Asymmetric Prosthetic Valve Leaflet Stiffness Gradient
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Solution Overview
Problem
Bioprosthetic valves prone to calcification and cusp tears, and synthetic leaflet valves suffer from premature failure due to suboptimal design and lack of durable materials, leading to issues with controlled leaflet movement, increased closing volume, and blood pooling.
Innovation Solution
A flexible leaflet prosthetic valve design with asymmetric movement and regions of increased stiffness to control leaflet opening and closing, reducing stress zones and blood pooling, and enhancing blood flow by creating spiral and axial vortex flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If very flexible leaflet material is used to improve valve durability and mimic native valve function, then the valve can provide excellent hemodynamic performance, but the leaflets do not open and close in a controlled manner leading to increased closing volume and potential blood pooling
Solution Approach 1:
The patent applies local quality by creating regions of different stiffness within the leaflet structure. Specifically, the leaflet includes a first region with higher stiffness and a second region with lower stiffness, allowing different portions of the leaflet to perform different functions during opening and closing cycles. This gradient in mechanical properties enables controlled movement while maintaining overall flexibility and durability.
Solution Approach 2:
The patent segments the leaflet into distinct regions with different mechanical properties. The leaflet is divided into a first region (with higher stiffness) and a second region (with lower stiffness), allowing independent optimization of each region's function. This segmentation enables the valve to achieve both controlled movement and durability through differentiated regional characteristics.
2Adaptability or versatility
If unrestricted leaflet bending is allowed to maintain flexibility, then the leaflet can move freely, but creases and intersecting creases form producing high stress zones that cause holes and tears under repetitive loading
Solution Approach 1:
The patent addresses this contradiction by implementing local quality through a stiffness gradient. The first region has higher stiffness to resist crease formation and control bending patterns, while the second region has lower stiffness to maintain necessary flexibility. This localized differentiation allows the leaflet to bend in a controlled manner that prevents stress concentration and crease intersection, thereby improving durability while preserving flexibility.
Solution Approach 2:
The patent applies preliminary anti-action by designing the stiffness distribution to preemptively prevent crease formation. The higher stiffness in the first region acts in advance to control the bending trajectory and prevent the formation of harmful creases and stress zones before they can develop during the opening-closing cycle, thus protecting the leaflet from fatigue damage.
3Productivity
If asymmetric stiffness distribution is implemented to control leaflet opening and closing, then closing volume is reduced and blood flow is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent implements local quality through asymmetric stiffness distribution, where the first region has higher stiffness and the second region has lower stiffness. This asymmetric design controls the leaflet's opening and closing motion to reduce closing volume and improve blood flow patterns. The gradient in mechanical properties is achieved through material selection or structural design in each region, enabling functional optimization while managing manufacturing complexity through systematic material or structural differentiation.
Data Source
AI summary
Described embodiments are directed toward prosthetic valves having leaflets that move asymmetrically in that a leaflet second side region of the leaflet initially moves toward the open position before a leaflet first side region and the leaflet first side region initially moves toward the closed position before the leaflet second side region. In the fully open position, the leaflet first side region opens less than the leaflet second side region. Asymmetric opening and final open position, in synchrony with the other leaflets having the same motion and final open position creates spiral flow exiting the open valve that increases blood flow on the downstream side of the leaflet and thus reduces stagnation of the blood that might lead to thrombus formation. Controlled asymmetric movement of the leaflet reduces closing volume by initiating closure on the leaflet first side region and finishing closures on the leaflet second side region.