Stent Structure With Alternating Hoop And Flex Cells
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Solution Overview
Problem
Current stents, particularly self-expanding ones, face challenges in providing sufficient radial force while maintaining flexibility for delivery through small sheaths and expansion to support larger body vessels, which can result in reduced performance and increased risk of deformation in peripheral vessels.
Innovation Solution
A stent structure featuring alternating hoop cells and flex cells with interconnected struts, where the flex struts are wider than the hoop struts by at least 15% but no more than 25%, providing increased radial force and flexibility, allowing for delivery through small sheaths and expansion to larger diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If self-expanding stent design is used, then flexibility for delivery through small sheaths is improved, but radial force is insufficient
Solution Approach 1:
The stent structure implements local quality by creating alternating hoop cells and flex cells with different structural characteristics. Hoop cells provide radial support force while flex cells provide flexibility for delivery, allowing each local region to optimize its function rather than requiring the entire stent to compromise between these conflicting requirements.
Solution Approach 2:
The stent is segmented into distinct functional units - hoop cells and flex cells - that alternate along the stent structure. This segmentation allows the stent to combine regions optimized for radial force (hoop cells) with regions optimized for flexibility (flex cells), resolving the contradiction between these two properties.
2Force
If stent structure is made more rigid to provide sufficient radial force, then radial force is improved, but deliverability through small sheaths deteriorates
Solution Approach 1:
Rather than making the entire stent structure uniformly rigid, the invention applies rigidity locally to hoop cells where radial force is needed, while maintaining flexibility in interspaced flex cells. This allows the stent to achieve sufficient radial force without sacrificing overall deliverability through small sheaths.
Solution Approach 2:
The stent structure is divided into alternating rigid hoop cells and flexible flex cells. This segmentation enables the stent to have localized rigid regions that provide radial force while flexible regions that enable compression for delivery through small sheaths, resolving the contradiction between radial force and deliverability.
3Force
If wider struts are used, then radial force is improved, but flexibility and expandability deteriorate
Solution Approach 1:
The invention applies wider struts locally only in hoop cells where radial force is required, while flex cells use narrower struts to maintain flexibility and expandability. This local differentiation resolves the contradiction by providing wide struts where needed for force while preserving flexibility in other regions.
Solution Approach 2:
The stent is segmented into hoop cells with wider struts for radial force and flex cells with narrower struts for flexibility. This segmentation allows the structure to simultaneously achieve radial force and flexibility/expandability by distributing these conflicting requirements to different segments.
Data Source
Figure 1
Figure 2A~2B
AI summary
A stent structure (10) is provided with an alternating arrangement of hoop cells (12) and flex cells (14). Longitudinal struts (20) extend through the hoop cells but do not extend through the flex cells. The flex struts (18) in the flex cells are wider than the hoop struts (16) in the hoop cells.