1
|
Vellaparambil R, Han WS, Di Giovanni P, Avril S. Computational Comparison of the Mechanical Behavior of Aortic Stent-Grafts Derived from Auxetic Unit Cells. Cardiovasc Eng Technol 2024; 15:199-210. [PMID: 38110763 PMCID: PMC11149442 DOI: 10.1007/s13239-023-00706-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023]
Abstract
PURPOSE Inappropriate stent-graft (SG) flexibility has been frequently associated with endovascular aortic repair (EVAR) complications such as endoleaks, kinks, and SG migration, especially in tortuous arteries. Stents derived from auxetic unit cells have shown some potential to address these issues as they offer an optimum trade-off between radial stiffness and bending flexibility. METHODS In this study, we utilized an established finite element (FE)-based approach to replicate the mechanical response of a SG iliac limb derived from auxetic unit cells in a virtual tortuous iliac aneurysm using a combination of a 180° U-bend and intraluminal pressurization. This study aimed to compare the mechanical performance (flexibility and durability) of SG limbs derived from auxetic unit cells and two commercial SG limbs (Z-stented SG and circular-stented SG models) in a virtual tortuous iliac aneurysm. Maximal graft strain and maximum stress in stents were employed as criteria to estimate the durability of SGs, whereas the maximal luminal reduction rate and the bending stiffness were used to assess the flexibility of the SGs. RESULTS SG limbs derived from auxetic unit cells demonstrated low luminal reduction (range 4-12%) with no kink, in contrast to Z-stented SG, which had a kink in its central area alongside a high luminal reduction (44%). CONCLUSIONS SG limbs derived from auxetic unit cells show great promise for EVAR applications even at high angulations such as 180°, with acceptable levels of durability and flexibility.
Collapse
Affiliation(s)
- Rahul Vellaparambil
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, 42023, Saint-Etienne, France
- Research and Development Department, HSL S.R.L, Trento, Italy
| | - Woo-Suck Han
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, 42023, Saint-Etienne, France
| | | | - Stéphane Avril
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, 42023, Saint-Etienne, France.
| |
Collapse
|
2
|
Derycke L, Avril S, Vermunt J, Perrin D, El Batti S, Alsac JM, Albertini JN, Millon A. Computational prediction of proximal sealing in endovascular abdominal aortic aneurysm repair with unfavorable necks. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 244:107993. [PMID: 38142515 DOI: 10.1016/j.cmpb.2023.107993] [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: 06/22/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023]
Abstract
BACKGROUND AND OBJECTIVE Endovascular aortic aneurysm repair (EVAR) has become the standard treatment for abdominal aortic aneurysms in most centers. However, proximal sealing complications leading to endoleaks and migrations sometimes occur, particularly in unfavorable aortic anatomies and are strongly dependent on biomechanical interactions between the aortic wall and the endograft. The objective of the present work is to develop and validate a computational patient-specific model that can accurately predict these complications. METHODS Based on pre-operative CT-scans, we developed finite element models of the aorta of 10 patients who underwent endovascular aortic aneurysm repair, 7 with standard morphologies and 3 with unfavorable anatomies. We simulated the deployment of stent grafts in each aorta by solving mechanical equilibrium with a virtual shell method. Eventually we compared the actual stent ring positions from post-operative computed-tomography-scans with the predicted simulated positions. RESULTS A successful deployment simulation could be performed for each patient. Relative radial, transverse and longitudinal deviations were 6.3 ± 4.4%, 2.5 ± 0.9 mm and 1.4 ± 1.1 mm, respectively. CONCLUSIONS The numerical model predicted accurately stent-graft positions in the aortic neck of 10 patients, even in complex anatomies. This shows the potential of computer simulation to anticipate possible proximal endoleak complications before EVAR interventions.
Collapse
Affiliation(s)
- L Derycke
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France; Department of Vascular Surgery, Hôpital Paris Saint-Joseph, F-75014 Paris, France
| | - S Avril
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France.
| | | | | | - S El Batti
- Department of Cardio-Vascular and Vascular Surgery, Hôpital Européen Georges Pompidou, F-75015 Paris, France
| | - J-M Alsac
- Department of Cardio-Vascular and Vascular Surgery, Hôpital Européen Georges Pompidou, F-75015 Paris, France
| | | | - A Millon
- Department of Vascular and Endovascular Surgery, Hospices Civils de Lyon, Louis Pradel University, Hospital, F-69500 Bron, France
| |
Collapse
|
3
|
Sengupta S, Yuan X, Maga L, Pirola S, Nienaber CA, Xu XY. Aortic haemodynamics and wall stress analysis following arch aneurysm repair using a single-branched endograft. Front Cardiovasc Med 2023; 10:1125110. [PMID: 37283581 PMCID: PMC10240084 DOI: 10.3389/fcvm.2023.1125110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/08/2023] [Indexed: 06/08/2023] Open
Abstract
Introduction Thoracic endovascular aortic repair (TEVAR) of the arch is challenging given its complex geometry and the involvement of supra-aortic arteries. Different branched endografts have been designed for use in this region, but their haemodynamic performance and the risk for post-intervention complications are not yet clear. This study aims to examine aortic haemodynamics and biomechanical conditions following TVAR treatment of an aortic arch aneurysm with a two-component single-branched endograft. Methods Computational fluid dynamics and finite element analysis were applied to a patient-specific case at different stages: pre-intervention, post-intervention and follow-up. Physiologically accurate boundary conditions were used based on available clinical information. Results Computational results obtained from the post-intervention model confirmed technical success of the procedure in restoring normal flow to the arch. Simulations of the follow-up model, where boundary conditions were modified to reflect change in supra-aortic vessel perfusion observed on the follow-up scan, predicted normal flow patterns but high levels of wall stress (up to 1.3M MPa) and increased displacement forces in regions at risk of compromising device stability. This might have contributed to the suspected endoleaks or device migration identified at the final follow up. Discussion Our study demonstrated that detailed haemodynamic and biomechanical analysis can help identify possible causes for post-TEVAR complications in a patient-specific setting. Further refinement and validation of the computational workflow will allow personalised assessment to aid in surgical planning and clinical decision making.
Collapse
Affiliation(s)
- Sampad Sengupta
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Xun Yuan
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Cardiology and Aortic Centre, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Ludovica Maga
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
- Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands
| | - Selene Pirola
- Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands
| | - Christoph A. Nienaber
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Cardiology and Aortic Centre, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| |
Collapse
|
4
|
Derycke L, Avril S, Millon A. Patient-Specific Numerical Simulations of Endovascular Procedures in Complex Aortic Pathologies: Review and Clinical Perspectives. J Clin Med 2023; 12:jcm12030766. [PMID: 36769418 PMCID: PMC9917982 DOI: 10.3390/jcm12030766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
The endovascular technique is used in the first line treatment in many complex aortic pathologies. Its clinical outcome is mostly determined by the appropriate selection of a stent-graft for a specific patient and the operator's experience. New tools are still needed to assist practitioners with decision making before and during procedures. For this purpose, numerical simulation enables the digital reproduction of an endovascular intervention with various degrees of accuracy. In this review, we introduce the basic principles and discuss the current literature regarding the use of numerical simulation for endovascular management of complex aortic diseases. Further, we give the future direction of everyday clinical applications, showing that numerical simulation is about to revolutionize how we plan and carry out endovascular interventions.
Collapse
Affiliation(s)
- Lucie Derycke
- Department of Cardio-Vascular and Vascular Surgery, Hôpital Européen Georges Pompidou, F-75015 Paris, France
- Centre CIS, Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France
| | - Stephane Avril
- Centre CIS, Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France
| | - Antoine Millon
- Department of Vascular and Endovascular Surgery, Hospices Civils de Lyon, Louis Pradel University Hospital, F-69500 Bron, France
- Correspondence:
| |
Collapse
|
5
|
Characterizing the Mechanical Performance of a Bare-Metal Stent with an Auxetic Cell Geometry. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12020910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This study develops and characterizes the distinctive mechanical features of a stainless-steel metal stent with a tailored structure. A high-precision femtosecond laser was used to micromachine a stent with re-entrant hexagonal (auxetic) cell geometry. We then characterized its mechanical behavior under various mechanical loadings using in vitro experiments and through finite element analysis. The stent properties, such as the higher capability of the stent to bear upon bending, exceptional advantage at elevated levels of twisting angles, and proper buckling, all ensured a preserved opening to maintain the blood flow. The outcomes of this preliminary study present a potential design for a stent with improved physiologically relevant mechanical conditions such as longitudinal contraction, radial strength, and migration of the stent.
Collapse
|
6
|
Ramella A, Migliavacca F, Rodriguez Matas JF, Heim F, Dedola F, Marconi S, Conti M, Allievi S, Mandigers TJ, Bissacco D, Domanin M, Trimarchi S, Luraghi G. Validation and Verification of High-Fidelity Simulations of Thoracic Stent-Graft Implantation. Ann Biomed Eng 2022; 50:1941-1953. [PMID: 35854187 PMCID: PMC9794542 DOI: 10.1007/s10439-022-03014-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/08/2022] [Indexed: 12/31/2022]
Abstract
Thoracic Endovascular Aortic Repair (TEVAR) is the preferred treatment option for thoracic aortic pathologies and consists of inserting a self-expandable stent-graft into the pathological region to restore the lumen. Computational models play a significant role in procedural planning and must be reliable. For this reason, in this work, high-fidelity Finite Element (FE) simulations are developed to model thoracic stent-grafts. Experimental crimp/release tests are performed to calibrate stent-grafts material parameters. Stent pre-stress is included in the stent-graft model. A new methodology for replicating device insertion and deployment with explicit FE simulations is proposed. To validate this simulation, the stent-graft is experimentally released into a 3D rigid aortic phantom with physiological anatomy and inspected in a computed tomography (CT) scan at different time points during deployment with an ad-hoc set-up. A verification analysis of the adopted modeling features compared to the literature is performed. With the proposed methodology the error with respect to the CT is on average 0.92 ± 0.64%, while it is higher when literature models are adopted (on average 4.77 ± 1.83%). The presented FE tool is versatile and customizable for different commercial devices and applicable to patient-specific analyses.
Collapse
Affiliation(s)
- Anna Ramella
- grid.4643.50000 0004 1937 0327Computational Biomechanics Laboratory – LaBS, Department of Chemistry, Materials and Chemical Engineering ‘Giulio Natta’, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy
| | - Francesco Migliavacca
- grid.4643.50000 0004 1937 0327Computational Biomechanics Laboratory – LaBS, Department of Chemistry, Materials and Chemical Engineering ‘Giulio Natta’, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy
| | - Jose Felix Rodriguez Matas
- grid.4643.50000 0004 1937 0327Computational Biomechanics Laboratory – LaBS, Department of Chemistry, Materials and Chemical Engineering ‘Giulio Natta’, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy
| | - Frederic Heim
- grid.9156.b0000 0004 0473 5039Laboratoire de Physique et Mécanique des Textiles, Université de Haute-Alsace, 11 rue Alfred Werner, 68093 Mulhouse, France
| | - Francesca Dedola
- grid.4708.b0000 0004 1757 2822Clinical and Community Sciences Department, Università degli Studi di Milano, Via della Commenda 19, 20122 Milan, Italy
| | - Stefania Marconi
- grid.8982.b0000 0004 1762 5736Department of Civil Engineering and Architecture (DICAr), University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
| | - Michele Conti
- grid.8982.b0000 0004 1762 5736Department of Civil Engineering and Architecture (DICAr), University of Pavia, Via Ferrata 3, 27100 Pavia, Italy
| | - Sara Allievi
- grid.4708.b0000 0004 1757 2822Clinical and Community Sciences Department, Università degli Studi di Milano, Via della Commenda 19, 20122 Milan, Italy
| | - Tim J. Mandigers
- grid.414818.00000 0004 1757 8749Unit of Vascular Surgery, I.R.C.C.S. Fondazione Cà Granda Policlinico Milano, Via Francesco Sforza 35, Milan, Italy
| | - Daniele Bissacco
- grid.414818.00000 0004 1757 8749Unit of Vascular Surgery, I.R.C.C.S. Fondazione Cà Granda Policlinico Milano, Via Francesco Sforza 35, Milan, Italy
| | - Maurizio Domanin
- grid.4708.b0000 0004 1757 2822Clinical and Community Sciences Department, Università degli Studi di Milano, Via della Commenda 19, 20122 Milan, Italy ,grid.414818.00000 0004 1757 8749Unit of Vascular Surgery, I.R.C.C.S. Fondazione Cà Granda Policlinico Milano, Via Francesco Sforza 35, Milan, Italy
| | - Santi Trimarchi
- grid.4708.b0000 0004 1757 2822Clinical and Community Sciences Department, Università degli Studi di Milano, Via della Commenda 19, 20122 Milan, Italy ,grid.414818.00000 0004 1757 8749Unit of Vascular Surgery, I.R.C.C.S. Fondazione Cà Granda Policlinico Milano, Via Francesco Sforza 35, Milan, Italy
| | - Giulia Luraghi
- grid.4643.50000 0004 1937 0327Computational Biomechanics Laboratory – LaBS, Department of Chemistry, Materials and Chemical Engineering ‘Giulio Natta’, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy
| |
Collapse
|
7
|
Avril S, Gee MW, Hemmler A, Rugonyi S. Patient-specific computational modeling of endovascular aneurysm repair: State of the art and future directions. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3529. [PMID: 34490740 DOI: 10.1002/cnm.3529] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Endovascular aortic repair (EVAR) has become the preferred intervention option for aortic aneurysms and dissections. This is because EVAR is much less invasive than the alternative open surgery repair. While in-hospital mortality rates are smaller for EVAR than open repair (1%-2% vs. 3%-5%), the early benefits of EVAR are lost after 3 years due to larger rates of complications in the EVAR group. Clinicians follow instructions for use (IFU) when possible, but are left with personal experience on how to best proceed and what choices to make with respect to stent-graft (SG) model choice, sizing, procedural options, and their implications on long-term outcomes. Computational modeling of SG deployment in EVAR and tissue remodeling after intervention offers an alternative way of testing SG designs in silico, in a personalized way before intervention, to ultimately select the strategies leading to better outcomes. Further, computational modeling can be used in the optimal design of SGs in cases of complex geometries. In this review, we address some of the difficulties and successes associated with computational modeling of EVAR procedures. There is still work to be done in all areas of EVAR in silico modeling, including model validation, before models can be applied in the clinic, but much progress has already been made. Critical to clinical implementation are current efforts focusing on developing fast algorithms that can achieve (near) real-time solutions, as well as ways of dealing with inherent uncertainties related to patient aortic wall degradation on an individualized basis. We are optimistic that EVAR modeling in the clinic will soon become a reality to help clinicians optimize EVAR interventions and ultimately reduce EVAR-associated complications.
Collapse
Affiliation(s)
- Stéphane Avril
- Mines Saint-Étienne, Univ Lyon, Univ Jean Monnet, INSERM, Saint-Étienne, France
| | - Michael W Gee
- Mechanics & High Performance Computing Group, Department of Mechanical Engineering, Technical University of Munich, Garching, Germany
| | - André Hemmler
- Mechanics & High Performance Computing Group, Department of Mechanical Engineering, Technical University of Munich, Garching, Germany
| | - Sandra Rugonyi
- Biomedical Engineering Department, Oregon Health & Science University, Portland, Oregon, USA
| |
Collapse
|
8
|
A Computational Framework Examining the Mechanical Behaviour of Bare and Polymer-Covered Self-Expanding Laser-Cut Stents. Cardiovasc Eng Technol 2021; 13:466-480. [PMID: 34850370 DOI: 10.1007/s13239-021-00597-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 11/16/2021] [Indexed: 01/22/2023]
Abstract
PURPOSE Polymer covered stents have demonstrated promising clinical outcomes with improved patency rates compared to traditional bare-metal stents. However, little is known on the mechanical implication of stent covering. This study aims to provide insight into the role of a polymeric cover on the biomechanical performance of self-expanding laser-cut stents through a combined experimental-computational approach. METHODS Experimental bench top tests were conducted on bare and covered versions of a commercial stent to evaluate the radial, axial and bending response. In parallel, a computational framework with a novel covering strategy was developed that accurately predicts stent mechanical performance. Different stent geometries and polymer materials were also considered to further improve understanding on covered stent mechanics. RESULTS Results show that stent covering causes increased initial axial stiffness and up to 60% greater radial resistive force at small crimp diameters as the cover folds and self-contacts. The incorporation of a cover allows stent designs without interconnecting struts, thereby providing improved flexibility without compromising radial force. It was also shown that use of a stiffer PET polymeric covering material caused significant alterations to the radial and axial response, with the initial axial stiffness increasing six-fold and the maximum radial resistive force increasing four-fold compared to a PTFE-PU covered stent. CONCLUSION This study demonstrates that stent covering has a substantial effect on the overall stent mechanical performance and highlights the importance of considering the mechanical properties of the combined cover and stent.
Collapse
|
9
|
Concannon J, Moerman KM, Hynes N, Sultan S, McGarry JP. Influence of shape-memory stent grafts on local aortic compliance. Biomech Model Mechanobiol 2021; 20:2373-2392. [PMID: 34541627 PMCID: PMC8595172 DOI: 10.1007/s10237-021-01514-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/18/2021] [Indexed: 12/19/2022]
Abstract
The effect of repair techniques on the biomechanics of the aorta is poorly understood, resulting in significant levels of postoperative complications for patients worldwide. This study presents a computational analysis of the influence of Nitinol-based devices on the biomechanical performance of a healthy patient-specific human aorta. Simulations reveal that Nitinol stent-grafts stretch the artery wall so that collagen is stretched to a straightened high-stiffness configuration. The high-compliance regime (HCR) associated with low diastolic lumen pressure is eliminated, and the artery operates in a low-compliance regime (LCR) throughout the entire cardiac cycle. The slope of the lumen pressure–area curve for the LCR post-implantation is almost identical to that of the native vessel during systole. This negligible change from the native LCR slope occurs because the stent-graft increases its diameter from the crimped configuration during deployment so that it reaches a low-stiffness unloading plateau. The effective radial stiffness of the implant along this unloading plateau is negligible compared to the stiffness of the artery wall. Provided the Nitinol device unloads sufficiently during deployment to the unloading plateau, the degree of oversizing has a negligible effect on the pressure–area response of the vessel, as each device exerts approximately the same radial force, the slope of which is negligible compared to the LCR slope of the native artery. We show that 10% oversizing based on the observed diastolic diameter in the mid descending thoracic aorta results in a complete loss of contact between the device and the wall during systole, which could lead to an endoleak and stent migration. 20% oversizing reaches the Dacron enforced area limit (DEAL) during the pulse pressure and results in an effective zero-compliance in the later portion of systole.
Collapse
Affiliation(s)
- J Concannon
- Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland
| | - K M Moerman
- Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland
| | - N Hynes
- Western Vascular Institute, National University of Ireland Galway, Galway, Ireland
| | - S Sultan
- Western Vascular Institute, National University of Ireland Galway, Galway, Ireland
| | - J P McGarry
- Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland.
| |
Collapse
|
10
|
Osswald A, Schucht R, Schlosser T, Jánosi RA, Thielmann M, Weymann A, Ruhparwar A, Tsagakis K. Changes of stent-graft orientation after frozen elephant trunk treatment in aortic dissection. Eur J Cardiothorac Surg 2021; 61:142-149. [PMID: 34329387 DOI: 10.1093/ejcts/ezab297] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 04/29/2021] [Accepted: 05/13/2021] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Our goal was to evaluate the extent of stent-graft (SG) elastic recoil in the descending aorta after the frozen elephant trunk procedure in acute (AAD) and chronic (CAD) aortic dissection as well as the impact of SG movement on distal stent graft-induced new entry (d-SINE). METHODS We retrospectively analysed 149 (105 AAD, 44 CAD) of 259 aortic dissection patients after the frozen elephant trunk procedure between January 2005 and April 2019. Inclusion criteria were at least 1-year computed tomography angiography (CTA) aortic examinations during a follow-up time of 3.8 ± 2.7 years and absence of open or endovascular reintervention. Multiplanar reconstruction of CTA scans was used to define the SG vector position and movement in a virtual Cartesian coordinate system. The angle φ of vector movement and changes of aortic areas at the distal landing zone were analysed. RESULTS The distal SG position changed over time in the cranial (10.06 ± 11.12 mm), dorsal (8.45 ± 11.12 mm) and lateral (4.96 ± 9.89 mm) directions (P < 0.001). The total change of φ (4.08 ± 7.03°) was greater in AAD than in CAD (P = 0.026). d-SINE was more common in CAD (P < 0.001) and was associated with the size of the aortic area, aortic area enlargement and continuous SG unfolding (P < 0.001). CONCLUSIONS With the frozen elephant trunk technique, movement and change of SG orientation in the descending aorta were observed over time. Elastic recoil was greater in AAD than in CAD. The incidence of d-SINE was particularly dependent on the size of the aortic lumen and SG radial expansion and less on elastic recoil.
Collapse
Affiliation(s)
- Anja Osswald
- Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Robert Schucht
- Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Thomas Schlosser
- Department of Radiology, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Rolf Alexander Jánosi
- Department of Cardiology, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Matthias Thielmann
- Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Alexander Weymann
- Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Arjang Ruhparwar
- Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, Essen, Germany
| | - Konstantinos Tsagakis
- Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, Essen, Germany
| |
Collapse
|
11
|
Kwiecinski J, Cheng CP, Uberoi R, Hadi M, Hempel P, Degel C, You Z. Thoracic aortic parallel stent-graft behaviour when subjected to radial loading. J Mech Behav Biomed Mater 2021; 118:104407. [PMID: 33740690 DOI: 10.1016/j.jmbbm.2021.104407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/20/2020] [Accepted: 02/12/2021] [Indexed: 10/22/2022]
Abstract
To manage complex aortic arch disease using minimally invasive techniques, interventionalists have reported the use of multiple stent-graft devices deployed in a parallel configuration. The structural device-device and device-artery interactions arising during aortic arch parallel endografting, also known as chimney thoracic endovascular aortic repair (ch-TEVAR), is not well understood. Through the use of a radial force testing system we sought to characterise both the loading and deformation behaviour of parallel endografts in representative ch-TEVAR configurations. Four commercially available devices (Bentley BeGraft, Gore TAG, Gore Viabahn, and Medtronic Valiant) were subjected to uniform radial load individually, and in six combinations, to quantify loading profiles. Image data collected during testing were analysed to evaluate mechanical deformations in terms of gutters, chimney and main endograft compression, as well as graft infolding. Parallel endografting was found to increase radial loads when compared to standard TEVAR. Chronic outward force during ch-TEVAR was dependent on main endograft manufacturer, with TAG combinations leading to consistently higher loads than Valiant, but independent of chimney graft type. Endograft deformations were dependent on chimney graft type, with Viabahn combinations presenting with lower gutter areas and increased lumen compression than BeGraft. Chimney graft deformations were also influenced by deployment arrangement in the case of double ch-TEVAR. This study emphasizes the significant variability in both radial loads and mechanical deformations between clinically relevant ch-TEVAR configurations.
Collapse
Affiliation(s)
- Jakub Kwiecinski
- Department of Engineering Science, University of Oxford, Oxford, UK.
| | | | - Raman Uberoi
- Department of Vascular Surgery, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Mohammed Hadi
- Department of Vascular Surgery, Oxford University Hospitals NHS Trust, Oxford, UK
| | | | | | - Zhong You
- Department of Engineering Science, University of Oxford, Oxford, UK
| |
Collapse
|
12
|
McKenna CG, Vaughan TJ. A finite element investigation on design parameters of bare and polymer-covered self-expanding wire braided stents. J Mech Behav Biomed Mater 2021; 115:104305. [PMID: 33454463 DOI: 10.1016/j.jmbbm.2020.104305] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/02/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023]
Abstract
Self-expanding covered braided stents are routinely used across a diverse range of clinical applications, but few computational studies have attempted to replicate their complex behaviour. In this study, a computational framework was developed to predict the functional performance of bare and covered self-expanding wire braided stents, with a systematic evaluation on the effect of various braid and cover parameters presented. Simulated radial force and kink deformation tests show good agreement to experimental data for covered braided stents across a range of braid angles and cover thicknesses. Our results demonstrate that braid angle is a key governing parameter that dictates the radial and kink performance of both bare-metal and covered wire braided stents. It was also demonstrated that addition of a polymeric cover to a wire braided stent causes a stiffer radial response across all braid angles, particularly when thicker and/or stiffer covering systems were considered. This study represents the first experimentally-validated computational model for covered wire braided stent systems and has excellent potential to be used in future design of these devices for a range of applications.
Collapse
Affiliation(s)
- Ciara G McKenna
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
| | - Ted J Vaughan
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland.
| |
Collapse
|
13
|
Meekel JP, van Schaik TG, Lely RJ, Groot G, van der Meijs BB, Wisselink W, Blankensteijn JD, Yeung KK. Gutter Characteristics and Stent Compression of Self-Expanding vs Balloon-Expandable Chimney Grafts in Juxtarenal Aneurysm Models. J Endovasc Ther 2020; 27:452-461. [PMID: 32314658 PMCID: PMC7288858 DOI: 10.1177/1526602820915262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Purpose: To assess in silicone juxtarenal aneurysm models the gutter characteristics and compression of different types of chimney graft (CG) configurations. Materials and Methods: Fifty-seven combinations of Excluder C3 or Conformable Excluder stent-grafts (23, 26, and 28.5 mm) were deployed in 2 silicone juxtarenal aneurysm models with 3 types of CGs: Viabahn self-expanding (VSE; 6 and 13 mm) or Viabahn balloon-expandable (VBX; 6, 10, and 12 mm) stent-grafts and Advanta V12 balloon-expandable stent-grafts (ABX; 6 and 12 mm). Setups were divided into 4 groups on the basis of increasing CG and main graft (MG) diameters. Two independent observers assessed gutter size and type as well as CG compression on computed tomography scans using postprocessing software. Results: In the smaller diameter combinations (6-mm CG and 23-, 26-, and 28.5-mm MGs), both VSE (p=0.006 to 0.050) and ABX (p=0.045 to 0.050) showed lower gutter areas and volumes compared with VBX. In turn, the VBX showed a nonsignificant tendency to decreased compression, especially compared to ABX. Use of the Excluder C3 showed a 6-fold increase in type A1 gutters (related to type Ia endoleak) as compared to the Conformable Excluder (p=0.018). Balloon-expandable stent-grafts (both ABX and VBX) showed a 3-fold increase in type A1 gutters in comparison with self-expanding stent-grafts (p=0.008). Conclusion: The current study suggests that use of the Conformable Excluder in combination with VSE chimney grafts is superior to the other tested CG/MG combinations in terms of gutter size, gutter type, and CG compression.
Collapse
Affiliation(s)
- Jorn P Meekel
- Department of Vascular Surgery, Amsterdam University Medical Centers, VU Medical Center, Amsterdam, the Netherlands.,Department of Physiology, Amsterdam University Medical Centers, VU Medical Center, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands.,Department of Surgery, Zaans Medisch Centrum, Zaandam, the Netherlands
| | - Theodorus G van Schaik
- Department of Vascular Surgery, Amsterdam University Medical Centers, VU Medical Center, Amsterdam, the Netherlands.,Department of Physiology, Amsterdam University Medical Centers, VU Medical Center, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands.,Department of Surgery, Zaans Medisch Centrum, Zaandam, the Netherlands
| | - Rutger J Lely
- Department of Interventional Radiology, Amsterdam Medical Centers, VU Medical Center, Amsterdam, the Netherlands
| | - Gerie Groot
- Department of Interventional Radiology, Amsterdam Medical Centers, VU Medical Center, Amsterdam, the Netherlands
| | - Bram B van der Meijs
- Department of Interventional Radiology, Amsterdam Medical Centers, VU Medical Center, Amsterdam, the Netherlands
| | - Willem Wisselink
- Department of Vascular Surgery, Amsterdam University Medical Centers, VU Medical Center, Amsterdam, the Netherlands
| | - Jan D Blankensteijn
- Department of Vascular Surgery, Amsterdam University Medical Centers, VU Medical Center, Amsterdam, the Netherlands
| | - Kak K Yeung
- Department of Vascular Surgery, Amsterdam University Medical Centers, VU Medical Center, Amsterdam, the Netherlands.,Department of Physiology, Amsterdam University Medical Centers, VU Medical Center, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| |
Collapse
|
14
|
Jayendiran R, Nour B, Ruimi A. Computational analysis of Nitinol stent-graft for endovascular aortic repair (EVAR) of abdominal aortic aneurysm (AAA): Crimping, sealing and fluid-structure interaction (FSI). Int J Cardiol 2020; 304:164-171. [PMID: 31791620 DOI: 10.1016/j.ijcard.2019.11.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/20/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVES We evaluate the crimping strain, sealing stress and contact forces on a Nitinol stent deployed in the aorta during endovascular aortic (or aneurysm) repair (EVAR) procedures. Nitinol shape memory effect (SME) is used. We also study the fluid-structure interaction (FSI) of the blood flow on the stented aorta. METHODS We employ Solidworks to generate a closed-cell honeycomb stent structure used to treat abdominal aortic aneurysm (AAA). We use the commercial Abaqus/Simulia finite element (FEM) simulation package to study the displacements and stresses experienced by the stent during the crimping phase and deployment into the aortic segment. The Nitinol stent is covered with Dacron, a popular graft material. We implement our own user-material (UMAT) subroutines to model the shape memory effect (SME) of Nitinol. The effect of the stent geometry is analyzed. We use the FSI analysis in Abaqus/Simulia to understand the effect of hemodynamic loading on the stent. RESULTS Results indicate that the crimping strain increases as the stent strut spacing increases. This is also the case for the radius of curvature. Maximum strains developed on the stent during crimping are in the order of 10%. Stresses exerted by the stent needed to completely seal the aorta are found to be below the yield stress values of Nitinol (700 MPa). Wall shear stresses (WSS) on the stented aorta are close to WSS obtained on the aorta alone. CONCLUSION Using Nitinol's thermo-reactivity property as opposed to its superelasticity causes the stent-graft to deploy more gently.
Collapse
Affiliation(s)
- Raja Jayendiran
- Mechanical Engineering Program, Texas A&M University at Qatar, Doha, Qatar.
| | - Bakr Nour
- Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Annie Ruimi
- Mechanical Engineering Program, Texas A&M University at Qatar, Doha, Qatar.
| |
Collapse
|
15
|
Hemmler A, Lin A, Thierfelder N, Franz T, Gee MW, Bezuidenhout D. Customized stent-grafts for endovascular aneurysm repair with challenging necks: A numerical proof of concept. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3316. [PMID: 32022404 DOI: 10.1002/cnm.3316] [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: 07/12/2019] [Revised: 12/05/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Endovascular aortic repair (EVAR) is a challenging intervention whose long-term success strongly depends on the appropriate stent-graft (SG) selection and sizing. Most off-the-shelf SGs are straight and cylindrical. Especially in challenging vessel morphologies, the morphology of off-the-shelf SGs is not able to meet the patient-specific demands. Advanced manufacturing technologies facilitate the development of highly customized SGs. Customized SGs that have the same morphology as the luminal vessel surface could considerably improve the quality of the EVAR outcome with reduced likelihoods of EVAR related complications such as endoleaks type I and SG migration. In this contribution, we use an in silico EVAR methodology that approximates the deployed state of the elastically deformable SG in a hyperelastic, anisotropic vessel. The in silico EVAR results of off-the-shelf SGs and customized SGs are compared qualitatively and quantitatively in terms of mechanical and geometrical parameters such as stent stresses, contact tractions, SG fixation forces and the SG-vessel attachment. In a numerical proof of concept, eight different vessel morphologies, such as a conical vessel, a barrel shaped vessel and a curved vessel, are used to demonstrate the added value of customized SGs compared to off-the-shelf SGs. The numerical investigation has shown large benefits of the highly customized SGs compared to off-the-shelf SGs with respect to a better SG-vessel attachment and a considerable increase in SG fixation forces of up to 50% which indicate decreased likelihoods of EVAR related complications. Hence, this numerical proof of concept motivates further research and development of highly customized SGs for the use in challenging vessel morphologies.
Collapse
Affiliation(s)
- André Hemmler
- Mechanics & High Performance Computing Group, Technische Universität München, Garching bei München, Germany
| | - Andrew Lin
- Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| | - Nikolaus Thierfelder
- Herzchirurgische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, München, Germany
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Observatory, South Africa
| | - Michael W Gee
- Mechanics & High Performance Computing Group, Technische Universität München, Garching bei München, Germany
| | - Deon Bezuidenhout
- Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| |
Collapse
|
16
|
Evaluation of a New Approach for Modeling Full Ring Stent Bundles with the Inclusion of Manufacturing Strains. Ann Biomed Eng 2019; 48:144-156. [PMID: 31317366 PMCID: PMC6927927 DOI: 10.1007/s10439-019-02322-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/11/2019] [Indexed: 11/12/2022]
Abstract
Ring stent bundles have been used in several biomedical stent-graft devices for decades, yet in the published literature, the numerical models of these structures always present significant simplifications. In this paper, a finite element (FE) ring stent bundle has been developed and evaluated with a combination of beam and surface elements. With this approach, the shape, the global stiffness and the strains of the structure can all be well predicted at a low computational cost while the approach is suitable for application to non-symmetrical, patient-specific implant simulations. The model has been validated against analytical and experimental data showing that the manufacturing strains can be predicted to a 0.1% accuracy and the structural stiffness with 0–7% precision. The model has also been compared with a more computationally expensive FE model of higher fidelity, revealing a discrepancy of 0–5% of the strain value. Finally, it has been shown that the exclusion of the manufacturing process from the simulation, a technique used in the literature, quadruples the analysis error. This is the first model that can capture the mechanical state of a full ring stent bundle, suitable for complex implant geometry simulations, with such accuracy.
Collapse
|
17
|
Predictive Numerical Simulations of Double Branch Stent-Graft Deployment in an Aortic Arch Aneurysm. Ann Biomed Eng 2019; 47:1051-1062. [PMID: 30706308 DOI: 10.1007/s10439-019-02215-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/18/2019] [Indexed: 01/04/2023]
Abstract
Total endovascular repair of the aortic arch represents a promising option for patients ineligible to open surgery. Custom-made design of stent-grafts (SG), such as the Terumo Aortic® RelayBranch device (DB), requires complex preoperative measures. Accurate SG deployment is required to avoid intraoperative or postoperative complications, which is extremely challenging in the aortic arch. In that context, our aim is to develop a computational tool able to predict SG deployment in such highly complex situations. A patient-specific case is performed with complete deployment of the DB and its bridging stents in an aneurysmal aortic arch. Deviations of our simulation predictions from actual stent positions are estimated based on post-operative scan and a sensitivity analysis is performed to assess the effects of material parameters. Results show a very good agreement between simulations and post-operative scan, with especially a torsion effect, which is successfully reproduced by our simulation. Relative diameter, transverse and longitudinal deviations are of 3.2 ± 4.0%, 2.6 ± 2.9 mm and 5.2 ± 3.5 mm respectively. Our numerical simulations show their ability to successfully predict the DB deployment in complex anatomy. The results emphasize the potential of computational simulations to assist practitioners in planning and performing complex and secure interventions.
Collapse
|
18
|
CHIANG CHENGHSIEN, HUNG TINKAN, YEH MINGLONG, CHEN WEILING, KAN CHUNGDANN. FIXATION STUDY OF SINGLE AND DOUBLE STENT GRAFTS FOR ENDOVASCULAR AORTIC REPAIR. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519418500549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Application of double-barreled cannon stent grafts aortic repair (DoBAR) was reported in 2011 for extremely large aortic aneurysms of patients when there was no proper size of grafts for the emergent treatment. Fixation characteristics of the double stent grafts are obtained in a laboratory setting, and are incorporated with those of single Zenith TX2 grafts of sizes from 34 to 42[Formula: see text]mm. Radial stress and shear increase linearly with the oversizing parameter but decrease with increasing stent diameter. The slope of the linear relationship is practically the same for this group of grafts. When the original circular stent grafts of diameter 36 and 38[Formula: see text]mm are deformed to form DoBAR of diameter 44 or 46.4[Formula: see text]mm, the formation could provide higher radial stress and shear to secure fixation for endo-aortic repair. The experimental results of single and DoBAR grafts can be incorporated for clinical application of DoBAR for emergent treatment.
Collapse
Affiliation(s)
- CHENG-HSIEN CHIANG
- Department of Biomedical Engineering, National Cheng Kung University, No. 1, Daxue Road, East District, Tainan City 701, Taiwan
| | - TIN-KAN HUNG
- Department of Bioengineering, University of Pittsburgh, 700 O’Hara Street, Pittsburgh, PA 15261, USA
| | - MING-LONG YEH
- Department of Biomedical Engineering, National Cheng Kung University, No. 1, Daxue Road, East District, Tainan City 701, Taiwan
| | - WEI-LING CHEN
- Department of Engineering and Maintenance, Kaohsiung Veterans General Hospital, No. 386, Dazhong 1st Road, Zuoying District, Kaohsiung City 81362, Taiwan
| | - CHUNG-DANN KAN
- Division of Cardiovascular Surgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No. 138 Sheng-Li Road, Tainan 704, Taiwan
| |
Collapse
|
19
|
Hemmler A, Lutz B, Reeps C, Kalender G, Gee MW. A methodology for in silico endovascular repair of abdominal aortic aneurysms. Biomech Model Mechanobiol 2018; 17:1139-1164. [PMID: 29752606 DOI: 10.1007/s10237-018-1020-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/23/2018] [Indexed: 11/29/2022]
Abstract
Endovascular aneurysm repair (EVAR) can involve some unfavorable complications such as endoleaks or stent-graft (SG) migration. Such complications, resulting from the complex mechanical interaction of vascular tissue, SG and blood flow or incompatibility of SG design and vessel geometry, are difficult to predict. Computational vascular mechanics models can be a predictive tool for the selection, sizing and placement process of SGs depending on the patient-specific vessel geometry and hence reduce the risk of potential complications after EVAR. In this contribution, we present a new in silico EVAR methodology to predict the final state of the deployed SG after intervention and evaluate the mechanical state of vessel and SG, such as contact forces and wall stresses. A novel method to account for residual strains and stresses in SGs, resulting from the precompression of stents during the assembly process of SGs, is presented. We suggest a parameter continuation approach to model various different sizes of SGs within one in silico EVAR simulation which can be a valuable tool when investigating the issue of SG oversizing. The applicability and robustness of the proposed methods are demonstrated on the example of a synthetic abdominal aortic aneurysm geometry.
Collapse
Affiliation(s)
- André Hemmler
- Mechanics and High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany
| | - Brigitta Lutz
- Klinik für Viszeral-, Thorax- und Gefäßchirurgie, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - Christian Reeps
- Klinik für Viszeral-, Thorax- und Gefäßchirurgie, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - Günay Kalender
- Klinik für vaskuläre und endovaskuläre Chirurgie, DRK Kliniken Berlin, Salvador-Allende-Straße 2-8, 12559, Berlin, Germany
| | - Michael W Gee
- Mechanics and High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany.
| |
Collapse
|
20
|
McGrath DJ, Thiebes AL, Cornelissen CG, O'Brien B, Jockenhoevel S, Bruzzi M, McHugh PE. Evaluating the interaction of a tracheobronchial stent in an ovine in-vivo model. Biomech Model Mechanobiol 2017; 17:499-516. [PMID: 29177931 DOI: 10.1007/s10237-017-0974-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 10/28/2017] [Indexed: 12/19/2022]
Abstract
Tracheobronchial stents are used to restore patency to stenosed airways. However, these devices are associated with many complications such as stent migration, granulation tissue formation, mucous plugging and stent strut fracture. Of these, granulation tissue formation is the complication that most frequently requires costly secondary interventions. In this study a biomechanical lung modelling framework recently developed by the authors to capture the lung in-vivo stress state under physiological loading is employed in conjunction with ovine pre-clinical stenting results and device experimental data to evaluate the effect of stent interaction on granulation tissue formation. Stenting is simulated using a validated model of a prototype covered laser-cut tracheobronchial stent in a semi-specific biomechanical lung model, and physiological loading is performed. Two computational methods are then used to predict possible granulation tissue formation: the standard method which utilises the increase in maximum principal stress change, and a newly proposed method which compares the change in contact pressure over a respiratory cycle. These computational predictions of granulation tissue formation are then compared to pre-clinical stenting observations after a 6-week implantation period. Experimental results of the pre-clinical stent implantation showed signs of granulation tissue formation both proximally and distally, with a greater proximal reaction. The standard method failed to show a correlation with the experimental results. However, the contact change method showed an apparent correlation with granulation tissue formation. These results suggest that this new method could be used as a tool to improve future device designs.
Collapse
Affiliation(s)
- Donnacha J McGrath
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland
| | - Anja Lena Thiebes
- Department of Biohybrid and Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, ITA-Institut für Textiltechnik, RWTH Aachen University and at AMIBM Maastricht University, Maastricht, The Netherlands, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Christian G Cornelissen
- Department of Biohybrid and Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, ITA-Institut für Textiltechnik, RWTH Aachen University and at AMIBM Maastricht University, Maastricht, The Netherlands, Pauwelsstr. 20, 52074, Aachen, Germany.,Department for Internal Medicine - Section for Pneumology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Barry O'Brien
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland
| | - Stefan Jockenhoevel
- Department of Biohybrid and Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, ITA-Institut für Textiltechnik, RWTH Aachen University and at AMIBM Maastricht University, Maastricht, The Netherlands, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Mark Bruzzi
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland
| | - Peter E McHugh
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland.
| |
Collapse
|
21
|
Understanding the requirements of self-expandable stents for heart valve replacement: Radial force, hoop force and equilibrium. J Mech Behav Biomed Mater 2017; 68:252-264. [PMID: 28219851 DOI: 10.1016/j.jmbbm.2017.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/03/2017] [Accepted: 02/05/2017] [Indexed: 11/22/2022]
Abstract
A proper interpretation of the forces developed during stent crimping and deployment is of paramount importance for a better understanding of the requirements for successful heart valve replacement. The present study combines experimental and computational methods to assess the performance of a nitinol stent for tissue-engineered heart valve implantation. To validate the stent model, the mechanical response to parallel plate compression and radial crimping was evaluated experimentally. Finite element simulations showed good agreement with the experimental findings. The computational models were further used to determine the hoop force on the stent and radial force on a rigid tool during crimping and self-expansion. In addition, stent deployment against ovine and human pulmonary arteries was simulated to determine the hoop force on the stent-artery system and the equilibrium diameter for different degrees of oversizing.
Collapse
|
22
|
Chen W, Clauser J, Thiebes AL, McGrath DJ, McHugh PE, Steinseifer U, Jockenhoevel S, Hennink WE, Kok RJ. Selection and fabrication of a non-woven polycarbonate urethane cover for a tissue engineered airway stent. Int J Pharm 2016; 514:255-262. [DOI: 10.1016/j.ijpharm.2016.06.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/17/2016] [Accepted: 06/18/2016] [Indexed: 11/16/2022]
|
23
|
McGrath D, O’Brien B, Bruzzi M, Kelly N, Clauser J, Steinseifer U, McHugh P. Evaluation of cover effects on bare stent mechanical response. J Mech Behav Biomed Mater 2016; 61:567-580. [DOI: 10.1016/j.jmbbm.2016.04.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/25/2016] [Accepted: 04/15/2016] [Indexed: 11/28/2022]
|
24
|
Perrin D, Badel P, Orgeas L, Geindreau C, du Roscoat SR, Albertini JN, Avril S. Patient-specific simulation of endovascular repair surgery with tortuous aneurysms requiring flexible stent-grafts. J Mech Behav Biomed Mater 2016; 63:86-99. [PMID: 27344232 DOI: 10.1016/j.jmbbm.2016.06.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 05/10/2016] [Accepted: 06/11/2016] [Indexed: 10/21/2022]
Abstract
The rate of post-operative complications is the main drawback of endovascular repair, a technique used to treat abdominal aortic aneurysms. Complex anatomies, featuring short aortic necks and high vessel tortuosity for instance, have been proved likely prone to these complications. In this context, practitioners could benefit, at the preoperative planning stage, from a tool able to predict the post-operative position of the stent-graft, to validate their stent-graft sizing and anticipate potential complications. In consequence, the aim of this work is to prove the ability of a numerical simulation methodology to reproduce accurately the shapes of stent-grafts, with a challenging design, deployed inside tortuous aortic aneurysms. Stent-graft module samples were scanned by X-ray microtomography and subjected to mechanical tests to generate finite-element models. Two EVAR clinical cases were numerically reproduced by simulating stent-graft models deployment inside the tortuous arterial model generated from patient pre-operative scan. In the same manner, an in vitro stent-graft deployment in a rigid polymer phantom, generated by extracting the arterial geometry from the preoperative scan of a patient, was simulated to assess the influence of biomechanical environment unknowns in the in vivo case. Results were validated by comparing stent positions on simulations and post-operative scans. In all cases, simulation predicted stents deployed locations and shapes with an accuracy of a few millimetres. The good results obtained in the in vitro case validated the ability of the methodology to simulate stent-graft deployment in very tortuous arteries and led to think proper modelling of biomechanical environment could reduce the few local discrepancies found in the in vivo case. In conclusion, this study proved that our methodology can achieve accurate simulation of stent-graft deployed shape even in tortuous patient specific aortic aneurysms and may be potentially helpful to help practitioners plan their intervention.
Collapse
Affiliation(s)
- David Perrin
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, SAINBIOSE, F-42023 Saint-Etienne, France; CNRS, 3SR Lab, F-38000 Grenoble, France; Univ. Grenoble Alpes, 3SR Lab, F-38000 Grenoble, France; INSERM U1059, SAINBIOSE, F-42023 Saint-Etienne, France; Université de Lyon, F-69000 Lyon, France
| | - Pierre Badel
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, SAINBIOSE, F-42023 Saint-Etienne, France; INSERM U1059, SAINBIOSE, F-42023 Saint-Etienne, France; Université de Lyon, F-69000 Lyon, France
| | - Laurent Orgeas
- CNRS, 3SR Lab, F-38000 Grenoble, France; Univ. Grenoble Alpes, 3SR Lab, F-38000 Grenoble, France
| | - Christian Geindreau
- CNRS, 3SR Lab, F-38000 Grenoble, France; Univ. Grenoble Alpes, 3SR Lab, F-38000 Grenoble, France
| | | | - Jean-Noël Albertini
- INSERM U1059, SAINBIOSE, F-42023 Saint-Etienne, France; Université de Lyon, F-69000 Lyon, France; CHU Hôpital Nord Saint-Etienne, Department of CardioVascular Surgery, Saint-Etienne F-42055, France
| | - Stéphane Avril
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, SAINBIOSE, F-42023 Saint-Etienne, France; INSERM U1059, SAINBIOSE, F-42023 Saint-Etienne, France; Université de Lyon, F-69000 Lyon, France.
| |
Collapse
|
25
|
Perrin D, Badel P, Orgéas L, Geindreau C, Dumenil A, Albertini JN, Avril S. Patient-specific numerical simulation of stent-graft deployment: Validation on three clinical cases. J Biomech 2015; 48:1868-75. [PMID: 25979382 DOI: 10.1016/j.jbiomech.2015.04.031] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/25/2015] [Accepted: 04/23/2015] [Indexed: 11/17/2022]
Abstract
Endovascular repair of abdominal aortic aneurysms faces some adverse outcomes, such as kinks or endoleaks related to incomplete stent apposition, which are difficult to predict and which restrain its use although it is less invasive than open surgery. Finite element simulations could help to predict and anticipate possible complications biomechanically induced, thus enhancing practitioners' stent-graft sizing and surgery planning, and giving indications on patient eligibility to endovascular repair. The purpose of this work is therefore to develop a new numerical methodology to predict stent-graft final deployed shapes after surgery. The simulation process was applied on three clinical cases, using preoperative scans to generate patient-specific vessel models. The marketed devices deployed during the surgery, consisting of a main body and one or more iliac limbs or extensions, were modeled and their deployment inside the corresponding patient aneurysm was simulated. The numerical results were compared to the actual deployed geometry of the stent-grafts after surgery that was extracted from postoperative scans. We observed relevant matching between simulated and actual deployed stent-graft geometries, especially for proximal and distal stents outside the aneurysm sac which are particularly important for practitioners. Stent locations along the vessel centerlines in the three simulations were always within a few millimeters to actual stents locations. This good agreement between numerical results and clinical cases makes finite element simulation very promising for preoperative planning of endovascular repair.
Collapse
Affiliation(s)
- David Perrin
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, CNRS: UMR5307, LGF, F-42023 Saint-Etienne, France; CNRS, 3SR Lab, F-38000 Grenoble, France; Université Grenoble Alpes, 3SR Lab, F-38000 Grenoble, France
| | - Pierre Badel
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, CNRS: UMR5307, LGF, F-42023 Saint-Etienne, France
| | - Laurent Orgéas
- CNRS, 3SR Lab, F-38000 Grenoble, France; Université Grenoble Alpes, 3SR Lab, F-38000 Grenoble, France
| | - Christian Geindreau
- CNRS, 3SR Lab, F-38000 Grenoble, France; Université Grenoble Alpes, 3SR Lab, F-38000 Grenoble, France
| | - Aurélien Dumenil
- INSERM, U1099, F-35000 Rennes, France; Université de Rennes 1, LTSI, F-35000 Rennes, France; Therenva, F-35000 Rennes, France
| | - Jean-Noël Albertini
- CHU Hôpital Nord Saint-Etienne, Department of CardioVascular Surgery, Saint-Etienne F-42055, France; Université Jean Monnet, GRT EA 3065, Saint-Etienne F-42023, France
| | - Stéphane Avril
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, CNRS: UMR5307, LGF, F-42023 Saint-Etienne, France.
| |
Collapse
|
26
|
Perrin D, Demanget N, Badel P, Avril S, Orgéas L, Geindreau C, Albertini JN. Deployment of stent grafts in curved aneurysmal arteries: toward a predictive numerical tool. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015; 31:e02698. [PMID: 25399927 DOI: 10.1002/cnm.2698] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 10/16/2014] [Accepted: 11/10/2014] [Indexed: 06/04/2023]
Abstract
The mechanical behavior of aortic stent grafts plays an important role in the success of endovascular surgery for aneurysms. In this study, finite element analysis was carried out to simulate the expansion of five marketed stent graft iliac limbs and to evaluate quantitatively their mechanical performances. The deployment was modeled in a simplified manner according to the following steps: (i) stent graft crimping and insertion in the delivery sheath, (ii) removal of the sheath and stent graft deployment in the aneurysm, and (iii) application of arterial pressure. In the most curved aneurysm and for some devices, a decrease of stent graft cross-sectional area up to 57% was found at the location of some kinks. Apposition defects onto the arterial wall were also clearly evidenced and quantified. Aneurysm inner curve presented significantly more apposition defects than outer curve. The feasibility of finite element analysis to simulate deployment of marketed stent grafts in curved aneurysm models was demonstrated. The study of the influence of aneurysm tortuosity on stent graft mechanical behavior shows that increasing vessel curvature leads to stent graft kinks and inadequate apposition against the arterial wall. Such simulation approach opens a very promising way toward surgical planning tools able to predict intra and/or post-operative short-term stent graft complications.
Collapse
Affiliation(s)
- David Perrin
- Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, CNRS:UMR5307, LGF, F-42023, Saint Etienne, France; CNRS, 3SR Lab, F-38000, Grenoble, France; Univ. Grenoble Alpes, 3SR Lab, F-38000, Grenoble, France
| | | | | | | | | | | | | |
Collapse
|
27
|
Altnji HE, Bou-Saïd B, Walter-Le Berre H. Morphological and stent design risk factors to prevent migration phenomena for a thoracic aneurysm: A numerical analysis. Med Eng Phys 2015; 37:23-33. [DOI: 10.1016/j.medengphy.2014.09.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 08/21/2014] [Accepted: 09/30/2014] [Indexed: 10/24/2022]
|
28
|
De Bock S, Iannaccone F, De Beule M, Vermassen F, Segers P, Verhegghe B. What if you stretch the IFU? A mechanical insight into stent graft Instructions For Use in angulated proximal aneurysm necks. Med Eng Phys 2014; 36:1567-76. [DOI: 10.1016/j.medengphy.2014.08.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 07/23/2014] [Accepted: 08/10/2014] [Indexed: 10/24/2022]
|