Capsule Pull Wire Steering for Vascular Navigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current delivery catheters face challenges in navigating tortuous vasculature due to competing design considerations such as flexibility, axial strength, and torsional strength, requiring a balance that is difficult to achieve, especially in the distal portion where a prosthesis is held in a compressed state.
Innovation Solution
A delivery device with a handle, sheath, and capsule featuring a pull wire that is tensioned to bend the capsule, allowing for navigation through the vasculature, and a tubular body with ribs and slots for flexibility, along with an indented segment to secure the pull wire, facilitating deployment of a prosthesis from a radially compressed state to an expanded state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the delivery catheter is made flexible to navigate tortuous vasculature, then navigation capability is improved, but axial strength and torsional strength deteriorate
Solution Approach 1:
The delivery catheter is divided into multiple segments including a flexible distal portion and a more rigid proximal portion. The distal portion contains the prosthesis in a compressed state and is designed with enhanced flexibility for navigation, while the proximal portion provides structural support and strength for manipulation and deployment.
Solution Approach 2:
Different portions of the delivery catheter are assigned different mechanical properties tailored to their specific functions. The distal portion has higher flexibility for navigating tortuous vasculature, while the proximal portion has higher axial and torsional strength for withstanding manipulation forces and torque during steering and deployment.
2Length of moving object
If the outer diameter of the delivery catheter is reduced to facilitate navigation, then profile is improved, but structural strength deteriorates
Solution Approach 1:
The delivery catheter employs a segmented construction where the distal portion has a smaller outer diameter optimized for navigation through tortuous vasculature, while the proximal portion has a larger outer diameter that provides the necessary structural strength and stiffness for manipulation and deployment.
Solution Approach 2:
The catheter wall thickness and material properties are varied along its length. The distal portion uses thinner walls and more flexible materials to achieve a low profile for navigation, while the proximal portion uses thicker walls and stiffer materials to provide structural strength for withstanding axial and torsional loads during operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the ability to steer and deploy prostheses through complex vascular anatomy by improving flexibility and axial strength, reducing the force required for bending and maintaining radial strength, thus facilitating precise placement of medical devices like stents and valves.
Implementation Method 1
The pull wire is tensioned to bend the capsule
Data Source
AI summary
A delivery device includes a handle, a sheath distally extending from the handle, a capsule distally extending from the sheath, and a pull wire having a proximal end attached to the handle and a distal end attached to the capsule. The sheath defines a central lumen there-through and has a longitudinally-extending lumen formed within a wall of the sheath. The capsule has a tubular body with an intermediate region having a plurality of ribs and a plurality of slots defined therein. The capsule includes an indented segment defined on the tubular body, the indented segment being disposed radially inward relative to the tubular body. The pull wire is tensioned to bend the capsule. The pull wire is slidably disposed within the longitudinally-extending lumen of the sheath and along an inner surface of the tubular body of the capsule with a portion of the pull wire crossing over an outer surface of the indented segment.