Steerable Catheter Multi-Zone Stiffness Profile
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Solution Overview
Problem
Current steerable intra-vascular catheters face challenges in achieving optimal distal torque transmission, trackability, pushability, and lateral stability due to uniform stiffness profiles, which limits their effectiveness in navigating tortuous anatomy and maintaining electrode stability during arrhythmia treatments.
Innovation Solution
A steerable catheter with a heterogeneous, multi-zone stiffness profile that transitions smoothly between different stiffness sections, incorporating varying materials and extrusion technologies to create distinct stiffness zones and transition zones, enhancing torque transmission, trackability, and lateral stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a uniform stiffness profile is used in the catheter shaft, then the structure is simple and easy to manufacture, but distal torque transmission and lateral stability are insufficient
Solution Approach 1:
The catheter shaft is divided into multiple distinct stiffness zones (distal, intermediate, and proximal sections) with different flexibility characteristics. This segmentation allows each zone to be optimized for specific functions: the distal section provides flexibility for navigation, the intermediate section enables torque transmission, and the proximal section offers structural support, thereby resolving the contradiction between torque transmission and structural simplicity.
Solution Approach 2:
Different sections of the shaft are assigned different stiffness properties tailored to their specific functional requirements. The distal section has lower stiffness for trackability, the intermediate section has transitional stiffness for torque transmission, and the proximal section has higher stiffness for pushability. This local differentiation resolves the contradiction by optimizing each region's properties rather than using a uniform structure.
2Ease of operation
If a uniform stiffness profile is used in the catheter shaft, then manufacturing is simplified, but trackability through tortuous anatomy is compromised
Solution Approach 1:
The shaft is segmented into a flexible distal section specifically designed for trackability through tortuous vasculature, an intermediate transition section, and a stiffer proximal section. This segmentation allows the distal portion to conform to complex anatomical paths while maintaining overall structural integrity, resolving the contradiction between trackability and structural simplicity.
Solution Approach 2:
The stiffness parameter of the shaft is varied along its length, with the distal section having lower stiffness values optimized for trackability through tortuous anatomy. This gradual parameter change from distal to proximal sections resolves the contradiction by allowing the shaft to be flexible where needed while maintaining structural support elsewhere.
3Force
If a uniform stiffness profile is used in the catheter shaft, then the design is simpler, but pushability through anatomy is reduced
Solution Approach 1:
The proximal section of the shaft is designed with higher stiffness to provide the necessary pushability for advancing the catheter through the vascular system. This local quality enhancement in the proximal region, combined with a flexible distal section, resolves the contradiction between pushability and structural simplicity by concentrating stiffness where it is most needed for force transmission.
4Stability of the object's composition
If a uniform stiffness profile is used in the catheter shaft, then the structure is more uniform and easier to manufacture, but lateral stability of the distal tip electrode is insufficient
Solution Approach 1:
The shaft is segmented into distinct stiffness zones, with the intermediate section providing transitional support and the proximal section offering enhanced structural stability. This segmentation creates a gradient of support that improves lateral stability of the distal tip electrode while maintaining manufacturing feasibility through standardized section design.
Data Source
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AI summary
A flexible, steerable intravascular catheter includes an elongate flexible shaft having a heterogeneous or multi-zone stiffness profile or structure. A first or distal section of the catheter shaft may have a substantially constant or distinct stiffness or flexibility, a second, intermediate or transition section is proximal relative to, and less flexible than, the first section, and a third section is proximal relative to, and also less more flexible than, the first section. The third section also includes a substantially constant or distinct stiffness or flexibility. The flexibility or stiffness of the second section varies along its length, e.g., in a substantially linear, step-like or ramp-like manner to provide a smooth or gradual transition between the stiffness of the first or distal section and the flexibility or stiffness of the third or proximal section.