Balloon Catheter Inner Lumen and Outer Diameter Design
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Solution Overview
Problem
Current microcatheters face challenges in achieving a balance between minimizing outer diameter for access through small vessels and maximizing inner lumen size for therapeutic agent delivery, while also requiring flexibility to navigate tortuous vasculature and the ability to transmit torque for precise placement.
Innovation Solution
The design incorporates a thin-walled balloon catheter with an outer and inner shaft configuration, where the balloon is secured radially inward to maintain a small outer diameter, and a proximal stiff section for torque transmission and a distal flexible section for navigation, with discrete connection points to facilitate both flexibility and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the outer diameter of the microcatheter is minimized for access through small vessels, then the ability to navigate small vessels is improved, but the inner lumen size for therapeutic agent delivery is reduced
Solution Approach 1:
The catheter is divided into multiple functional segments: a proximal shaft portion with larger diameter for torque transmission, a distal shaft portion with smaller diameter for vessel navigation, and a balloon portion with intermediate diameter for therapeutic agent delivery. This segmentation allows each segment to be optimized for its specific function while working together as an integrated system.
Solution Approach 2:
Different sections of the catheter have different structural properties: the proximal section has thicker walls and larger diameter for stiffness and torque transmission, the distal section has thinner walls and smaller diameter for flexibility and navigation, and the balloon section has controlled wall thickness for controlled expansion and drug delivery. This local differentiation resolves the contradiction by providing appropriate properties in appropriate locations.
2Adaptability or versatility
If the catheter is made flexible to navigate tortuous vasculature, then the ability to navigate tortuous vasculature is improved, but the ability to transmit torque for precise placement is reduced
Solution Approach 1:
The catheter shaft is segmented into proximal and distal portions with different flexibility characteristics. The proximal portion is stiffer to transmit torque from the operator's hand to the distal end, while the distal portion is more flexible to navigate tortuous vessels. This segmentation allows simultaneous optimization of both torque transmission and navigational flexibility.
Solution Approach 2:
The catheter has spatially varying mechanical properties along its length, with the proximal section designed for high torque transmission and the distal section designed for high flexibility. This local differentiation in mechanical properties resolves the contradiction between torque transmission and flexibility by providing the appropriate property in the appropriate location.
3Area of stationary object
If the balloon is secured radially inward to maintain a small outer diameter, then the outer diameter is minimized, but the structural support for the balloon is reduced
Solution Approach 1:
The balloon is positioned radially inward within the catheter assembly, utilizing the internal volume rather than extending the outer diameter. This dimensional repositioning allows the balloon to be supported by the catheter structure while maintaining a compact outer profile, resolving the contradiction between small outer diameter and adequate structural support.
Solution Approach 2:
The balloon is nested within the catheter shaft structure, with the catheter providing external support and confinement. This nesting arrangement allows the balloon to be supported by the catheter's structural integrity while maintaining a small overall outer diameter, as the balloon does not need to be self-supporting at full diameter.
Data Source
AI summary
Balloon catheters that includes inner and outer elongate shafts, each of which is secured relative to an end of an inflatable member. The inner and outer elongate shafts are secured relative to one another at one more discrete connection locations. The balloon bonding locations are disposed radially inward relative to an outer dimension of the outer elongate shaft.