Dual-Laminate Coated Braid Catheter for Kink Resistance
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Solution Overview
Problem
Existing catheters face issues with kinking and electrical shorts due to insufficient flexibility and durability of braid wire assemblies, which fail after a limited number of articulations, hindering their effectiveness in navigating tortuous vasculature and delivering electrical energy.
Innovation Solution
A catheter shaft with a braid assembly coated with a dual-laminate coating, comprising a flexible non-electrically-conductive polymer and a thermoplastic bonding adhesive, which enhances insulation and flexibility, allowing the braid wires to serve as conductive elements and withstand multiple articulations without tearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing insulative coatings are used on braid wires, then electrical insulation is provided, but the coatings are too stiff and tear after only 10-12 articulations
Solution Approach 1:
The patent applies a dual-laminate coating system consisting of an inner flexible insulative layer (e.g., polyurethane with Shore A 50-70 durometer) and an outer bonding layer (e.g., polyamide with Shore D 40-50 durometer). This composite structure combines the flexibility needed for repeated articulations with the bonding strength required for durability, resolving the contradiction between coating flexibility and durability.
Solution Approach 2:
The patent specifies precise durometer ranges for the coating materials (Shore A 50-70 for the inner layer, Shore D 40-50 for the outer layer) to optimize both flexibility and durability. By controlling these physical parameters, the coating can withstand more than 50 articulations without tearing while maintaining electrical insulation properties.
2Shape
If metallic wire braiding is added to provide flexibility and kink resistance, then catheter flexibility is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines the structural support function and electrical insulation function into a single integrated braid assembly with dual-laminate coated wires. The coated braid members provide both mechanical flexibility/kink resistance and electrical insulation, eliminating the need for separate insulation layers and reducing overall device complexity.
Solution Approach 2:
The braid assembly serves multiple functions simultaneously: providing structural support for catheter flexibility, preventing kinking, and providing electrical insulation for the conductive elements. This multi-functionality reduces the number of separate components needed in the catheter construction.
3Device complexity
If braid wires are used as electrical wires without insulation, then device complexity is reduced, but electrical shorts occur due to contact between adjacent braid wires
Solution Approach 1:
The dual-laminate coating system provides reliable electrical insulation while maintaining flexibility. The inner flexible insulative layer (polyurethane, Shore A 50-70) prevents electrical contact between adjacent braid wires, while the outer bonding layer (polyamide, Shore D 40-50) ensures durable attachment, achieving both insulation reliability and flexibility.
4Volume of moving object
If the catheter shaft is made thinner to increase usable inner diameter, then productivity and energy delivery efficiency are improved, but structural integrity and kink resistance deteriorate
Solution Approach 1:
The dual-laminate coating on the braid members provides enhanced structural integrity and kink resistance even in thinner catheter shafts. The combination of flexible insulative material and bonding layer creates a durable composite structure that maintains strength while allowing for reduced overall catheter diameter.
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 provides catheters with improved flexibility and durability, enabling them to withstand a higher number of articulations without electrical shorts, reducing thickness, and increasing the usable inner diameter while maintaining effective energy delivery.
Implementation Method 1
The second coating is made of a thermoplastic bonding adhesive that bonds to the outer layer
Data Source
AI summary
A catheter includes a braid assembly having a dual-laminate coating. The braid assembly includes a plurality of braid members interwoven to provide for interstices between the braid members, each braid member having an electrically conductive element, a flexible non-electrically-conductive polymer coating that insulates the electrically conductive element and a thermoplastic bonding adhesive coating. The braid assembly is formed between an inner polymer layer and an outer polymer layer. One or more of the braid members may be coupled to an energy delivery element.