3D CAD Based Conceptual Design of a Novel Aortic Valve Stent

Abstract

Vascular support structures are an important tool for treating valve stenosis. A large population of patients are treated for valvular disease and the principal mode of treatment is the use of percutaneous valvuloplasty. Stent devices are proving to be an improved treatment method; these devices now account for 20% of treatments in Europe. This new technology provides highly effective results at minimal cost and short duration of hospitalization. Accurate and reliable structural analysis provides essential information to the design team in an environment where in vivio experimentation is extremely expensive, or impossible. This paper describe the design of vascular support structure (stents), to provide designers with estimates of the critical parameters which are essential to restore the functions of the endothelium of the Aorta during and after implantation without injuring it. Stent geometries were uniquely defined using the following parameters. (a) Diameter of the aorta; (b) Distance between the aortic root and the coronary artery roots; (c) Position of the coronary arteries; (d) Diameter of the coronaries; (e) Stent–Endothelium Mechanics. Keeping these parameters into consideration a novel stent model was designed to suit its requirement for percutaneous replacement. The 3D geometry of the repeatable units of the stent was generated using SOLIDWORKS modeling software. Using the repeating unit geometry of each stent design, solid models were generated. The unit consisted of 8 lips with two non crossing struts making a circular diameter of 16 mm at the center and 18 mm at either ends. The upper and the lower portions of the prosthesis has a high radial force, the upper portion flared to fix the stent firmly in the ascending aorta and the lower portion to expand against the calcified leaflets and to avoid recoil. The middle portion which bears the valve is constrained and narrower to avoid obstruction of the coronary arteries. This varying diameter of different parts of the stent creates the blunt hooks at either end of the stent. The methodology described in this paper is proposed as a method to compare and analyze the existing stents and the ones proposed here. However, further analysis and studies are needed before these stents are fabricated and deployed. Animal experiments are being planned currently for this purpose.