Intravascular Stent Plastic Deformation Control
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Solution Overview
Problem
Intravascular stents lack sufficient plastic deformation capacity, leading to fractures during expansion and implantation, which can cause mechanical vascular stimulation, inflammation, neointimal hyperplasia, thrombosis, and blood flow blockage, posing clinical risks due to inadequate structural support and material microstructure optimization.
Innovation Solution
The development of an implantable device with a metal substrate containing particles sized 1 μm and above, where the wall thickness and particle size are carefully controlled to optimize microstructure, reducing the risk of abnormal fracture by limiting particle size and content based on wall thickness and theoretical over-expansion capacity, using materials like nitrided iron, cobalt-chromium alloys, and magnesium alloys, and processing methods such as electroslag remelting and vacuum arc melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stent undergoes repeated large deformations during crimping and expansion process, then the stent can be delivered and expanded to the lesion, but the stent lacks sufficient plastic deformation capacity resulting in fracture due to fatigue
Solution Approach 1:
The patent applies parameter changes by controlling the microstructure parameters of the metal substrate, specifically grain size (5-20 μm) and orientation, to optimize plastic deformation capacity. By adjusting these microstructural parameters, the stent achieves sufficient deformation capacity during crimping and expansion while maintaining fracture resistance through fatigue.
Solution Approach 2:
The patent uses composite materials by combining metal substrate with controlled microstructure and particles having specific size (1-10 μm) and content (10-100 ppm). This composite approach creates a material structure that provides both the necessary deformation capacity and fracture resistance, resolving the contradiction between adaptability and reliability.
2Ease of manufacture
If the stent is made with conventional material microstructure, then the manufacturing process is simple, but the plastic deformation capacity is insufficient leading to fracture during expansion
Solution Approach 1:
The patent changes material parameters by specifying grain size (5-20 μm) and particle content (10-100 ppm) in the metal substrate microstructure. These parameter changes enhance plastic deformation capacity while maintaining manufacturing feasibility through controlled metallurgical processes such as electroslag remelting and vacuum arc melting.
Solution Approach 2:
The patent applies local quality by optimizing the microstructure at the material level rather than changing the overall device structure. By controlling grain size and particle distribution locally within the metal substrate, the patent enhances plastic deformation capacity without complicating the overall manufacturing process.
3Strength
If the stent fractures, then the structural support is lost, but the fracture causes mechanical vascular stimulation, inflammation, neointimalhyperplasia, thrombosis and blood flow blockage
Solution Approach 1:
The patent prevents the harmful effects of fracture by using durable materials with optimized microstructure that provide sufficient plastic deformation capacity. By ensuring the stent maintains its structural integrity through controlled grain size and particle content, the patent eliminates the need for replacement or repair, avoiding the harmful effects associated with fractured stents.
Solution Approach 2:
The patent applies beforehand cushioning by optimizing the microstructure before implantation to prevent fracture from occurring in the first place. By controlling grain size and particle content during manufacturing, the stent is prepared in advance to withstand the mechanical stresses of deployment and vascular movement, cushioning against the harmful effects of potential fracture.
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
This approach enhances the plastic deformation capacity of the implantable device, reducing the risk of abnormal fracture and improving the stent's durability and performance by optimizing the microstructure and material properties, thereby ensuring effective radial support and minimizing clinical risks.
Implementation Method 1
processing methods such as electroslag remelting and vacuum arc melting
Implementation Method 2
processing methods such as electroslag remelting and vacuum arc melting
Implementation Method 3
The plastic deformation capacity of the intravascular stent is mainly related to its structural design and stent material
Data Source
AI summary
An implantable device including a metal substrate; that contains particles having a size of 1 μm or more; if the wall thickness of the metal substrate is greater than or equal to 0.04 mm and less than or equal to 0.12 mm, the largest particle size is less than or equal to 15 μm and the average content of the particles is less than or equal to 40 ppm; if the wall thickness of the metal substrate is greater than 0.12 mm and less than or equal to 0.2 mm, the largest particle size is less than or equal to 20 μm and the average content of the particles is less than or equal to 100 ppm; The size of the particles and the average content of the particles are reasonably controlled according to the wall thickness of the metal substrate, improving the plastic deformation capability of the implantable device.