Platinum-Tungsten Alloy Intravascular Devices for Flow Diversion
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Solution Overview
Problem
Current intravascular medical devices, particularly those made from platinum-tungsten alloys, face limitations in mechanical strength, radiopacity, and magnetic susceptibility, with the 8% tungsten composition being optimal but not suitable for flow diversion stents due to low radial expansion force and increased brittleness with higher tungsten content.
Innovation Solution
Developing medical devices using a platinum-tungsten alloy with a tungsten percentage equal to or greater than 10% by weight, which enhances mechanical strength, radiopacity, and reduces magnetic susceptibility, while maintaining manufacturability and biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tungsten content in platinum-tungsten alloy is increased to enhance mechanical strength and radial expansion force, then the modulus and strength improve, but brittleness increases compromising device performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the tungsten content within a specific range (6-16 wt%) rather than using fixed compositions. This optimization of compositional parameters achieves the desired balance between mechanical strength and ductility, resolving the contradiction between enhanced strength and reduced brittleness
Solution Approach 2:
The patent uses composite materials by creating a platinum-tungsten alloy system where tungsten particles are distributed within a platinum matrix. This composite structure allows the material to combine the high strength of tungsten with the ductility of platinum, achieving both improved mechanical properties and reduced brittleness
2Strength
If cobalt-chromium alloy is used to achieve suitable radial force, then the mechanical strength improves, but magnetic susceptibility increases causing MR image artifact
Solution Approach 1:
The patent changes the material composition parameters by using platinum-tungsten alloy with specific tungsten content (6-16 wt%) to achieve the desired mechanical properties. This compositional change provides equivalent or superior radial force compared to cobalt-chromium while eliminating the magnetic susceptibility issue, as platinum and tungsten are non-magnetic materials
Solution Approach 2:
The patent replaces expensive cobalt-chromium alloy with a more cost-effective platinum-tungsten composition. By optimizing the tungsten content within a specific range, the invention achieves the required mechanical performance at lower material cost, making the device more economically viable
3Ease of manufacture
If platinum-8% tungsten alloy is used to enhance mechanical strength and handling, then the manufacturability improves, but radial expansion force becomes insufficient for flow diversion stents
Solution Approach 1:
The patent applies parameter changes by increasing the tungsten content from the conventional 8 wt% to a higher range (6-16 wt%, preferably 10-14 wt%). This parameter optimization enhances the radial expansion force and mechanical strength while maintaining adequate ductility and manufacturability, directly resolving the insufficient radial force issue
Data Source
AI summary
Implantable medical devices, such as embolic devices and blood flow filters are disclosed, the devices being made at least partially out of a platinum-tungsten alloy, wherein a percentage of tungsten in the alloy is equal to or greater than about 10% of the alloy by weight.