Expandable Stent Outflow Commissure Posts for Valve Durability
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Solution Overview
Problem
Existing transcatheter valve prostheses face challenges in balancing valve-frame integration and mechanical performance, where reinforcing the valve to the frame can hinder mechanical performance, and existing designs often compromise between these competing needs.
Innovation Solution
A transcatheter valve prosthesis with a radially-expandable stent and prosthetic valve configuration, featuring a unique outflow portion with three commissure posts that vary in thickness and material, allowing for flexible alignment and secure attachment of the valve leaflets while maintaining mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve is reinforced to the frame at certain locations, then valve-frame integration is improved, but mechanical performance of the frame is hindered
Solution Approach 1:
The stent structure implements local quality by providing reinforced attachment at specific locations (crowns at inflow end and commissure posts at outflow end) while maintaining open cell structures in other areas. This allows the valve to be securely attached where needed without compromising the overall mechanical performance and flexibility of the frame.
Solution Approach 2:
The stent is segmented into distinct functional zones: an inflow portion with multiple crowns for valve attachment, an outflow portion with commissure posts for alignment, and intermediate sections with open cells for mechanical flexibility. This segmentation allows simultaneous optimization of valve-frame integration and frame mechanical performance in different regions.
2Reliability
If the stent is made more rigid to support the valve, then valve stability is improved, but deliverability through vasculature is hindered
Solution Approach 1:
The stent structure exhibits dynamic properties by transitioning from a compressed delivery configuration to an expanded deployed configuration. The open cell design and strategically placed reinforcement elements allow the stent to be flexible and compressible during delivery, then become stable and rigid when expanded at the implantation site.
Solution Approach 2:
The stent incorporates thin-walled structural elements that provide flexibility during delivery but maintain structural integrity when expanded. The open cell structure acts as a flexible framework that can be compressed for delivery through the catheter while providing sufficient support for valve attachment in the expanded state.
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 design enhances tissue durability and stent strength, allowing for reliable valve function and reduced stress on the valve leaflets, thereby improving the longevity and performance of the transcatheter valve prosthesis.
Implementation Method 1
The stent has a crimped configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve. The stent is mechanically or balloon expandable.
Implementation Method 2
A thickness of each commissure post varies along a length thereof such that a first end is relatively thicker than a second end, the first end being coupled to the crown of the inflow portion. Each commissure post is configured to flex radially inward during loading of the transcatheter valve prosthesis.
Data Source
AI summary
A transcatheter valve prosthesis includes a stent and a prosthetic valve. The stent is mechanically or balloon expandable. The stent has an inflow portion and an outflow portion. The inflow portion includes a plurality of side openings defined by a plurality of crowns and a plurality of struts. The outflow portion has three circumferentially spaced apart commissure posts. The prosthetic valve is disposed within and secured to at least the outflow portion of the stent. The prosthetic valve is configured to block blood flow in one direction to regulate blood flow through a central lumen of the stent. The commissure posts are configured to flex or bend flex radially inwardly to reduce stresses observed during valve loading and thereby improve or increase tissue durability of the prosthetic valve.