Quantitative Mapping of Vascular Geometry for Implant Sites

Abstract

In vivo characterization of the complex dynamic forces and repetitive deformations experienced by pelvic and leg vasculature is important to improve the evaluation of safety and effectiveness of implantable interventional devices such as stents [1]. The goal of this study was to use image based geometric modeling and analytical techniques to characterize the vascular deformations that occur with pelvic-hind limb motion in swine.

Geometric changes in the ilio-femoral vessels were evaluated across a full range of motion in anesthetized swine. Computed tomography angiograms were obtained at each position and processed for model construction and geometric analysis of vascular segment length, curvature and twist.

Local geometric changes between positions were evaluated and compared for each arterial segment over the full length of the iliac-femoral-popliteal artery. The greatest changes in axial length, twist and curvature were observed in the femoral segments between positions of hip extension to flexion. The total change in iliac-femoral-popliteal artery axial length and twist between the positions were -5.4cm and 112°, respectively. Similarly, the maximum change in curvature along the artery was 0.46 cm^− 1.

Reported device failures in the ilio-femoral-popliteal vessels of human may be due in part to the wide range of physical forces and deformations imposed on these vessels during normal motion. Improved knowledge of the biomechanical behavior of the sites of vascular implants will make bench and preclinical testing more predictive for these devices, improving early evaluation of safety and effectiveness.