An in vitro study of silk stent morphology.
BACKGROUND
Morphology of the Silk stent (Balt, Montmorency, France) after deployment is not fully understood, especially in tortuous vessels. An in vitro study was conducted to study morphology and flow-diverting parameters of this stent.


METHODS
Two sets of different-sized and curved polytetrafluoroethylene tubes were studied. To simulate the aneurysm neck, a small hole was created in a tube. A stent was placed in each of the different tubes. Angiographic computerized tomography and macroscopic photography were then obtained. The images were analyzed to calculate a Percentage of Area Coverage (PAC).


RESULTS
Good stent conformability was observed. The PAC was 21% in the straight model with matched stent and vessel diameter. In the straight model with an oversized stent, the PAC was increased. In the curved models, dynamic wire repositioning occurred. The repositioning was affected by the size of the stent and the angle of the vessel curve. Compared to the straight model, this increased the PAC in two instances: on the convexity (oversized stent), and on the concavity (matched stent and vessel diameter). The PAC did not significantly change at the sides of the curve.


CONCLUSIONS
By design, the wires of the silk stent move relative to each other. In a curved model, the PAC is different at the convexity, concavity, and lateral walls. The stent diameter affects the PAC. These results are clinically relevant because it is desirable to maximize and minimize the PAC across the aneurysm neck and branch vessel orifice, respectively.
Aurboonyawat
Thaweesak
T
Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, University of Paris 7 Bichat School of Medicine, Paris, France. aurboonyawat@gmail.com
Blanc
Raphaël
R
Schmidt
Paul
P
Piotin
Michel
M
Spelle
Laurent
L
Nakib
Amir
A
Moret
Jacques
J
D000783:Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy*; D006801:Humans; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods; D011138:Polytetrafluoroethylene; D011474:Prosthesis Design / Q000295:instrumentation* / Q000379:methods; D047011:Silk; D015607:Stents; D014057:Tomography, X-Ray Computed
D047011:Silk; D011138:Polytetrafluoroethylene