Intravascular Catheter Micro-Tape Reinforcement for Torque and Kink Resistance
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Solution Overview
Problem
Existing intravascular catheters face a trade-off between flexibility for navigation and rigidity for torque transmission, with metal-reinforced catheters being incompatible with MRI scans and polymeric fibrous strand-reinforced catheters lacking sufficient stiffness to prevent kinking.
Innovation Solution
A micro-tape with a width less than 0.5 mm and a cross-sectional aspect ratio of 2 to 20, made from high-performance fibers like aramid or polyetheretherketone, is used as reinforcing means, fixed with a cured resin, and wound over a pre-oriented substrate, surrounded by a tubular superstrate to provide both flexibility and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal wire braid is used as reinforcing means, then torque transmission and kink resistance are improved, but MRI compatibility deteriorates
Solution Approach 1:
The patent removes metal components from the catheter structure by replacing the metal wire braid with a polymeric fibrous braid. This extraction of the harmful metal element eliminates MRI incompatibility while maintaining the reinforcing function through the polymeric alternative.
Solution Approach 2:
The patent employs a composite structure consisting of a polymeric fibrous braid combined with a thermoset polyurethane impregnation. This composite material provides both the mechanical reinforcement needed for torque transmission and the MRI compatibility required for safe imaging procedures.
2Object-affected harmful factors
If polymeric fibrous strands are used as reinforcing means, then MRI compatibility is improved, but kink resistance deteriorates
Solution Approach 1:
The patent creates a composite material system where polymeric fibrous strands are impregnated with thermoset polyurethane. This combination enhances the mechanical properties of the polymeric braid, providing sufficient stiffness and kink resistance while maintaining MRI compatibility.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the polymeric fibrous strands through impregnation with thermoset polyurethane. This process changes the material properties to achieve the required balance between flexibility for navigation and rigidity for kink prevention.
3Strength
If catheter rigidity is increased for torque transmission, then torque transmission is improved, but flexibility for navigation deteriorates
Solution Approach 1:
The patent applies different structural characteristics to different parts of the catheter. The reinforcing braid provides localized stiffness for torque transmission where needed, while the overall catheter structure maintains flexibility for navigation through its construction with pre-oriented tubular substrate and controlled braid tension.
Solution Approach 2:
The composite construction of polymeric fibrous braid with thermoset polyurethane impregnation creates a material that exhibits both flexibility and controlled rigidity. This allows the catheter to bend for navigation while maintaining sufficient torque transmission capability.
Data Source
AI summary
A catheter, such as an intravascular catheter, includes a longitudinally pre-oriented tubular substrate and reinforcing means surrounding and in contact with the substrate, the reinforcing means wound over the substrate, and a tubular superstrate surrounding the reinforcing means forcing the reinforcing means against the substrate and maintaining the reinforcing means wound over the substrate. The reinforcing means is a micro-tape having a width less than 0.5 mm and includes a filament layer having a cross sectional aspect ratio (width/height) of 2 to 20, wherein the filaments are fixated by a cured or solidified resin or wax, which constitutes 2 to 40 wt % of the micro-tape.