Flexible Stent-Graft with Movable Wire Stent
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Solution Overview
Problem
Traditional stent-grafts with textile layers have a high profile, limiting their flexibility and ability to accommodate longitudinal compression, which is essential for conforming to bodily structures, especially when the top and bottom layers are fully fused.
Innovation Solution
The development of a flexible stent-graft with polymeric, non-textile graft layers that allow the stent to move freely between or among the graft layers, creating open pockets for increased flexibility and reduced profile, achieved by selectively securing and unsecuring the graft portions to accommodate the stent's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If textile graft layers are used to ensure fluid tightness, then sealing performance is improved, but profile increases and flexibility deteriorates
Solution Approach 1:
The patent replaces traditional thick textile graft layers with thin polymeric film layers that provide fluid tightness while maintaining flexibility. The polymeric films are substantially non-porous and can be heat-sealed to create fluid-tight barriers without the bulk associated with woven textile structures, directly resolving the contradiction between sealing performance and profile thickness.
Solution Approach 2:
The patent employs composite construction by combining multiple thin polymeric film layers with the stent structure. This includes using different polymeric materials with complementary properties - some layers provide fluid tightness while others provide flexibility or radial strength. The composite approach allows achievement of fluid tightness without relying on thick single-layer textile constructions.
2Strength
If graft layers are fully fused together in cylindrical form, then structural integrity is improved, but longitudinal flexibility deteriorates
Solution Approach 1:
The patent divides the graft structure into multiple circumferential layers that are not fully fused together. The layers are separated by spacing elements or gaps, allowing them to move independently relative to each other during longitudinal compression. This segmentation maintains structural integrity through the cumulative effect of multiple layers while enabling the flexibility needed for anatomical adaptation.
Solution Approach 2:
The patent creates a dynamic graft structure where the polymeric layers can move relative to each other during deployment and in vivo. The layers transition from a compressed, closely-spaced configuration during delivery to an expanded, more mobile configuration after deployment, allowing the structure to adapt dynamically to longitudinal forces and anatomical variations.
3Strength
If stent is secured to graft layers through sutures, then attachment strength is improved, but flexibility and profile are worsened
Solution Approach 1:
The patent removes the suture attachment mechanism entirely from the stent-graft construction. Instead of using sutures to attach the graft to the stent, the invention uses integrated attachment methods where the polymeric graft layers are directly bonded or mechanically interlocked with the stent structure during manufacturing, eliminating the need for separate suture elements and their associated bulk.
Solution Approach 2:
The patent merges the attachment function into the manufacturing process itself. The graft layers and stent are attached through integrated processes such as heat sealing, adhesive bonding, or mechanical interlocking that occur during a single manufacturing step, rather than requiring separate attachment operations with sutures. This combining of functions reduces overall profile while maintaining attachment strength.
Data Source
AI summary
A flexible stent-graft has polymeric, non-textile graft layers with a stent disposed between or among the graft layers while allowing for movement of the stent between or among the layers. The stent includes an undulating wire stent disposed within pockets of non-secured graft portions between graft layers. The stent may be a ribbon stent having a ribbon or ribbons of graft layers.