Prosthetic Valve Anchoring in Soft Tissue
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Solution Overview
Problem
Current prosthetic heart valves, particularly balloon-expandable and self-expanding types, face challenges in securely anchoring and maintaining position within the heart valve annulus, especially in cases of aortic or mitral insufficiency where leaflets are soft or non-calcified, leading to potential displacement and further dilation of the annulus.
Innovation Solution
A medical device comprising a support structure, stent, and deflector is used to securely anchor a prosthetic valve within the heart valve, with the support structure engaging the native valve leaflets and the stent extending into the vessel, while the deflector abates blood flow and secures the device in place, utilizing a combination of self-expanding and balloon-expandable mechanisms to ensure a stable fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If self-expanding prosthetic valves are used to replace defective native valves, then the valve can be implanted without requiring calcified leaflets, but the continuous outward force exerted on the valve annulus causes further dilation and the valve may be quickly ejected from the delivery sheath
Solution Approach 1:
The patent employs a counterbalancing mechanism where a compression force is applied to oppose the outward expansion force of the self-expanding valve. This is achieved through a delivery system that maintains radial compression of the valve during implantation, preventing the valve from exerting excessive outward force on the annulus and causing dilation. The compression force acts as a counterweight to stabilize the annulus size while still allowing valve deployment.
Solution Approach 2:
The valve is pre-compressed and held in a compressed state within the delivery sheath before implantation. This preliminary compression prevents premature expansion and allows controlled deployment at the target site. The delivery system maintains this compressed state during navigation and positioning, ensuring the valve is ready for implantation without having already exerted expansion force on the annulus.
2Strength
If balloon-expandable valves are used to treat heart valve stenosis with calcified leaflets, then the catheter balloon can apply sufficient expanding force to anchor the frame to calcified tissue, but the leaflets are too soft to provide sufficient support when the aortic annulus is dilated
Solution Approach 1:
The patent divides the anchoring function into separate components: the valve frame provides one type of anchoring while a separate support structure (such as a stent or reinforcement element) provides additional anchoring in the dilated annulus. This segmentation allows each component to be optimized for its specific function - the valve frame for controlled expansion and the support structure for providing additional radial strength in soft, dilated tissue.
Solution Approach 2:
The patent utilizes composite construction combining different materials with complementary properties. The valve frame may be made of self-expanding material (such as shape memory alloy) while the support structure uses balloon-expandable material or alternative anchoring mechanisms. This composite approach allows the device to leverage both the adaptability of self-expanding materials and the controlled deployment and radial strength of balloon-expandable materials.
3Reliability
If a larger prosthetic valve size is used to treat aortic or mitral insufficiency, then the valve can address the insufficiency condition, but the delivery procedure becomes much more difficult
Solution Approach 1:
The patent employs a nested delivery system where the large prosthetic valve is contained within a delivery catheter that is itself contained within an outer delivery sheath. The valve is compressed to a small profile and nested within the delivery system, allowing it to be delivered through peripheral vessels despite its large final implanted size. The nested structure allows progressive deployment - first the inner components, then the outer valve - facilitating control during the delivery of large valves.
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 secure and stable anchoring system for prosthetic heart valves, preventing further annulus dilation and ensuring reliable blood flow, even in cases where native leaflets are soft or non-calcified, thereby improving the efficacy of valve replacement procedures.
Implementation Method 1
one or more of the native heart valve leaflets to be frictionally secured between the support structure and the expanded prosthetic heart valve
Implementation Method 2
The stent is configured to couple to the support structure and extend from the support structure into the vessel
Implementation Method 3
The deflector is configured to be supported by the stent and abate blood flow against the vessel
Implementation Method 4
The valve at the catheter tip is then expanded to its functional size at the site of the defective native valve
Implementation Method 5
such as by inflating a balloon on which the valve is mounted
Data Source
AI summary
A medical device configured for placement in a blood vessel, in which an elastic tube extends between first and second expandable anchoring stents. The elastic tube is constructed of a resilient material that deflects outward in response to increased blood pressure of a heart beat and that moves back inward as the blood pressure drops, thereby aiding the heart's pumping action.