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Bernini M, Hellmuth R, O'Sullivan M, Dunlop C, McKenna CG, Lucchetti A, Gries T, Ronan W, Vaughan TJ. Shape-Setting of Self-Expanding Nickel-Titanium Laser-Cut and Wire-Braided Stents to Introduce a Helical Ridge. Cardiovasc Eng Technol 2024; 15:317-332. [PMID: 38315312 PMCID: PMC11239776 DOI: 10.1007/s13239-024-00717-2] [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: 10/12/2023] [Accepted: 01/02/2024] [Indexed: 02/07/2024]
Abstract
PURPOSE Altered hemodynamics caused by the presence of an endovascular device may undermine the success of peripheral stenting procedures. Flow-enhanced stent designs are under investigation to recover physiological blood flow patterns in the treated artery and reduce long-term complications. However, flow-enhanced designs require the development of customised manufacturing processes that consider the complex behaviour of Nickel-Titanium (Ni-Ti). While the manufacturing routes of traditional self-expanding Ni-Ti stents are well-established, the process to introduce alternative stent designs is rarely reported in the literature, with much of this information (especially related to shape-setting step) being commercially sensitive and not reaching the public domain, as yet. METHODS A reliable manufacturing method was developed and improved to induce a helical ridge onto laser-cut and wire-braided Nickel-Titanium self-expanding stents. The process consisted of fastening the stent into a custom-built fixture that provided the helical shape, which was followed by a shape-setting in air furnace and rapid quenching in cold water. The parameters employed for the shape-setting in air furnace were thoroughly explored, and their effects assessed in terms of the mechanical performance of the device, material transformation temperatures and surface finishing. RESULTS Both stents were successfully imparted with a helical ridge and the optimal heat treatment parameters combination was found. The settings of 500 °C/30 min provided mechanical properties comparable with the original design, and transformation temperatures suitable for stenting applications (Af = 23.5 °C). Microscopy analysis confirmed that the manufacturing process did not alter the surface finishing. Deliverability testing showed the helical device could be loaded onto a catheter delivery system and deployed with full recovery of the expanded helical configuration. CONCLUSION This demonstrates the feasibility of an additional heat treatment regime to allow for helical shape-setting of laser-cut and wire-braided devices that may be applied to further designs.
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Affiliation(s)
- Martina Bernini
- Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland
- Vascular Flow Technologies, Dundee, UK
| | - Rudolf Hellmuth
- Vascular Flow Technologies, Dundee, UK
- Division of Imaging and Science Technology, School of Medicine, Dundee, UK
- National Heart and Lung Institute, Imperial College London, London, UK
| | | | | | - Ciara G McKenna
- Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland
| | - Agnese Lucchetti
- Institut für Textiltechnik of RWTH, Aachen University, Aachen, Germany
| | - Thomas Gries
- Institut für Textiltechnik of RWTH, Aachen University, Aachen, Germany
| | - William Ronan
- Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland
| | - Ted J Vaughan
- Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland.
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Danielli F, Berti F, Fanni BM, Gasparotti E, Celi S, Pennati G, Petrini L. Left atrial appendage occlusion: On the need of a numerical model to simulate the implant procedure. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3814. [PMID: 38504482 DOI: 10.1002/cnm.3814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/23/2024] [Accepted: 03/10/2024] [Indexed: 03/21/2024]
Abstract
Left atrial appendage occlusion (LAAO) is a percutaneous procedure to prevent thromboembolism in patients affected by atrial fibrillation. Despite its demonstrated efficacy, the LAA morphological complexity hinders the procedure, resulting in postprocedural drawbacks (device-related thrombus and peri-device leakage). Local anatomical features may cause difficulties in the device's positioning and affect the effectiveness of the device's implant. The current work proposes a detailed FE model of the LAAO useful to investigate implant scenarios and derive clinical indications. A high-fidelity model of the Watchman FLX device and simplified parametric conduits mimicking the zone of the LAA where the device is deployed were developed. Device-conduit interactions were evaluated by looking at clinical indicators such as device-wall gap, possible cause of leakage, and device protrusion. As expected, the positioning of the crimped device before the deployment was found to significantly affect the implant outcomes: clinician's choices can be improved if FE models are used to optimize the pre-operative planning. Remarkably, also the wall mechanical stiffness plays an important role. However, this parameter value is unknown for a specific LAA, a crucial point that must be correctly defined for developing an accurate FE model. Finally, numerical simulations outlined how the device's configuration on which the clinician relies to assess the implant success (i.e., the deployed configuration with the device still attached to the catheter) may differ from the actual final device's configuration, relevant for achieving a safe intervention.
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Affiliation(s)
- Francesca Danielli
- LaBS - Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Francesca Berti
- LaBS - Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | | | | | - Simona Celi
- BioCardioLab, Fondazione Toscana G. Monasterio, Massa, Italy
| | - Giancarlo Pennati
- LaBS - Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Lorenza Petrini
- Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy
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Zhong Z, Gao Y, Kovács S, Vij V, Nelles D, Spano L, Nickenig G, Sonntag S, De Backer O, Søndergaard L, Sedaghat A, Mela P. Impact of left atrial appendage occlusion device position on potential determinants of device-related thrombus: a patient-specific in silico study. Clin Res Cardiol 2023:10.1007/s00392-023-02228-x. [PMID: 37291248 DOI: 10.1007/s00392-023-02228-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 05/08/2023] [Indexed: 06/10/2023]
Abstract
BACKGROUND Device-related thrombus (DRT) after left atrial appendage occlusion (LAAO) is potentially linked to adverse events. Although clinical reports suggest an effect of the device type and position on the DRT risk, in-depth studies of its mechanistic basis are needed. This in silico study aimed to assess the impact of the position of non-pacifier (Watchman) and pacifier (Amulet) LAAO devices on surrogate markers of DRT risk. METHODS The LAAO devices were modeled with precise geometry and virtually implanted in different positions into a patient-specific left atrium. Using computational fluid dynamics, the following values were quantified: residual blood, wall shear stress (WSS) and endothelial cell activation potential (ECAP). RESULTS In comparison to an ostium-fitted device position, deep implantation led to more residual blood, lower average WSS and higher ECAP surrounding the device, especially on the device's atrial surface and the surrounding tissue, suggesting increased risk for potential thrombus. For the non-pacifier device, an off-axis device orientation resulted in even more residual blood, higher ECAP and similar average WSS as compared to an ostium-fitted device position. Overall, the pacifier device showed less residual blood, higher average WSS and lower ECAP, compared to the non-pacifier device. CONCLUSIONS In this in silico study, both LAAO device type and implant position showed an impact on potential markers of DRT in terms of blood stasis, platelet adhesion and endothelial dysfunction. Our results present a mechanistic basis for clinically observed risk factors of DRT and the proposed in silico model may aid in the optimization of device development and procedural aspects.
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Affiliation(s)
- Zhaoyang Zhong
- Chair of Medical Materials and Implants, TUM School of Engineering and Design and Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Yiting Gao
- Chair of Medical Materials and Implants, TUM School of Engineering and Design and Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Soma Kovács
- Chair of Medical Materials and Implants, TUM School of Engineering and Design and Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Vivian Vij
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
| | - Dominik Nelles
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
| | - Lukas Spano
- Chair of Medical Materials and Implants, TUM School of Engineering and Design and Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Georg Nickenig
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
| | | | - Ole De Backer
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lars Søndergaard
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Alexander Sedaghat
- Department of Cardiology, University Hospital Bonn, Bonn, Germany.
- RheinAhrCardio, Praxis für Kardiologie, Bad Neuenahr-Ahrweiler, Germany.
| | - Petra Mela
- Chair of Medical Materials and Implants, TUM School of Engineering and Design and Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany.
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Uncertainty Quantification in the In Vivo Image-Based Estimation of Local Elastic Properties of Vascular Walls. J Cardiovasc Dev Dis 2023; 10:jcdd10030109. [PMID: 36975873 PMCID: PMC10058982 DOI: 10.3390/jcdd10030109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/15/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Introduction: Patient-specific computational models are a powerful tool for planning cardiovascular interventions. However, the in vivo patient-specific mechanical properties of vessels represent a major source of uncertainty. In this study, we investigated the effect of uncertainty in the elastic module (E) on a Fluid–Structure Interaction (FSI) model of a patient-specific aorta. Methods: The image-based χ-method was used to compute the initial E value of the vascular wall. The uncertainty quantification was carried out using the generalized Polynomial Chaos (gPC) expansion technique. The stochastic analysis was based on four deterministic simulations considering four quadrature points. A deviation of about ±20% on the estimation of the E value was assumed. Results: The influence of the uncertain E parameter was evaluated along the cardiac cycle on area and flow variations extracted from five cross-sections of the aortic FSI model. Results of stochastic analysis showed the impact of E in the ascending aorta while an insignificant effect was observed in the descending tract. Conclusions: This study demonstrated the importance of the image-based methodology for inferring E, highlighting the feasibility of retrieving useful additional data and enhancing the reliability of in silico models in clinical practice.
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Luraghi G, Bridio S, Rodriguez Matas JF, Dubini G, Boodt N, Gijsen FJH, van der Lugt A, Fereidoonnezhad B, Moerman KM, McGarry P, Konduri PR, Arrarte Terreros N, Marquering HA, Majoie CBLM, Migliavacca F. The first virtual patient-specific thrombectomy procedure. J Biomech 2021; 126:110622. [PMID: 34298290 DOI: 10.1016/j.jbiomech.2021.110622] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/11/2021] [Accepted: 07/05/2021] [Indexed: 12/24/2022]
Abstract
Treatment of acute ischemic stroke has been recently improved with the introduction of endovascular mechanical thrombectomy, a minimally invasive procedure able to remove a clot using aspiration devices and/or stent-retrievers. Despite the promising and encouraging results, improvements to the procedure and to the stent design are the focus of the recent efforts. Computational studies can pave the road to these improvements, providing their ability to describe and accurately reproduce a real procedure. A patient with ischemic stroke due to intracranial large vessel occlusion was selected and after the creation of the cerebral vasculature from computed tomography images and a histologic analysis to determine the clot composition, the entire thrombectomy procedure was virtually replicated. As in the real situation, the computational replica showed that two attempts were necessary to remove the clot, as a result of the position of the stent retriever with respect to the clot. Furthermore, the results indicated that clot fragmentation did not occur as the deformations were mainly in a compressive state without the possibility for clot cracks to propagate. The accurate representation of the procedure can be used as an important step for operative optimization planning and future improvements of stent designs.
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Affiliation(s)
- Giulia Luraghi
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Sara Bridio
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Jose Felix Rodriguez Matas
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Gabriele Dubini
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Nikki Boodt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Neurology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Frank J H Gijsen
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | | | - Kevin M Moerman
- School of Engineering, National University of Ireland Galway, Galway, Ireland
| | - Patrick McGarry
- School of Engineering, National University of Ireland Galway, Galway, Ireland
| | - Praneeta R Konduri
- Department of Biomedical Engineering and Physics, Amsterdam UMC, location AMC, Amsterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Amsterdam UMC, location AMC, Amsterdam, the Netherlands
| | - Nerea Arrarte Terreros
- Department of Biomedical Engineering and Physics, Amsterdam UMC, location AMC, Amsterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Amsterdam UMC, location AMC, Amsterdam, the Netherlands
| | - Henk A Marquering
- Department of Biomedical Engineering and Physics, Amsterdam UMC, location AMC, Amsterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Amsterdam UMC, location AMC, Amsterdam, the Netherlands
| | - Charles B L M Majoie
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, location AMC, Amsterdam, the Netherlands
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy.
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