Leaflet Abrasion Mitigation in Prosthetic Heart Valves
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Solution Overview
Problem
Collapsible prosthetic heart valves face issues with leaflet abrasion due to high strain and stress, particularly where they attach to the stent, leading to potential wear and tear, which can be exacerbated by the valve's operation and contact with anatomical features like calcium nodules.
Innovation Solution
Incorporating deflective features such as swatches and cuff flaps that add bulk and stiffness to the leaflets and cuff, respectively, to limit deflection and prevent abrasion by spacing the leaflets away from the stent and other structures during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the valve leaflets are made thin and flexible to enable collapsibility for minimally invasive delivery, then the ease of delivery is improved, but the leaflets become more susceptible to abrasion and wear during operation
Solution Approach 1:
The leaflet structure is divided into multiple layers including a thin flexible base layer for collapsibility and additional reinforcement layers or coatings applied to critical areas. This segmentation allows different regions of the leaflet to have different thickness and mechanical properties, maintaining flexibility for delivery while providing abrasion resistance during operation.
Solution Approach 2:
The valve leaflets are constructed using composite materials that combine a thin flexible substrate with reinforcement materials or coatings. This composite structure enables the leaflet to be sufficiently thin for collapsible delivery while incorporating materials with high abrasion resistance to withstand operational stresses and contact with anatomical features.
2Reliability
If the leaflets are reinforced to prevent abrasion, then the durability is improved, but the valve structure becomes more complex and larger in size
Solution Approach 1:
Reinforcement is applied selectively to specific high-wear areas of the leaflets such as the free edges and regions adjacent to the stent attachment, rather than uniformly across the entire leaflet structure. This localized reinforcement approach enhances durability in critical areas while minimizing the addition of structural complexity and maintaining overall valve compactness.
3Reliability
If the leaflets are reinforced to prevent abrasion, then the durability is improved, but the valve size increases affecting deliverability
Solution Approach 1:
Reinforcement materials or coatings are applied only to specific high-wear regions of the leaflets rather than the entire surface. This localized approach provides necessary abrasion resistance to extend durability while minimizing the overall volume increase, allowing the valve to maintain its collapsible design for minimally invasive delivery.
Solution Approach 2:
The reinforcement strategy is segmented into discrete applications at critical locations such as free edges and attachment regions, rather than uniform reinforcement. This segmentation allows the valve to achieve improved durability through targeted reinforcement without significantly increasing the overall valve size, preserving its ability to be compressed for delivery through small access vessels.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
A prosthetic heart valve (700) includes a stent (702) extending in a longitudinal direction and having a plurality of commissure features (714a, 714b, 714c). A valve assembly is secured to the stent, the valve assembly including a cuff (706) and a plurality of leaflets. Each of the leaflets has a pair of attachment regions and a free edge extending between the attachment regions. A deflection feature (720a, 720b, 720c, 720d) disposed in each attachment region is configured and arranged to prevent the free edges of the leaflets from contacting at least one of the stent or the cuff.