Artificial Heart Valve Leaflet Composite Design
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Solution Overview
Problem
Current artificial heart valves, particularly for young adults and children, face challenges such as limited durability, susceptibility to calcification, and the need for lifelong anticoagulation with mechanical valves, while bioprosthetic valves have short lifespans and require invasive surgery for replacement, lacking a suitable option for patients in developing nations.
Innovation Solution
An artificial heart valve design featuring a flexible leaflet connected to a support structure with straight lines of attachment, allowing movement between open and closed configurations, reducing bending stresses, and utilizing a lateral cross-section with convex and concave portions to mimic natural blood flow, enabling improved haemodynamic performance and durability without the need for anticoagulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bioprosthetic valves are used to avoid anticoagulation, then thrombo-embolic risk is reduced, but durability is limited due to calcification and degeneration
Solution Approach 1:
The valve combines a biostable polyurethane matrix with dispersed elastomeric particles to create a composite material that achieves both flexibility and durability. The elastomeric particles dispersed throughout the polyurethane matrix provide enhanced elastic recovery and stress distribution, preventing the calcification and degeneration that limit bioprosthetic valve lifespan while maintaining the blood-compatible surface that reduces thrombo-embolic risk
Solution Approach 2:
The invention changes the material parameters by selecting polyurethanes with specific durometer ranges (40-80 Shore A) and controlling the size and distribution of elastomeric particles (0.1-10 micrometers). These parameter optimizations enable the material to withstand cyclic bending stresses for extended periods while maintaining flexibility and blood compatibility, thereby extending valve lifespan without increasing thrombotic risk
2Duration of action of stationary object
If synthetic polyurethane is used to replace biological material, then durability is improved, but stiffness increases making the valve too rigid for satisfactory function
Solution Approach 1:
The composite structure of biostable polyurethane with dispersed elastomeric particles creates a material that exhibits both the durability of synthetic polymers and the flexibility needed for proper valve function. The elastomeric particles act as micro-spring elements that enhance the overall flexibility and elastic recovery of the leaflet material, allowing it to open and close readily while maintaining structural integrity and durability
Solution Approach 2:
The invention applies local quality by creating regions of different material properties within the leaflet structure. The dispersed elastomeric particles create localized flexible zones throughout the polyurethane matrix, allowing the leaflet to bend and deform appropriately during operation while maintaining overall structural strength and durability. This local variation in material properties enables both flexibility and durability to coexist
3Reliability
If reinforcement such as carbon nanotubes or fibres is added to polyurethane, then biostability is enhanced, but stiffness increases preventing satisfactory haemodynamic function
Solution Approach 1:
The invention uses a composite approach where elastomeric particles are dispersed in the polyurethane matrix without adding traditional rigid reinforcements like carbon nanotubes or fibres. This composite structure provides biostability through the inherent properties of the polyurethane-elastomer combination while maintaining flexibility because the elastomeric particles are soft and compliant, unlike rigid fibrous reinforcements. The composite achieves enhanced reliability without sacrificing the leaflet flexibility required for satisfactory haemodynamic function
Data Source
Figure 1(a)~1(e)
Figure 2(a)~2(c)
Figure 3(a)~3(e)
AI summary
An artificial heart valve comprises a support structure which defines an aperture for blood flow and a through hole. The artificial heart valve further comprises a leaflet material integrally formed around the support structure so as to define a flexible leaflet. The leaflet material extends through the through hole and around a portion of the support structure. Such an arrangement may serve to anchor the leaflet robustly to the support structure.