Segmented Guide Wire Coil for Torque and Pushing
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Solution Overview
Problem
Existing guide wires face issues with plastic deformation and reduced torque transmission when navigating sharp bends in coronary arteries due to excessive force and friction, leading to compromised pushing and torque capabilities.
Innovation Solution
A guide wire design featuring a tapered distal end with a helically formed coil, comprising a first coil portion with higher initial tensile forces and a second coil portion with lower initial tensile forces, along with a resin coating to reduce friction, allowing for improved flexibility and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the guide wire is pushed in when the coil comes to a sharp bend of the coronary artery, then the guide wire can navigate the constricted area, but undue forces are applied to the coil causing plastic deformation and reduced pushing capability
Solution Approach 1:
The coil is divided into two distinct portions: a first coil portion covering the tapered portion with adjacent turns in contact and high initial tensile forces, and a second coil portion covering the constant diameter portion with adjacent turns spaced apart and low initial tensile forces. This segmentation allows different regions to handle different mechanical stresses during navigation.
Solution Approach 2:
Different regions of the coil are given different properties: the first coil portion has high initial tensile forces and contact between adjacent turns to resist compression forces at sharp bends, while the second coil portion has spaced turns and low initial tensile forces to reduce friction at the distal end. Each region's properties are optimized for its specific functional requirement.
2Ease of operation
If the coil has a hydrophilic lubricating layer to reduce friction, then the guide wire can be inserted more smoothly, but relatively large frictional resistance is developed depending on wire thickness when coming to a sharp bend
Solution Approach 1:
The coil is segmented into two portions with different turn configurations. The first coil portion with contact between adjacent turns provides structural support to reduce frictional resistance when encountering sharp bends, while the second coil portion with spaced turns maintains the lubricating layer's effectiveness for smooth insertion.
Solution Approach 2:
The first coil portion is designed with contact between adjacent turns and high initial tensile forces to specifically address friction reduction at sharp bends, while the second coil portion maintains spaced turns for general lubrication. Each region's local structure is optimized for its specific friction-reduction requirement.
3Reliability
If the coil turns are held in contact to prevent deformation, then the pushing force is reliably transmitted, but the torque transmitting capability is reduced due to increased friction
Solution Approach 1:
The coil is divided into two portions with different turn contact configurations. The first coil portion has adjacent turns in contact to ensure reliable pushing force transmission and prevent plastic deformation, while the second coil portion has adjacent turns spaced apart to maintain torque transmitting capability by reducing friction.
Solution Approach 2:
Different regions of the coil have different turn contact properties matched to local requirements. The first coil portion near the tapered end has contact between turns for pushing force transmission, while the second coil portion at the constant diameter section has spaced turns for torque transmission, with each region's properties optimized for its specific function.
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 guide wire effectively navigates constricted areas with increased flexibility and operability, maintaining pushing and torque capabilities while reducing the risk of deformation and frictional resistance.
Implementation Method 1
initial tensile forces developed for pushing the turns of the wire in the first wire portion against each other axially of the wire body in their free state are greater than initial tensile forces developed in the second coil portion
Implementation Method 2
a tapered portion disposed on a distal end portion thereof and having an outside diameter progressively reduced toward a distal end thereof
Implementation Method 3
a covering layer (a covering member of synthetic resin, a hydrophilic lubricating layer) covering the outermost surfaces of the wire body and the coil
Data Source
AI summary
A guide wire includes a wire body having a tapered portion disposed on a distal end portion thereof and having an outside diameter progressively reduced toward a distal end thereof. The guide wire also includes a coil having a first coil portion covering an outer circumferential surface of the tapered portion and a second coil portion disposed adjacent to a proximal end of the first coil portion and covering an outer circumferential surface of a constant-outside-diameter portion of the wire body. Initial tensile forces of the first coil portion are greater than initial tensile forces of the second coil portion.