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Ann Biomed Eng. 2019 Aug;47(8):1738-1747. doi: 10.1007/s10439-019-02278-1. Epub 2019 May 1.

Comparison of Covered Laser-cut and Braided Respiratory Stents: From Bench to Pre-Clinical Testing.

Author information

1
Department of Biohybrid & Medical Textiles (BioTex), AME - Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Forckenbeckstr. 55, 52074, Aachen, Germany.
2
Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland.
3
Institute for Textile Engineering, RWTH Aachen University, Otto-Blumenthal-Str. 1, 52074, Aachen, Germany.
4
Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany.
5
Department of Biohybrid & Medical Textiles (BioTex), AME - Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Forckenbeckstr. 55, 52074, Aachen, Germany. jockenhoevel@ame.rwth-aachen.de.
6
Clinic for Pneumology and Internistic Intensive Medicine (Medical Clinic V), Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.

Abstract

Lung cancer patients often suffer from severe airway stenosis, the symptoms of which can be relieved by the implantation of stents. Different respiratory stents are commercially available, but the impact of their mechanical performance on tissue responses is not well understood. Two novel laser-cut and hand-braided nitinol stents, partially covered with polycarbonate urethane, were bench tested and implanted in Rhön sheep for 6 weeks. Bench testing highlighted differences in mechanical behavior: the laser-cut stent showed little foreshortening when crimped to a target diameter of 7.5 mm, whereas the braided stent elongated by more than 50%. Testing also revealed that the laser-cut stent generally exerted higher radial resistive and chronic outward forces than the braided stent, but the latter produced significantly higher radial resistive forces at diameters below 9 mm. No migration was observed for either stent type in vivo. In terms of granulation, most stents exerted a low to medium tissue response with only minimal formation of granulation tissue. We have developed a mechanical and in vivo framework to compare the behavior of different stent designs in a large animal model, providing data, which may be employed to improve current stent designs and to achieve better treatment options for lung cancer patients.

KEYWORDS:

Airway stenting; Animal trial; Nitinol stent; Sheep model; Stent development

PMID:
31044340
DOI:
10.1007/s10439-019-02278-1

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