Expandable Implantable Frame for Secure Valve Seating in Enlarged Aortas
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Solution Overview
Problem
Transcatheter heart valves (THVs) are often too small to securely implant in larger native valves or deployment sites, such as enlarged aortas, and may lack a suitable seat for secure placement, leading to complications during transcatheter valve implantation.
Innovation Solution
A radially expandable and compressible stent frame with connecting posts that form a mesh structure, featuring a delivery device with a retainer mechanism for controlled deployment and recapture, allowing precise placement and adjustment of the frame within the vasculature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard-sized transcatheter heart valve is used, then the valve can be implanted in typical native valves, but the valve is too small to securely implant in enlarged aortas or larger native valves
Solution Approach 1:
The frame is divided into multiple expandable sections with varying diameters, allowing different portions of the frame to expand to different sizes. This segmentation enables the frame to adapt to enlarged aortas while maintaining secure anchoring in suitable anatomical regions.
Solution Approach 2:
The frame utilizes shape memory alloy material that can change its physical parameters (dimensions, shape) in response to temperature changes. The frame is deployed in a compressed state at body temperature and then expanded using external heating to restore its predetermined larger configuration, enabling adaptation to enlarged implantation sites.
2Area of stationary object
If the valve is expanded to a larger size to fit enlarged aortas, then the valve can cover the implantation site, but the valve may not have a good seat for secure placement
Solution Approach 1:
The frame includes multiple expandable sections with different final diameters, allowing the distal and proximal portions to expand to different sizes. This creates an tapered or stepped configuration that can simultaneously achieve broad coverage of enlarged aortas while maintaining intimate contact with suitable anatomical structures for secure seating.
Solution Approach 2:
The frame transitions from a compressed delivery state to an expanded functional state through controlled deformation. The dynamic expansion process allows the frame to conform to the implantation site geometry, optimizing both coverage and seating through the shape memory effect and radial expansion mechanics.
3Area of stationary object
If the frame is made larger to fit enlarged aortas, then the frame can cover the implantation site, but the delivery catheter size must be increased, making delivery more difficult
Solution Approach 1:
The large-diameter frame is nested within a delivery catheter in a compressed state. The frame is crimped or collapsed to a small diameter that fits within the delivery catheter lumen, allowing percutaneous delivery through the vasculature. Upon deployment, the frame expands to its full large diameter to cover enlarged aortas, achieving both compact delivery and large final size.
Solution Approach 2:
The frame undergoes dramatic parameter changes from a compressed delivery configuration to an expanded functional configuration. This transformation allows the frame to be delivered through small catheters while achieving large implantation size, resolving the contradiction between deliverability and final size requirements.
4Speed
If the frame is expanded rapidly to functional size, then deployment is quick, but the frame may jump or dislocate during expansion
Solution Approach 1:
The frame expansion is performed in a controlled, staged manner rather than as a single rapid action. The selective expansion mechanism allows different sections to expand sequentially or at different rates, providing periodic control over the expansion process. This staged expansion minimizes sudden force changes that could cause jumping while maintaining overall deployment efficiency.
Solution Approach 2:
The delivery catheter and retention mechanisms serve as intermediaries that control and mediate the frame expansion process. These intermediaries provide controlled radial forces during expansion, preventing uncontrolled jumping while enabling rapid deployment. The retention mechanism acts as a mediator that secures the frame during expansion and releases it upon completion.
5Strength
If the frame is made from rigid material to maintain structural integrity, then the frame provides strong support, but the frame is more susceptible to corrosion and material deformation
Solution Approach 1:
The frame utilizes shape memory alloy material that combines the strength of metals with unique functional properties. These composite-like materials provide both structural integrity for mechanical support and enhanced resistance to corrosion and deformation through their inherent material properties and phase transformation capabilities.
Solution Approach 2:
The frame material undergoes controlled parameter changes through phase transformation rather than permanent deformation. The shape memory effect allows the material to reversibly change shape in response to temperature changes, providing structural support while resisting permanent deformation and corrosion that would affect conventional rigid materials.
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
Enables secure and precise implantation of transcatheter valves in various anatomical sites by minimizing jumping and ensuring even pressure distribution, reducing the risk of corrosion and material deformation, and facilitating partial or full expansion as needed.
Implementation Method 1
The frame can be made from a shape memory alloy and can be transformed from a delivery configuration to a functional configuration as the result of applying a heating stimulus to the frame
Implementation Method 2
the valve can have a resilient, self-expanding stent or frame that expands the valve to its functional size when it is advanced from a delivery sheath
Data Source
Figure 1A~1B
Figure 2A~3C
Figure 4A~4D
AI summary
Embodiments of an implantable frame are disclosed. The frame can have a plurality of struts interconnected to each other to form a mesh structure that is radially expandable and compressible. The frame can have a connecting post extending from an end of the frame. The connecting post can have a body portion and a head portion affixed to an end of the body portion. The head portion can have a first edge extending outwardly of the body portion. The first edge can have a substantially flat portion that is substantially perpendicular to the body portion.