Nested Seal Support for Transcatheter Stent-Valve Leakage
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Solution Overview
Problem
Existing transcatheter stent-valves face challenges in preventing para-valve leakage due to irregular native anatomy and calcification, which can hinder full deployment and create gaps for blood leakage, and current solutions like external skirts add bulk and hinder compressibility.
Innovation Solution
A stent-valve design incorporating a flexible and/or compliant seal supported by a collapsible seal support that deploys radially outwardly to fill gaps between the stent-valve and the surrounding anatomy, allowing for self-deployment or expansion to ensure a sealing fit without increasing the stent-valve's bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external skirt or cover is incorporated to prevent para-valve leakage, then sealing effectiveness is improved, but the bulk of the stent-valve increases and compressibility deteriorates
Solution Approach 1:
The seal support is nested within the stent structure during compression, allowing the seal to be contained within the stent's internal volume. This nesting approach enables the seal to provide effective sealing without adding external bulk that would compromise compressibility for delivery catheter passage.
Solution Approach 2:
The seal support is designed to be collapsible and deployable, transitioning from a compressed state during delivery to an expanded state at the implantation site. This dynamic structure allows the seal to achieve effective sealing only when needed, while maintaining a compact form factor during delivery.
2Reliability
If the skirt material is made thicker to occlude gaps and effect a seal, then sealing effectiveness is improved, but compressibility and deliverability deteriorate
Solution Approach 1:
The thicker seal material is nested within the stent's internal cavity rather than adding external thickness. This allows sufficient material volume for effective sealing while maintaining a compact external diameter that can be compressed for delivery catheter passage.
Solution Approach 2:
The seal support structure enables the seal material to be compressed to a thin profile during delivery, then expand to a thicker configuration at the implantation site. This dynamic thickness adjustment allows the seal to provide effective sealing without compromising deliverability.
3Reliability
If a rigid seal structure is used to ensure sealing fit, then sealing effectiveness is improved, but adaptability to irregular anatomy deteriorates
Solution Approach 1:
The seal support is constructed from flexible materials that can deform and conform to irregular anatomical surfaces. This flexibility enables the seal to adapt to varying native anatomy while maintaining contact and sealing effectiveness across non-uniform surfaces.
Solution Approach 2:
The seal support's mechanical properties are designed to change under compression and deployment forces, transitioning from a rigid state during delivery to a flexible state at the implantation site. This parameter change enables the seal to conform to irregular anatomy while maintaining sealing fit.
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 effectively mitigates para-valve leakage by providing a flexible seal that conforms to irregular anatomy and deploys to fill gaps, ensuring a secure fit without compromising the stent-valve's compressibility for delivery.
Implementation Method 1
a seal support that deploys radially outwardly to fill gaps between the stent-valve and the surrounding anatomy
Implementation Method 2
The seal support may be of shape memory material, for example, nitinol
Data Source
AI summary
Some embodiments of the present disclosure provide a stent-valve for transcatheter implantation to replace a cardiac valve. In some embodiments, the stent valve being compressible to a compressed state for delivery, and expandable to an operative state for implantation. In some embodiments, the stent-valve comprises a stent, a plurality of leaflets for defining a prosthetic valve, an inner skirt, an outer skirt, and a paravalve seal for sealing against surrounding tissue. In some embodiments, the paravalve seal comprising material that swells in response to contact with blood or components thereof.