Polymeric Stent Tip Deflection Reduction in Prosthetic Heart Valves
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Solution Overview
Problem
Conventional metallic stents used in prosthetic heart valves are prone to deformation during handling and implantation due to their plastic behavior, necessitating the development of stent designs that are less prone to deformation while maintaining reliability and durability.
Innovation Solution
A prosthetic heart valve with an annular stent made from polymeric material, specifically polyetheretherketone, having a thickness between 0.50 mm and 1.15 mm, and a unique geometry with a sewing cuff structure, fabric covering, and tissue layers to minimize deformation and ensure reliable production and implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic stents are used in prosthetic heart valves, then structural strength is provided, but deformation occurs during handling and implantation due to plastic behavior
Solution Approach 1:
The patent changes the material parameter from metal to polymer (specifically polyetheretherketone), fundamentally altering the mechanical behavior from plastic deformation to elastic deformation. This allows the stent to return to its original shape after compression and expansion cycles during handling and implantation, eliminating permanent deformation while maintaining structural strength.
Solution Approach 2:
The patent employs a composite structure combining polymeric stent material with fabric and tissue layers. The polymeric stent provides elastic deformation characteristics and structural framework, while the fabric and tissue layers provide additional strength and biological compatibility, creating a composite material system that resolves the contradiction between strength and deformation resistance.
2Stability of the object's composition
If polymeric material is used for stent, then deformation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent divides the stent into multiple functional segments: the polymeric stent framework, the fabric layer, and the tissue layers. Each segment can be manufactured separately using optimized processes (injection molding for polymer, weaving for fabric, processing for tissue) and then assembled, reducing overall manufacturing complexity while maintaining deformation resistance.
Solution Approach 2:
The fabric layer serves as an intermediary between the polymeric stent and the tissue layers, facilitating assembly and providing a stable interface for attachment. This intermediary component simplifies the manufacturing process by providing a stable platform for layer-by-layer construction while maintaining the deformation-resistant properties of the polymeric structure.
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 polymeric stent design reduces deformation during handling and implantation, maintains structural integrity, and allows for greater durability and flexibility, achieving tip deflection of less than 3 mm, comparable to conventional metallic stents, while providing improved mechanical properties and ease of production.
Implementation Method 1
the polymeric stent design reduces deformation during handling and implantation, maintains structural integrity, and allows for greater durability and flexibility, achieving tip deflection of less than 3 mm
Data Source
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AI summary
A prosthetic heart valve includes annularly spaced commissure portions, each of which includes a tip. The stent (100) is formed from a polymeric material, and is specifically configured to perform similarly to conventional metal stents. A first fabric (200) covers each of the tips, and a second fabric covers the first fabric and remaining exposed portions of the stent. A first layer (600) of tissue covers the second fabric, and a second layer of tissue (800) overlies the second fabric. The second layer of tissue includes leaflet portions that extend inwardly between annularly adjacent ones of the commissure portions.