Intraluminal Guide Wire Stiffness Transition via Weld Joint Sleeve

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Solution Overview

Problem

Existing guide wires for intravascular use face a challenge in balancing column strength and flexibility, as improvements in one characteristic often compromise the other, leading to unsatisfactory performance in navigating tortuous vasculature and supporting balloon catheters.

Innovation Solution

A multi-segment intravascular guide wire with a distal core wire portion made of a first metallic material and a proximal core wire portion made of a second material, joined end-to-end by a solid-state weld joint, and covered with a stiffness adjusting sleeve to create a gradual bending stiffness transition profile, enhancing flexibility and support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the guide wire uses a uniform structure with high stiffness material, then column strength is improved, but flexibility to navigate tortuous vasculature deteriorates

Engineering Contradiction:

Improvecolumn strengthVSAvoidflexibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The guide wire is divided into multiple segments with different materials and stiffness characteristics: a distal flexible segment for navigation, a proximal stiff segment for support, and an intermediate transition segment. This segmentation allows each portion to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the guide wire are assigned different local properties: the distal portion uses a flexible material (e.g., shape memory alloy) for ease of navigation, while the proximal portion uses a stiffer material for mechanical support. This local differentiation resolves the contradiction between overall strength and localized flexibility.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the guide wire uses a uniform structure with low stiffness material, then flexibility to navigate tortuous vasculature is improved, but column strength deteriorates

Engineering Contradiction:

ImproveflexibilityVSAvoidcolumn strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the guide wire uses dissimilar metal materials for different segments, then optimal flexibility and strength are achieved, but manufacturing complexity increases

Engineering Contradiction:

ImproveflexibilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

A transition segment acts as an intermediary between the dissimilar metal materials, providing a gradual stiffness transition and facilitating the joining of different materials. This intermediary structure manages the complexity of dissimilar metal fabrication while achieving the desired performance gradient.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The transition segment utilizes parameter changes in material composition and structure to gradually bridge the properties of dissimilar metals. By varying the material parameters continuously or in controlled steps, the fabrication complexity is managed while achieving smooth mechanical property transitions.

Inventive Principle:

Principle #35Parameter changes

4Strength

If a weld joint directly joins dissimilar metal segments, then structural integrity is achieved, but abrupt stiffness transition causes performance deterioration

Engineering Contradiction:

Improvestructural integrityVSAvoidstiffness transition smoothness

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The weld joint region is further segmented into a transition segment with intermediate stiffness properties between the two dissimilar metals. This segmentation creates a gradual stiffness gradient rather than an abrupt change, improving performance while maintaining structural integrity through the weld connection.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11129970B2Mechanisms for improving the stiffness transition across a dissimilar metal weld joint

Publication Date: 2021.09.28 ABBOTT CARDIOVASCULAR SYSTEMS INC

AI summary

The present disclosure is directed to multi-segment intraluminal guide wires including an elongate distal portion comprising a first metallic material (e.g., nitinol), an elongate proximal portion comprising a second metallic material (e.g., stainless steel). The distal and proximal portions may be directly joined together end to end by a solid-state weld joint. A diameter of the weld region surrounding the weld joint on either side of the weld joint may be reduced (e.g., ground down) relative to the diameter of the distal and proximal portions of the guide wire on either side of the weld region. A stiffness adjusting sleeve may be disposed over the weld joint so that a transition profile of bending stiffness across the weld region is gradual, rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire. A polymer jacket may cover the sleeve and distal portion.