Volume 6, Issue 9 (October 2009)

    In-Vitro Modeling of the Dynamic Forces in the Femoropopliteal Artery

    (Received 6 January 2009; accepted 1 July 2009)

    Published Online: 2009

    CODEN: JAIOAD

      Format Pages Price  
    PDF 7 $25   ADD TO CART


    Abstract

    The use of intravascular stents in the femoropopliteal artery (FPA) continues to be controversial due to the potential fractures in the dynamic environment. The purpose of this study was to (1) develop a representative in-vitro model that simulates physiological motion of the FPA during knee and hip flexion and (2) use the model to characterize the types and ranges of stent distortion produced by extremity movement. This model eliminates inconsistencies often observed in cadaveric models and clinical subjects due to individual anatomical differences, and allows testing with large sample sizes in a controlled environment for variable (tubing length, material, diameter, and thickness) modification. A comparative evaluation of axial mechanical property and elasticity was conducted between the tubing intended to simulate arteries and the ex-vivo porcine carotid arteries, favoring the selection of silicone tubing. The model was assessed for its unstented and stented arterial bending and axial compression under three physiological motions: straight leg, walking (knee/hip flexion 70°/20°), and sitting/stair climbing (knee/hip flexion 90°/90°). Self-expanding nitinol stents implanted in the simulated mid-superficial femoral artery and popliteal artery (PA) of the model exhibit axial compression of 4.5±0.3 % and 7±0.3 % (knee/hip flexion 70°/20°), and 8.4±0.7 % and 8±0.2 % (knee/hip flexion 90°/90°). Stents implanted in the simulated PA exhibit bending of 40° and 74° from knee/hip angle changes to 70°/20° and to 90°/90°, respectively. The model demonstrated stent bending and compression as previously observed in cadaver studies. Additional analysis of stent motion (torsion, localized bending, radial compression) may be evaluated with more advanced imaging techniques and additional model development. The data generated in these analyses could support appropriate modes and parameters for stent fatigue testing, and better understanding of vascular device performance in the dynamic FPA.


    Author Information:

    Nikanorov, Alexander
    MD, Abbott Vascular, Santa Clara, CA

    Mach, Albert J.
    Abbott Vascular, Santa Clara, CA

    Lenaway, Lisa
    Abbott Vascular, Santa Clara, CA

    Zhao, Hugh
    Abbott Vascular, Santa Clara, CA

    Schwartz, Lewis B.
    MD, Abbott Vascular, Santa Clara, CA


    Stock #: JAI102324

    ISSN: 1546-962X

    DOI: 10.1520/JAI102324

    ASTM International is a member of CrossRef.

    Author
    Title In-Vitro Modeling of the Dynamic Forces in the Femoropopliteal Artery
    Symposium Presented at the ASTM Second Symposium on Fatigue and Fracture of Medical Metallic Materials and Devices, 2008-05-07
    Committee E08