Uniformly Expandable Stent Architecture for Foreshortening Control
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Solution Overview
Problem
Existing stents face challenges in achieving uniform expansion and preventing foreshortening during deployment, which can lead to inaccurate placement and potential graft material tearing or detachment.
Innovation Solution
The stent architecture features a series of stent elements with varying orientations and connectors, including V-shaped and R-shaped elements, connected by curved or straight connectors, designed to promote uniform expansion and minimize foreshortening, with optional graft layers made of ePTFE for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional stent architectures are used, then stents can be deployed in blood vessels, but uniform expansion and foreshortening prevention cannot be achieved
Solution Approach 1:
The stent is divided into multiple repeating units, each comprising V-shaped and inverted V-shaped elements connected by bridges. This segmentation allows each unit to expand uniformly while contributing to the overall stent expansion, preventing foreshortening through coordinated deformation of individual units.
Solution Approach 2:
The stent employs asymmetric strut configurations with V-shaped elements having different orientations (first, second, third, and fourth orientations) and varying widths. The first and second struts have different widths, creating asymmetric expansion characteristics that promote uniform radial expansion while preventing foreshortening.
2Manufacturing precision
If stent struts are made with varying widths to promote uniform expansion, then expansion uniformity improves, but structural complexity increases
Solution Approach 1:
Different portions of the stent structure have different strut widths tailored to local expansion requirements. The first and second struts have different widths, and the third and fourth struts have different widths, creating local variations that promote uniform overall expansion while maintaining a repeating unit pattern for manufacturing efficiency.
3Reliability
If graft material is used to cover the stent, then stent stability and biocompatibility improve, but graft material tearing and detachment risks increase during expansion
Solution Approach 1:
The stent employs dynamic expansion characteristics with controlled foreshortening that adapts during the expansion process. The repeating units with varying strut widths provide progressive expansion that reduces sudden stress on the graft material, preventing tearing and detachment while maintaining stability.
Data Source
AI summary
An intraluminal prosthesis includes a stent architecture having a series of stent elements repeating along a circumferential axis. One series of stent elements includes v-shaped stent elements having at least four different orientations, and V-shaped stent elements connecting adjacent v-shaped stent elements. One series of stent elements includes R-shaped stent elements having at least four different orientations, and U-shaped stent elements having at least two different orientations, the U-shaped stent elements connecting adjacent R-shaped stent elements. Adjacent series of stent elements can be connected by connectors. Portions of the stent elements may narrow in width along a length thereof. The stent architecture may include radiopaque element receiving members. The stent architecture may be formed by machining a metal or polymer tube. The intraluminal prosthesis may include one or more graft layers.