Stent Valve Seal with Swellable Envelope for Leakage Control
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Solution Overview
Problem
Existing stent-valves, particularly cardiac stent-valves, face challenges in implementing a reliable seal that addresses issues such as manufacturability, shelf-life in toxic solutions, crimpability, hydrogel containment, ease of preparation and use, reliable deployment, and reducing the risk of seal malfunction without compromising recaptuability/resheathability.
Innovation Solution
A prosthesis comprising a stent and a seal with a hollow seal envelope that extends circumferentially around the stent, featuring a toroid configuration and made of flexible, compliant material to adapt to irregular anatomical contours. The seal includes swellable material that swells in response to blood contact, and diffusion barrier wall portions to prevent liquid penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is implemented in a stent-valve to prevent para-prosthesis leakage, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The seal is nested within the stent-valve structure, with the seal envelope integrated into the stent framework. The swellable material is contained within the envelope, creating a nested configuration that provides sealing functionality without adding external components, thereby improving reliability while controlling complexity.
Solution Approach 2:
The seal utilizes the body's own blood to activate the swellable material, which automatically expands to seal against para-prosthesis leakage. This self-activating mechanism eliminates the need for external activation systems or complex control mechanisms, improving sealing reliability while maintaining device simplicity.
2Adaptability or versatility
If swellable material is used in the seal to adapt to irregular anatomy, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The seal employs swellable material that changes its physical parameters (volume and shape) in response to blood contact. This parameter change allows the seal to adapt to irregular anatomical contours without requiring precise manufacturing to match each unique anatomy, as the material self-adjusts post-implantation.
Solution Approach 2:
The seal combines flexible envelope material with swellable hydrogel material to create a composite structure. The envelope provides structural integrity and contains the swellable material, while the hydrogel provides adaptability. This composite approach balances manufacturing feasibility with anatomical adaptability.
3Reliability
If a hollow seal envelope with toroid configuration is used to contain hydrogel, then seal effectiveness is improved, but ease of manufacture decreases
Solution Approach 1:
The seal envelope is constructed from flexible, thin-walled material that can be formed into a toroid configuration. This flexible shell contains the hydrogel while allowing the seal to conform to anatomical irregularities. The thin-film construction facilitates manufacturing through conventional forming processes while maintaining seal effectiveness.
4Reliability
If diffusion barrier wall portions are added to prevent liquid penetration, then reliability is improved, but device complexity increases
Solution Approach 1:
The seal envelope is divided into multiple wall portions, with diffusion barrier layers integrated into specific sections. This segmentation allows the barrier functionality to be concentrated where most needed (at potential leakage points) rather than requiring barriers throughout the entire envelope, improving reliability while controlling complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a reliable and effective seal for stent-valves, enhancing manufacturability, shelf-life, and deployment while reducing the risk of seal malfunction and maintaining recaptuability/resheathability.
Implementation Method 1
The seal may comprise swellable material that swells in response to contact with blood (or a blood component)
Data Source
AI summary
Various embodiments of a seal for a stent-valve, and methods of production, are described. In some embodiments, the seal or a skirt comprises a fabric wall portion and a polymeric material fused to the fabric wall portion, the polymeric material having a melting temperature that is lower than that of the fabric wall portion. The fibres of the fabric may remain unmelted at the interface with the polymeric material, the polymeric material being attached to material to the fibres of the fabric wall portion by fusion. The polymeric material may provide a welded joint to another fabric wall portion and/or may reinforce the fabric and/or may occlude pores of the fabric.