Non-Convex Stent Radial Profile Reduction
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Solution Overview
Problem
Existing stents have a relatively large radial diameter, making it difficult to deliver them through small diameter lumens and increasing the risk to patients during percutaneous heart valve replacement and repair procedures.
Innovation Solution
An expandable stent that collapses into a non-convex shape and expands into a convex shape, utilizing materials like superelastic Nitinol or shape memory alloys to minimize its radial profile, allowing it to transform from a collapsed non-convex state to an expanded convex state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the stent is designed with a conventional convex collapsed shape, then the structural integrity is maintained, but the radial diameter remains relatively large making delivery through small lumens difficult
Solution Approach 1:
The patent transforms the stent from a conventional convex collapsed shape to a non-convex collapsed shape, utilizing dimensional reconfiguration to reduce the radial profile. The non-convex geometry allows the stent to collapse into a more compact form with reduced radial diameter while maintaining structural integrity through specific hinge configurations and strut arrangements.
2Length of moving object
If the stent is collapsed into a smaller radial diameter, then deliverability through small lumens is improved, but the expansion capability may be compromised
Solution Approach 1:
The patent employs dynamic hinge mechanisms that allow the stent to transition between collapsed and expanded states. The hinges are designed to flex and rotate, enabling the stent to expand fully at the deployment site while maintaining a compact collapsed form for delivery. This dynamic structure ensures both reduced deliverability profile and adequate expansion capability.
Solution Approach 2:
The patent utilizes shape memory alloys or superelastic materials that change their mechanical properties based on temperature or stress conditions. These materials allow the stent to maintain a compact collapsed shape during delivery, then transform to its expanded configuration at the target site through controlled parameter changes such as temperature increase or radial force application.
3Ease of manufacture
If the stent uses conventional materials, then manufacturing is straightforward, but the ability to achieve minimal radial profile in collapsed state is limited
Solution Approach 1:
The patent employs composite structures combining rigid struts with flexible hinge regions, or integrates shape memory alloys with conventional metallic structures. This composite approach allows the stent to achieve minimal radial profile in the collapsed state while maintaining manufacturability through established fabrication techniques for composite metallic structures.
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 stent achieves a significantly reduced radial diameter in its collapsed state, facilitating easier delivery and deployment while maintaining the necessary expanded shape for functionality, thereby enhancing procedural efficacy and minimizing patient risk.
Implementation Method 1
utilizing materials like superelastic Nitinol or shape memory alloys to minimize its radial profile, allowing it to transform from a collapsed non-convex state to an expanded convex state
Implementation Method 2
utilizing materials like superelastic Nitinol or shape memory alloys to minimize its radial profile, allowing it to transform from a collapsed non-convex state to an expanded convex state
Data Source
AI summary
An expandable stent that can transform between a collapsed state and an expanded state is described. The stent includes a first cross-sectional shape and a second cross-sectional shape. The first cross-sectional shape is a non-convex shape when the stent is in the collapsed state. Alternatively, the second cross-sectional shape is a convex shape when the stent is in an expanded state. The stent can be formed of super elastic Nitinol, which allows it to be shape set in the desired shape. Due to its shape setting properties and the non-convex cross-section, the stent is capable of dramatically reducing its cross-sectional radial profile which is beneficial in a variety of procedures.