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Corso P, Obrist D. On the role of aortic valve architecture for physiological hemodynamics and valve replacement, Part I: Flow configuration and vortex dynamics. Comput Biol Med 2024; 176:108526. [PMID: 38749328 DOI: 10.1016/j.compbiomed.2024.108526] [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: 11/20/2023] [Revised: 04/22/2024] [Accepted: 04/26/2024] [Indexed: 05/31/2024]
Abstract
Aortic valve replacement has become an increasing concern due to the rising prevalence of aortic stenosis in an ageing population. Existing replacement options have limitations, necessitating the development of improved prosthetic aortic valves. In this study, flow characteristics during systole in a stenotic aortic valve case are compared with those downstream of two newly designed surgical bioprosthetic aortic valves (BioAVs). To do so, advanced three-dimensional fluid-structure interaction simulations are conducted and dedicated analysis methods to investigate jet flow configuration and vortex dynamics are developed. Our findings reveal that the stenotic case maintains a high jet flow eccentricity due to a fixed orifice geometry, resulting in flow separation and increased vortex stretching and tilting in the commissural low-flow regions. One BioAV design introduces non-axisymmetric leaflet motion, which reduces the maximum jet velocity and forms more vortical structures. The other BioAV design produces a fixed symmetric triangular jet shape due to non-moving leaflets and exhibits favourable vorticity attenuation, revealed by negative temporally and spatially averaged projected vortex stretching values, and significantly reduced drag. Therefore, this study highlights the benefits of custom-designed aortic valves in the context of their replacement through comprehensive and novel flow analyses. The results emphasise the importance of analysing jet flow, vortical structures, momentum balance and vorticity transport for thoroughly evaluating aortic valve performance.
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Affiliation(s)
- Pascal Corso
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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2
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Shahbad R, Pipinos M, Jadidi M, Desyatova A, Gamache J, MacTaggart J, Kamenskiy A. Structural and Mechanical Properties of Human Superficial Femoral and Popliteal Arteries. Ann Biomed Eng 2024; 52:794-815. [PMID: 38321357 DOI: 10.1007/s10439-023-03435-3] [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: 10/02/2023] [Accepted: 12/26/2023] [Indexed: 02/08/2024]
Abstract
The femoropopliteal artery (FPA) is the main artery in the lower limb. It supplies blood to the leg muscles and undergoes complex deformations during limb flexion. Atherosclerotic disease of the FPA (peripheral arterial disease, PAD) is a major public health burden, and despite advances in surgical and interventional therapies, the clinical outcomes of PAD repairs continue to be suboptimal, particularly in challenging calcified lesions and biomechanically active locations. A better understanding of human FPA mechanical and structural characteristics in relation to age, risk factors, and the severity of vascular disease can help develop more effective and longer-lasting treatments through computational modeling and device optimization. This review aims to summarize recent research on the main biomechanical and structural properties of human superficial femoral and popliteal arteries that comprise the FPA and describe their anatomy, composition, and mechanical behavior under different conditions.
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Affiliation(s)
- Ramin Shahbad
- Department of Biomechanics, University of Nebraska at Omaha, Biomechanics Research Building, Omaha, NE, 68182, USA
| | - Margarita Pipinos
- Department of Biomechanics, University of Nebraska at Omaha, Biomechanics Research Building, Omaha, NE, 68182, USA
| | - Majid Jadidi
- Department of Biomechanics, University of Nebraska at Omaha, Biomechanics Research Building, Omaha, NE, 68182, USA
| | - Anastasia Desyatova
- Department of Biomechanics, University of Nebraska at Omaha, Biomechanics Research Building, Omaha, NE, 68182, USA
| | - Jennifer Gamache
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jason MacTaggart
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Alexey Kamenskiy
- Department of Biomechanics, University of Nebraska at Omaha, Biomechanics Research Building, Omaha, NE, 68182, USA.
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3
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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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4
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de Azevedo FS, Almeida GDC, Alvares de Azevedo B, Ibanez Aguilar IF, Azevedo BN, Teixeira PS, Camargo GC, Correia MG, Nieckele AO, Oliveira GMM. Stress Load and Ascending Aortic Aneurysms: An Observational, Longitudinal, Single-Center Study Using Computational Fluid Dynamics. Bioengineering (Basel) 2024; 11:204. [PMID: 38534478 DOI: 10.3390/bioengineering11030204] [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: 12/27/2023] [Revised: 02/05/2024] [Accepted: 02/15/2024] [Indexed: 03/28/2024] Open
Abstract
Ascending aortic aneurysm (AAoA) is a silent disease with high mortality; however, the factors associated with a worse prognosis are not completely understood. The objective of this observational, longitudinal, single-center study was to identify the hemodynamic patterns and their influence on AAoA growth using computational fluid dynamics (CFD), focusing on the effects of geometrical variations on aortic hemodynamics. Personalized anatomic models were obtained from angiotomography scans of 30 patients in two different years (with intervals of one to three years between them), of which 16 (53%) showed aneurysm growth (defined as an increase in the ascending aorta volume by 5% or more). Numerically determined velocity and pressure fields were compared with the outcome of aneurysm growth. Through a statistical analysis, hemodynamic characteristics were found to be associated with aneurysm growth: average and maximum high pressure (superior to 100 Pa); average and maximum high wall shear stress (superior to 7 Pa) combined with high pressure (>100 Pa); and stress load over time (maximum pressure multiplied by the time interval between the exams). This study provides insights into a worse prognosis of this serious disease and may collaborate for the expansion of knowledge about mechanobiology in the progression of AAoA.
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Affiliation(s)
- Fabiula Schwartz de Azevedo
- Department of Cardiology, Federal University of Rio de Janeiro, Rio de Janeiro 21941-913, RJ, Brazil
- Research and Teaching Department, Instituto Nacional de Cardiologia, Rio de Janeiro 22240-006, RJ, Brazil
| | - Gabriela de Castro Almeida
- Department of Mechanical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | - Bruno Alvares de Azevedo
- Department of Mechanical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | - Ivan Fernney Ibanez Aguilar
- Department of Mechanical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | - Bruno Nieckele Azevedo
- Department of Mechanical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | | | - Gabriel Cordeiro Camargo
- Research and Teaching Department, Instituto Nacional de Cardiologia, Rio de Janeiro 22240-006, RJ, Brazil
| | - Marcelo Goulart Correia
- Research and Teaching Department, Instituto Nacional de Cardiologia, Rio de Janeiro 22240-006, RJ, Brazil
| | - Angela Ourivio Nieckele
- Department of Mechanical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
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5
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Torre M, Morganti S, Pasqualini FS, Reali A. Current progress toward isogeometric modeling of the heart biophysics. BIOPHYSICS REVIEWS 2023; 4:041301. [PMID: 38510845 PMCID: PMC10903424 DOI: 10.1063/5.0152690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 10/24/2023] [Indexed: 03/22/2024]
Abstract
In this paper, we review a powerful methodology to solve complex numerical simulations, known as isogeometric analysis, with a focus on applications to the biophysical modeling of the heart. We focus on the hemodynamics, modeling of the valves, cardiac tissue mechanics, and on the simulation of medical devices and treatments. For every topic, we provide an overview of the methods employed to solve the specific numerical issue entailed by the simulation. We try to cover the complete process, starting from the creation of the geometrical model up to the analysis and post-processing, highlighting the advantages and disadvantages of the methodology.
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Affiliation(s)
- Michele Torre
- Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
| | - Simone Morganti
- Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100 Pavia, Italy
| | - Francesco S. Pasqualini
- Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
| | - Alessandro Reali
- Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
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Gu Z, Ong CW, Mi Y, Seetharaman A, Ling RR, Ramanathan K, Leo HL. The Impact of Left Ventricular Assist Device Outflow Graft Positioning on Aortic Hemodynamics: Improving Flow Dynamics to Mitigate Aortic Insufficiency. Biomimetics (Basel) 2023; 8:465. [PMID: 37887596 PMCID: PMC10604423 DOI: 10.3390/biomimetics8060465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/27/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023] Open
Abstract
Heart failure is a global health concern with significant implications for healthcare systems. Left ventricular assist devices (LVADs) provide mechanical support for patients with severe heart failure. However, the placement of the LVAD outflow graft within the aorta has substantial implications for hemodynamics and can lead to aortic insufficiency during long-term support. This study employs computational fluid dynamics (CFD) simulations to investigate the impact of different LVAD outflow graft locations on aortic hemodynamics. The introduction of valve morphology within the aorta geometry allows for a more detailed analysis of hemodynamics at the aortic root. The results demonstrate that the formation of vortex rings and subsequent vortices during the high-velocity jet flow from the graft interacted with the aortic wall. Time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) indicate that modification of the outflow graft location changes mechanical states within the aortic wall and aortic valve. Among the studied geometric factors, both the height and inclination angle of the LVAD outflow graft are important in controlling retrograde flow to the aortic root, while the azimuthal angle primarily determines the rotational direction of blood flow in the aortic arch. Thus, precise positioning of the LVAD outflow graft emerges as a critical factor in optimizing patient outcomes by improving the hemodynamic environment.
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Affiliation(s)
- Zhuohan Gu
- Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore; (Z.G.); (A.S.)
| | - Chi Wei Ong
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 639798, Singapore
| | - Yongzhen Mi
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), Singapore 138632, Singapore;
| | - Ashwin Seetharaman
- Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore; (Z.G.); (A.S.)
| | - Ryan Ruiyang Ling
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore (K.R.)
| | - Kollengode Ramanathan
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore (K.R.)
- Cardiothoracic Intensive Care Unit, National University Heart Centre Singapore, National Univeristy Health System, Singapore 119228, Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore; (Z.G.); (A.S.)
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7
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Wang X, Carpenter HJ, Ghayesh MH, Kotousov A, Zander AC, Amabili M, Psaltis PJ. A review on the biomechanical behaviour of the aorta. J Mech Behav Biomed Mater 2023; 144:105922. [PMID: 37320894 DOI: 10.1016/j.jmbbm.2023.105922] [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: 03/06/2023] [Revised: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 06/17/2023]
Abstract
Large aortic aneurysm and acute and chronic aortic dissection are pathologies of the aorta requiring surgery. Recent advances in medical intervention have improved patient outcomes; however, a clear understanding of the mechanisms leading to aortic failure and, hence, a better understanding of failure risk, is still missing. Biomechanical analysis of the aorta could provide insights into the development and progression of aortic abnormalities, giving clinicians a powerful tool in risk stratification. The complexity of the aortic system presents significant challenges for a biomechanical study and requires various approaches to analyse the aorta. To address this, here we present a holistic review of the biomechanical studies of the aorta by categorising articles into four broad approaches, namely theoretical, in vivo, experimental and combined investigations. Experimental studies that focus on identifying mechanical properties of the aortic tissue are also included. By reviewing the literature and discussing drawbacks, limitations and future challenges in each area, we hope to present a more complete picture of the state-of-the-art of aortic biomechanics to stimulate research on critical topics. Combining experimental modalities and computational approaches could lead to more comprehensive results in risk prediction for the aortic system.
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Affiliation(s)
- Xiaochen Wang
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Harry J Carpenter
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Mergen H Ghayesh
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Andrei Kotousov
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Anthony C Zander
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Marco Amabili
- Department of Mechanical Engineering, McGill University, Montreal H3A 0C3, Canada
| | - Peter J Psaltis
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Cardiology, Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia; Vascular Research Centre, Heart Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, South Australia 5000, Australia
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8
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Pajaziti E, Montalt-Tordera J, Capelli C, Sivera R, Sauvage E, Quail M, Schievano S, Muthurangu V. Shape-driven deep neural networks for fast acquisition of aortic 3D pressure and velocity flow fields. PLoS Comput Biol 2023; 19:e1011055. [PMID: 37093855 PMCID: PMC10159343 DOI: 10.1371/journal.pcbi.1011055] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 05/04/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023] Open
Abstract
Computational fluid dynamics (CFD) can be used to simulate vascular haemodynamics and analyse potential treatment options. CFD has shown to be beneficial in improving patient outcomes. However, the implementation of CFD for routine clinical use is yet to be realised. Barriers for CFD include high computational resources, specialist experience needed for designing simulation set-ups, and long processing times. The aim of this study was to explore the use of machine learning (ML) to replicate conventional aortic CFD with automatic and fast regression models. Data used to train/test the model consisted of 3,000 CFD simulations performed on synthetically generated 3D aortic shapes. These subjects were generated from a statistical shape model (SSM) built on real patient-specific aortas (N = 67). Inference performed on 200 test shapes resulted in average errors of 6.01% ±3.12 SD and 3.99% ±0.93 SD for pressure and velocity, respectively. Our ML-based models performed CFD in ∼0.075 seconds (4,000x faster than the solver). This proof-of-concept study shows that results from conventional vascular CFD can be reproduced using ML at a much faster rate, in an automatic process, and with reasonable accuracy.
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Affiliation(s)
- Endrit Pajaziti
- University College London, Institution of Cardiovascular Science, London, United Kingdom
| | - Javier Montalt-Tordera
- University College London, Institution of Cardiovascular Science, London, United Kingdom
| | - Claudio Capelli
- University College London, Institution of Cardiovascular Science, London, United Kingdom
| | - Raphaël Sivera
- University College London, Institution of Cardiovascular Science, London, United Kingdom
| | - Emilie Sauvage
- University College London, Institution of Cardiovascular Science, London, United Kingdom
| | - Michael Quail
- Great Ormond Street Hospital, Cardiac Unit, London, United Kingdom
| | - Silvia Schievano
- University College London, Institution of Cardiovascular Science, London, United Kingdom
| | - Vivek Muthurangu
- University College London, Institution of Cardiovascular Science, London, United Kingdom
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Moretti S, Tauro F, Orrico M, Mangialardi N, Facci AL. Comparative Analysis of Patient-Specific Aortic Dissections through Computational Fluid Dynamics Suggests Increased Likelihood of Degeneration in Partially Thrombosed False Lumen. Bioengineering (Basel) 2023; 10:bioengineering10030316. [PMID: 36978707 PMCID: PMC10045026 DOI: 10.3390/bioengineering10030316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
Aortic dissection is a life-threatening vascular disease associated with high rates of morbidity and mortality, especially in medically underserved communities. Understanding patients’ blood flow patterns is pivotal for informing evidence-based treatment as they greatly influence the disease outcome. The present study investigates the flow patterns in the false lumen of three aorta dissections (fully perfused, partially thrombosed, and fully thrombosed) in the chronic phase, and compares them to a healthy aorta. Three-dimensional geometries of aortic true and false lumens (TLs and FLs) are reconstructed through an ad hoc developed and minimally supervised image analysis procedure. Computational fluid dynamics (CFD) is performed through a finite volume unsteady Reynolds-averaged Navier–Stokes approach assuming rigid wall aortas, Newtonian and homogeneous fluid, and incompressible flow. In addition to flow kinematics, we focus on time-averaged wall shear stress and oscillatory shear index that are recognized risk factors for aneurysmal degeneration. Our analysis shows that partially thrombosed dissection is the most prone to false lumen degeneration. In all dissections, the arteries connected to the false lumen are generally poorly perfused. Further, both true and false lumens present higher turbulence levels than the healthy aorta, and critical stagnation points. Mesh sensitivity and a thorough comparison against literature data together support the reliability of the CFD methodology. Image-based CFD simulations are efficient tools to assess the possibility of aortic dissection to lead to aneurysmal degeneration, and provide new knowledge on the hemodynamic characteristics of dissected versus healthy aortas. Similar analyses should be routinely included in patient-specific hemodynamics investigations, to plan and design tailored therapeutic strategies, and to timely assess their effectiveness.
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Affiliation(s)
- Simona Moretti
- DEIM Department of Economics, Engineering, Society and Business Administration, University of Tuscia, Largo dell’Università, 01100 Viterbo, Italy
| | - Flavia Tauro
- DIBAF Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, Via San Camillo de Lellis, 01100 Viterbo, Italy
- Correspondence: ; Tel.: +39-0761-357355
| | - Matteo Orrico
- Vascular and Endovascular Surgery Unit, San Camillo Forlanini Hospital, Circonvallazione Gianicolense 87, 00149 Roma, Italy
| | - Nicola Mangialardi
- Vascular and Endovascular Surgery Unit, San Camillo Forlanini Hospital, Circonvallazione Gianicolense 87, 00149 Roma, Italy
| | - Andrea Luigi Facci
- DEIM Department of Economics, Engineering, Society and Business Administration, University of Tuscia, Largo dell’Università, 01100 Viterbo, Italy
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Montalt-Tordera J, Pajaziti E, Jones R, Sauvage E, Puranik R, Singh AAV, Capelli C, Steeden J, Schievano S, Muthurangu V. Automatic segmentation of the great arteries for computational hemodynamic assessment. J Cardiovasc Magn Reson 2022; 24:57. [PMID: 36336682 PMCID: PMC9639271 DOI: 10.1186/s12968-022-00891-z] [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: 11/29/2021] [Accepted: 10/03/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Computational fluid dynamics (CFD) is increasingly used for the assessment of blood flow conditions in patients with congenital heart disease (CHD). This requires patient-specific anatomy, typically obtained from segmented 3D cardiovascular magnetic resonance (CMR) images. However, segmentation is time-consuming and requires expert input. This study aims to develop and validate a machine learning (ML) method for segmentation of the aorta and pulmonary arteries for CFD studies. METHODS 90 CHD patients were retrospectively selected for this study. 3D CMR images were manually segmented to obtain ground-truth (GT) background, aorta and pulmonary artery labels. These were used to train and optimize a U-Net model, using a 70-10-10 train-validation-test split. Segmentation performance was primarily evaluated using Dice score. CFD simulations were set up from GT and ML segmentations using a semi-automatic meshing and simulation pipeline. Mean pressure and velocity fields across 99 planes along the vessel centrelines were extracted, and a mean average percentage error (MAPE) was calculated for each vessel pair (ML vs GT). A second observer (SO) segmented the test dataset for assessment of inter-observer variability. Friedman tests were used to compare ML vs GT, SO vs GT and ML vs SO metrics, and pressure/velocity field errors. RESULTS The network's Dice score (ML vs GT) was 0.945 (interquartile range: 0.929-0.955) for the aorta and 0.885 (0.851-0.899) for the pulmonary arteries. Differences with the inter-observer Dice score (SO vs GT) and ML vs SO Dice scores were not statistically significant for either aorta or pulmonary arteries (p = 0.741, p = 0.061). The ML vs GT MAPEs for pressure and velocity in the aorta were 10.1% (8.5-15.7%) and 4.1% (3.1-6.9%), respectively, and for the pulmonary arteries 14.6% (11.5-23.2%) and 6.3% (4.3-7.9%), respectively. Inter-observer (SO vs GT) and ML vs SO pressure and velocity MAPEs were of a similar magnitude to ML vs GT (p > 0.2). CONCLUSIONS ML can successfully segment the great vessels for CFD, with errors similar to inter-observer variability. This fast, automatic method reduces the time and effort needed for CFD analysis, making it more attractive for routine clinical use.
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Affiliation(s)
| | | | - Rod Jones
- Great Ormond Street Hospital, London, UK
| | - Emilie Sauvage
- UCL Institute of Cardiovascular Science, UCL, London, UK
| | - Rajesh Puranik
- Children’s Hospital at Westmead, Sydney, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Aakansha Ajay Vir Singh
- Children’s Hospital at Westmead, Sydney, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, Australia
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11
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Patient-Specific Image-Based Computational Fluid Dynamics Analysis of Abdominal Aorta and Branches. J Pers Med 2022; 12:jpm12091502. [PMID: 36143287 PMCID: PMC9503755 DOI: 10.3390/jpm12091502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
The complicated abdominal aorta and its branches are a portion of the circulatory system prone to developing atherosclerotic plaque and aneurysms. These disorders are closely connected to the changing blood flow environment that the area’s complicated architecture produces (between celiac artery and iliac artery bifurcation); this phenomenon is widespread at arterial bifurcations. Based on computed tomography angiography (CTA) scans, this current work offers a numerical analysis of a patient-specific reconstruction of the abdominal aorta and its branches to identify and emphasize the most likely areas to develop atherosclerosis. The simulations were run following the heart cycle and under physiological settings. The wall shear stress (WSS), velocity field, and streamlines were examined. According to the findings, complex flow is primarily present at the location of arterial bifurcations, where abnormal flow patterns create recirculation zones with low and fluctuating WSS (<0.5 Pa), which are known to affect endothelial homeostasis and cause adverse vessel remodeling. The study provides a patient-specific hemodynamic analysis model, which couples in vivo CT imaging with in silico simulation under physiological circumstances. The study offers quantitative data on the range fluctuations of important hemodynamic parameters, such as WSS and recirculation region expansion, which are directly linked to the onset and progression of atherosclerosis. The findings could also help drug targeting at this vascular level by understanding blood flow patterns in the abdominal aorta and its branches.
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12
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Faraji A, Sahebi M, SalavatiDezfouli S. Numerical investigation of different viscosity models on pulsatile blood flow of thoracic aortic aneurysm (TAA) in a patient-specific model. Comput Methods Biomech Biomed Engin 2022; 26:986-998. [PMID: 35882063 DOI: 10.1080/10255842.2022.2102423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Aortic aneurysm is one of the most common aortic diseases that can lead to unfortunate consequences. Numerical simulations have an important role in the prediction of the aftereffects of vascular diseases including aneurysm. In this research, numerical simulation of pulsatile blood flow is performed for a 3-dimensional patient-specific model of a thoracic aortic aneurysm (TAA). Since the choice of blood viscosity model may have a significant impact on the simulation results, the effects of four non-Newtonian models of blood viscosity namely Carreau, Casson, Herschel-Bulkley, power low, and the Newtonian model on the wall shear stress (WSS) distribution, shear rate, and oscillatory shear index (OSI) have been analyzed. Simulation results showed that all the non-Newtonian and Newtonian models generally, predict similar patterns for blood flow and shear rate. At high flow rates in the cardiac cycle, the WSS value for all the models are similar to each other except for the power-law model due to the shear thinning behavior. All models predict high values of OSI on the inner wall of the ascending aorta and broad areas of the inner wall of the aneurysm sac. However, the Newtonian model predicts the OSI less than the non-Newtonian models in some areas of the aneurysm sac. Results indicated that the Newtonian model generally can predict the hemodynamic parameters of the blood flow similar to the non-Newtonian but for more precise analysis and to predict the regions prone to rupture and atherosclerosis, choosing a proper non-Newtonian model is recommended.
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Affiliation(s)
- Amir Faraji
- Department of Mechanical Engineering, Qom University of Technology, Qom, Iran
| | - Mahdi Sahebi
- Department of Mechanical Engineering, Qom University of Technology, Qom, Iran
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Celi S, Vignali E, Capellini K, Gasparotti E. On the Role and Effects of Uncertainties in Cardiovascular in silico Analyses. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:748908. [PMID: 35047960 PMCID: PMC8757785 DOI: 10.3389/fmedt.2021.748908] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/14/2021] [Indexed: 12/13/2022] Open
Abstract
The assessment of cardiovascular hemodynamics with computational techniques is establishing its fundamental contribution within the world of modern clinics. Great research interest was focused on the aortic vessel. The study of aortic flow, pressure, and stresses is at the basis of the understanding of complex pathologies such as aneurysms. Nevertheless, the computational approaches are still affected by sources of errors and uncertainties. These phenomena occur at different levels of the computational analysis, and they also strongly depend on the type of approach adopted. With the current study, the effect of error sources was characterized for an aortic case. In particular, the geometry of a patient-specific aorta structure was segmented at different phases of a cardiac cycle to be adopted in a computational analysis. Different levels of surface smoothing were imposed to define their influence on the numerical results. After this, three different simulation methods were imposed on the same geometry: a rigid wall computational fluid dynamics (CFD), a moving-wall CFD based on radial basis functions (RBF) CFD, and a fluid-structure interaction (FSI) simulation. The differences of the implemented methods were defined in terms of wall shear stress (WSS) analysis. In particular, for all the cases reported, the systolic WSS and the time-averaged WSS (TAWSS) were defined.
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Affiliation(s)
- Simona Celi
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Emanuele Vignali
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Katia Capellini
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
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14
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Nannini G, Caimi A, Palumbo MC, Saitta S, Girardi LN, Gaudino M, Roman MJ, Weinsaft JW, Redaelli A. Aortic hemodynamics assessment prior and after valve sparing reconstruction: A patient-specific 4D flow-based FSI model. Comput Biol Med 2021; 135:104581. [PMID: 34174756 DOI: 10.1016/j.compbiomed.2021.104581] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/09/2021] [Accepted: 06/13/2021] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Valve-sparing root replacement (VSRR) of the ascending aorta is a life-saving procedure for the treatment of aortic aneurysms, but patients remain at risk for post-operative events involving the downstream native aorta, the mechanism for which is uncertain. It is possible that proximal graft replacement of the ascending aorta induces hemodynamics alterations in the descending aorta, which could trigger adverse events. Herein, we present a fluid-structure interaction (FSI) protocol, based on patient-specific geometry and boundary conditions, to assess impact of proximal aortic grafts on downstream aortic hemodynamics and distensibility. METHODS Cardiac magnetic resonance (CMR), including MRA, cine-CMR and 4D flow sequences, was performed prior and after VSRR on one subject. Central blood pressure was non-invasively acquired at the time of the CMR: data were used to reconstruct the pre- and post-VSRR model and derive patient-specific boundary conditions for the FSI and a computational fluid dynamic (CFD) analysis with the same settings. Results were validated comparing the predicted velocity field against 4D flow dataset, over four landmarks along the aorta, and the predicted distensibility against the cine-CMR derived value. RESULTS Instantaneous velocity magnitudes extracted from 4D flow and FSI were similar (p > 0.05), while CFD-predicted velocity was significantly higher (p < 0.001), especially in the descending aorta of the pre-VSRR model (vmax was 73 cm/s, 76 cm/s and 99 cm/s, respectively). As measured in cine-CMR, FSI predicted an increase in descending aorta distensibility after grafting (i.e., 4.02 to 5.79 10-3 mmHg-1). In the descending aorta, the post-VSRR model showed increased velocity, aortic distensibility, stress and strain and wall shear stress. CONCLUSIONS Our Results indicate that i) the distensibility of the wall cannot be neglected, and hence the FSI method is necessary to obtain reliable results; ii) graft implantation induces alterations in the hemodynamics and biomechanics along the thoracic aorta, that may trigger adverse vessel remodeling.
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Affiliation(s)
- Guido Nannini
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy.
| | - Alessandro Caimi
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Maria Chiara Palumbo
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Simone Saitta
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Leonard N Girardi
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Mario Gaudino
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Mary J Roman
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
| | - Jonathan W Weinsaft
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
| | - Alberto Redaelli
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
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15
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Ninos G, Bartzis V, Merlemis N, Sarris IE. Uncertainty quantification implementations in human hemodynamic flows. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 203:106021. [PMID: 33721602 DOI: 10.1016/j.cmpb.2021.106021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Human hemodynamic modeling is usually influenced by uncertainties occurring from a considerable unavailability of information linked to the boundary conditions and the physical properties used in the numerical models. Calculating the effect of these uncertainties on the numerical findings along the cardiovascular system is a demanding process due to the complexity of the morphology of the body and the area dynamics. To cope with all these difficulties, Uncertainty Quantification (UQ) methods seem to be an ideal tool. RESULTS This study focuses on analyzing and summarizing some of the recent research efforts and directions of implementing UQ in human hemodynamic flows by analyzing 139 research papers. Initially, the suitability of applying this approach is analyzed and demonstrated. Then, an overview of the most significant research work in various fields of biomedical hemodynamic engineering is presented. Finally, it is attempted to identify any possible forthcoming directions for research and methodological progress of UQ in biomedical sciences. CONCLUSION This review concludes that by finding the best statistical methods and parameters to represent the propagated uncertainties, while achieving a good interpretation of the interaction between input-output, is crucial for implementing UQ in biomedical sciences.
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Affiliation(s)
- G Ninos
- Department of Biomedical Sciences, University of West Attica, 12243, Athens, Greece; Department of Mechanical Engineering, University of West Attica, 12244, Athens, Greece.
| | - V Bartzis
- Department of Food Science & Technology, University of West Attica, 12243, Athens, Greece
| | - N Merlemis
- Deptartment of Surveying and Geoinformatics Engineering, University of West Attica, 12243 Athens, Greece
| | - I E Sarris
- Department of Mechanical Engineering, University of West Attica, 12244, Athens, Greece
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16
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Riva A, Sturla F, Caimi A, Pica S, Giese D, Milani P, Palladini G, Lombardi M, Redaelli A, Votta E. 4D flow evaluation of blood non-Newtonian behavior in left ventricle flow analysis. J Biomech 2021; 119:110308. [PMID: 33631666 DOI: 10.1016/j.jbiomech.2021.110308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/03/2021] [Indexed: 12/31/2022]
Abstract
Blood is generally modeled as a Newtonian fluid, assuming a standard and constant viscosity; however, this assumption may not hold for the highly pulsatile and recirculating intracavitary flow in the left ventricle (LV), hampering the quantification of fluid dynamic indices of potential clinical relevance. Herein, we investigated the effect of three viscosity models on the patient-specific quantification of LV blood energetics, namely on viscous energy loss (EL), from 4D Flow magnetic resonance imaging: I) Newtonian with standard viscosity (3.7 cP), II) Newtonian with subject-specific hematocrit-dependent viscosity, III) non-Newtonian accounting for the effect of hematocrit and shear rate. Analyses were performed on 5 controls and 5 patients with cardiac light-chain amyloidosis. In Model II, viscosity ranged between 3.0 (-19%) and 4.3 cP (+16%), mildly deviating from the standard value. In the non-Newtonian model, this effect was emphasized: viscosity ranged from 3.2 to 6.0 cP, deviating maximally from the standard value in low shear rate (i.e., <100 s-1) regions. This effect reflected on EL quantifications: in particular, as compared to Model I, Model III yielded markedly higher EL values (up to +40%) or markedly lower (down to -21%) for subjects with hematocrit higher than 39.5% and lower than 30%, respectively. Accounting for non-Newtonian blood behavior on a patient-specific basis may enhance the accuracy of intracardiac energetics assessment by 4D Flow, which may be explored as non-invasive index to discriminate between healthy and pathologic LV.
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Affiliation(s)
- Alessandra Riva
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy; 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Francesco Sturla
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
| | - Alessandro Caimi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Silvia Pica
- Multimodality Cardiac Imaging Section, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | | | - Paolo Milani
- Amyloidosis Research and Treatment Center, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy
| | - Giovanni Palladini
- Amyloidosis Research and Treatment Center, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy
| | - Massimo Lombardi
- Multimodality Cardiac Imaging Section, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Emiliano Votta
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy; 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
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17
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Azriff Basri A, Zuber M, Illyani Basri E, Shukri Zakaria M, Fazli Abd Aziz A, Tamagawa M, Arifin Ahmad K. Fluid-Structure Interaction in Problems of Patient Specific Transcatheter Aortic Valve Implantation with and Without Paravalvular Leakage Complication. FLUID DYNAMICS & MATERIALS PROCESSING 2021; 17:531-553. [DOI: 10.32604/fdmp.2021.010925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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18
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Salmasi MY, Pirola S, Sasidharan S, Fisichella SM, Redaelli A, Jarral OA, O'Regan DP, Oo AY, Moore JE, Xu XY, Athanasiou T. High Wall Shear Stress can Predict Wall Degradation in Ascending Aortic Aneurysms: An Integrated Biomechanics Study. Front Bioeng Biotechnol 2021; 9:750656. [PMID: 34733832 PMCID: PMC8558434 DOI: 10.3389/fbioe.2021.750656] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/24/2021] [Indexed: 01/16/2023] Open
Abstract
Background: Blood flow patterns can alter material properties of ascending thoracic aortic aneurysms (ATAA) via vascular wall remodeling. This study examines the relationship between wall shear stress (WSS) obtained from image-based computational modelling with tissue-derived mechanical and microstructural properties of the ATAA wall using segmental analysis. Methods: Ten patients undergoing surgery for ATAA were recruited. Exclusions: bicuspid aortopathy, connective tissue disease. All patients had pre-operative 4-dimensional flow magnetic resonance imaging (4D-MRI), allowing for patient-specific computational fluid dynamics (CFD) analysis and anatomically precise WSS mapping of ATAA regions (6-12 segments per patient). ATAA samples were obtained from surgery and subjected to region-specific tensile and peel testing (matched to WSS segments). Computational pathology was used to characterize elastin/collagen abundance and smooth muscle cell (SMC) count. Results: Elevated values of WSS were predictive of: reduced wall thickness [coef -0.0489, 95% CI (-0.0905, -0.00727), p = 0.022] and dissection energy function (longitudinal) [-15,0, 95% CI (-33.00, -2.98), p = 0.048]. High WSS values also predicted higher ultimate tensile strength [coef 0.136, 95% CI (0 0.001, 0.270), p = 0.048]. Additionally, elevated WSS also predicted a reduction in elastin levels [coef -0.276, 95% (CI -0.531, -0.020), p = 0.035] and lower SMC count ([oef -6.19, 95% CI (-11.41, -0.98), p = 0.021]. WSS was found to have no effect on collagen abundance or circumferential mechanical properties. Conclusions: Our study suggests an association between elevated WSS values and aortic wall degradation in ATAA disease. Further studies might help identify threshold values to predict acute aortic events.
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Affiliation(s)
- M Yousuf Salmasi
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Sumesh Sasidharan
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Serena M Fisichella
- Department of Chemical Engineering, Imperial College London, London, United Kingdom.,Politecnico di Milano, Milan, Italy
| | | | - Omar A Jarral
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Declan P O'Regan
- MRC London Institute of Medical Sciences, Imperial College London, London, United Kingdom
| | - Aung Ye Oo
- Barts Heart Centre, London, United Kingdom
| | - James E Moore
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Thanos Athanasiou
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
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19
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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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20
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Kim YW, Moon JY, Li WJ, Kim JH, Park YH, Lee JS, Jang Y. Effect of membrane insertion for tricuspid regurgitation using immersed-boundary lattice Boltzmann method. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 191:105421. [PMID: 32146209 DOI: 10.1016/j.cmpb.2020.105421] [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: 12/03/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Tricuspid regurgitation is treated by valve repair or replacement. However, these methods have limitations, and alternative treatment methods are therefore required. OBJECTIVES In this study, a new method of tricuspid valve treatment using artificial membrane insertion is analyzed. We performed tricuspid valve simulations using an artificial membrane inserted into the right ventricle (RV) or right atrium (RA). METHODS We use the lattice Boltzmann method with the immersed boundary condition to model the structural motion of the valve leaflet. The effect of membrane insertion is analyzed in terms of the stress, force, and impulse on the valve leaflet, along with the velocity, pressure, jet volume, and Reynolds stress in the flow field. RESULTS While the use of either membrane (RA or RV) leads to improved valve closure relative to the use of no membrane, the RV membrane is more effective than the RA membrane in achieving improved valve closure. In addition, a larger membrane area with a shorter distance between the leaflet and membrane increases membrane efficacy. CONCLUSION Our results suggest that membrane insertion can form an effective new method for the treatment of tricuspid regurgitation.
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Affiliation(s)
- Young Woo Kim
- Department of Mechanical Engineering, Yonsei University, Korea
| | | | - Wen Jie Li
- Department of Mechanical Engineering, Yonsei University, Korea
| | - June-Hong Kim
- Cardiovascular Center, Pusan National University Yangsan Hospital, Korea
| | - Yong-Hyun Park
- Cardiovascular Center, Pusan National University Yangsan Hospital, Korea
| | - Joon Sang Lee
- Department of Mechanical Engineering, Yonsei University, Korea.
| | - Yeongho Jang
- Department of Pain Medicine and Anesthesiology, Saedongsan Hospital, Korea
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21
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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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22
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Qiao Y, Mao L, Ding Y, Fan J, Zhu T, Luo K. Hemodynamic consequences of TEVAR with in situ double fenestrations of left carotid artery and left subclavian artery. Med Eng Phys 2019; 76:32-39. [PMID: 31882394 DOI: 10.1016/j.medengphy.2019.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 10/02/2019] [Accepted: 10/20/2019] [Indexed: 11/25/2022]
Abstract
The aortic major branches after thoracic endovascular aortic repair (TEVAR) could be preserved by in situ fenestration (ISF). This study aims to explore the hemodynamic consequences of ISF-TEVAR with double fenestrations. Two patients with aortic dissection and aneurysm, respectively, were treated by ISF-TEVAR and both the left carotid artery (LCA) and left subclavian artery (LSA) were reconstructed by fenestration technique. The blood was considered a non-Newtonian fluid and the Windkessel model was adopted at the aortic outlets. Simulations were performed in two postoperative models to analyze the effects of the double fenestration stents on the hemodynamics. The postoperative wall pressure of the LCA and LSA is relatively low and the pressure difference between the inner and outer walls of the protruding segment of the LSA stent is found. Acceleration occurs when blood flows around the fenestration stents and the shear-thinning rheological behavior is observed at the aortic arch. Moreover, regions susceptible to thrombosis are identified and the surface exposed to high relative residence time is located at the aortic arch after the LSA stent. The presence of the double fenestration stents has a profound impact on the postoperative hemodynamics, and the aortic arch and rebuilt branches should be closely watched during follow-up.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Le Mao
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ying Ding
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
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23
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Ho R, McDonald C, Pauls JP, Li Z. Aortic cannula orientation and flow impacts embolic trajectories: computational cardiopulmonary bypass. Perfusion 2019; 35:409-416. [PMID: 31814525 DOI: 10.1177/0267659119889777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Emboli events are associated with the aortic cannula insertion and final position in the ascending aorta. However, the impact of subtle changes in aortic cannula movement and flow influencing embolic transport throughout the aortic arch is not well understood. The present study evaluated the aortic cannula's outflow and orientation effect on emboli entering the aortic branch arteries. METHODS A simplified aortic computational model was anteriorly cannulated in the distal ascending aorta with a 21-French straight aortic cannula, and two orientations were analysed by injecting gaseous and solid emboli at pump flows 2, 3 and 5 L/minute. The first aortic cannula orientation (forward flow cannula) was directed towards the lesser curvature. The second aortic cannula orientation (rear flow cannula) was tilted slightly backwards by 15°, providing flow in the retrograde direction. RESULTS Forward flow cannula produced a primary arch flow, whereas rear flow cannula produced a secondary arch flow resulting in four times longer emboli arch resident times than forward flow cannula. The rear flow cannula had the highest percentage of gaseous emboli entering the brachiocephalic artery of 8%, 12% and 36% (at 2, 3 and 5 L/minute, respectively). Rear flow cannula provided a positive aortic branch arterial flow at all pump flows, whereas at forward flow cannula, the brachiocephalic artery experienced retrograde flows of -1.0% (3 L/minute) and -4.0% (5 L/minute), with the left common carotid -0.23% (5 L/minute). No significant number of solid emboli entered the aortic branch arteries. CONCLUSION This numerical study illustrated distinct trajectory behaviours between gaseous and solid emboli where slight changes in aortic cannula orientation influenced idealised emboli direction with higher pump flows magnifying the effects.
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Affiliation(s)
- Raymond Ho
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Charles McDonald
- Department of Anaesthesia and Perfusion, The Prince Charles Hospital, Chermside, QLD, Australia
| | - Jo P Pauls
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.,School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia.,School of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Zhiyong Li
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD, Australia
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Qiao Y, Zeng Y, Ding Y, Fan J, Luo K, Zhu T. Numerical simulation of two-phase non-Newtonian blood flow with fluid-structure interaction in aortic dissection. Comput Methods Biomech Biomed Engin 2019; 22:620-630. [PMID: 30822150 DOI: 10.1080/10255842.2019.1577398] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Yujie Zeng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Ying Ding
- Department of Radiology, Zhongshan Hospital Fudan University, Shanghai, China
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
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25
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Boccadifuoco A, Mariotti A, Capellini K, Celi S, Salvetti MV. Validation of Numerical Simulations of Thoracic Aorta Hemodynamics: Comparison with In Vivo Measurements and Stochastic Sensitivity Analysis. Cardiovasc Eng Technol 2018; 9:688-706. [DOI: 10.1007/s13239-018-00387-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/11/2018] [Indexed: 10/28/2022]
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26
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Pirola S, Jarral OA, O'Regan DP, Asimakopoulos G, Anderson JR, Pepper JR, Athanasiou T, Xu XY. Computational study of aortic hemodynamics for patients with an abnormal aortic valve: The importance of secondary flow at the ascending aorta inlet. APL Bioeng 2018; 2:026101. [PMID: 31069298 PMCID: PMC6481743 DOI: 10.1063/1.5011960] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/06/2018] [Indexed: 12/05/2022] Open
Abstract
Blood flow in the aorta is helical, but most computational studies ignore the presence of secondary flow components at the ascending aorta (AAo) inlet. The aim of this study is to ascertain the importance of inlet boundary conditions (BCs) in computational analysis of flow patterns in the thoracic aorta based on patient-specific images, with a particular focus on patients with an abnormal aortic valve. Two cases were studied: one presenting a severe aortic valve stenosis and the other with a mechanical valve. For both aorta models, three inlet BCs were compared; these included the flat profile and 1D through-plane velocity and 3D phase-contrast magnetic resonance imaging derived velocity profiles, with the latter being used for benchmarking. Our results showed that peak and mean velocities at the proximal end of the ascending aorta were underestimated by up to 41% when the secondary flow components were neglected. The results for helical flow descriptors highlighted the strong influence of secondary velocities on the helical flow structure in the AAo. Differences in all wall shear stress (WSS)-derived indices were much more pronounced in the AAo and aortic arch (AA) than in the descending aorta (DAo). Overall, this study demonstrates that using 3D velocity profiles as inlet BC is essential for patient-specific analysis of hemodynamics and WSS in the AAo and AA in the presence of an abnormal aortic valve. However, predicted flow in the DAo is less sensitive to the secondary velocities imposed at the inlet; hence, the 1D through-plane profile could be a sufficient inlet BC for studies focusing on distal regions of the thoracic aorta.
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Affiliation(s)
- S Pirola
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - O A Jarral
- Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London W2 1NY, United Kingdom
| | - D P O'Regan
- Institute of Clinical Science, Imperial College London, Hammersmith Hospital, London W12 0HS, United Kingdom
| | - G Asimakopoulos
- Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, United Kingdom
| | - J R Anderson
- Hammersmith Hospital, Imperial College Healthcare NHS Trust, Du Cane Road, London W12 0HS, United Kingdom
| | - J R Pepper
- Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, United Kingdom
| | - T Athanasiou
- Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London W2 1NY, United Kingdom
| | - X Y Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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27
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Numerical Study of the Effect of Winglets on the Performance of a Straight Blade Darrieus Water Turbine. ENERGIES 2018. [DOI: 10.3390/en11020297] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Darlis N, Osman K, Padzillah MH, Dillon J, Md Khudzari AZ. Modification of Aortic Cannula With an Inlet Chamber to Induce Spiral Flow and Improve Outlet Flow. Artif Organs 2017; 42:493-499. [DOI: 10.1111/aor.13021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 07/11/2017] [Accepted: 08/07/2017] [Indexed: 11/27/2022]
Affiliation(s)
| | - Kahar Osman
- Faculty of Biosciences and Medical Engineering; Universiti Teknologi Malaysia; Malaysia
- IJN-UTM Cardiovascular Engineering Centre; Institute of Human Centred Engineering, Universiti Teknologi Malaysia; Kuala Lumpur Malaysia
| | - Muhamad Hasbullah Padzillah
- Faculty of Mechanical Engineering; Universiti Teknologi Malaysia; Kuala Lumpur Malaysia
- UTM-Centre for Low Carbon Transport (Locartic); Universiti Teknologi Malaysia; Kuala Lumpur Malaysia
| | | | - Ahmad Zahran Md Khudzari
- Faculty of Biosciences and Medical Engineering; Universiti Teknologi Malaysia; Malaysia
- IJN-UTM Cardiovascular Engineering Centre; Institute of Human Centred Engineering, Universiti Teknologi Malaysia; Kuala Lumpur Malaysia
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29
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Doost SN, Zhong L, Morsi YS. Ventricular Assist Devices: Current State and Challenges. J Med Device 2017. [DOI: 10.1115/1.4037258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cardiovascular disease (CVD), as the most prevalent human disease, incorporates a broad spectrum of cardiovascular system malfunctions/disorders. While cardiac transplantation is widely acknowledged as the optional treatment for patients suffering from end-stage heart failure (HF), due to its related drawbacks, such as the unavailability of heart donors, alternative treatments, i.e., implanting a ventricular assist device (VAD), it has been extensively utilized in recent years to recover heart function. However, this solution is thought problematic as it fails to satisfactorily provide lifelong support for patients at the end-stage of HF, nor does is solve the problem of their extensive postsurgery complications. In recent years, the huge technological advancements have enabled the manufacturing of a wide variety of reliable VAD devices, which provides a promising avenue for utilizing VAD implantation as the destination therapy (DT) in the future. Along with typical VAD systems, other innovative mechanical devices for cardiac support, as well as cell therapy and bioartificial cardiac tissue, have resulted in researchers proposing a new HF therapy. This paper aims to concisely review the current state of VAD technology, summarize recent advancements, discuss related complications, and argue for the development of the envisioned alternatives of HF therapy.
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Affiliation(s)
- Siamak N. Doost
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 1 Alfred Street, Hawthorn VIC 3122, Australia e-mail:
| | - Liang Zhong
- National Heart Research Institute of Singapore, National Heart Centre, 5 Hospital Drive, Singapore 169609, Singapore; Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore e-mail:
| | - Yosry S. Morsi
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 1 Alfred Street, Hawthorn VIC 3122, Australia e-mail:
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30
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Fedele M, Faggiano E, Dedè L, Quarteroni A. A patient-specific aortic valve model based on moving resistive immersed implicit surfaces. Biomech Model Mechanobiol 2017; 16:1779-1803. [PMID: 28593469 DOI: 10.1007/s10237-017-0919-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 05/12/2017] [Indexed: 11/26/2022]
Abstract
In this paper, we propose a full computational framework to simulate the hemodynamics in the aorta including the valve. Closed and open valve surfaces, as well as the lumen aorta, are reconstructed directly from medical images using new ad hoc algorithms, allowing a patient-specific simulation. The fluid dynamics problem that accounts from the movement of the valve is solved by a new 3D-0D fluid-structure interaction model in which the valve surface is implicitly represented through level set functions, yielding, in the Navier-Stokes equations, a resistive penalization term enforcing the blood to adhere to the valve leaflets. The dynamics of the valve between its closed and open position is modeled using a reduced geometric 0D model. At the discrete level, a finite element formulation is used and the SUPG stabilization is extended to include the resistive term in the Navier-Stokes equations. Then, after time discretization, the 3D fluid and 0D valve models are coupled through a staggered approach. This computational framework, applied to a patient-specific geometry and data, allows to simulate the movement of the valve, the sharp pressure jump occurring across the leaflets, and the blood flow pattern inside the aorta.
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Affiliation(s)
- Marco Fedele
- CMCS - MATHICSE - SB, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- CompMech Group, Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Elena Faggiano
- CMCS - MATHICSE - SB, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
- CompMech Group, Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy.
| | - Luca Dedè
- CMCS - MATHICSE - SB, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- MOX, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | - Alfio Quarteroni
- CMCS - MATHICSE - SB, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- MOX, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
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31
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Zhu C, Seo JH, Bakhshaee H, Mittal R. A Computational Method for Analyzing the Biomechanics of Arterial Bruits. J Biomech Eng 2017; 139:2612942. [PMID: 28303271 DOI: 10.1115/1.4036262] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Indexed: 11/08/2022]
Abstract
A computational framework consisting of a one-way coupled hemodynamic-acoustic method and a wave-decomposition based postprocessing approach is developed to investigate the biomechanics of arterial bruits. This framework is then applied for studying the effect of the shear wave on the generation and propagation of bruits from a modeled stenosed artery. The blood flow in the artery is solved by an immersed boundary method (IBM) based incompressible flow solver. The sound generation and propagation in the blood volume are modeled by the linearized perturbed compressible equations, while the sound propagation through the surrounding tissue is modeled by the linear elastic wave equation. A decomposition method is employed to separate the acoustic signal into a compression/longitudinal component (curl free) and a shear/transverse component (divergence free), and the sound signals from cases with and without the shear modulus are monitored on the epidermal surface and are analyzed to reveal the influence of the shear wave. The results show that the compression wave dominates the detected sound signal in the immediate vicinity of the stenosis, whereas the shear wave has more influence on surface signals further downstream of the stenosis. The implications of these results on cardiac auscultation are discussed.
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Affiliation(s)
- Chi Zhu
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 e-mail:
| | - Jung-Hee Seo
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 e-mail:
| | - Hani Bakhshaee
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 e-mail:
| | - Rajat Mittal
- Professor Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 e-mail:
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32
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Agujetas R, Ferrera C, Marcos AC, Alejo JP, Montanero JM. Numerical and experimental analysis of the transitional flow across a real stenosis. Biomech Model Mechanobiol 2017; 16:1447-1458. [PMID: 28343259 DOI: 10.1007/s10237-017-0898-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/15/2017] [Indexed: 11/25/2022]
Abstract
In this paper, we present a numerical study of the pulsatile transitional flow crossing a severe real stenosis located right in front of the bifurcation between the right subclavian and right common carotid arteries. The simulation allows one to determine relevant features of this subject-specific flow, such as the pressure waves in the right subclavian and right common carotid arteries. We explain the subclavian steal syndrome suffered by the patient in terms of the drastic pressure drop in the right subclavian artery. This pressure drop is caused by both the diverging part of the analyzed stenosis and the reverse flow in the bifurcation induced by another stenosis in the right internal carotid artery.
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Affiliation(s)
- R Agujetas
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, 06006, Badajoz, Spain
| | - C Ferrera
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, 06006, Badajoz, Spain
| | - A C Marcos
- Depto. de Expresión Gráfica, Universidad de Extremadura, 06006, Badajoz, Spain
| | - J P Alejo
- Servicio de Radiología, Hospital Infanta Cristina, 06006, Badajoz, Spain
| | - J M Montanero
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, 06006, Badajoz, Spain.
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33
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Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta. Proc Inst Mech Eng H 2017; 232:103-113. [DOI: 10.1177/0954411917699237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Computational fluid dynamics is a tool capable of accurately measuring metrics currently used to predict the behaviour of cardiovascular diseases. This study quantifies the impact various commonly used inlet and outlet boundary conditions have on various shear rate–based haemodynamic metrics currently used for predicting the localisation of cardiovascular diseases. Simulations are conducted on an accurately represented rabbit aorta configuration and comparison has been made against available in vivo data. The boundary conditions studied include two different inlet profiles, three outlet boundary conditions, and steady-state versus pulsatile flow cases. Large variations were found in the results, particularly when using different outlet boundary conditions, and the discrepancies were evaluated both quantitatively and qualitatively. The results clearly highlight the importance of the type of boundary condition used when simulating complex cardiovascular models. By restricting the attention to the flow within the aorta and the intercostal branches, the results suggest that prescribing transient simulation and fully developed flow at the inlet are not required. Furthermore, assuming the widely accepted low wall shear stress theory of Caro, it was found that Murray’s law–based outlet boundary condition returns the most physiologically accurate results when compared to in vivo data.
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34
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Andersson M, Lantz J, Ebbers T, Karlsson M. Multidirectional WSS disturbances in stenotic turbulent flows: A pre- and post-intervention study in an aortic coarctation. J Biomech 2016; 51:8-16. [PMID: 27919417 DOI: 10.1016/j.jbiomech.2016.11.064] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/29/2016] [Accepted: 11/19/2016] [Indexed: 01/01/2023]
Abstract
Wall shear stress (WSS) disturbances are commonly expressed at sites of abnormal flow obstructions and may play an essential role in the pathogenesis of various vascular diseases. In laminar flows these disturbances have recently been assessed by the transverse wall shear stress (transWSS), which accounts for the WSS multidirectionality. Site-specific estimations of WSS disturbances in pulsatile transitional and turbulent type of flows are more challenging due to continuous and unpredictable changes in WSS behavior. In these complex flow settings, the transWSS may serve as a more comprehensive descriptor for assessing WSS disturbances of general nature compared to commonly used parameters. In this study large eddy simulations (LES) were used to investigate the transWSS properties in flows subjected to different pathological turbulent flow conditions, governed by a patient-specific model of an aortic coarctation pre and post balloon angioplasty. Results showed that regions of strong near-wall turbulence were collocated with regions of elevated transWSS and turbulent WSS, while in more transitional-like near-wall flow regions a closer resemblance was found between transWSS and low, and oscillatory WSS. Within the frame of this study, the transWSS parameter demonstrated a more multi-featured picture of WSS disturbances when exposed to different types of flow regimes, characteristics which were not depicted by the other parameters alone.
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Affiliation(s)
- Magnus Andersson
- Department of Management and Engineering (IEI), Linköping University, Linköping, Sweden.
| | - Jonas Lantz
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Tino Ebbers
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Matts Karlsson
- Department of Management and Engineering (IEI), Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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35
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Hütter L, Geoghegan PH, Docherty PD, Lazarjan MS, Clucas D, Jermy M. Fabrication of a compliant phantom of the human aortic arch for use in Particle Image Velocimetry (PIV) experimentation. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2016. [DOI: 10.1515/cdbme-2016-0109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractCompliant phantoms of the human aortic arch can mimic patient specific cardiovascular dysfunctions in vitro. Hence, phantoms may enable elucidation of haemodynamic disturbances caused by aortic dysfunction. This paper describes the fabrication of a thin-walled silicone phantom of the human ascending aorta and brachiocephalic artery. The model geometry was determined via a meta-analysis and modelled in SolidWorks before 3D printing. The solid model surface was smoothed and scanned with a 3D scanner. An offset outer mould was milled from Ebalta S-Model board. The final phantom indicated that ABS was a suitable material for the internal model, the Ebalta S-Model board yielded a rough external surface. Co-location of the moulds during silicone pour was insufficient to enable consistent wall thickness. The resulting phantom was free of air bubbles but did not have the desired wall thickness consistency.
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Affiliation(s)
- Larissa Hütter
- 1Department of Mechanical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Patrick H. Geoghegan
- 2Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Paul D. Docherty
- 2Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Milad S. Lazarjan
- 2Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Donald Clucas
- 2Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Mark Jermy
- 2Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
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36
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Asociación entre el calcio de la aorta torácica y la geometría de esta en una cohorte de sujetos asintomáticos con riesgo cardiovascular aumentado. Rev Esp Cardiol 2016. [DOI: 10.1016/j.recesp.2016.01.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Association Between Thoracic Aorta Calcium and Thoracic Aorta Geometry in a Cohort of Asymptomatic Participants at Increased Cardiovascular Risk. ACTA ACUST UNITED AC 2016; 69:827-35. [PMID: 27156641 DOI: 10.1016/j.rec.2016.01.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/15/2016] [Indexed: 01/01/2023]
Abstract
INTRODUCTION AND OBJECTIVES Thoracic aorta calcium detection is known to improve cardiovascular risk prediction for cardiac and noncardiac events beyond traditional risk factors. We investigated the influence of thoracic aorta morphometry on the presence and extent of aortic calcifications. METHODS Nonenhanced computed tomography heart scans were performed in 970 asymptomatic participants at increased cardiovascular risk. An automated algorithm estimated the geometry of the entire thoracic aorta and quantified the aortic calcium Agatston score. A nonparametric model was used to analyze the percentiles of calcium score by age. Logistic regression models were calculated to identify anatomical associations with calcium levels. RESULTS Calcifications were concentrated in the aortic arch and descending portions. Higher amounts of calcium were associated with an enlarged, unfolded, less tapered and more tortuous aorta. The size of the ascending aorta was not correlated with aortic calcium score, whereas enlargement of the descending aorta had the strongest association: the risk of having a global calcium score > 90th percentile was 3.62 times higher (confidence interval, 2.30-5.91; P < .001) for each 2.5-mm increase in descending aorta diameter. Vessel taper, tortuosity, unfolding and aortic arch and descending volumes were also correlated with higher amounts of calcium. CONCLUSIONS Thoracic aorta calcium was predominantly found at the arch and descending aorta and was positively associated with the size of the descending aorta and the aortic arch, but not with the size of the ascending aorta. These findings suggest that aortic dilatation may have different mechanisms and may consequently require different preventive strategies according to the considered segments.
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38
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Doost SN, Zhong L, Su B, Morsi YS. The numerical analysis of non-Newtonian blood flow in human patient-specific left ventricle. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2016; 127:232-247. [PMID: 26849955 DOI: 10.1016/j.cmpb.2015.12.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
Recently, various non-invasive tools such as the magnetic resonance image (MRI), ultrasound imaging (USI), computed tomography (CT), and the computational fluid dynamics (CFD) have been widely utilized to enhance our current understanding of the physiological parameters that affect the initiation and the progression of the cardiovascular diseases (CVDs) associated with heart failure (HF). In particular, the hemodynamics of left ventricle (LV) has attracted the attention of the researchers due to its significant role in the heart functionality. In this study, CFD owing its capability of predicting detailed flow field was adopted to model the blood flow in images-based patient-specific LV over cardiac cycle. In most published studies, the blood is modeled as Newtonian that is not entirely accurate as the blood viscosity varies with the shear rate in non-linear manner. In this paper, we studied the effect of Newtonian assumption on the degree of accuracy of intraventricular hemodynamics. In doing so, various non-Newtonian models and Newtonian model are used in the analysis of the intraventricular flow and the viscosity of the blood. Initially, we used the cardiac MRI images to reconstruct the time-resolved geometry of the patient-specific LV. After the unstructured mesh generation, the simulations were conducted in the CFD commercial solver FLUENT to analyze the intraventricular hemodynamic parameters. The findings indicate that the Newtonian assumption cannot adequately simulate the flow dynamic within the LV over the cardiac cycle, which can be attributed to the pulsatile and recirculation nature of the flow and the low blood shear rate.
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Affiliation(s)
- Siamak N Doost
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia.
| | - Liang Zhong
- Duke-NUS Graduate Medical School, Singapore; National Heart Research Institute of Singapore, National Heart Centre, Singapore.
| | - Boyang Su
- National Heart Research Institute of Singapore, National Heart Centre, Singapore
| | - Yosry S Morsi
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia
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Son JW, Hong GR, Hong W, Kim M, Houle H, Vannan MA, Pedrizzetti G, Chung N. Differences in aortic vortex flow pattern between normal and patients with stroke: qualitative and quantitative assessment using transesophageal contrast echocardiography. Int J Cardiovasc Imaging 2015; 32 Suppl 1:45-52. [PMID: 26621756 DOI: 10.1007/s10554-015-0818-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 11/25/2015] [Indexed: 11/26/2022]
Abstract
The flow in the aorta forms a vortex, which is a critical determinant of the flow dynamics in the aorta. Arteriosclerosis can alter the blood flow pattern of the aorta and cause characteristic alterations of the vortex. However, this change in aortic vortex has not yet been studied. This study aimed to characterize aortic vortex flow pattern using transesophageal contrast echocardiography in normal and stroke patients. A total of 85 patients who diagnosed with ischemic stroke and 16 normal controls were recruited for this study. The 16 normal control subjects were designated as the control group, and the 85 ischemic stroke patients were designated as the stroke group. All subjects underwent contrast transesophageal echocardiography (TEE), and particle image velocimetry was used to assess aortic vortex flow. Qualitative and quantitative analyses of vortex flow morphology, location, phasic variation, and pulsatility were undertaken and compared between the groups. In the control group, multiple irregularly-shaped vortices were observed in a peripheral location in the descending thoracic aorta. In contrast, the stroke group had a single, round, merged, and more centrally located aortic vortex flow. In the quantitative analysis of vortex, vortex depth, which represents the location of the major vortex in the aorta, was significantly higher in the control group than in the stroke group (0.599 ± 0.159 vs. 0.522 ± 0.101, respectively, P = 0.013). Vortex relative strength, which is the pulsatility parameter of the vortex itself, was significantly higher in the stroke group than in the control group (0.367 ± 0.148 vs. 0.304 ± 0.087, respectively, P = 0.025). It was feasible to visualize and quantify the characteristic morphology and pulsatility of the aortic vortex flow using contrast TEE, and aortic vortex pattern significantly differed between normal and stroke patients.
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Affiliation(s)
- Jang-Won Son
- Division of Cardiology, Yeungnam University Hospital, Yeungnam University College of Medicine, Daegu, Korea
| | - Geu-Ru Hong
- Division of Cardiology, Department of Internal Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul, 120-752, Korea.
| | | | - Minji Kim
- School of Medicine, University of Queensland, Herston, QLD, Australia
| | - Helene Houle
- Siemens Medical Solutions, Mountain View, CA, USA
| | - Mani A Vannan
- Department of Cardiovascular Imaging, Piedmont Heart Institute, Atlanta, GA, USA
| | - Gianni Pedrizzetti
- Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Namsik Chung
- Division of Cardiology, Department of Internal Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul, 120-752, Korea
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40
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Erratum to: Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions. Cardiovasc Eng Technol 2015; 6:577-89. [DOI: 10.1007/s13239-015-0243-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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41
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Abstract
Aortic cannula is one of major factors leading to adverse events such as thrombosis and atherosclerosis development during open heart surgery. This is due to oxygenated blood outflow with high velocity jet from heart lung machine when exiting the cannula tip into ascending aorta. It was discovered, and validated by several researchers that blood flow out of the left ventricle into the aorta is spiral in nature. In this study, a novel design in which internal profile of the cannula was made to induce spiral flow were tested by way of numerical simulation, and compared against existing commercial cannula. Three designs were tested, which differed in number of groove employed. Among the cannula model designs, cannula design with 4 grooves yielded the lowest value of maximum wall shear stress at testing tube with 3.778 Pa and highest value of area weighted helicity density at 40 mm from cannula tips with 11.829 m/s2. Overall, spiral cannula models were showed highly potential in inducing spiral flow, and also the effect on blood hemolysis is acceptable.
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Andersson M, Lantz J, Ebbers T, Karlsson M. Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions. Cardiovasc Eng Technol 2015; 6:281-93. [PMID: 26577361 DOI: 10.1007/s13239-015-0218-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 02/13/2015] [Indexed: 01/01/2023]
Abstract
Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies.
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Affiliation(s)
- Magnus Andersson
- Department of Management and Engineering (IEI), Linköping University, 581 83, Linköping, Sweden. .,Swedish e-Science Research Center (SeRC), Stockholm, Sweden.
| | - Jonas Lantz
- Department of Science and Technology, Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| | - Tino Ebbers
- Department of Science and Technology, Linköping University, Linköping, Sweden.,Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| | - Matts Karlsson
- Department of Management and Engineering (IEI), Linköping University, 581 83, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
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Huetter L, Geoghegan PH, Docherty PD, Lazarjan MS, Clucas D, Jermy M. Application of a meta-analysis of aortic geometry to the generation of a compliant phantom for use in particle image velocimetry experimentation. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.ifacol.2015.10.174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Gallo D, Gülan U, Di Stefano A, Ponzini R, Lüthi B, Holzner M, Morbiducci U. Analysis of thoracic aorta hemodynamics using 3D particle tracking velocimetry and computational fluid dynamics. J Biomech 2014; 47:3149-55. [DOI: 10.1016/j.jbiomech.2014.06.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 06/05/2014] [Accepted: 06/12/2014] [Indexed: 11/24/2022]
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45
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Lantz J, Dyverfeldt P, Ebbers T. Improving Blood Flow Simulations by Incorporating Measured Subject-Specific Wall Motion. Cardiovasc Eng Technol 2014. [DOI: 10.1007/s13239-014-0187-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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Caballero A, Laín S. Numerical simulation of non-Newtonian blood flow dynamics in human thoracic aorta. Comput Methods Biomech Biomed Engin 2014; 18:1200-1216. [DOI: 10.1080/10255842.2014.887698] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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