Prosthetic Valve Frame with Localized Stiffness via Longitudinal Compression
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Solution Overview
Problem
Conventional self-expanding nitinol frames for prosthetic heart valves often have insufficient flat plate stiffness, leading to either inadequate performance or chronic radial forces on surrounding tissues, which can cause issues like conduction system disturbances and the need for pacemaker implantation.
Innovation Solution
The design incorporates a support structure with distinct regions of varying transverse deformation resistance, where a second region with higher radial compressive resistance and flat plate stiffness is achieved through longitudinal compression, allowing for enhanced tissue reshaping and reduced chronic outward forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional self-expanding nitinol frames are used, then the device can be deployed into a calcified aortic annulus, but the flat plate stiffness is insufficient leading to inadequate performance
Solution Approach 1:
The support structure incorporates distinct regions with varying transverse deformation resistance. The second region has higher radial compressive resistance and flat plate stiffness compared to the first region, allowing different portions of the device to have optimized properties for different functional requirements.
Solution Approach 2:
The patent achieves varying transverse deformation resistance by changing the geometric parameters of frame elements, specifically the ratio of width to thickness in the radial and longitudinal directions. This allows control over the stiffness characteristics of different regions.
2Force
If conventional self-expanding nitinol frames are used, then the device can be deployed, but chronic radial forces are exerted on surrounding tissue causing conduction system disturbances
Solution Approach 1:
The support structure has non-uniform transverse deformation resistance with a second region providing higher radial compressive resistance. This localized stiffness enhancement reduces the overall chronic radial forces exerted on surrounding tissue while maintaining necessary structural support.
Solution Approach 2:
The device transitions from a compressed delivery configuration to a deployed configuration where the second region is longitudinally compressed to achieve the desired transverse deformation resistance, allowing dynamic adjustment of mechanical properties upon implantation.
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
This approach enhances the prosthetic valve's ability to maintain optimal leaflet kinematics and tissue reshaping, reducing the risk of complications associated with chronic radial forces and improving the valve's performance and durability.
Implementation Method 1
Self-expanding nitinol frames are often used as a support structure for replacement heart valves
Data Source
AI summary
Various examples address support structures (e.g., prosthetic valve support structures or frames) that incorporate a frame that, upon transitioning to a deployed configuration, include a proximal section has increased stiffness, or resistance to deformation in a transverse plane to a longitudinal axis of a device, including resistance to a change in shape, size, or both. Such an increase in transverse deformation resistance may be measured as an increase in radial compressive resistance or an increase in flat plate stiffness, for example, or both. Such increases in transverse deformation resistance may be realized through a reduction in length of the increased stiffness region of the support structure, such as through longitudinal compression of the region following an initial radial expansion of the region.