Prosthetic Valve Frame with Variable Strut Angles
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Solution Overview
Problem
Existing prosthetic heart valves face challenges in achieving a balance between crimpability for percutaneous delivery and expandability for effective implantation, with rigid struts leading to uneven crimping and assembly difficulties due to the need for obtuse angles that compromise crimping predictability.
Innovation Solution
A partially collapsed stent frame with multiple bends forming obtuse angles is used, allowing for crimping to a smaller diameter for delivery and expanding to enhance rigidity upon implantation, along with a flexible skirt or folding device to facilitate valve member attachment, ensuring even assembly and expanded shape retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid struts with obtuse angles are used to maximize frame rigidity, then the frame can retain expanded shape better, but crimping becomes uneven and unpredictable
Solution Approach 1:
The strut design transitions from a static rigid structure to a dynamic structure that adapts its geometry during crimping. The struts are configured to bend at specific locations, allowing them to flex during crimping while maintaining obtuse angles when expanded. This dynamic behavior enables both rigid shape retention when deployed and predictable crimping during delivery.
Solution Approach 2:
The patent changes the geometric parameters of the strut configuration. By designing struts with specific bend locations and angles that allow them to transition between expanded and crimped states, the system achieves both rigidity when expanded and predictability during crimping. The struts are engineered to maintain obtuse angles in the expanded state while accommodating the crimping process through controlled deformation.
2Ease of manufacture
If the valve assembly is assembled in expanded state, then valve member attaches properly, but crimping to delivery profile becomes difficult
Solution Approach 1:
The valve assembly is pre-assembled in the expanded state with the valve member properly attached to the frame, ensuring correct positioning and secure attachment. The frame is then crimped to a smaller profile for delivery while maintaining the assembled configuration. This preliminary assembly approach simplifies manufacturing while the crimping process is managed through the frame's engineered flexibility.
3Strength
If frame is made with more metal to increase rigidity, then expanded shape is retained better, but crimping profile size increases
Solution Approach 1:
The frame is divided into multiple struts with specific bend locations, creating a segmented structure that can be crimped effectively. This segmentation allows the frame to maintain rigidity when expanded through the obtuse angle configuration while enabling compact crimping to a smaller profile for delivery through vascular pathways.
Data Source
AI summary
An implantable prosthetic valve assembly having a frame comprising a first frame portion and a second frame portion connected end-to-end exhibits enhanced rigidity. Each frame portion includes a plurality of circumferential struts formed with multiple bends, with the bends of the first frame portion having angles that are less than the bends of the second frame portion. Some embodiments of the frame have a semi-collapsed state in which the first frame portion is frustoconical and the second frame portion is generally cylindrical. A valve member is attached to the first frame portion.