[Performance characteristics of self-expanding peripheral nitinol stents].
OBJECTIVE
To evaluate geometric-mechanical characteristics of self-expanding peripheral nitinol stents, such as alignment to the vessel wall, flexibility and radial force, in order to obtain information as to which stent is most appropriate depending on the characteristics of the arterial lesion.


METHODS
The in vitro tests were done on seven stent systems: Acculink, Zilverstent, Philon, Precise, Luminexx, SelfX and Sinus Super-Flex. All stents had a diameter of 8 mm and a length from 37 - 44 mm. The stents were evaluated for traceability and profile, radial force, flexibility and radiopacity. Stents were even evaluated for alignment to the vessel wall using a zigzag-shaped model and a model with a diameter step from 5 to 7 mm. Assessment considered the distance to the vessel wall and diameter reduction and in step-mode the smooth and harmonic transition.


RESULTS
At a stent diameter of 7 mm, radial forces between 1.09 (Sinus Super-Flex) and 2.59 N (Philon) were measured. The flexibility of the expanded stents ranged from 11.7 (Acculink) to 88.1 Nmm (2) (Luminexx). The Precise and Philon stents yielded the best alignment to the vessel wall, while the SelfX and Sinus Superflex stents had the highest reduction in diameter and the largest distance from the vessel wall in a tortuous vessel model. Differences in vessel diameter were best bridged by stents with short segments (Acculink, Precise). All stents were readily visible after expansion.


CONCLUSIONS
The alignment to the vessel wall mostly depends on the stent structure instead of radial force and flexibility. The presented results may be able to help physicians find the most suitable stent depending on the lesion characteristics.
Institut für diagnostische und interventionelle Radiologie/Neuroradiologie, Westküstenklinikum Heide, Akademisches Lehrkrankenhaus der Universitäten Kiel, Lübeck und Hamburg. cwissgott@gmx.de
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Wissgott
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Schmidt
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Behrens
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KP
Schmitz
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Andresen
D000497:Alloys; D001807:Blood Vessel Prosthesis; D019544:Equipment Failure Analysis; D011474:Prosthesis Design; D015607:Stents
D000497:Alloys; C013616:nitinol