Mixed Coil Catheter Design for Vessel Navigation
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Solution Overview
Problem
Existing catheters face challenges in accessing remote and complex vascular sites due to stiffness and flexibility requirements, often causing trauma and difficulty in navigating through narrow blood vessels, especially when using guidewires, and prior designs fail to minimize outer diameter effectively.
Innovation Solution
A mixed coil catheter design with a single support cord coiled around an inner liner, transitioning pitch to form an end wall, and a distal marker band, covered by an outer liner to maintain a minimized outer diameter, enhancing flexibility and resistance to kinking while maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a catheter is made stiff at the proximal end to allow pushing and manipulation, then the catheter can be easily manipulated during insertion, but it becomes difficult to pass through narrow blood vessels and causes trauma to vessels
Solution Approach 1:
The catheter is divided into multiple sections with different flexibility characteristics. The proximal section contains tighter coil windings providing stiffness for manipulation, while the distal section has looser windings providing flexibility for navigating narrow vessels, eliminating the need to compromise either end's performance
Solution Approach 2:
Different sections of the catheter are given different structural properties through varying coil winding parameters. The proximal portion maintains higher rigidity for operator control while the distal portion transitions to lower rigidity for safe vessel navigation, allowing each section to optimize its function locally
2Object-affected harmful factors
If a catheter is made flexible at the distal end to allow passage through loops and narrow blood vessels, then the catheter can navigate complex vasculature, but it lacks the strength to resist kinking and maintain structural integrity
Solution Approach 1:
The catheter structure is segmented into proximal and distal sections with different coil configurations. The distal section uses looser windings for flexibility while maintaining sufficient structural support through the coil architecture, preventing kinking even in highly flexible regions
Solution Approach 2:
The catheter employs a composite construction combining flexible polymer materials with embedded coil structures. This composite approach provides both the flexibility needed for navigation and the structural strength to resist kinking, achieving both contradictory requirements simultaneously
3Stability of the object's composition
If additional anchoring structures are added to secure the catheter in place, then the catheter stability improves, but the outer diameter increases making it difficult to access small vessels
Solution Approach 1:
The anchoring function is merged with the existing coil structure rather than adding separate anchoring components. The coils themselves provide stabilization through their mechanical properties and interaction with vessel walls, eliminating the need for additional anchoring structures that would increase diameter
Solution Approach 2:
The coil structure serves multiple functions simultaneously: providing structural support, enabling flexibility, and delivering stabilization/anchoring. This multi-functionality eliminates the need for dedicated anchoring components, maintaining small outer diameter while achieving stability
4Volume of moving object
If the catheter outer diameter is minimized to access small vessels, then access to remote sites is improved, but the catheter loses strength and becomes more prone to kinking
Solution Approach 1:
The catheter employs a thin-walled flexible construction with integrated coil support. The flexible polymer shell provides the small outer diameter needed for vessel access while the embedded coil structure supplies the necessary structural strength, achieving both miniaturization and durability
Solution Approach 2:
A composite structure combining flexible polymer material with reinforcing coil elements provides both small diameter and high strength. The synergistic combination allows the catheter to be thin enough for small vessel access while remaining resistant to kinking and structural failure
Data Source
AI summary
A mixed coil catheter includes a hollow inner liner defining a lumen, having an exterior surface, and defining a middle point, a single support cord coiled around the exterior surface of the inner liner starting from an intermediate point in a distal direction up to a support end plane and then reversed in the proximal direction proximally away from the support end plane at least past the middle point of the inner liner, having a maximum outer diameter, and forming an end wall at the support end plane, and an outer liner covering the inner liner and the support cord to fix the support cord in place.