Segmented Catheter Shaft Stiffness for Vessel Navigation
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Solution Overview
Problem
Catheter shafts face challenges in achieving a balance between longitudinal rigidity, torsional stiffness, and flexibility to effectively navigate through tortuous blood vessels while transmitting forces and torque.
Innovation Solution
The catheter shaft is constructed with a combination of inner and outer polymer structures, braids, and a coil, featuring varying stiffness along its length to provide enhanced pushability and torqueability, with specific designs for the distal portion to facilitate navigation through tortuous vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the catheter shaft is made more rigid to improve pushability, then longitudinal rigidity is improved, but flexibility to navigate tortuous vessels deteriorates
Solution Approach 1:
The catheter shaft is divided into multiple segments with different stiffness characteristics. The proximal portion has higher stiffness for pushability, while the distal portion has lower stiffness for navigation, creating a segmented structure that resolves the contradiction between rigidity and flexibility
Solution Approach 2:
Different portions of the catheter shaft are assigned different local properties: the proximal portion is designed with higher rigidity for force transmission, while the distal portion is designed with lower rigidity for bending and navigation, allowing each region to optimize its function locally
2Adaptability or versatility
If the catheter shaft is made more flexible to improve navigation through tortuous vessels, then flexibility is improved, but torqueability deteriorates
Solution Approach 1:
The shaft is segmented into proximal and distal portions with different torsional properties. The proximal portion maintains higher torsional stiffness for torque transmission, while the distal portion has reduced torsional stiffness for navigation, resolving the contradiction between torqueability and flexibility
Solution Approach 2:
Local quality variations are implemented where the proximal portion has higher torsional rigidity for operator control, while the distal portion has lower torsional rigidity for vessel navigation, allowing each region to have optimized local properties
3Device complexity
If the catheter shaft uses a simpler construction to reduce device complexity, then device complexity is reduced, but ability to balance pushability and torqueability deteriorates
Solution Approach 1:
The catheter shaft employs composite construction combining multiple materials and structural elements (proximal and distal portions with different stiffness characteristics) to simultaneously achieve pushability and torqueability, resolving the contradiction between simplicity and performance balance
Data Source
AI summary
Systems, devices, and methods for detaching an implantable device from a delivery system are disclosed herein. One aspect of the present technology, for example, is directed toward an elongated shaft having an inner surface that defines a lumen that extends distally from the proximal portion to an opening at a distal terminus of a distal portion. In some embodiments the distal portion includes an inner polymer structure having a first portion and a second portion positioned distal of the first portion along the length of the inner polymer structure. The first portion can have a first stiffness and the second portion can have a second stiffness less than the first stiffness. The distal portion can further include an outer polymer structure disposed around the inner polymer structure and a coil wound around the inner polymer structure and disposed within the outer polymer structure.