Catheter Tip Helical Threads Kink Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing catheter designs face challenges in navigating through winding vascular passages due to stiffness and difficulty in maintaining structural properties like pushability, torqueability, and resistance to kinking, especially when reduced in diameter for advanced lengths.
Innovation Solution
A catheter design featuring an elongate shaft body with a liner, a braid or coil member, and a polymer cover, along with helical threads on the outer surface, which allows for controlled rotation and advancement through tortuous vessels without kinking, utilizing a guidewire as a rail for support and navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the catheter diameter is reduced to increase length and reach, then the catheter can access more distant target sites, but the catheter loses structural strength and becomes difficult to push through vascular passages
Solution Approach 1:
The catheter employs a composite structure combining a flexible polymer shaft with an embedded wire reinforcement element. The wire provides tensile strength and pushability while the polymer coating maintains flexibility and biocompatibility. This composite design allows the catheter to achieve both extended length and sufficient structural strength for navigation through vascular passages.
Solution Approach 2:
The catheter is divided into distinct functional segments: a flexible polymer shaft portion for navigation, an embedded wire reinforcement portion for strength and pushability, and a tip portion for target site engagement. This segmentation allows each component to optimize its specific function while working together to achieve both length and strength requirements.
2Strength
If the catheter wall is made thicker to improve pushability and structural strength, then the catheter can navigate vascular passages more effectively, but the catheter diameter increases and flexibility is reduced
Solution Approach 1:
Instead of increasing wall thickness, the invention uses a composite of polymer and embedded wire. The wire provides the necessary structural strength and pushability, while the thin polymer coating maintains flexibility and allows the catheter to navigate tortuous vascular passages without kinking or losing maneuverability.
Solution Approach 2:
The catheter uses a thin polymer shaft that appears flexible and compliant, yet contains an embedded wire reinforcement. This thin-film approach with internal reinforcement provides sufficient strength for pushability while maintaining the flexibility needed for navigation through winding vascular passages.
3Stability of the object's composition
If the catheter is made stiffer to improve resistance to kinking, then the catheter maintains structural integrity during manipulation, but the catheter becomes difficult to rotate and torque is reduced
Solution Approach 1:
The composite structure of polymer and embedded wire creates a catheter that resists kinking through the wire reinforcement while allowing rotation through the flexible polymer matrix. The wire prevents collapse and kinking during manipulation, while the polymer's flexibility enables controlled rotation for torque delivery to the target site.
Solution Approach 2:
The catheter exhibits different mechanical properties in different regions: the embedded wire provides localized strength and kink resistance, while the polymer shaft provides overall flexibility and torqueability. This local differentiation of material properties allows simultaneous achievement of kink resistance and rotational capability.
Data Source
AI summary
Catheters and related methods for supporting a guidewire or delivering an agent through a vessel stenosis or other tortuous anatomy are disclosed. A catheter can comprise an elongate shaft body and a polymer tip member disposed at a distal end of the shaft body. The shaft body and the tip member can include a liner, one or both of a braid member or a coil member surrounding the liner, and a polymer cover surrounding the braid member or the coil member. The tip member can further include one or more filaments extending from a position overlapping, underlapping, or abutting a distal end of the braid member or the coil member on their proximal ends to a position distal to the braid member or the coil member on their distal ends. The one or more filaments can include a plurality of filaments arranged in a series of contacting helical windings about the liner, the braid member, or the coil member.