Guidewire Coils with Distinct Cross Sections for Torque and Support
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Solution Overview
Problem
Conventional guidewires lack sufficient distal support and steerability, particularly in navigating tortuous vasculature, and often cause vessel damage due to stiffness issues and abrupt resistance changes during advancement.
Innovation Solution
A guidewire design featuring a radiopaque inner coil and a non-radiopaque outer coil, with a solder distal tip formed using a mold or laser dimpling, and varying cross-section shapes such as I-beam and parabolic grind profiles to enhance torqueability and flexibility, while maintaining distal tip integrity and reducing kink resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional helical coil or tubular body is used, then the guidewire is flexible, but it lacks sufficient distal support and steerability
Solution Approach 1:
The distal tip of the guidewire is formed with a rounded shape while the proximal portion maintains a different geometry, creating localized structural properties that provide both flexibility and steerability. The distal tip's rounded configuration allows smooth navigation through tortuous vasculature while the proximal portion's structure enables torque transmission for steering.
Solution Approach 2:
The guidewire combines a core member with a flexible body of polymeric material, creating a composite structure that integrates the strength and support characteristics of the core with the flexibility and biocompatibility of the polymeric coating. This composite construction enables simultaneous achievement of distal support and steerability.
2Strength
If the guidewire is made stiffer to provide better support, then distal support improves, but the risk of vessel damage increases
Solution Approach 1:
The guidewire features a flexible polymeric body that acts as a protective shell around the core member, allowing the wire to bend and conform to vascular anatomy without imposing excessive stress on the vessel lining. This flexible outer layer reduces the risk of mechanical damage while the core provides necessary structural support.
3Ease of operation
If a tapered section is added to the distal end, then steerability improves, but abrupt stiffness change causes resistance problems
Solution Approach 1:
The distal tip of the guidewire is formed with a rounded configuration rather than an abrupt taper, creating a smooth curved transition that gradually changes the cross-sectional area. This rounded geometry eliminates sudden stiffness changes and reduces resistance during advancement through tortuous vasculature while maintaining the ability to steer.
4Strength
If the guidewire is designed for high distal support, then torque response improves, but flexibility decreases
Solution Approach 1:
The guidewire is divided into distinct functional segments: a proximal portion optimized for torque transmission and a distal tip optimized for flexibility and navigation. This segmentation allows each portion to have different structural characteristics, enabling the wire to provide both torque response and flexibility simultaneously.
Data Source
AI summary
A guidewire for use in intravascular procedures has an inner coil that is radiopaque and an outer coil that is non-radiopaque at the distal end of the guidewire. The radiopaque inner coil is visible under fluoroscopy so that the physician can monitor the location of the distal end of the guidewire during a procedure. The inner coil and the outer coil can be formed from a single wire or a multi-filar wire. The inner coil and the outer coil can have any of the following cross-sections for enhanced torquability: I-beam; vertical rectangular; vertical ellipse; square; peanut shape; vertical hexagonal; horizontal hexagonal; and horizontal ellipse.