Biodegradable Metallic Stent With Segmented Crown Contour
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Solution Overview
Problem
Biodegradable stents face challenges such as inferior mechanical properties, stress concentration, and corrosion fatigue due to their design, which limits their effectiveness in vascular applications, particularly in peripheral and coronary artery diseases.
Innovation Solution
A biodegradable metallic vascular stent with a tubular base body featuring a distinctive design of circumferential support structures and connectors that minimize stress and plastic deformation, utilizing a sequence of repeat units including arched, bump, diagonal, and kink elements, ensuring homogeneous stress distribution and improved corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional uniform width struts are used in Mg alloy stent, then manufacturing is simplified, but stress concentration increases and corrosion fatigue life decreases
Solution Approach 1:
The patent applies local quality by varying the strut width along its length, with wider sections at critical stress points and narrower sections elsewhere. This non-uniform width distribution optimizes stress distribution and reduces stress concentration factors in high-stress regions, thereby improving corrosion fatigue life while maintaining manufacturing feasibility through controlled variation patterns.
2Strength
If high curvature crown contour is used in stent design, then radial strength is improved, but crown contour damage occurs during crimping and expanding
Solution Approach 1:
The patent segments the crown contour into multiple discrete elements rather than using a continuous high-curvature arc. This segmentation allows each element to be independently optimized for both strength and deformability, enabling the crown to maintain radial strength while accommodating the plastic deformation required during crimping and expanding operations without contour damage.
Solution Approach 2:
The patent introduces dynamic characteristics to the crown contour design, allowing the structure to adapt its stiffness and deformation behavior during the crimping and expanding process. The segmented elements can rotate and deform in a controlled manner, enabling the crown to achieve high radial strength in the deployed state while maintaining integrity through the dynamic deformation process.
3Object-affected harmful factors
If biodegradable polymer stent is used, then biocompatibility is improved, but greater strut thickness is required and radial strength decreases
Solution Approach 1:
The patent employs composite material strategies by combining biodegradable polymer with reinforcing elements or hybrid structures. This allows the stent to maintain the biocompatibility advantages of polymer materials while compensating for their lower tensile strength through composite construction, achieving adequate radial strength without requiring excessive strut thickness that would compromise flexibility and deliverability.
Data Source
AI summary
A biodegradable metallic vascular stent includes: a base body which is tubular with a lumen along a longitudinal axis, wherein the base body has a plurality of circumferential support structures which are successively positioned along the longitudinal axis. The circumferential support structures are each composed of a sequence of repeat units and has two or more connectors, wherein two adjacent circumferential support structures are joined together by at least one of the connectors, and each of the connectors is attached to one of arched elements in the repeat units of the two adjacent circumferential support structures to be connected. The biodegradable metallic vascular stent possesses suited radial pressure, flexibility and fatigue strength. Furthermore, the stent is design for peripheral vascular disease and coronary artery disease treatment as well.