Shape-Setting of Self-Expanding Nickel-Titanium Laser-Cut and Wire-Braided Stents to Introduce a Helical Ridge.
Cardiovasc Eng Technol
; 2024 Feb 05.
Article
in En
| MEDLINE
| ID: mdl-38315312
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.
Full text:
1
Database:
MEDLINE
Language:
En
Journal:
Cardiovasc Eng Technol
Year:
2024
Type:
Article
Affiliation country:
Ireland