Polymeric Heart Valve Flexible Stent Leaflet Design
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Solution Overview
Problem
Existing prosthetic heart valves face durability issues, require life-long anticoagulation, and fail to meet durability and efficiency requirements, with bioprostheses needing frequent replacement and mechanical valves causing thrombosis.
Innovation Solution
A polymeric heart valve with a flexible stent and leaflets in a partially open position at rest, allowing for reduced forward flow pressure loss and improved durability, featuring flexible stent posts that flex inward to close leaflets without excessive stress, made from biocompatible materials like silicone and polyurethane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bioprosthetic valves are used, then biological compatibility is improved, but durability deteriorates requiring frequent replacement
Solution Approach 1:
The invention uses composite materials combining biocompatible polymers (such as silicone or polyurethane) for the valve body and leaflets with a supportive stent structure. This composite approach allows the valve to maintain biological compatibility while achieving enhanced durability through the reinforced polymer-stent composite construction, eliminating the need for frequent replacements associated with traditional bioprosthetics.
Solution Approach 2:
The invention changes the material parameters by using elastomeric polymers with specific mechanical properties (elasticity, tensile strength) that differ from traditional biological tissues. The polymer material is engineered to have optimized stress-strain characteristics that improve durability while maintaining biocompatibility, representing a parameter change from natural tissue to engineered polymer materials.
2Duration of action of stationary object
If mechanical valves are used, then durability is improved, but thrombosis risk increases requiring life-long anticoagulation
Solution Approach 1:
The invention changes the surface parameters of the valve by using biocompatible polymer materials with specific surface properties that are thromboresistant. The polymer surface characteristics (smoothness, chemical composition) are engineered to prevent blood clot formation, eliminating the thrombosis risk associated with mechanical valves while maintaining durability through the robust polymer construction.
Solution Approach 2:
The invention replaces the need for life-long anticoagulation therapy (a continuous harmful intervention) with a single implantation of a durable polymer valve that inherently resists thrombosis. The valve is designed as a permanent implant that eliminates the need for ongoing medical management, effectively replacing a long-term therapeutic regimen with a one-time surgical solution.
3Ease of manufacture
If polymeric valves with closed leaflet position are used, then manufacturing simplicity is improved, but forward flow pressure loss increases
Solution Approach 1:
The invention applies preliminary action by pre-positioning the polymer leaflets in a partially open configuration during manufacturing and implantation. This pre-positioning creates an initial gap between leaflets that reduces resistance to forward blood flow, lowering pressure loss while maintaining the manufacturing simplicity of forming leaflets in a fixed position. The leaflets are manufactured in a partially open state rather than requiring complex post-manufacturing adjustment mechanisms.
Solution Approach 2:
The invention changes the geometric parameter of the leaflet position from fully closed to partially open. This parameter change in the resting position creates a larger effective orifice area for forward flow, reducing pressure loss while maintaining the simplicity of the manufacturing process. The partial opening is achieved by controlling the attachment geometry rather than requiring complex mechanisms.
4Strength
If thicker leaflets are used, then strength is improved, but forward flow pressure loss increases
Solution Approach 1:
The invention changes the material parameter by using high-strength elastomeric polymers that provide sufficient mechanical strength at reduced thickness. The polymer material is engineered with optimized tensile strength and elasticity parameters that allow thinner leaflet construction compared to traditional materials, thereby reducing pressure loss while maintaining or improving strength characteristics.
Solution Approach 2:
The invention uses composite construction where the polymer leaflets are reinforced or supported by the stent structure, creating a composite system that provides the necessary strength without requiring thick leaflet material. The stent-polymer composite provides structural support that enables thinner leaflet design while maintaining mechanical integrity and strength requirements.
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 flexible stent and leaflet design enhances durability and efficiency by reducing forward flow pressure loss, minimizing leaflet tears, and preventing thrombosis, while allowing for thinner leaflets that improve performance and reliability.
Implementation Method 1
The flexibility of the stent allows the leaflets to properly close to block reverse blood flow without experiences excessive stress or strain
Implementation Method 2
WO 03/063750 and US 2003/114924 disclose methods of making valves where the leaflets are formed by dip-coating
Data Source
Figure 1
Figure 1A~1B
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AI summary
A polymeric heart valve is disclosed including: a valve body having a central axis having a body fluid pathway extending along the central axis from an inflow end to an outflow end; a flexible stent disposed about an outer circumference of the body and including at least three flexible stent posts each extending in the axial direction to a tip; and at least three flexible leaflets extending from the stent, each of the leaflets having an attached edge defining an attachment curve along the stent extending between a respective pair of stent posts.