Shape-Setting of Self-Expanding Nickel-Titanium Laser-Cut and Wire-Braided Stents to Introduce a Helical Ridge.

Autor: Bernini M; Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland.; Vascular Flow Technologies, Dundee, UK., Hellmuth R; 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., O'Sullivan M; Vascular Flow Technologies, Dundee, UK., Dunlop C; Vascular Flow Technologies, Dundee, UK., McKenna CG; Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland., Lucchetti A; Institut für Textiltechnik of RWTH, Aachen University, Aachen, Germany., Gries T; Institut für Textiltechnik of RWTH, Aachen University, Aachen, Germany., Ronan W; Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland., Vaughan TJ; Biomechanics Research Centre (BioMEC), School of Engineering and Informatics, University of Galway, Galway, Ireland. ted.vaughan@universityofgalway.ie.
Jazyk: angličtina
Zdroj: Cardiovascular engineering and technology [Cardiovasc Eng Technol] 2024 Jun; Vol. 15 (3), pp. 317-332. Date of Electronic Publication: 2024 Feb 05.
DOI: 10.1007/s13239-024-00717-2
Abstrakt: 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 (A f  = 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.
(© 2024. The Author(s).)
Databáze: MEDLINE
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