Stent Leaflet Attachment via Cusp-Embedded Dip Molding
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Solution Overview
Problem
Current implantable prosthetic valves face challenges in securing synthetic polymeric leaflets to the stent, leading to potential detachment under cyclic stress from blood pressure, which affects the longevity and reliability of the valve.
Innovation Solution
A stent design with a leaflet support section featuring elongated members with cusps and recesses, where the leaflets are secured using openings in the members, and a dip-molding process to form leaflets that adhere to the stent, distributing stress and enhancing attachment security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If synthetic polymeric leaflets are attached to the stent using conventional methods, then the valve can be manufactured with durable materials, but the leaflets may detach under cyclic stress from blood pressure
Solution Approach 1:
The stent is divided into distinct functional sections: a proximal section with elongated members and a leaflet support section with members featuring cusps and recesses. This segmentation allows different portions of the stent to perform specialized functions, with the leaflet support section specifically designed to securely attach leaflets while distributing cyclic stresses away from attachment points
Solution Approach 2:
The leaflet support section features members with cusps and recesses that create localized geometric features for securing leaflets. These local structural variations provide enhanced attachment geometry at critical locations while maintaining overall stent flexibility and radial expandability
2Ease of operation
If the stent is designed with a mesh-like structure for radial expansion, then the valve can be implanted via catheterization, but the attachment between leaflets and stent becomes less secure under cyclic loading
Solution Approach 1:
The stent is divided into distinct functional sections: a proximal section with elongated members and a leaflet support section with members featuring cusps and recesses. This segmentation allows different portions of the stent to perform specialized functions, with the leaflet support section specifically designed to securely attach leaflets while distributing cyclic stresses away from attachment points
Solution Approach 2:
The leaflet support members incorporate cusps and recesses that create three-dimensional geometric features for leaflet attachment. These dimensional features provide mechanical interlocking and stress distribution in multiple directions, enhancing attachment security while maintaining the overall radial expandability of the mesh structure
3Strength
If the leaflet support members have larger mean perimeters, then the attachment area increases and stress distribution improves, but the device complexity increases
Solution Approach 1:
The stent is divided into distinct functional sections: a proximal section with elongated members and a leaflet support section with members featuring cusps and recesses. This segmentation allows different portions of the stent to perform specialized functions, with the leaflet support section specifically designed to securely attach leaflets while distributing cyclic stresses away from attachment points
Solution Approach 2:
The leaflet support members with cusps and recesses serve multiple functions: they provide attachment geometry for leaflets, distribute cyclic stresses, and maintain radial expandability. This multi-functionality achieves improved stress distribution without proportionally increasing device complexity
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 design provides a secure and durable attachment between the leaflets and the stent, capable of withstanding significant cyclic stress, thereby improving the longevity and reliability of the prosthetic valve.
Implementation Method 1
depositing a flowable composition on the mandrel and the stent so that the composition forms layers on the leaflet-forming surfaces spanning between the members of the stent, contacts the members of the stent, and penetrates into the openings of the members
Implementation Method 2
the composition forms layers on the leaflet-forming surfaces spanning between the members of the stent, contacts the members of the stent, and penetrates into the openings of the members
Data Source
AI summary
A collapsible stent for an implantable prosthetic valve incorporates leaflet-supporting members having relatively large surface area in comparison to other members defining the remainder of the stent. The leaflet-supporting members may have openings extending through them. The valve leaflets may be attached to the stent so that an attached edge of each leaflet extends along the leaflet-supporting members and is attached to the members by polymer integral with the leaflet overlying the leaflet supporting members and extending into the openings of the leaflet supporting members. The secure attachment resists stress on the leaflets.