Amorphous Metal Core Push Wire for Endoluminal Devices

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Solution Overview

Problem

Endoluminal medical devices face challenges in navigating tortuous paths due to the conflicting requirements of flexibility and stiffness in push wires, which often result in kinking or inadequate trackability.

Innovation Solution

The use of a push wire with a flexible amorphous metal alloy core surrounded by a stiff crystalline metallic sheath, allowing for tailored flexibility, kink resistance, and pushability, where the sheath maintains most of the strength and prevents fracturing of the amorphous core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a push wire is made from solid crystalline metallic material to provide stiffness, then pushability is improved, but flexibility and trackability through tortuous paths deteriorate

Engineering Contradiction:
ImprovepushabilityVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The push wire employs a composite structure with an amorphous metal alloy core providing flexibility and a crystalline metallic sheath providing stiffness. This composite construction allows the wire to simultaneously achieve both flexibility for tracking through tortuous vasculature and stiffness for pushability, resolving the contradiction between these two opposing requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different portions of the push wire are given different material properties: the core is made from amorphous metal alloy for flexibility while the outer sheath is made from crystalline metal for stiffness. This local differentiation of material properties allows each layer to perform its specific function optimally, with the core providing trackability and the sheath providing pushability.

Inventive Principle:
Principle #3Local quality

2Strength

If the push wire is made stiffer to maintain pushability through long distances, then pushability is improved, but resistance to kinking deteriorates

Engineering Contradiction:
ImprovepushabilityVSAvoidkink resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The composite structure with amorphous core and crystalline sheath allows the wire to maintain stiffness for pushability while the amorphous core's inherent flexibility provides resistance to kinking. The combination ensures the wire remains reliable during navigation through tortuous paths without sacrificing pushability over long distances.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters by using amorphous metal alloy instead of conventional crystalline metal for the core. This parameter change in material structure provides superior flexibility and kink resistance while maintaining adequate pushability when combined with the crystalline sheath.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the push wire is made more flexible to improve trackability, then flexibility is improved, but stiffness and pushability deteriorate

Engineering Contradiction:
ImproveflexibilityVSAvoidpushability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The composite construction with flexible amorphous core and stiff crystalline sheath allows the push wire to achieve both flexibility for trackability and stiffness for pushability. The sheath maintains sufficient stiffness to push devices through vessels while the core provides the flexibility needed for navigation through tortuous anatomy.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The push wire employs local quality differentiation where the core region is optimized for flexibility while the peripheral sheath region is optimized for stiffness. This spatial differentiation of material properties allows the wire to exhibit both flexible trackability and adequate pushability simultaneously.

Inventive Principle:
Principle #3Local quality

4Ease of operation

If a thin sheath is used to improve flexibility, then flexibility is improved, but strength and pushability deteriorate

Engineering Contradiction:
ImproveflexibilityVSAvoidpushability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention changes the material parameters by using amorphous metal alloy for the core, which provides superior flexibility properties. This allows the sheath to be made relatively thin while maintaining adequate overall flexibility, as the amorphous core contributes significantly to the flexible response even at reduced sheath thickness.

Inventive Principle:
Principle #35Parameter changes

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 configuration enhances the ability of push wires to navigate long distances through tortuous anatomy while maintaining sufficient stiffness and pushability, improving flexibility and kink resistance compared to solid crystalline metallic push wires.

Implementation Method 1

The core comprises an amorphous metal alloy

Methodology Applied
Scientific EffectAmorphous metal structure:

Implementation Method 2

the sheath comprises a crystalline metallic material

Methodology Applied
Scientific EffectCrystalline metal structure: Crystallisation

Implementation Method 3

The sheath may also serve to prevent fracturing of the amorphous core

Methodology Applied
Scientific EffectEncapsulation: Physical Containment

Data Source

PatentEP3612265B1Push wire for endoluminal medical device
Publication Date: 2024.07.24 MEDTRONIC VASCULAR INC
  • EP3612265B1 patent drawingFigure 1~2
  • EP3612265B1 patent drawingFigure 3~4
  • EP3612265B1 patent drawingFigure 5~9

AI summary

An elongate body extending from a proximal end (350) to a distal end (450) includes a core (150) comprising an amorphous metal alloy and includes a sheath (250) that comprises a crystalline metallic material. The sheath surrounds the core. The elongate body may be a part, or a portion, of an endoluminal medical device, for example, included with an endoluminal delivery assembly.