Multimaterial Stent Braid Pattern for Enhanced X-Ray Visibility
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Solution Overview
Problem
Self-expanding stents are difficult to locate with X-ray due to their small size and low radiopacity, which complicates accurate placement and subsequent examination, often requiring a trade-off between radiopacity and mechanical properties.
Innovation Solution
A tubular metallic braid pattern is created using a combination of filaments made from different materials, including radiopaque materials like platinum and support materials like cobalt chromium alloys, arranged in specific configurations to enhance radiopacity without compromising mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the stent is made with fine-meshed braided configuration to reduce size, then the stent can be delivered through small and curved vessels, but the radiopacity is reduced making it extremely difficult to locate with X-ray
Solution Approach 1:
The patent applies local quality by incorporating radiopaque segments at specific locations along the stent structure, particularly at the distal and proximal ends, while maintaining fine-meshed braided configurations in other areas. This allows the stent to maintain small overall size for delivery through curved vessels while providing localized radiopaque markers for X-ray detection and positioning verification.
2Difficulty of detecting and measuring
If the radiopaque material is increased to enhance X-ray visibility, then the stent becomes easier to locate and position, but the mechanical properties such as strength, ductility, and fatigue resistance are compromised
Solution Approach 1:
The patent employs composite materials by combining radiopaque materials (such as platinum, gold, or tungsten) with biocompatible structural materials (such as nitinol or stainless steel) in a segmented configuration. The radiopaque segments provide X-ray visibility while the structural segments maintain mechanical strength, ductility, and fatigue resistance. This composite approach allows both radiopacity and mechanical properties to be optimized independently in different segments of the same stent.
3Difficulty of detecting and measuring
If the mass and thickness of radiopaque parts are increased to improve visibility, then the stent appears more clearly on imaging, but the stent size increases making delivery through small vessels more difficult
Solution Approach 1:
The patent applies local quality by concentrating radiopaque material in specific localized segments rather than uniformly throughout the entire stent. The radiopaque segments are positioned at critical locations such as the distal and proximal ends where visualization is most important for positioning, while the intermediate sections maintain thinner, more flexible construction for delivery through small vessels. This localized approach provides sufficient radiopacity for imaging while minimizing overall stent size and mass.
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 enhanced radiopacity allows for better visualization of stent placement and deployment, maintaining mechanical properties such as radial pressure and apposition, enabling precise positioning within body vessels.
Implementation Method 1
because of their small size, these stents are extremely difficult to locate with X-ray. The only parts of the stent that appear on imaging are those with sufficient radiopacity
Data Source
AI summary
An implantable metallic braid is formed out of groups of filaments of a first material, groups of filaments of a second material different from the first material, and groups of filaments of a third material different from the first material and the second material. The filaments are braided together by a braiding machine and are arranged in a starting filament arrangement on the braiding machine before braiding begins, wherein the first material is a radiopaque material, the second material is a support material, and the third material is a DFT comprising the first and second materials. Different arrangements of the filaments in the starting filament arrangement and in the braid result in different levels of detail that can be observed in images of the braid, wherein certain arrangements of the filaments result in enhanced radiopacity without affecting other mechanical properties of the braid.