Helical Stent Segmented Struts Emboli Resistance
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Solution Overview
Problem
Existing helical stents for vascular applications have limitations in terms of strut configuration, leading to inadequate drug distribution, increased restenosis rates, and poor resistance to emboli due to large gaps and thick struts, which hinder effective tissue coverage and mechanical integrity.
Innovation Solution
A helical stent design with a significantly higher number of shorter struts around the circumference, optimized for drug-eluting coatings, featuring paddle-shaped markers and sacrificial bridges to enhance flexibility and resistance to emboli, while maintaining structural integrity and ease of deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional helical stent design with fewer longer struts is used, then the manufacturing process is simpler, but the drug distribution is inadequate and restenosis rates increase
Solution Approach 1:
The stent is divided into a higher number of shorter struts arranged helically around the circumference. This segmentation increases the number of drug delivery points and improves uniform drug distribution across the stent surface, directly addressing the inadequate drug distribution problem while maintaining manufacturability through standardized strut geometry
2Strength
If stents with thick struts and large gaps are used, then the structural integrity is maintained, but the resistance to emboli is poor and tissue coverage is inadequate
Solution Approach 1:
The stent structure is segmented into numerous shorter struts that create smaller inter-strut gaps. This segmentation improves emboli resistance by preventing larger particles from passing through while maintaining structural integrity through the helical arrangement and optimized strut thickness
Solution Approach 2:
The strut thickness and spacing are locally optimized to balance structural support and emboli filtration. The helical configuration provides continuous radial support while the increased number of struts creates a finer mesh that blocks emboli more effectively
3Reliability
If a higher number of shorter struts are used, then the drug distribution is improved and restenosis rates are reduced, but the manufacturing complexity increases
Solution Approach 1:
The stent is segmented into a higher number of identical or similar short strut elements arranged in a repeating helical pattern. This standardization of strut geometry simplifies manufacturing processes such as laser cutting or machining, as the same pattern repeats around the circumference, reducing the overall manufacturing complexity despite the increased number of struts
4Ease of operation
If conventional stent designs are used, then the deployment process is straightforward, but the flexibility and tissue coverage are poor
Solution Approach 1:
The stent is divided into numerous shorter segments that can flex and conform to the vessel geometry more easily. This segmentation improves flexibility and adaptability to irregular vessel shapes while maintaining ease of deployment through the self-expanding or balloon-expandable mechanism that activates all struts simultaneously
Data Source
AI summary
A stent that has a reduced state, an expanded state, and a delivery state, includes helical windings, a bridge, and a sacrificial bridge. The helical windings define a cylinder with a helical axis including a strut having a straight portion connected to a curved portion, wherein the straight portion aligns with the helical axis. The bridge connects adjacent windings. The sacrificial bridge connects adjacent windings and is configured for removal in the expanded state.