be validated with the clinical results.
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Affiliation(s)
- Fahmida Ashraf
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Tehmina Ambreen
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Cheol Woo Park
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Dong-Ik Kim
- Division of Vascular Surgery, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, South Korea
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29
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Combining 4D Flow MRI and Complex Networks Theory to Characterize the Hemodynamic Heterogeneity in Dilated and Non-dilated Human Ascending Aortas. Ann Biomed Eng 2021; 49:2441-2453. [PMID: 34080100 PMCID: PMC8455395 DOI: 10.1007/s10439-021-02798-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/17/2021] [Indexed: 12/29/2022]
Abstract
Motivated by the evidence that the onset and progression of the aneurysm of the ascending aorta (AAo) is intertwined with an adverse hemodynamic environment, the present study characterized in vivo the hemodynamic spatiotemporal complexity and organization in human aortas, with and without dilated AAo, exploring the relations with clinically relevant hemodynamic and geometric parameters. The Complex Networks (CNs) theory was applied for the first time to 4D flow magnetic resonance imaging (MRI) velocity data of ten patients, five of them presenting with AAo dilation. The time-histories along the cardiac cycle of velocity-based quantities were used to build correlation-based CNs. The CNs approach succeeded in capturing large-scale coherent flow features, delimiting flow separation and recirculation regions. CNs metrics highlighted that an increasing AAo dilation (expressed in terms of the ratio between the maximum AAo and aortic root diameter) disrupts the correlation in forward flow reducing the correlation persistence length, while preserving the spatiotemporal homogeneity of secondary flows. The application of CNs to in vivo 4D MRI data holds promise for a mechanistic understanding of the spatiotemporal complexity and organization of aortic flows, opening possibilities for the integration of in vivo quantitative hemodynamic information into risk stratification and classification criteria.
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30
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Han L, Ren Q, Lian J, Luo L, Liu H, Ma T, Li X, Deng X, Liu X. Numerical analysis of the hemodynamics of rat aorta based on magnetic resonance imaging and fluid-structure interaction. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3457. [PMID: 33750033 DOI: 10.1002/cnm.3457] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 03/14/2021] [Indexed: 06/12/2023]
Abstract
Murine models have been widely used to investigate the mechanobiology of aortic atherosclerosis and dissections, which develop preferably at different anatomic locations of aorta. Based MRI and finite element analysis with fluid-structure interaction, we numerically investigated factors that may affect the blood flow and structural mechanics of rat aorta. The results indicated that aortic root motion greatly increases time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), displacement of the aorta, and enhances helical flow pattern but has limited influence on effective stress, which is highly modulated by blood pressure. Moreover, the influence of the motion component on these indicators is different with axial motion more obvious than planar motion. Surrounding fixation of the intercostal arteries and the branch vessels on aortic arch would reduce the influence of aortic root motion. The compliance of the aorta has different influences at different regions, leading to decrease in TAWSS and helical flow, increase in OSI, RRT at the aortic arch, but has reversed effects on the branch vessels. When compared with the steady flow, the pulsatile blood flow would obviously increase the WSS, the displacement, and the effective stress in most regions. In conclusion, to accurately quantify the blood flow and structural mechanics of rat aorta, the motion of the aortic root, the compliance of aortic wall, and the pulsation of blood flow should be considered. However, when only focusing on the effective stress in rat aorta, the motion of the aortic root may be neglected.
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Affiliation(s)
- Longzhu Han
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Quan Ren
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jianxiu Lian
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Liyi Luo
- School of Instrumentation Science & Opto-electronics Engineering, Beihang University, Beijing, China
| | - Huawei Liu
- Department of Stomatology, Chinese PLA General Hospital, Beijing, China
| | - Tianxiang Ma
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xin Li
- Miyun Hospital, Peking University First Hospital, Beijing, China
| | - Xiaoyan Deng
- Artificial Intelligence Key Laboratory of Sichuan Province, School of Automation and Information Engineering, Sichuan University of Science and Engineering, Zigong, China
| | - Xiao Liu
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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31
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Johnston L, Allen R, Hall Barrientos P, Mason A, Kazakidi A. Hemodynamic Abnormalities in the Aorta of Turner Syndrome Girls. Front Cardiovasc Med 2021; 8:670841. [PMID: 34141729 PMCID: PMC8203817 DOI: 10.3389/fcvm.2021.670841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/06/2021] [Indexed: 01/15/2023] Open
Abstract
Congenital abnormalities in girls and women with Turner syndrome (TS), alongside an underlying predisposition to obesity and hypertension, contribute to an increased risk of cardiovascular disease and ultimately reduced life expectancy. We observe that children with TS present a greater variance in aortic arch morphology than their healthy counterparts, and hypothesize that their hemodynamics is also different. In this study, computational fluid dynamic (CFD) simulations were performed for four TS girls, and three age-matched healthy girls, using patient-specific inlet boundary conditions, obtained from phase-contrast MRI data. The visualization of multidirectional blood flow revealed an increase in vortical flow in the arch, supra-aortic vessels, and descending aorta, and a correlation between the presence of aortic abnormalities and disturbed flow. Compared to the relatively homogeneous pattern of time-averaged wall shear stress (TAWSS) on the healthy aortae, a highly heterogeneous distribution with elevated TAWSS values was observed in the TS geometries. Visualization of further shear stress parameters, such as oscillatory shear index (OSI), normalized relative residence time (RRTn), and transverse WSS (transWSS), revealed dissimilar heterogeneity in the oscillatory and multidirectional nature of the aortic flow. Taking into account the young age of our TS cohort (average age 13 ± 2 years) and their obesity level (75% were obese or overweight), which is believed to accelerate the initiation and progression of endothelial dysfunction, these findings may be an indication of atherosclerotic disease manifesting earlier in life in TS patients. Age, obesity and aortic morphology may, therefore, play a key role in assessing cardiovascular risk in TS children.
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Affiliation(s)
- Lauren Johnston
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Ruth Allen
- Department of Radiology, Royal Hospital for Children, Glasgow, United Kingdom
| | | | - Avril Mason
- Department of Paediatric Endocrinology, Royal Hospital for Children, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - Asimina Kazakidi
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
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32
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Wall Shear Stress Topological Skeleton Analysis in Cardiovascular Flows: Methods and Applications. MATHEMATICS 2021. [DOI: 10.3390/math9070720] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A marked interest has recently emerged regarding the analysis of the wall shear stress (WSS) vector field topological skeleton in cardiovascular flows. Based on dynamical system theory, the WSS topological skeleton is composed of fixed points, i.e., focal points where WSS locally vanishes, and unstable/stable manifolds, consisting of contraction/expansion regions linking fixed points. Such an interest arises from its ability to reflect the presence of near-wall hemodynamic features associated with the onset and progression of vascular diseases. Over the years, Lagrangian-based and Eulerian-based post-processing techniques have been proposed aiming at identifying the topological skeleton features of the WSS. Here, the theoretical and methodological bases supporting the Lagrangian- and Eulerian-based methods currently used in the literature are reported and discussed, highlighting their application to cardiovascular flows. The final aim is to promote the use of WSS topological skeleton analysis in hemodynamic applications and to encourage its application in future mechanobiology studies in order to increase the chance of elucidating the mechanistic links between blood flow disturbances, vascular disease, and clinical observations.
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33
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Effects of Ageing on Aortic Circulation During Atrial Fibrillation; a Numerical Study on Different Aortic Morphologies. Ann Biomed Eng 2021; 49:2196-2213. [PMID: 33655419 PMCID: PMC8455405 DOI: 10.1007/s10439-021-02744-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/01/2021] [Indexed: 01/21/2023]
Abstract
Atrial fibrillation (AF) can alter intra-cardiac flow and cardiac output that subsequently affects aortic flow circulation. These changes may become more significant where they occur concomitantly with ageing. Aortic ageing is accompanied with morphological changes such as dilation, lengthening, and arch unfolding. While the recognition of AF mechanism has been the subject of numerous studies, less focus has been devoted to the aortic circulation during the AF and there is a lack of such investigation at different ages. The current work aims to address the present gap. First, we analyse aortic flow distribution in three configurations, which attribute to young, middle and old people, using geometries constructed via clinical data. We then introduce two transient inlet flow conditions representative of key AF-associated defects. Results demonstrate that both AF and ageing negatively affect flow circulation. The main consequence of concomitant occurrence is enhancement of endothelial cell activation potential (ECAP) throughout the vascular domain, mainly at aortic arch and descending thoracic aorta, which is consistent with some clinical observations. The outcome of the current study suggests that AF exacerbates the vascular defects occurred due to the ageing, which increases the possibility of cardiovascular diseases per se.
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34
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Zhang Z, Zhou X, Suarez-Pierre A, Lui C, Kearney S, Yeung E, Halperin H, Choi CW, Katz J. Time-Resolved Echo-Particle Image/Tracking Velocimetry Measurement of Interactions Between Native Cardiac Output and Veno-Arterial ECMO Flows. J Biomech Eng 2021; 143:021008. [PMID: 32914854 DOI: 10.1115/1.4048424] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Indexed: 11/08/2022]
Abstract
Determination of optimal hemodynamic and pressure-volume loading conditions for patients undergoing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) would benefit from understanding the impact of ECMO flow rates (QE) on the native cardiac output in the admixing zone, i.e., aortic root. This study characterizes the flow in the aortic root of a pig with severe myocardial ischemia using contrast-enhanced ultrasound particle image/tracking velocimetry (echo-PIV/PTV). New methods for data preprocessing are introduced, including autocontouring to remove surrounding tissues, followed by blind deconvolution to identify the centers of elongated bubble traces in images with low signal to noise ratio. Calibrations based on synthetic images show that this procedure increases the number of detected bubbles and reduces the error in their locations by 50%. Then, an optimized echo-PIV/PTV procedure, which integrates image enhancement with velocity measurements, is used for characterizing the time-resolved two-dimensional (2D) velocity distributions. Phase-averaged and instantaneous flow fields show that the ECMO flow rate influences the velocity and acceleration of the cardiac output during systole, and secondary flows during diastole. When QE is 3.0 L/min or higher, the cardiac ejection velocity, phase interval with open aortic valve, velocity-time integral (VTI), and mean arterial pressure (MAP) increase with decreasing QE, all indicating sufficient support. For lower QE, the MAP and VTI decrease as QE is reduced, and the deceleration during transition to diastole becomes milder. Hence, for this specific case, the optimal ECMO flow rate is 3.0 L/min.
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Affiliation(s)
- Zeng Zhang
- Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Latrobe b31, Baltimore, MD 21218
| | - Xun Zhou
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287
| | - Alejandro Suarez-Pierre
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287
| | - Cecillia Lui
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287
| | - Sean Kearney
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287
| | - Enoch Yeung
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287; Department of Surgery, Robert Packer Hospital, 1 Guthrie Square, Sayre, PA 18840
| | - Henry Halperin
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287
| | - Chun Woo Choi
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287
| | - Joseph Katz
- Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Latrobe 122, Baltimore, MD 21218
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35
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Capellini K, Gasparotti E, Cella U, Costa E, Fanni BM, Groth C, Porziani S, Biancolini ME, Celi S. A novel formulation for the study of the ascending aortic fluid dynamics with in vivo data. Med Eng Phys 2020; 91:68-78. [PMID: 33008714 DOI: 10.1016/j.medengphy.2020.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/20/2020] [Accepted: 09/12/2020] [Indexed: 01/18/2023]
Abstract
Numerical simulations to evaluate thoracic aortic hemodynamics include a computational fluid dynamic (CFD) approach or fluid-structure interaction (FSI) approach. While CFD neglects the arterial deformation along the cardiac cycle by applying a rigid wall simplification, on the other side the FSI simulation requires a lot of assumptions for the material properties definition and high computational costs. The aim of this study is to investigate the feasibility of a new strategy, based on Radial Basis Functions (RBF) mesh morphing technique and transient simulations, able to introduce the patient-specific changes in aortic geometry during the cardiac cycle. Starting from medical images, aorta models at different phases of cardiac cycle were reconstructed and a transient shape deformation was obtained by proper activating incremental RBF solutions during the simulation process. The results, in terms of main hemodynamic parameters, were compared with two performed CFD simulations for the aortic model at minimum and maximum volume. Our implemented strategy copes the actual arterial variation during cardiac cycle with high accuracy, capturing the impact of geometrical variations on fluid dynamics, overcoming the complexity of a standard FSI approach.
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Affiliation(s)
- Katia Capellini
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Ubaldo Cella
- Department of Enterprise Engineering, University of Rome Tor Vergata, Rome, Italy
| | | | - Benigno Marco Fanni
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Corrado Groth
- Department of Enterprise Engineering, University of Rome Tor Vergata, Rome, Italy
| | - Stefano Porziani
- Department of Enterprise Engineering, University of Rome Tor Vergata, Rome, Italy
| | | | - Simona Celi
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy.
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36
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Deciphering ascending thoracic aortic aneurysm hemodynamics in relation to biomechanical properties. Med Eng Phys 2020; 82:119-129. [DOI: 10.1016/j.medengphy.2020.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/19/2020] [Accepted: 07/09/2020] [Indexed: 12/20/2022]
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37
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Lodi Rizzini M, Gallo D, De Nisco G, D'Ascenzo F, Chiastra C, Bocchino PP, Piroli F, De Ferrari GM, Morbiducci U. Does the inflow velocity profile influence physiologically relevant flow patterns in computational hemodynamic models of left anterior descending coronary artery? Med Eng Phys 2020; 82:58-69. [PMID: 32709266 DOI: 10.1016/j.medengphy.2020.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/03/2020] [Accepted: 07/08/2020] [Indexed: 12/13/2022]
Abstract
Patient-specific computational fluid dynamics is a powerful tool for investigating the hemodynamic risk in coronary arteries. Proper setting of flow boundary conditions in computational hemodynamic models of coronary arteries is one of the sources of uncertainty weakening the findings of in silico experiments, in consequence of the challenging task of obtaining in vivo 3D flow measurements within the clinical framework. Accordingly, in this study we evaluated the influence of assumptions on inflow velocity profile shape on coronary artery hemodynamics. To do that, (1) ten left anterior descending coronary artery (LAD) geometries were reconstructed from clinical angiography, and (2) eleven velocity profiles with realistic 3D features such as eccentricity and differently shaped (single- and double-vortex) secondary flows were generated analytically and imposed as inflow boundary conditions. Wall shear stress and helicity-based descriptors obtained prescribing the commonly used parabolic velocity profile were compared with those obtained with the other velocity profiles. Our findings indicated that the imposition of idealized velocity profiles as inflow boundary condition is acceptable as long the results of the proximal vessel segment are not considered, in LAD coronary arteries. As a pragmatic rule of thumb, a conservative estimation of the length of influence of the shape of the inflow velocity profile on LAD local hemodynamics can be given by the theoretical entrance length for cylindrical conduits in laminar flow conditions.
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Affiliation(s)
- Maurizio Lodi Rizzini
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Diego Gallo
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Giuseppe De Nisco
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Fabrizio D'Ascenzo
- Hemodynamic Laboratory, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Claudio Chiastra
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Pier Paolo Bocchino
- Hemodynamic Laboratory, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Francesco Piroli
- Hemodynamic Laboratory, Department of Medical Sciences, University of Turin, Turin, Italy
| | | | - Umberto Morbiducci
- PoliTo(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
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38
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Abstract
Magnetic resonance imaging (MRI) has become an important tool for the clinical evaluation of patients with cardiac and vascular diseases. Since its introduction in the late 1980s, quantitative flow imaging with MRI has become a routine part of standard-of-care cardiothoracic and vascular MRI for the assessment of pathological changes in blood flow in patients with cardiovascular disease. More recently, time-resolved flow imaging with velocity encoding along all three flow directions and three-dimensional (3D) anatomic coverage (4D flow MRI) has been developed and applied to enable comprehensive 3D visualization and quantification of hemodynamics throughout the human circulatory system. This article provides an overview of the use of 4D flow applications in different cardiac and vascular regions in the human circulatory system, with a focus on using 4D flow MRI in cardiothoracic and cerebrovascular diseases.
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Affiliation(s)
- Gilles Soulat
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Patrick McCarthy
- Division of Cardiac Surgery, Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois 60208, USA
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39
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Ortega J, Antón R, Ramos JC, Rivas A, Larraona GS, Sangro B, Bilbao JI, Aramburu J. On the importance of spiral-flow inflow boundary conditions when using idealized artery geometries in the analysis of liver radioembolization: A parametric study. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3337. [PMID: 32212316 DOI: 10.1002/cnm.3337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 03/04/2020] [Accepted: 03/16/2020] [Indexed: 06/10/2023]
Abstract
In the last decades, the numerical studies on hemodynamics have become a valuable explorative scientific tool. The very first studies were done over idealized geometries, but as numerical methods and the power of computers have become more affordable, the studies tend to be patient specific. We apply the study to the numerical analysis of tumor-targeting during liver radioembolization (RE). RE is a treatment for liver cancer, and is performed by injecting radiolabeled microspheres via a catheter placed in the hepatic artery. The objective of the procedure is to maximize the release of radiolabeled microspheres into the tumor and avoid a healthy tissue damage. Idealized virtual arteries can serve as a generalist approach that permits to separately analyze the effect of a variable in the microsphere distribution with respect to others. However, it is important to use proper physiological boundary conditions (BCs). It is not obvious, the need to account for the effect of tortuosity when using an idealized virtual artery. We study the use of idealized geometry of a hepatic artery as a valid research tool, exploring the importance of using realistic spiral-flow inflow BC. By using a literature-based cancer scenario, we vary two parameters to analyze the microsphere distribution through the outlets of the geometry. The parameters varied are the type of microspheres injected and the microsphere injection velocity. The results with realistic inlet velocity profile showed that the particle distribution in the liver segments is not affected by the analyzed injection velocity values neither by the particle density. NOVELTY STATEMENT: In this article, we assessed the use of idealized geometries as a valid research tool and applied the use of an idealized geometry to the case of an idealized hepatic artery to study the particle-hemodynamics during radioembolization (RE). We studied three different inflow boundary conditions (BCs) to assess the usefulness of the geometry, two types of particle injection velocities and two types of commercially available microspheres for RE treatment. In recent years, the advent in computational resources allowed for more detailed patient-specific geometry generation and discretization and hemodynamics simulations. However, general studies based on idealized geometries can be performed in order to provide medical doctors with some basic and general guidelines when using a given catheter for a given cancer scenario. Moreover, using an idealized geometry can be a reasonable approach which allows us to isolate a given parameter and control other parameters, so that parameters can be independently assessed. Even though an idealized geometry does not match any patient's geometry, the use of an idealized geometry can be valid when drawing general conclusions that may be useful in patient-specific cases. However, we believe that even if an idealized hepatic artery geometry is used for the study, it is necessary to account for the upstream and downstream tortuosity of vessels through the BCs. In this work, we highlighted the need of modeling the tortuosity of upstream and downstream vasculatures through the BCs.
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Affiliation(s)
- Julio Ortega
- Escuela de Ingeniería Mecánica, Pontificia Universidad Católica de Valparaíso, Quilpué, Chile
- Departamento de Ingeniería Mecánica y Materiales, niversidad de Navarra, TECNUN - Escuela de Ingenieros, San Sebastián, Spain
| | - Raul Antón
- Departamento de Ingeniería Mecánica y Materiales, niversidad de Navarra, TECNUN - Escuela de Ingenieros, San Sebastián, Spain
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Juan C Ramos
- Departamento de Ingeniería Mecánica y Materiales, niversidad de Navarra, TECNUN - Escuela de Ingenieros, San Sebastián, Spain
| | - Alejandro Rivas
- Departamento de Ingeniería Mecánica y Materiales, niversidad de Navarra, TECNUN - Escuela de Ingenieros, San Sebastián, Spain
| | - Gorka S Larraona
- Departamento de Ingeniería Mecánica y Materiales, niversidad de Navarra, TECNUN - Escuela de Ingenieros, San Sebastián, Spain
| | - Bruno Sangro
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- Clínica Universidad de Navarra, Pamplona, Spain
| | - Jose I Bilbao
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- Clínica Universidad de Navarra, Pamplona, Spain
| | - Jorge Aramburu
- Departamento de Ingeniería Mecánica y Materiales, niversidad de Navarra, TECNUN - Escuela de Ingenieros, San Sebastián, Spain
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40
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Chen X, Zhuang J, Wu Y. The effect of Womersley number and particle radius on the accumulation of lipoproteins in the human aorta. Comput Methods Biomech Biomed Engin 2020; 23:571-584. [PMID: 32309993 DOI: 10.1080/10255842.2020.1752681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The purpose of this study is to compare the effects of the different physical factors on lipoproteins accumulation in the aorta artery. Results revealed that hemodynamic parameters (WSS, OSI, RRT) together affect spatial distributions of lipoproteins concentration in the human aorta. Moreover, decreasing the frequency of pulsatile flow and particle size leads to more lipoproteins accumulated on the luminal surface. In addition, given the same flow rate, the pulsatile flow could reduce lipoproteins concentration in the luminal surface of aorta relative to a steady flow condition. The present computer strategy may have great potential in predicting the local atherosclerosis lesion.
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Affiliation(s)
- Xueping Chen
- Institute of Biomechanics, School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, P.R. China
| | - Jian Zhuang
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
| | - Yueheng Wu
- Institute of Biomechanics, School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, P.R. China.,Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
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41
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A parametric model for studying the aorta hemodynamics by means of the computational fluid dynamics. J Biomech 2020; 103:109691. [PMID: 32147240 DOI: 10.1016/j.jbiomech.2020.109691] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/20/2020] [Accepted: 02/21/2020] [Indexed: 11/23/2022]
Abstract
Perturbed aorta hemodynamics, as for the carotid and the coronary artery, has been identified as potential predicting factor for cardiovascular diseases. In this study, we propose a parametric study based on the computational fluid dynamics with the aim of providing information regarding aortic disease. In particular, the blood flow inside a parametrized aortic arch is computed as a function of morphological changes of baseline aorta geometry. Flow patterns, wall shear stress, time average wall shear stress and oscillatory shear index were calculated during the cardiac cycle. The influence of geometrical changes on the hemodynamics and on these variables was evaluated. The results suggest that the distance between inflow and aortic arch and the angle between aortic arch and descending trunk are the most influencing parameters regarding the WSS-related indices while the effect of the inlet diameter seems limited. In particular, an increase of the aforementioned distance produces a reduction of the spatial distribution of the higher values of the time average wall shear stress and of the oscillatory shear index independently on the other two parameters while an increase of the angle produce an opposite effect. Moreover, as expected, the analysis of the wall shear stress descriptors suggests that the inlet diameter influences only the flow intensity. As conclusion, the proposed parametric study can be used to evaluate the aorta hemodynamics and could be also applied in the future, for analyzing pathological cases and virtual situations, such as pre- and/or post-operative cardiovascular surgical states that present enhanced changes in the aorta morphology yet promoting important variations on the considered indexes.
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Tomaszewski M, Sybilski K, Baranowski P, Małachowski J. Experimental and numerical flow analysis through arteries with stent using particle image velocimetry and computational fluid dynamics method. Biocybern Biomed Eng 2020. [DOI: 10.1016/j.bbe.2020.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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43
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Helical flow: A means to identify unstable plaques and a new direction for the design of vascular grafts and stents. Atherosclerosis 2020; 300:34-36. [PMID: 32216972 DOI: 10.1016/j.atherosclerosis.2020.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/25/2022]
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44
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Jarral OA, Tan MKH, Salmasi MY, Pirola S, Pepper JR, O'Regan DP, Xu XY, Athanasiou T. Phase-contrast magnetic resonance imaging and computational fluid dynamics assessment of thoracic aorta blood flow: a literature review. Eur J Cardiothorac Surg 2020; 57:438-446. [PMID: 31638698 DOI: 10.1093/ejcts/ezz280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/06/2019] [Accepted: 09/17/2019] [Indexed: 11/14/2022] Open
Abstract
The death rate from thoracic aortic disease is on the rise and represents a growing global health concern as patients are often asymptomatic before acute events, which have devastating effects on health-related quality of life. Biomechanical factors have been found to play a major role in the development of both acquired and congenital aortic diseases. However, much is still unknown and translational benefits of this knowledge are yet to be seen. Phase-contrast cardiovascular magnetic resonance imaging of thoracic aortic blood flow has emerged as an exceptionally powerful non-invasive tool enabling visualization of complex flow patterns, and calculation of variables such as wall shear stress. This has led to multiple new findings in the areas of phenotype-dependent bicuspid valve flow patterns, thoracic aortic aneurysm formation and aortic prosthesis performance assessment. Phase-contrast cardiovascular magnetic resonance imaging has also been used in conjunction with computational fluid modelling techniques to produce even more sophisticated analyses, by allowing the calculation of haemodynamic variables with exceptional temporal and spatial resolution. Translationally, these technologies may potentially play a major role in the emergence of precision medicine and patient-specific treatments in patients with aortic disease. This clinically focused review will provide a systematic overview of key insights from published studies to date.
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Affiliation(s)
- Omar A Jarral
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Matthew K H Tan
- Department of Surgery and Cancer, Imperial College London, London, UK
| | | | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, UK
| | - John R Pepper
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Declan P O'Regan
- MRC London Institute of Medical Sciences, Imperial College London, London, UK
| | - Xiao Y Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Thanos Athanasiou
- Department of Surgery and Cancer, Imperial College London, London, UK
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Ebel S, Dufke J, Köhler B, Preim B, Behrendt B, Riekena B, Jung B, Stehning C, Kropf S, Grothoff M, Gutberlet M. Automated Quantitative Extraction and Analysis of 4D flow Patterns in the Ascending Aorta: An intraindividual comparison at 1.5 T and 3 T. Sci Rep 2020; 10:2949. [PMID: 32076060 PMCID: PMC7031260 DOI: 10.1038/s41598-020-59826-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 01/29/2020] [Indexed: 12/28/2022] Open
Abstract
4D flow MRI enables quantitative assessment of helical flow. Current methods are susceptible to noise. To evaluate helical flow patterns in healthy volunteers and patients with bicuspid aortic valves (BAV) at 1.5 T and 3 T using pressure-based helix-extraction in 4D flow MRI. Two intraindividual 4D flow MRI examinations were performed at 1.5 T and 3 T in ten healthy volunteers (5 females, 32 ± 3 years) and 2 patients with BAV using different acceleration techniques (kt-GRAPPA and centra). Several new quantitative parameters for the evaluation of volumes [ml], lengths [mm] as well as temporal parameters [ms] of helical flow were introduced and analyzed using the software tool Bloodline. We found good correlations between measurements in volunteers at 1.5 T and 3 T regarding helical flow volumes (R = 0.98) and temporal existence (R = 0.99) of helices in the ascending aorta. Furthermore, we found significantly larger (11.7 vs. 77.6 ml) and longer lasting (317 vs. 769 ms) helices in patients with BAV than in volunteers. The assessed parameters do not depend on the magnetic field strength used for the acquisition. The technique of pressure-based extraction of 4D flow MRI pattern is suitable for differentiation of normal and pathological flow.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany. .,Department of Diagnostic and Interventional Radiology, University of Leipzig, Leipzig, Germany.
| | - Josefin Dufke
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Benjamin Köhler
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Bernhard Preim
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Benjamin Behrendt
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Boris Riekena
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and paediatric Radiology, University of Bern, Bern, Switzerland
| | | | - Siegfried Kropf
- Institute for Biometrics and Medical Informatics, University of Magdeburg, Magdeburg, Germany
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
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De Nisco G, Gallo D, Siciliano K, Tasso P, Lodi Rizzini M, Mazzi V, Calò K, Antonucci M, Morbiducci U. Hemodialysis arterio-venous graft design reducing the hemodynamic risk of vascular access dysfunction. J Biomech 2020; 100:109591. [PMID: 31902610 DOI: 10.1016/j.jbiomech.2019.109591] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/04/2019] [Accepted: 12/18/2019] [Indexed: 11/18/2022]
Abstract
Although arterio-venous grafts (AVGs) represent the second choice as permanent vascular access for hemodialysis, this solution is still affected by a relevant failure rate due to graft thrombosis, and development of neointimal hyperplasia (IH) at the distal vein. As a key role in these processes has been attributed to the abnormal hemodynamics establishing in the distal vein, the optimization of AVGs design aimed at minimizing flow disturbances would reduce AVG hemodynamic-related risks. In this study we used computational fluid dynamics to investigate the impact of alternative AVG designs on the reduction of IH and thrombosis risk at the distal venous anastomosis. The performance of the newly designed AVGs was compared to that of commercially available devices. In detail, a total of eight AVG models in closed-loop configuration were constructed: two models resemble the commercially available straight conventional and helical-shaped AVGs; six models are characterized by the insertion of a flow divider (FD), straight or helical shaped, differently positioned inside the graft. Unfavorable hemodynamic conditions were analyzed by assessing the exposure to disturbed shear at the distal vein. Bulk flow was investigated in terms of helical blood flow features, potential thrombosis risk, and pressure drop over the graft. Findings from this study clearly show that using a helically-shaped FD located at the venous side of the graft could induce beneficial helical flow patterns that, minimizing flow disturbances, reduce the IH-related risk of failure at the distal vein, with a clinically irrelevant increase in thrombosis risk and pressure drop over the graft.
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Affiliation(s)
- Giuseppe De Nisco
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Diego Gallo
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Katia Siciliano
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Paola Tasso
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Maurizio Lodi Rizzini
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Valentina Mazzi
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Karol Calò
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | | | - Umberto Morbiducci
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
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The impact of helical flow on coronary atherosclerotic plaque development. Atherosclerosis 2020; 300:39-46. [PMID: 32085872 DOI: 10.1016/j.atherosclerosis.2020.01.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/18/2019] [Accepted: 01/29/2020] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND AIMS Atherosclerosis has been associated with near-wall hemodynamics and wall shear stress (WSS). However, the role of coronary intravascular hemodynamics, in particular of the helical flow (HF) patterns that physiologically develop in those arteries, is rarely considered. The purpose of this study was to assess how HF affects coronary plaque initiation and progression, definitively demonstrating its atheroprotective nature. METHODS The three main coronary arteries of five adult hypercholesterolemic mini-pigs on a high fat diet were imaged by computed coronary tomography angiography (CCTA) and intravascular ultrasound (IVUS) at 3 (T1, baseline) and 9.4 ± 1.9 (T2) months follow-up. The baseline geometries of imaged coronary arteries (n = 15) were reconstructed, and combined with pig-specific boundary conditions (based on in vivo Doppler blood flow measurements) to perform computational fluid dynamic simulations. Local wall thickness (WT) was measured on IVUS images at T1 and T2, and its temporal changes were assessed. Descriptors of HF and WSS nature were computed for each model, and statistically compared to WT data. RESULTS HF intensity was strongly positively associated with WSS magnitude (p < 0.001). Overall, coronary segments exposed to high baseline levels of HF intensity exhibited a significantly lower WT growth (p < 0.05), compared to regions with either mid or low HF intensity. CONCLUSIONS This study confirms the physiological significance of HF in coronary arteries, revealing its protective role against atherosclerotic WT growth and its potential in predicting regions undergoing WT development. These findings support future in vivo measurement of coronary HF as atherosclerotic risk marker, overcoming current limitations of in vivo WSS assessment.
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Hansen KL, Møller-Sørensen H, Kjaergaard J, Jensen JA, Nielsen MB. Vector Flow Imaging of the Ascending Aorta in Patients with Tricuspid and Bicuspid Aortic Valve Stenosis Treated with Biological and Mechanical Implants. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:64-72. [PMID: 31677849 DOI: 10.1016/j.ultrasmedbio.2019.09.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/26/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
Aortic valve stenosis (AS) is treated with biological prostheses (BPs) and mechanical prostheses (MPs). Vector flow imaging (VFI), an angle-independent ultrasound method, can quantify flow complexity (vector concentration (VC)) and secondary rotation (SR). Ten patients (mean age: 70.7 y) with tricuspid AS scheduled for BPs, 10 patients (mean age: 56.2 y) with bicuspid AS scheduled for MPs and 10 patients (mean age: 63.9 y) with normal aortic valves were scanned intra-operatively on the ascending aorta with VFI and conventional spectral Doppler. Bicuspid AS (peak systolic velocity (PSV): 380.9 cm/s, SR: 16.7 Hz, VC: 0.21) had more complex flow (p < 0.02) than tricuspid AS (PSV: 346.1 cm/s, SR: 17.1 Hz, VC: 0.33). Both groups had more complex and faster flow (p < 0.0001) than normal aortic valve patients (PSV: 124.0 cm/s, SR: 4.3 Hz, VC: 0.79). VC (r = 0.87) and SR (r = 0.89) correlated to PSV. After surgery, flow parameters changed (p < 0.0001) for patients with MPs (PSV: 250.4 cm/s, SR: 9.8 Hz, VC: 0.54) and BPs (PSV: 232.4 cm/s, SR: 12.5 Hz, VC: 0.61), with MPs having slower SR (p < 0.01). None of the implants had normal flow (p < 0.0001). In conclusion, VFI can provide new flow parameters for AS and implant assessment.
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Affiliation(s)
- Kristoffer Lindskov Hansen
- Department of Diagnostic Radiology, Copenhagen University Hospital, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Hasse Møller-Sørensen
- Department of Cardiothoracic Anesthesiology, Copenhagen University Hospital, Denmark
| | | | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, DTU Elektro, Technical University of Denmark, Denmark
| | - Michael Bachmann Nielsen
- Department of Diagnostic Radiology, Copenhagen University Hospital, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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49
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Calo K, Gallo D, Steinman DA, Mazzi V, Scarsoglio S, Ridolfi L, Morbiducci U. Spatiotemporal Hemodynamic Complexity in Carotid Arteries: An Integrated Computational Hemodynamics and Complex Networks-Based Approach. IEEE Trans Biomed Eng 2019; 67:1841-1853. [PMID: 31647419 DOI: 10.1109/tbme.2019.2949148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE The study of the arterial hemodynamics is essential for a better understanding of the risks associated with the onset/progression of vascular disease. However, conventional quantification and visualization paradigms are not sufficient to fully capture the spatiotemporal evolution of correlated blood flow patterns and their "sphere of influence" in complex vascular geometries. In the attempt to bridge this knowledge gap, an integrated computational hemodynamics and complex networks-based approach is proposed to unveil organization principles of cardiovascular flows. METHODS The approach is applied to ten patient-specific hemodynamic models of carotid bifurcation, a vascular bed characterized by a complex hemodynamics and clinically-relevant disease. Correlation-based networks are built starting from time-histories of two fluid mechanics quantities of physiological significance, respectively (1) the blood velocity vector axial component locally aligned with the main flow direction, and (2) the kinetic helicity density. RESULTS Unlike conventional hemodynamic analyses, here the spatiotemporal similarity of dynamic intravascular flow structures is encoded in a distance function. In the case of the carotid bifurcation, this study measures for the first time to what extent flow similarity is disrupted by vascular geometric features. CONCLUSION It emerges that a larger bifurcation expansion, a hallmark of vascular disease, significantly disrupts the network topological connections between axial flow structures, reducing also their anatomical persistence length. On the contrary, connections in helical flow patterns are overall less geometry-sensitive. SIGNIFICANCE The integrated approach proposed here, by exploiting the connections of hemodynamic patterns undergoing similar dynamical evolution, opens avenues for further comprehension of vascular physiopathology.
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50
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Guala A, Teixido-Tura G, Dux-Santoy L, Granato C, Ruiz-Muñoz A, Valente F, Galian-Gay L, Gutiérrez L, González-Alujas T, Johnson KM, Wieben O, Sao Avilés A, Evangelista A, Rodriguez-Palomares J. Decreased rotational flow and circumferential wall shear stress as early markers of descending aorta dilation in Marfan syndrome: a 4D flow CMR study. J Cardiovasc Magn Reson 2019; 21:63. [PMID: 31607265 PMCID: PMC6791020 DOI: 10.1186/s12968-019-0572-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 08/28/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Diseases of the descending aorta have emerged as a clinical issue in Marfan syndrome following improvements in proximal aorta surgical treatment and the consequent increase in life expectancy. Although a role for hemodynamic alterations in the etiology of descending aorta disease in Marfan patients has been suggested, whether flow characteristics may be useful as early markers remains to be determined. METHODS Seventy-five Marfan patients and 48 healthy subjects were prospectively enrolled. In- and through-plane vortexes were computed by 4D flow cardiovascular magnetic resonance (CMR) in the thoracic aorta through the quantification of in-plane rotational flow and systolic flow reversal ratio, respectively. Regional pulse wave velocity and axial and circumferential wall shear stress maps were also computed. RESULTS In-plane rotational flow and circumferential wall shear stress were reduced in Marfan patients in the distal ascending aorta and in proximal descending aorta, even in the 20 patients free of aortic dilation. Multivariate analysis showed reduced in-plane rotational flow to be independently related to descending aorta pulse wave velocity. Conversely, systolic flow reversal ratio and axial wall shear stress were altered in unselected Marfan patients but not in the subgroup without dilation. In multivariate regression analysis proximal descending aorta axial (p = 0.014) and circumferential (p = 0.034) wall shear stress were independently related to local diameter. CONCLUSIONS Reduced rotational flow is present in the aorta of Marfan patients even in the absence of dilation, is related to aortic stiffness and drives abnormal circumferential wall shear stress. Axial and circumferential wall shear stress are independently related to proximal descending aorta dilation beyond clinical factors. In-plane rotational flow and circumferential wall shear stress may be considered as an early marker of descending aorta dilation in Marfan patients.
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Affiliation(s)
- A. Guala
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - G. Teixido-Tura
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - L. Dux-Santoy
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - C. Granato
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - A. Ruiz-Muñoz
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - F. Valente
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - L. Galian-Gay
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - L. Gutiérrez
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - T. González-Alujas
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - K. M. Johnson
- Departments of Medical Physics & Radiology, University of Wisconsin – Madison, Madison, WI USA
| | - O. Wieben
- Departments of Medical Physics & Radiology, University of Wisconsin – Madison, Madison, WI USA
| | - A. Sao Avilés
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - A. Evangelista
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - J. Rodriguez-Palomares
- Hospital Universitari Vall d’Hebron, Department of Cardiology. CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Paseo Vall d’Hebron 119-129, 08035 Barcelona, Spain
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