Stent Grafts from Polymeric Material: A Novel Design to Improve the Implant Durability

Stent grafts have become a solution of choice to treat aneurysm diseases over the last 2 decades. As these devices are implanted in a mini-invasive way, the patients comfort related to the procedure is largely improved compared to open heart surgery. The long experience acquired in the clinic shows that a large range of thoracic as well as abdominal pathologies can be treated with a large range of devices varying in diameter and design. However, stent grafts being composed of a polymeric textile membrane and metallic stent segments, their durability depends largely on the interactions that occur between these 2 materials. Metallic segments are very abrasive and tend to degrade the textile cover through apex indentation or relative friction, when the stent graft undergoes cyclic loading. This work investigates a strategy to replace the metallic stent segments with less abrasive polymeric segments obtained from monofilament material. An additional goal is to integrate the polymeric stent segments directly into the textile membrane using the embroidery technique for secure assembling purpose. Limited relative movement between the composing elements is expected to improve the lifetime of the device. However, the mechanical properties of the embroidered assembly must match the deformability and elasticity required by the aneurysm treatment application. This was tested in the frame of this study.