Transcatheter Mitral Valve Fixation With Compliant Wire Frame
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Solution Overview
Problem
Challenges exist in anchoring collapsible prosthetic heart valves, particularly in the native mitral valve annulus, due to low profile requirements and reduced calcification, leading to potential paravalvular leakage and migration issues.
Innovation Solution
A prosthetic heart valve with a collapsible and expandable frame formed of compliant wires that forms an indentation at the engagement site with the native valve annulus, creating a sub-annular bulge for secure anchoring and preventing leakage, featuring a stent with expandable struts, pivot arms, and engagement arms that expand to anchor the valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a low profile prosthetic valve is used to avoid interfering with atrial function, then the valve can maintain a compact size, but the valve becomes difficult to securely anchor in place
Solution Approach 1:
The anchoring system is divided into multiple independent elements including hooks, engagement arms, and radial force elements that can be distributed around the valve annulus. This segmentation allows each element to contribute to anchoring stability without requiring a large overall valve profile, resolving the contradiction between compact size and secure anchoring.
Solution Approach 2:
The anchoring mechanisms are nested within or integrated with the valve frame structure itself. Hooks and engagement arms are positioned within the valve annulus or extend from the valve body, allowing the anchoring function to be embedded within the compact valve design rather than requiring external anchoring structures that would increase profile size.
2Reliability
If high radial force is applied to anchor the valve securely, then the valve anchoring stability improves, but the heart tissue may be damaged
Solution Approach 1:
The radial force application is localized to specific regions where hooks and engagement arms contact the valve annulus rather than distributing force across the entire valve circumference. This allows secure anchoring at discrete points while minimizing overall tissue stress and damage risk.
Solution Approach 2:
The design allows adjustment of radial force parameters through variable stiffness elements and configurable engagement arm positions. This enables optimization of the balance between anchoring stability and tissue protection by tuning the force application characteristics to match specific patient anatomy and tissue conditions.
3Object-affected harmful factors
If low radial force is applied to protect heart tissue, then tissue damage is minimized, but the valve may migrate from the native valve annulus
Solution Approach 1:
Hooks and engagement arms are pre-positioned to engage with the valve annulus before full valve deployment. This preliminary engagement establishes anchoring stability early in the deployment process, preventing valve migration before the full radial force is applied and ensuring the valve remains in the correct position throughout the procedure.
Solution Approach 2:
The anchoring system incorporates dynamic elements that can adapt their engagement characteristics during deployment. Engagement arms can transition from a compressed low-force state during delivery to an expanded high-force state upon deployment, providing progressive anchoring that prevents migration while protecting tissue from excessive force.
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 anchors the prosthetic heart valve within the native annulus, reducing paravalvular leakage and migration, while maintaining a low profile to avoid interference with atrial function.
Implementation Method 1
an expandable frame formed of compliant wires... whereby when the frame is expanded in the native valve annulus, the compliant wires form an indented region in the frame
Implementation Method 2
Self-expanding valves typically rely on the radial force exerted by expanding the stent against the native valve annulus to anchor the valve within the native valve annulus
Data Source
AI summary
A prosthetic heart valve includes stabilization features for anchoring the prosthetic heart valve within a native valve annulus. The prosthetic heart valve includes an expandable stent having an inflow end and an outflow end, and a valve assembly disposed within the stent. One such stabilization feature is a collapsible and an expandable frame formed of compliant wires. The frame has a body including a first end coupled to the stent, a second end, and a lumen extending therethrough for receiving the stent and the valve assembly. When the frame is expanded in the native valve annulus, the compliant wires form an indented region in the frame between the first and second ends of the body and a sub-annulus portion of the frame forms a bulge.