RF Guidewire Insulation Segmentation for Navigation and Safety
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Solution Overview
Problem
Existing RF guidewires face challenges in traversing through tough or calcified tissue due to high friction and inability to maintain mechanical, electrical, and thermal properties simultaneously, especially when equipped with hydrophilic coatings that enhance navigation but compromise insulation.
Innovation Solution
A novel RF guidewire design featuring a hydrophilic coating integrated with a unique insulation layer architecture that combines mechanical flexibility with sufficient electrical and thermal resistivity, using a combination of polymer layers such as polyimide and HDPE, and a ceramic thermal shield to minimize leakage current and heat exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydrophilic coating is applied to the RF guidewire to reduce friction and facilitate navigation through vasculature, then ease of operation is improved, but electrical insulation and thermal protection are compromised
Solution Approach 1:
The insulation layer is divided into multiple segments with different properties: a proximal segment with higher electrical insulation and a distal segment with lower electrical insulation but maintained mechanical flexibility. This segmentation allows different regions to serve different functions - the proximal region provides robust electrical insulation while the distal region maintains flexibility for navigation, resolving the contradiction between insulation reliability and ease of operation.
Solution Approach 2:
Different portions of the insulation layer are assigned different material properties and thicknesses. The proximal insulation layer uses materials with higher dielectric strength and thickness for robust electrical insulation, while the distal insulation layer uses materials with lower dielectric strength but maintained flexibility. This local differentiation allows the guidewire to achieve both reliable electrical insulation and ease of navigation through vasculature.
2Reliability
If the insulation layer thickness is increased to improve electrical insulation, then electrical insulation is improved, but mechanical flexibility deteriorates
Solution Approach 1:
The insulation layer is segmented into proximal and distal portions with different thickness characteristics. The proximal segment has greater thickness for enhanced electrical insulation, while the distal segment has reduced thickness to preserve mechanical flexibility. This segmentation enables the guidewire to achieve both reliable electrical insulation and ease of operation without requiring uniform thickness throughout.
Solution Approach 2:
The insulation layer exhibits non-uniform thickness distribution along its length, with the proximal region having greater thickness for electrical insulation and the distal region having lesser thickness for flexibility. This local quality variation allows the system to optimize both electrical insulation reliability and mechanical flexibility simultaneously, as each region is sized appropriately for its specific function.
3Reliability
If a ceramic thermal shield is added to protect the insulation from heat, then thermal protection is improved, but device complexity increases
Solution Approach 1:
The thermal shield is nested within the existing insulation layer structure, with the thermal shield positioned inside the insulation layer rather than as a separate external component. This nesting approach allows the thermal protection function to be integrated into the existing device architecture, minimizing the increase in device complexity while still providing effective thermal protection to the insulation layer from RF-generated heat.
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 solution enables smooth navigation through vascular anatomy while maintaining patient safety by reducing friction, minimizing leakage current, and protecting the guidewire from heat, allowing effective RF delivery without compromising mechanical flexibility.
Implementation Method 1
a hydrophilic coating integrated with a unique insulation layer architecture that combines mechanical flexibility with sufficient electrical and thermal resistivity
Implementation Method 2
a ceramic thermal shield to minimize leakage current and heat exposure
Implementation Method 3
maintaining patient safety by reducing friction, minimizing leakage current
Data Source
AI summary
A method and apparatus are disclosed for an RF guidewire for applying RF energy to create a channel through a region of tissue within a patient's body. The RF guidewire is configured to have a hydrophilic coating disposed thereon to reduce friction to facilitate traversal through vasculature while maintaining its mechanical, electrical and thermal properties. The RF guidewire includes an electrode tip at a distal end of the guidewire for delivering the energy and an electrically insulative thermal shield between the electrode tip and electrical insulation for thermally protecting the electrical insulation from heat produced by delivering the energy. Some embodiments include electrical insulation inside of the electrically insulative thermal shield.