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Zorrilla R, Soudah E. An efficient procedure for the blood flow computer simulation of patient-specific aortic dissections. Comput Biol Med 2024; 179:108832. [PMID: 39002313 DOI: 10.1016/j.compbiomed.2024.108832] [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: 03/12/2024] [Revised: 06/06/2024] [Accepted: 06/29/2024] [Indexed: 07/15/2024]
Abstract
In this work we present a novel methodology for the numerical simulation of patient-specific aortic dissections. Our proposal, which targets the seamless virtual prototyping of customized scenarios, combines an innovative two-step segmentation procedure with a CutFEM technique capable of dealing with thin-walled bodies such as the intimal flap. First, we generate the fluid mesh from the outer aortic wall disregarding the intimal flap, similarly to what would be done in a healthy aorta. Second, we create a surface mesh from the approximate midline of the intimal flap. This approach allows us to decouple the segmentation of the fluid volume from that of the intimal flap, thereby bypassing the need to create a volumetric mesh around a thin-walled body, an operation widely known to be complex and error-prone. Once the two meshes are obtained, the original configuration of the dissection into true and false lumen is recovered by embedding the surface mesh into the volumetric one and calculating a level set function that implicitly represents the intimal flap in terms of the volumetric mesh entities. We then leverage the capabilities of unfitted mesh methods, specifically relying on a CutFEM technique tailored for thin-walled bodies, to impose the wall boundary conditions over the embedded intimal flap. We tested the method by simulating the flow in four patient-specific aortic dissections, all involving intricate geometrical patterns. In all cases, the preprocess is greatly simplified with no impact on the computational times. Additionally, the obtained results are consistent with clinical evidence and previous research.
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Affiliation(s)
- Rubén Zorrilla
- Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya (UPC), Barcelona, 08034, Spain; International Center for Numerical Methods in Engineering (CIMNE), Barcelona, 08034, Spain.
| | - Eduardo Soudah
- Departament de Resistència de Materials i Estructures a l'Enginyeria, Universitat Politècnica de Catalunya (UPC), Barcelona, 08034, Spain; International Center for Numerical Methods in Engineering (CIMNE), Barcelona, 08034, Spain; Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, Expresión Gráfica en la Ingeniería, Ingeniería Cartográfica, Geodésica y Fotogrametría, Ingeniería Mecánica e Ingeniería de los Procesos de Fabricación, Universidad de Valladolid (UVA), Valladolid, 47011, Spain.
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Nishida H, Nakamura R, Tamaki R, Abe K. Inconsistent False Lumen Enhancement Predicts Late Aortic Events After Hemiarch Replacement in Acute Type A Aortic Dissection. Am J Cardiol 2024; 221:77-83. [PMID: 38636625 DOI: 10.1016/j.amjcard.2024.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 03/01/2024] [Accepted: 04/09/2024] [Indexed: 04/20/2024]
Abstract
The impact of inconsistent enhancement within the patent false lumen on the occurrence of late aortic events remains uncertain. We enrolled 55patients who exhibited a patent false lumen after hemiarch replacement. The Hounsfield unit (HU) measurements in the patent false lumen were obtained at 2 specific locations: the aortic arch (a) and the descending aorta (b). The false lumen HU score was calculated as the absolute value of 1 - a/b, representing the discrepancy in HUs within the patent false lumen. We investigated the cut-off value of the false lumen HU score with the receiver operating characteristics curve to predict the incidence of late aortic events. We divided the patients based on the cut-off value and compared the cumulative incidence of the late aortic events. The analysis of the receiver operating characteristics curve showed that the cut-off value of the false lumen HU score was 0.345. Based on this cut-off value, we divided them into 2 groups: Group A (score <0.345, n = 26) and Group B (score ≥0.345, n = 29). The baseline characteristics were similar between the 2 groups. The cumulative incidence of the late aortic events was significantly lower in Group A (7.8% at 5 years) than in Group B (39.9% at 5 years) (p = 0.02). The false lumen HU score might be useful to predict the incidence of late aortic events after hemiarch replacement.
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Affiliation(s)
- Hidefumi Nishida
- Department of Cardiovascular Surgery, St. Luke's International Hospital, Tokyo, Japan.
| | - Ryota Nakamura
- Department of Cardiovascular Surgery, St. Luke's International Hospital, Tokyo, Japan
| | - Rihito Tamaki
- Department of Cardiovascular Surgery, St. Luke's International Hospital, Tokyo, Japan
| | - Kohei Abe
- Department of Cardiovascular Surgery, St. Luke's International Hospital, Tokyo, Japan
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Armour C, Guo B, Saitta S, Guo D, Liu Y, Fu W, Dong Z, Xu XY. The Role of Multiple Re-Entry Tears in Type B Aortic Dissection Progression: A Longitudinal Study Using a Controlled Swine Model. J Endovasc Ther 2024; 31:104-114. [PMID: 35852439 PMCID: PMC10773162 DOI: 10.1177/15266028221111295] [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] [Indexed: 11/16/2022]
Abstract
PURPOSE False lumen (FL) expansion often occurs in type B aortic dissection (TBAD) and has been associated with the presence of re-entry tears. This longitudinal study aims to elucidate the role of re-entry tears in the progression of TBAD using a controlled swine model, by assessing aortic hemodynamics through combined imaging and computational modeling. MATERIALS AND METHODS A TBAD swine model with a primary entry tear at 7 cm distal to the left subclavian artery was created in a previous study. In the current study, reintervention was carried out in this swine model to induce 2 additional re-entry tears of approximately 5 mm in diameter. Computed tomography (CT) and 4-dimensional (4D) flow magnetic resonance imaging (MRI) scans were taken at multiple follow-ups before and after reintervention. Changes in aortic volume were measured on CT scans, and hemodynamic parameters were evaluated based on dynamic data acquired with 4D-flow MRI and computational fluid dynamics simulations incorporating all available in vivo data. RESULTS Morphological analysis showed FL growth of 20% following the initial TBAD-growth stabilized after the creation of additional tears and eventually FL volume reduced by 6%. Increasing the number of re-entry tears from 1 to 2 caused flow redistribution, with the percentage of true lumen (TL) flow increasing from 56% to 78%; altered local velocities; reduced wall shear stress surrounding the tears; and led to a reduction in FL pressure and pressure difference between the 2 lumina. CONCLUSION This study combined extensive in vivo imaging data with sophisticated computational methods to show that additional re-entry tears can alter dissection hemodynamics through redistribution of flow between the TL and FL. This helps to reduce FL pressure, which could potentially stabilize aortic growth and lead to reversal of FL expansion. This work provides a starting point for further study into the use of fenestration in controlling undesirable FL expansion. CLINICAL IMPACT Aortic growth and false lumen (FL) patency are associated with the presence of re-entry tears in type B aortic dissection (TBAD) patients. Guidelines on how to treat re-entry tears are lacking, especially with regards to the control and prevention of FL expansion. Through a combined imagining and computational hemodynamics study of a controlled swine model, we found that increasing the number of re-entry tears reduced FL pressure and cross lumen pressure difference, potentially stabilising aortic growth and leading to FL reduction. Our findings provide a starting point for further study into the use of fenestration in controlling undesirable FL expansion.
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Affiliation(s)
- Chlöe Armour
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Baolei Guo
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
- Department of Vascular Surgery, Qingpu Branch of Zhongshan Hospital Affiliated to Fudan University, Shanghai, China
| | - Simone Saitta
- Department of Chemical Engineering, Imperial College London, London, UK
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Daqiao Guo
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Yifan Liu
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
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Ritter JC, Munshi B, Letizia N, Parker LP, Kelsey LJ, Gilfillan M, Vo UG, Doyle BJ. Hemodynamic Implications of STABILISE Technique for Aortic Dissection Repair. Ann Vasc Surg 2024; 98:155-163. [PMID: 37805169 DOI: 10.1016/j.avsg.2023.07.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/03/2023] [Accepted: 07/22/2023] [Indexed: 10/09/2023]
Abstract
BACKGROUND The stent-assisted balloon-induced intimal disruption and relamination (STABILISE) technique for treatment of type B dissection has shown promising clinical results at mid-term. Computational modeling is a way of noninvasively obtaining hemodynamic effects, such as pressure and wall shear stress, leading to a better understanding of potential benefits. Particular areas of interest are (1) the effect of intimal disruption and re-lamination and (2) the effect of the bare metal stent in the visceral aortic segment. METHODS Single-center prospective case series. Data from 5 consecutive locally performed cases of STABILISE technique were analyzed. Included cases were type B aortic dissection with or without prior de-branching. The STABILISE procedure had to be performed without 30-day major complications. Preoperative and postoperative imaging data for each patient were transferred to the biomedical engineering team. Each case was reconstructed, meshed, and simulated with computational fluid dynamics using patient-specific data (heart rate, blood pressure, height, and weight). Hemodynamic parameters were then extracted from the simulations. RESULTS In all cases, computational analysis showed for postoperative patients: (1) a drop in pressure difference between lumina and (2) lower wall shear stress effects, compared to their preoperative status. These observations were most pronounced in the visceral aortic segment. CONCLUSIONS Computational modeling shows favourable changes in the flow dynamics of type B dissection treated using the STABILISE technique. This may suggest protective effects of this technique for long-term aortic healing and cicatrization.
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Affiliation(s)
- Jens C Ritter
- Department of Vascular and Endovascular Surgery, Fiona Stanley Hospital, Perth, Australia; Curtin University, School of Medicine, Perth, Australia.
| | - Bijit Munshi
- Department of Vascular and Endovascular Surgery, Fiona Stanley Hospital, Perth, Australia; Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
| | - Nathan Letizia
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia
| | - Louis P Parker
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia; Department of Engineering Mechanics, FLOW & BioMEx, Royal Institute of Technology, KTH, Stockholm, Sweden
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia
| | - Molly Gilfillan
- Department of Vascular and Endovascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Uyen G Vo
- Department of Vascular and Endovascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia
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Motoki K, Zhu Y, Mirsadraee S, Rosendahl U, Pepper J, Xu XY. A computational study of the effects of size, location, and number of tears on haemodynamics in surgically repaired type A aortic dissection. Front Cardiovasc Med 2023; 10:1215720. [PMID: 37388636 PMCID: PMC10301719 DOI: 10.3389/fcvm.2023.1215720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/05/2023] [Indexed: 07/01/2023] Open
Abstract
Objective This study aimed to comprehensively examine the roles of size, location, and number of tears in the progression of surgically repaired type A aortic dissection (TAAD) by assessing haemodynamic changes through patient-specific computational fluid dynamic (CFD) simulations. Methods Two patient-specific TAAD geometries with replaced ascending aorta were reconstructed based upon computed 15 tomography (CT) scans, after which 10 hypothetical models (5 per patient) with different tear configurations were artificially created. CFD simulations were performed on all the models under physiologically realistic boundary conditions. Results Our simulation results showed that increasing either the size or number of the re-entry tears reduced the luminal pressure difference (LPD) and maximum time-averaged wall shear stress (TAWSS), as well as areas exposed to abnormally high or low TAWSS values. Models with a large re-entry tear outperformed the others by reducing the maximum LPD by 1.88 mmHg and 7.39 mmHg, for patients 1 and 2, respectively. Moreover, proximally located re-entry tears in the descending aorta were more effective at reducing LPD than distal re-entry tears. Discussion These computational results indicate that the presence of a relatively large re-entry tear in the proximal descending aorta might help stabilize post-surgery aortic growth. This finding has important implications for the management and risk stratification of surgically repaired TAAD patients. Nevertheless, further validation in a large patient cohort is needed.
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Affiliation(s)
- Kyosuke Motoki
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Yu Zhu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Saeed Mirsadraee
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Radiology, Royal Brompton and Harefield Hospitals, London, United Kingdom
| | - Ulrich Rosendahl
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Cardiac Surgery, Royal Brompton and Harefield Hospitals, London, United Kingdom
| | - John Pepper
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Cardiac Surgery, Royal Brompton and Harefield Hospitals, London, United Kingdom
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
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Schafstedde M, Jarmatz L, Brüning J, Hüllebrand M, Nordmeyer S, Harloff A, Hennemuth A. Population-based reference values for 4D flow MRI derived aortic blood flow parameters. Physiol Meas 2023; 44. [PMID: 36735968 DOI: 10.1088/1361-6579/acb8fd] [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: 07/25/2022] [Accepted: 02/03/2023] [Indexed: 02/05/2023]
Abstract
Objective. This study assesses age-related differences of thoracic aorta blood flow profiles and provides age- and sex-specific reference values using 4D flow cardiovascular magnetic resonance (CMR) data.Approach. 126 volunteers (age 20-80 years, female 51%) underwent 4D flow CMR and 12 perpendicular analysis planes in the thoracic aorta were specified. For these planes the following parameters were evaluated: body surface area-adjusted aortic area (A'), normalized flow displacement (NFD), the degree of wall parallelism (WPD), the minimal relative cross-sectional area through which 80% of the volume flow passes (A80) and the angle between flow direction and centerline (α).Main results. Age-related differences in blood flow parameters were seen in the ascending aorta with higher values for NFD and angle and lower values for WPD and A80 in older subjects. All parameters describing blood flow patterns correlated with the cross-sectional area in the ascending aorta. No relevant sex-differences regarding blood flow profiles were found.Significance. These age- and sex-specific reference values for quantitative parameters describing blood flow within the aorta might help to study the clinical relevance of flow profiles in the future.
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Affiliation(s)
- Marie Schafstedde
- Institute of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany.,Department of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,Partner Site Berlin, German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Lina Jarmatz
- Institute of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany
| | - Jan Brüning
- Institute of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany.,Partner Site Berlin, German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Markus Hüllebrand
- Institute of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany.,Fraunhofer MEVIS, Bremen, Germany
| | - Sarah Nordmeyer
- Institute of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany.,Department of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany
| | - Andreas Harloff
- Department of Neurology, University Medical Center Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Germany
| | - Anja Hennemuth
- Institute of Congenital Heart Disease, German Heart Center Charité, Berlin, Germany.,Partner Site Berlin, German Centre for Cardiovascular Research (DZHK), Berlin, Germany.,Fraunhofer MEVIS, Bremen, Germany
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7
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Li D, Wang J, Zeng W, Zeng X, Liu Z, Cao H, Yuan D, Zheng T. The loss of helical flow in the thoracic aorta might be an identifying marker for the risk of acute type B aortic dissection. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107331. [PMID: 36621070 DOI: 10.1016/j.cmpb.2022.107331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/06/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE The occurrence of acute type B aortic dissection (TBAD) remained unclear. This study aimed to investigate the association between flow features and hemodynamic parameters in aortas that demonstrated the risk of TBAD occurrence. METHODS The geometries of 15 hyperacute TBAD and 12 control patients (with healthy aorta) were reconstructed from computed tomography angiography images. Pre-TBAD models were then obtained by eliminating the dissection flaps. Flow features and hemodynamic parameters, including wall shear stress-related parameters and helicities, were compared between pre-TBAD and control models using computational fluid dynamics. RESULTS There were no significant differences in baseline characteristics and anatomical parameters between the two groups. Significant contralateral helical blood flow was present in the healthy thoracic aorta, while almost no helical flow was observed in the pre-TBAD group. In addition, the mean normal transverse wall shear stress (NtransWSS) was significantly higher in the pre-TBAD group (aortic arch 0.49±0.09 vs. 0.40±0.05, P = 0.04; descending aorta: 0.46±0.05 vs. 0.33±0.02, P<0.01). Moreover, a significantly negative correlation was found between helicity and NtransWSS in the descending aorta. Moreover, the location of primary tears in 12 pre-TABD subjects matched well with regions of high NtransWSS. CONCLUSIONS Loss of helical flow in the aortic arch and descending aorta may be a major flow feature in patients with underlying TBAD, resulting in increased flow disturbance and wall lesions.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Jiarong Wang
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China
| | - Wen Zeng
- Division of radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangguo Zeng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Haoyao Cao
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Ding Yuan
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China; Med-X center for informatics, Sichuan University, Chengdu, China.
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China; Med-X center for informatics, Sichuan University, Chengdu, China.
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Kim T, van Bakel PAJ, Nama N, Burris N, Patel HJ, Williams DM, Figueroa CA. A Computational Study of Dynamic Obstruction in Type B Aortic Dissection. J Biomech Eng 2023; 145:031008. [PMID: 36459144 PMCID: PMC10854260 DOI: 10.1115/1.4056355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022]
Abstract
A serious complication in aortic dissection is dynamic obstruction of the true lumen (TL). Dynamic obstruction results in malperfusion, a blockage of blood flow to a vital organ. Clinical data reveal that increases in central blood pressure promote dynamic obstruction. However, the mechanisms by which high pressures result in TL collapse are underexplored and poorly understood. Here, we developed a computational model to investigate biomechanical and hemodynamical factors involved in Dynamic obstruction. We hypothesize that relatively small pressure gradient between TL and false lumen (FL) are sufficient to displace the flap and induce obstruction. An idealized fluid-structure interaction model of type B aortic dissection was created. Simulations were performed under mean cardiac output while inducing dynamic changes in blood pressure by altering FL outflow resistance. As FL resistance increased, central aortic pressure increased from 95.7 to 115.3 mmHg. Concurrent with blood pressure increase, flap motion was observed, resulting in TL collapse, consistent with clinical findings. The maximum pressure gradient between TL and FL over the course of the dynamic obstruction was 4.5 mmHg, consistent with our hypothesis. Furthermore, the final stage of dynamic obstruction was very sudden in nature, occurring over a short time (<1 s) in our simulation, consistent with the clinical understanding of this dramatic event. Simulations also revealed sudden drops in flow and pressure in the TL in response to the flap motion, consistent with first stages of malperfusion. To our knowledge, this study represents the first computational analysis of potential mechanisms driving dynamic obstruction in aortic dissection.
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Affiliation(s)
- T Kim
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48105
| | - P A J van Bakel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48105
| | - N Nama
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588
| | - N Burris
- Department of Radiology, University of Michigan, Ann Arbor, MI 48105
| | - H J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48105
| | - D M Williams
- Department of Radiology, University of Michigan, Ann Arbor, MI 48105
| | - C A Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48105; Department of Surgery, University of Michigan, Ann Arbor, MI 48105
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9
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Jafarinia A, Melito GM, Müller TS, Rolf-Pissarczyk M, Holzapfel GA, Brenn G, Ellermann K, Hochrainer T. Morphological parameters affecting false lumen thrombosis following type B aortic dissection: a systematic study based on simulations of idealized models. Biomech Model Mechanobiol 2023; 22:885-904. [PMID: 36630014 PMCID: PMC10167197 DOI: 10.1007/s10237-023-01687-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 01/02/2023] [Indexed: 01/12/2023]
Abstract
Type B aortic dissection (TBAD) carries a high risk of complications, particularly with a partially thrombosed or patent false lumen (FL). Therefore, uncovering the risk factors leading to FL thrombosis is crucial to identify high-risk patients. Although studies have shown that morphological parameters of the dissected aorta are related to FL thrombosis, often conflicting results have been reported. We show that recent models of thrombus evolution in combination with sensitivity analysis methods can provide valuable insights into how combinations of morphological parameters affect the prospect of FL thrombosis. Based on clinical data, an idealized geometry of a TBAD is generated and parameterized. After implementing the thrombus model in computational fluid dynamics simulations, a global sensitivity analysis for selected morphological parameters is performed. We then introduce dimensionless morphological parameters to scale the results to individual patients. The sensitivity analysis demonstrates that the most sensitive parameters influencing FL thrombosis are the FL diameter and the size and location of intimal tears. A higher risk of partial thrombosis is observed when the FL diameter is larger than the true lumen diameter. Reducing the ratio of the distal to proximal tear size increases the risk of FL patency. In summary, these parameters play a dominant role in classifying morphologies into patent, partially thrombosed, and fully thrombosed FL. In this study, we point out the predictive role of morphological parameters for FL thrombosis in TBAD and show that the results are in good agreement with available clinical studies.
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Affiliation(s)
- Alireza Jafarinia
- Institute of Strength of Materials, Graz University of Technology, Graz, Austria.
| | - Gian Marco Melito
- Institute of Mechanics, Graz University of Technology, Graz, Austria.
| | - Thomas Stephan Müller
- Institute of Fluid Mechanics and Heat Transfer, Graz University of Technology, Graz, Austria
| | | | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria.,Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Günter Brenn
- Institute of Fluid Mechanics and Heat Transfer, Graz University of Technology, Graz, Austria
| | - Katrin Ellermann
- Institute of Mechanics, Graz University of Technology, Graz, Austria
| | - Thomas Hochrainer
- Institute of Strength of Materials, Graz University of Technology, Graz, Austria
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10
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Wang Q, Guo X, Brooks M, Chuen J, Poon EKW, Ooi A, Lim RP. MRI in CFD for chronic type B aortic dissection: Ready for prime time? Comput Biol Med 2022; 150:106138. [PMID: 36191393 DOI: 10.1016/j.compbiomed.2022.106138] [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: 05/10/2022] [Revised: 08/31/2022] [Accepted: 09/18/2022] [Indexed: 11/24/2022]
Abstract
OBJECTIVES Better tools are needed for risk assessment of Type B aortic dissection (TBAD) to determine optimal treatment for patients with uncomplicated disease. Magnetic resonance imaging (MRI) has the potential to inform computational fluid dynamics (CFD) simulations for TBAD by providing individualised quantification of haemodynamic parameters, for assessment of complication risks. This systematic review aims to present an overview of MRI applications for CFD studies of TBAD. METHODS Following PRISMA guidelines, a search in Medline, Embase, and the Scopus Library identified 136 potentially relevant articles. Studies were included if they used MRI to inform CFD simulation in TBAD. RESULTS There were 20 articles meeting the inclusion criteria. 19 studies used phase contrast MRI (PC-MRI) to provide data for CFD flow boundary conditions. In 12 studies, CFD haemodynamic parameter results were validated against PC-MRI. In eight studies, geometric models were developed from MR angiography. In three studies, aortic wall or intimal flap motion data were derived from PC/cine MRI. CONCLUSIONS MRI provides complementary patient-specific information in CFD haemodynamic studies for TBAD that can be used for personalised care. MRI provides structural, dynamic and flow data to inform CFD for pre-treatment planning, potentially advancing its integration into clinical decision-making. The use of MRI to inform CFD in TBAD surgical planning is promising, however further validation and larger cohort studies are required.
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Affiliation(s)
- Qingdi Wang
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia.
| | - Xiaojing Guo
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Mark Brooks
- Department of Radiology, Austin Health, Heidelberg, VIC, 3084, Australia; School of Medicine, Deakin University, Melbourne, Australia
| | - Jason Chuen
- Department of Surgery, Austin Health, Heidelberg, VIC, 3084, Australia; Department of Surgery, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Eric K W Poon
- Department of Medicine, St Vincent's Hospital, Melbourne Medical School, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Andrew Ooi
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Ruth P Lim
- Department of Radiology, Austin Health, Heidelberg, VIC, 3084, Australia; Department of Surgery, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Fitzroy, VIC, 3065, Australia; Department of Radiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
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Peng Y, Zhang X, Li J, Zhang X, He H, Li X, Fang K, Zheng L, Shu C. Enlarged Lumen Volume of Proximal Aortic Segment and Acute Type B Aortic Dissection: A Computer Fluid Dynamics Study of Ideal Aortic Models. Int J Gen Med 2022; 15:535-543. [PMID: 35046712 PMCID: PMC8763263 DOI: 10.2147/ijgm.s343403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/01/2021] [Indexed: 11/23/2022] Open
Abstract
Background Recent study has revealed that enlarged diameters of the ascending aorta and proximal aortic arch enhance the probability of ATBAD. However, little is understood about the relation to ATBAD. Objective This study explored the differences in proximal aortic segment (PAS) morphology in patients with acute type B aortic dissection (ATBAD), and performed hemodynamic simulations to provide proof of principle. Materials and Methods The morphological characteristics of PAS in the ATBAD group (n = 163) and corresponding segment in the control group (n = 120) were retrospectively measured. The morphological parameters were analyzed using comprehensive statistical approaches. Ridge regression analysis was also performed to determine the association between independent variable and dependent variable. P < 0.01 was considered significant. Idealized aortic models were established based on variables of statistical significance, and hemodynamic simulations were performed to evaluate blood flow changes caused by morphology. Results Diameters at landmarks of PAS were significantly larger in the ATBAD group. The lumen volume (VPAS) of PAS in the ATBAD group was significantly enlarged than that of the control group (124,659.07 ± 34,089.27 mm3 vs 89,796.65 ± 30,334.40 mm3; P < 0.001). Furthermore, the VPAS was positively correlated to diameters. As the VPAS increased, the fluid kinetic energy in PAS enhanced linearly, and time-averaged wall shear stress and oscillatory shear index at the distal area of the left subclavian artery increased significantly. Conclusion In the ATBAD group, the enlarged VPAS and increased diameters of PAS are positively correlated. Meanwhile, the enlarged VPAS leads to more aggressive hemodynamic parameters at the distal area of the left subclavian artery, which may create a contributory condition for ATBAD.
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Affiliation(s)
- Yuan Peng
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, People’s Republic of China
| | - Jiehua Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Xiaolong Zhang
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Hao He
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Xin Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Kun Fang
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100037, People’s Republic of China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, People’s Republic of China
| | - Chang Shu
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100037, People’s Republic of China
- Correspondence: Chang Shu Tel +86-731-85295832 Email
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12
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Zilber ZA, Boddu A, Malaisrie SC, Hoel AW, Mehta CK, Vassallo P, Burris NS, Roldán-Alzate A, Collins JD, François CJ, Allen BD. Noninvasive Morphologic and Hemodynamic Evaluation of Type B Aortic Dissection: State of the Art and Future Perspectives. Radiol Cardiothorac Imaging 2021; 3:e200456. [PMID: 34235440 DOI: 10.1148/ryct.2021200456] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/21/2022]
Abstract
Stanford type B aortic dissection (TBAD) is associated with relatively high rates of morbidity and mortality, and appropriate treatment selection is important for optimizing patient outcomes. Depending on individualized risk factors, clinical presentation, and imaging findings, patients are generally stratified to optimal medical therapy anchored by antihypertensives or thoracic endovascular aortic repair (TEVAR). Using standard anatomic imaging with CT or MRI, several high-risk features including aortic diameter, false lumen (FL) features, size of entry tears, involvement of major aortic branch vessels, or evidence of visceral malperfusion have been used to select patients likely to benefit from TEVAR. However, even with these measures, the number needed to treat for TEVAR remains, and improved risk stratification is needed. Increasingly, the relationship between FL hemodynamics and adverse aortic remodeling in TBAD has been studied, and evolving noninvasive techniques can measure numerous FL hemodynamic parameters that may improve risk stratification. In addition to summarizing the current clinical state of the art for morphologic TBAD evaluation, this review provides a detailed overview of noninvasive methods for TBAD hemodynamics characterization, including computational fluid dynamics and four-dimensional flow MRI. Keywords: CT, Image Postprocessing, MRI, Cardiac, Vascular, Aorta, Dissection © RSNA, 2021.
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Affiliation(s)
- Zachary A Zilber
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Aayush Boddu
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - S Chris Malaisrie
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Andrew W Hoel
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Christopher K Mehta
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Patricia Vassallo
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Nicholas S Burris
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Alejandro Roldán-Alzate
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Jeremy D Collins
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Christopher J François
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Bradley D Allen
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
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Marlevi D, Sotelo JA, Grogan-Kaylor R, Ahmed Y, Uribe S, Patel HJ, Edelman ER, Nordsletten DA, Burris NS. False lumen pressure estimation in type B aortic dissection using 4D flow cardiovascular magnetic resonance: comparisons with aortic growth. J Cardiovasc Magn Reson 2021; 23:51. [PMID: 33980249 PMCID: PMC8117268 DOI: 10.1186/s12968-021-00741-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 03/16/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Chronic type B aortic dissection (TBAD) is associated with poor long-term outcome, and accurate risk stratification tools remain lacking. Pressurization of the false lumen (FL) has been recognized as central in promoting aortic growth. Several surrogate imaging-based metrics have been proposed to assess FL hemodynamics; however, their relationship to enlarging aortic dimensions remains unclear. We investigated the association between aortic growth and three cardiovascular magnetic resonance (CMR)-derived metrics of FL pressurization: false lumen ejection fraction (FLEF), maximum systolic deceleration rate (MSDR), and FL relative pressure (FL ΔPmax). METHODS CMR/CMR angiography was performed in 12 patients with chronic dissection of the descending thoracoabdominal aorta, including contrast-enhanced CMR angiography and time-resolved three-dimensional phase-contrast CMR (4D Flow CMR). Aortic growth rate was calculated as the change in maximal aortic diameter between baseline and follow-up imaging studies over the time interval, with patients categorized as having either 'stable' (< 3 mm/year) or 'enlarging' (≥ 3 mm/year) growth. Three metrics relating to FL pressurization were defined as: (1) FLEF: the ratio between retrograde and antegrade flow at the TBAD entry tear, (2) MSDR: the absolute difference between maximum and minimum systolic acceleration in the proximal FL, and (3) FL ΔPmax: the difference in absolute pressure between aortic root and distal FL. RESULTS FLEF was higher in enlarging TBAD (49.0 ± 17.9% vs. 10.0 ± 11.9%, p = 0.002), whereas FL ΔPmax was lower (32.2 ± 10.8 vs. 57.2 ± 12.5 mmHg/m, p = 0.017). MSDR and conventional anatomic variables did not differ significantly between groups. FLEF showed positive (r = 0.78, p = 0.003) correlation with aortic growth rate whereas FL ΔPmax showed negative correlation (r = - 0.64, p = 0.026). FLEF and FL ΔPmax remained as independent predictors of aortic growth rate after adjusting for baseline aortic diameter. CONCLUSION Comparative analysis of three 4D flow CMR metrics of TBAD FL pressurization demonstrated that those that focusing on retrograde flow (FLEF) and relative pressure (FL ΔPmax) independently correlated with growth and differentiated patients with enlarging and stable descending aortic dissections. These results emphasize the highly variable nature of aortic hemodynamics in TBAD patients, and suggest that 4D Flow CMR derived metrics of FL pressurization may be useful to separate patients at highest and lowest risk for progressive aortic growth and complications.
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Affiliation(s)
- David Marlevi
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Julio A Sotelo
- School of Biomedical Engineering, Universidad de Valparaíso, Valparaíso, Chile
- Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID-Millennium Science Initiative Program-Millennium Nucleus in Cardiovascular Magnetic Resonance, Santiago, Chile
| | - Ross Grogan-Kaylor
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Yunus Ahmed
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Sergio Uribe
- Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID-Millennium Science Initiative Program-Millennium Nucleus in Cardiovascular Magnetic Resonance, Santiago, Chile
- Department of Radiology, Schools of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Himanshu J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David A Nordsletten
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Nicholas S Burris
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
- Department of Radiology, University of Michigan, 1500 E. Medical Center Drive, Cardiovascular Center 5588, SPC-5030, Ann Arbor, MI, 48109-5030, USA.
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CRIMSON: An open-source software framework for cardiovascular integrated modelling and simulation. PLoS Comput Biol 2021; 17:e1008881. [PMID: 33970900 PMCID: PMC8148362 DOI: 10.1371/journal.pcbi.1008881] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 05/25/2021] [Accepted: 03/17/2021] [Indexed: 12/16/2022] Open
Abstract
In this work, we describe the CRIMSON (CardiovasculaR Integrated Modelling and SimulatiON) software environment. CRIMSON provides a powerful, customizable and user-friendly system for performing three-dimensional and reduced-order computational haemodynamics studies via a pipeline which involves: 1) segmenting vascular structures from medical images; 2) constructing analytic arterial and venous geometric models; 3) performing finite element mesh generation; 4) designing, and 5) applying boundary conditions; 6) running incompressible Navier-Stokes simulations of blood flow with fluid-structure interaction capabilities; and 7) post-processing and visualizing the results, including velocity, pressure and wall shear stress fields. A key aim of CRIMSON is to create a software environment that makes powerful computational haemodynamics tools accessible to a wide audience, including clinicians and students, both within our research laboratories and throughout the community. The overall philosophy is to leverage best-in-class open source standards for medical image processing, parallel flow computation, geometric solid modelling, data assimilation, and mesh generation. It is actively used by researchers in Europe, North and South America, Asia, and Australia. It has been applied to numerous clinical problems; we illustrate applications of CRIMSON to real-world problems using examples ranging from pre-operative surgical planning to medical device design optimization.
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15
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Roseland ME, Ahmed Y, van Herwaarden JA, Moll FL, Yang B, Patel HJ, Burris NS. False lumen enhancement characteristics on computed tomography angiography predict risk of aneurysm formation in acute type B aortic dissection. Interact Cardiovasc Thorac Surg 2021; 33:434-441. [PMID: 33963411 DOI: 10.1093/icvts/ivab095] [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: 11/03/2020] [Revised: 02/06/2021] [Accepted: 03/07/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Differential luminal enhancement [between true lumen (TL) and false lumen (FL)] results from differential flow patterns, most likely due to outflow restriction in the FL. We aimed to assess the impact of differential luminal enhancement at baseline computed tomography angiography on the risk of adverse events in patients with acute type B aortic dissection (TBAD). METHODS Baseline computed tomography angiographies of patients with acute TBAD between 2007 and 2016 (n = 48) were analysed using three-dimensional software at multiple sites along the descending thoraco-abdominal aorta. At each location, we measured contrast density in TL and FL [Houndsfield unit (HU)], maximal diameter (cm) and circumferential FL extent (°). Outcome data were collected via retrospective chart review. Multivariable logistic regression models were employed to determine the independent risk of TL-FL differential luminal enhancement on aneurysm formation (maximal diameter ≥55 mm) and medical treatment failure. RESULTS Patients were predominately male (75%) and 52.8±12.9 years at diagnosis. The mean follow-up was 5.9±2.6 years, and 42% (n = 20/48) patients were diagnosed with thoraco-abdominal aortic aneurysm. The baseline absolute difference between FL and TL contrast density measured at 2 cm distal to primary entry tear (TL-FLabs-Tear) was significantly higher among patients who developed aneurysm (26 HU, IQR: 15-53 vs 13 HU, IQR: 4-24, P = 0.001). Aneurysm development during follow-up was predicted by TL-FLabs-Tear (odds ratio 1.07, P = 0.012) and baseline maximal aortic diameter (odds ratio 1.90, P < 0.001). High (≥18 HU) differential luminal enhancement was associated with lower rates of aneurysm-free survival and higher rates of medical treatment failure. CONCLUSIONS Differential luminal enhancement may be a novel predictor of aneurysm formation among patients with acute TBAD.
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Affiliation(s)
- Molly E Roseland
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Yunus Ahmed
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | | | - Frans L Moll
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bo Yang
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Himanshu J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
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16
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Li D, Zheng T, Liu Z, Li Y, Yuan D, Fan Y. Influence of Distal Re-entry Tears on False Lumen Thrombosis After Thoracic Endovascular Aortic Repair in Type B Aortic Dissection Patients: A Computational Fluid Dynamics Simulation. Cardiovasc Eng Technol 2021; 12:426-437. [PMID: 33768445 DOI: 10.1007/s13239-021-00532-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/05/2021] [Indexed: 02/05/2023]
Abstract
PURPOSE Distal re-entry tears play a significant role in false lumen (FL) thrombosis, which will strongly affect the postoperative long-term survival of patients with type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR). This study aimed to investigate the influence of a peculiar morphological parameter of the residual re-entry tears in TBAD patients after TEVAR on long-term FL thrombosis using the computational fluid dynamics. METHODS Ideal population-based three-dimensional models of post-operative TBAD were established. Numerical simulation was performed to investigate the hemodynamic differences caused by different tear features, including the tear count, the maximum distance between tears, and the tear area. RESULTS Although the low relative residence time (RRT) area did not change significantly when the tear distance was fixed, the area of oscillatory shear index (OSI) > 0.45 and endothelial cell activation potential (ECAP) > 1.5 decreased significantly with the tear count and area increased and a dramatic increase in blood flow into the FL was also observed. When tear count and total area were fixed, for each 10-mm increase in the maximum distance between tears, the area of low RRT in the FL increased significantly, while the average pressure difference increased by 10.85%. CONCLUSION The different morphology of the re-entry tears had different effects on the thrombosis-related hemodynamic parameters in FL following TEVAR. and the number of re-entry tears was most crucial to the potential thrombosis in the post-TEVAR FL of TBAD patients.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Yan Li
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Ding Yuan
- Department Vascular Surgery of West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, China.
| | - Yubo Fan
- Beijing Advanced Innovation Center of Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, China.
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The effect of the entry and re-entry size in the aortic dissection: a two-way fluid-structure interaction simulation. Biomech Model Mechanobiol 2020; 19:2643-2656. [PMID: 32621161 DOI: 10.1007/s10237-020-01361-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/20/2020] [Indexed: 12/16/2022]
Abstract
Aortic dissection (AD) is one of the most catastrophic cardiovascular diseases. AD occurs when a layer inside the aorta is disrupted and gives rise to the formation of a true lumen and a false lumen. These lumens can be connected through tears in the intimal flap which are known as entries. Despite being known for about two centuries, the effects of many factors on the morbidity and mortality of this disease are still unknown. As the blood interaction with the aorta is crucial in the severity and the progression of the aortic dissection, a biomechanical approach is chosen to investigate the influence of different morphologies on the severity of this disease. Using the finite element method (FEM) and the fluid-structure interaction (FSI) approach, we have evaluated the blood flow characteristics along the diseased aorta, in conjunction with the deformation of the aortic wall. In this study, an idealized geometry of a dissected descending aorta (type B) with two entries has been studied. The values for the diameter of the entry tear were chosen to be 5 mm and 10 mm. Therefore, a total of four conditions were investigated. According to our results, the retrograde flow through the proximal tear is dependent on the size of the distal re-entry and vice versa. Our results revealed that when both entry and re-entry tears are 10 mm in diameter, the flow passes through the true and false lumens with smaller resistance, resulting in a smaller flutter of the intimal flap, and therefore more stable intimal flap. Major oscillation frequencies of 2.5 Hz and 7.4 Hz were observed for the oscillation of the intimal flap, and amplitudes of the waves with higher frequencies were negligible.
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Shape and Enhancement Analysis as a Useful Tool for the Presentation of Blood Hemodynamic Properties in the Area of Aortic Dissection. J Clin Med 2020; 9:jcm9051330. [PMID: 32370301 PMCID: PMC7290319 DOI: 10.3390/jcm9051330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/19/2020] [Accepted: 04/28/2020] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to create a mathematical approach for blood hemodynamic description with the use of brightness analysis. Medical data was collected from three male patients aged from 45 to 65 years with acute type IIIb aortic dissection that started proximal to the left subclavian artery and involved the renal arteries. For the recognition of wall dissection areas Digital Imaging and Communications in Medicine (DICOM) data were applied. The distance from descending aorta to the diaphragm was analyzed. Each time Feret (DF) and Hydraulic (DHy) diameter were calculated. Moreover, an average brightness (BAV) was analyzed. Finally, to describe blood hemodynamic in the area of aortic wall dissection, mathematical function combining difference in brightness value and diameter for each computed tomography (CT) scan was calculated. The results indicated that DF described common duct more accurately compare to DHy. While, DHy described more accurately true and false ducts. Each time when connection of true and false duct appeared, true duct had lower brightness compare to common duct and false duct. Moreover, false duct characterized with higher brightness compare to common duct. In summary, the proposed algorithm mimics changes in brightness value for patients with acute type IIIb aortic dissection.
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19
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Computational modeling of the fluid flow in type B aortic dissection using a modified finite element embedded formulation. Biomech Model Mechanobiol 2020; 19:1565-1583. [PMID: 31974816 DOI: 10.1007/s10237-020-01291-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
This work explores the use of an embedded computational fluid dynamics method to study the type B aortic dissection. The use of the proposed technique makes it possible to easily test different intimal flap configurations without any need of remeshing. To validate the presented methodology, we take as reference test case an in vitro experiment present in the literature. This experiment, which considers several intimal flap tear configurations (number, size and location), mimics the blood flow in a real type B aortic dissection. We prove the correctness and suitability of the presented approach by comparing the pressure values and waveform. The obtained results exhibit a remarkable similarity with the experimental reference data. Complementary, we present a feasible surgical application of the presented computer method. The aim is to help the clinicians in the decision making before the type B aortic dissection surgical fenestration. The capabilities of the proposed technique are exploited to efficiently create artificial reentry tear configurations. We highlight that only the radius and center of the reentry tear need to be specified by the clinicians, without any need to modify neither the model geometry nor the mesh. The obtained computational surgical fenestration results are in line with the medical observations in similar clinical studies.
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Munshi B, Parker LP, Norman PE, Doyle BJ. The application of computational modeling for risk prediction in type B aortic dissection. J Vasc Surg 2019; 71:1789-1801.e3. [PMID: 31831314 DOI: 10.1016/j.jvs.2019.09.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/04/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE New tools are urgently needed to help with surgical decision-making in type B aortic dissection (TBAD) that is uncomplicated at the time of initial presentation. This narrative review aims to answer the clinical question, Can computational modeling be used to predict risk in acute and chronic Stanford TBAD? METHODS The review (PROSPERO 2018 CRD42018104472) focused on risk prediction in TBAD. A comprehensive search of the Ovid MEDLINE database, using terms related to computational modeling and aortic dissection, was conducted to find studies of any form published between 1998 and 2018. Cohort studies, case series, and case reports of adults (older than 18 years) with computed tomography or magnetic resonance imaging diagnosis of TBAD were included. Computational modeling was applied in all selected studies. RESULTS There were 37 studies about computational modeling of TBAD identified from the search, and the findings were synthesized into a narrative review. Computational modeling can produce numerically calculated values of stresses, pressures, and flow velocities that are difficult to measure in vivo. Hemodynamic parameters-high or low wall shear stress, high pressure gradient between lumens during the cardiac cycle, and high false lumen flow rate-have been linked to the pathogenesis of branch malperfusion and aneurysm formation by numerous studies. Considering the major outcomes of end-organ failure, aortic rupture, and stabilization and remodeling, hypotheses have been generated about inter-relationships of measurable parameters in computational models with observable anatomic and pathologic changes, resulting in specific clinical outcomes. CONCLUSIONS There is consistency in study findings about computational modeling in TBAD, although a limited number of patients have been analyzed using various techniques. The mechanistic patterns of association found in this narrative review should be investigated in larger cohort prospective studies to further refine our understanding. It highlights the importance of patient-specific computational hemodynamic parameters in clinical decision-making algorithms. The current challenge is to develop and to test a risk assessment method that can be used by clinicians for TBAD.
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Affiliation(s)
- Bijit Munshi
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; Medical School, The University of Western Australia, Perth, Australia; Department of Vascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Louis P Parker
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia
| | - Paul E Norman
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; Medical School, The University of Western Australia, Perth, Australia; Department of Vascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia.
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Cao H, Qiu Y, Yuan D, Yu J, Li D, Jiang Y, Su L, Peng L, Zheng T. A computational fluid dynamics study pre- and post-fistula closure in a coronary artery fistula. Comput Methods Biomech Biomed Engin 2019; 23:33-42. [PMID: 31805773 DOI: 10.1080/10255842.2019.1699540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Haoyao Cao
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Yue Qiu
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Ding Yuan
- Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Jianqun Yu
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Da Li
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Yi Jiang
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Li Su
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Liqing Peng
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, China
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Ryzhakov P, Soudah E, Dialami N. Computational modeling of the fluid flow and the flexible intimal flap in type B aortic dissection via a monolithic arbitrary Lagrangian/Eulerian fluid-structure interaction model. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3239. [PMID: 31336022 DOI: 10.1002/cnm.3239] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 06/26/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
In the present work, we perform numerical simulations of the fluid flow in type B aortic dissection (AD), accounting for the flexibility of the intimal flap. The interaction of the flow with the intimal flap is modeled using a monolithic arbitrary Lagrangian/Eulerian fluid-structure interaction model. The model relies on choosing velocity as the kinematic variable in both domains (fluid and solid) facilitating the coupling. The fluid flow velocity and pressure evolution at different locations is studied and compared against the experimental evidence and the formerly published numerical simulation results. Several tear configurations are analyzed. Details of the fluid flow in the vicinity of the tears are highlighted. Influence of the tear size upon the fluid flow and the flap deformation is discussed.
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Affiliation(s)
- Pavel Ryzhakov
- Centre Internacional de Mètodes Numèrics a l'Enginyeria, CIMNE, Barcelona, Spain
- Universitat Politècnica de Catalunya, UPC, Barcelona, Spain
| | - Eduardo Soudah
- Centre Internacional de Mètodes Numèrics a l'Enginyeria, CIMNE, Barcelona, Spain
- Universitat Politècnica de Catalunya, UPC, Barcelona, Spain
| | - Narges Dialami
- Centre Internacional de Mètodes Numèrics a l'Enginyeria, CIMNE, Barcelona, Spain
- Universitat Politècnica de Catalunya, UPC, Barcelona, Spain
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Guo B, Dong Z, Pirola S, Liu Y, Menichini C, Xu XY, Guo D, Fu W. Dissection Level Within Aortic Wall Layers is Associated with Propagation of Type B Aortic Dissection: A Swine Model Study. Eur J Vasc Endovasc Surg 2019; 58:415-425. [PMID: 31337584 DOI: 10.1016/j.ejvs.2019.02.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/22/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Haemodynamic and geometric factors play pivotal roles in the propagation of acute type B aortic dissection (TBAD). The aim of this study was to evaluate the association between dissection level within all aortic layers and the propagation of acute TBAD in porcine aorta. METHODS In twelve pigs, two models of TBAD were created. In model A (n = 6), the aortic wall tear was superficial and close to the intima (thin intimal flap), whereas in model B (n = 6) it was deep and close to the adventitia (thick intimal flap). Dissection propagation was evaluated using angiography or computed tomography scans, and the haemodynamic measurements were acquired using Doppler wires. Most pigs were followed up at 1, 3, 6, 12, 18, and up to 24 months; four animals were euthanised at three and six months, respectively (two from each group). RESULTS Both models were successfully created. No statistical difference was observed for the median antegrade propagation distance intra-operatively between the two models (p = .092). At 24 months, the longitudinal propagation distance was significantly greater in model B than in model A (p = .016). No statistical difference in retrograde propagation was noted (p = .691). Over time, aortic wall dissection progressed most notably over the first three months in model A, whereas it continued over the first 12 months in model B. Flow velocity was significantly greater in the true lumen than in false lumen at the level of the primary tear (p = .001) and in the middle of the dissection (p = .004). The histopathological images at three and six months demonstrated the fibres were stretched linearly at the outside wall of false lumen in both models, while the depth of intimal tears developed to be superficial and similar at the distal dissection. CONCLUSION In this swine model of TBAD, a deeper intimal tear resulted in greater dissection propagation.
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Affiliation(s)
- Baolei Guo
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Yifan Liu
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Claudia Menichini
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Daqiao Guo
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China.
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China.
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Experimental Insight into the Hemodynamics and Perfusion of Radiological Contrast in Patent and Non-patent Aortic Dissection Models. Cardiovasc Eng Technol 2019; 10:314-328. [PMID: 30805874 DOI: 10.1007/s13239-019-00407-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 02/09/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE In a curved vessel such as the aortic arch, the velocity profile closer to the aortic root is normally skewed towards the inner curvature wall, while further downstream along the curve, the velocity profile becomes skewed towards the outer wall. In an aortic dissection (AD) disease, blood velocities in the true lumen (TL) and false lumen (FL) are hypothesized to depend on the proximity of the entry tear to the root of aortic arch. Faster velocity in the FL can lead to higher hemodynamic loading, and pose tearing risk. Furthermore, the luminal velocities control the perfusion rate of radiological contrast media during diagnostic imaging. The objective in this study is to investigate the effect of AD disease morphology and configuration on the blood velocity field in the TL and FL, and on the relative perfusion of radiological enhancement agents through the dissection. METHODS Eight in vitro models were studied, including patent and non-patent FL configurations. Particle image velocimetry (PIV) was used to quantify the AD velocity field, while laser-induced fluorescence (LIF) was implemented to visualize dynamical flow phenomena and to quantify the perfusion of injected dye, in mimicry of contrast-enhanced computed tomography (CT). RESULTS The location of the proximal entry tear along the aortic arch in a patent FL had a dramatic impact on whether the blood velocity was higher in the TL or FL. The luminal velocities were dependent on the entry/reentry tear size combination, with the smaller tear (whether distal or proximal) setting the upper limit on the maximal flow velocity in the FL. Upon merging near the distal reentry tear, the TL/FL velocity differential gave rise to the roll up and shedding of shear layer vortices that convected downstream in close proximity to the wall of the non-dissected aorta. In a non-patent FL, the flow velocity was practically null with all the blood passing through the TL. LIF imaging showed much slower perfusion of contrast dye in the FL compared to the TL. In a patent FL, however, dye had a comparable perfusion rate appearing around the same time as in the TL. CONCLUSIONS Blood velocities in the TL and FL were highly sensitive to the exact dissection configuration. Geometric case A1R, which had its proximal entry tear located further downstream along the aortic arch, and had its entry and reentry tears sufficiently sized, exhibited the highest FL flow velocity among the tested models, and it was also higher than in the TL, which suggest that this configuration had elevated hemodynamic loading and risk for tearing. In contrast-enhanced diagnostic imaging, a time-delayed acquisition protocol is recommended to improve the detection of suspected cases with a non-patent FL.
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Computational Fluid Dynamic Accuracy in Mimicking Changes in Blood Hemodynamics in Patients with Acute Type IIIb Aortic Dissection Treated with TEVAR. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8081309] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: We aimed to verify the accuracy of the Computational Fluid Dynamics (CFD) algorithm for blood flow reconstruction for type IIIb aortic dissection (TBAD) before and after thoracic endovascular aortic repair (TEVAR). Methods: We made 3D models of the aorta and its branches using pre- and post-operative CT data from five patients treated for TBAD. The CFD technique was used to quantify the displacement forces acting on the aortic wall in the areas of endograft, mass flow rate/velocity and wall shear stress (WSS). Calculated results were verified with ultrasonography (USG-Doppler) data. Results: CFD results indicated that the TEVAR procedure caused a 7-fold improvement in overall blood flow through the aorta (p = 0.0001), which is in line with USG-Doppler data. A comparison of CFD results and USG-Doppler data indicated no significant change in blood flow through the analysed arteries. CFD also showed a significant increase in flow rate for thoracic trunk and renal arteries, which was in accordance with USG-Doppler data (accuracy 90% and 99.9%). Moreover, we observed a significant decrease in WSS values within the whole aorta after TEVAR compared to pre-TEVAR (1.34 ± 0.20 Pa vs. 3.80 ± 0.59 Pa, respectively, p = 0.0001). This decrease was shown by a significant reduction in WSS and WSS contours in the thoracic aorta (from 3.10 ± 0.27 Pa to 1.34 ± 0.11Pa, p = 0.043) and renal arteries (from 4.40 ± 0.25 Pa to 1.50 ± 0.22 Pa p = 0.043). Conclusions: Post-operative remodelling of the aorta after TEVAR for TBAD improved hemodynamic patterns reflected by flow, velocity and WSS with an accuracy of 99%.
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Menichini C, Cheng Z, Gibbs RG, Xu XY. A computational model for false lumen thrombosis in type B aortic dissection following thoracic endovascular repair. J Biomech 2018; 66:36-43. [DOI: 10.1016/j.jbiomech.2017.10.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 09/28/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
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Clough R, Nienaber C, Ventikos Y. Commentary on “Computational Study of Anatomical Risk Factors in Idealized Models of Type B Aortic Dissection”. Eur J Vasc Endovasc Surg 2016; 52:746. [DOI: 10.1016/j.ejvs.2016.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 09/16/2016] [Indexed: 10/20/2022]
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