Stent Valve Delivery Catheter Torque Control
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Solution Overview
Problem
Transcatheter heart valve replacement devices face challenges in achieving controllable and consistent deployment and anchoring of stent-valves, particularly in variable anatomical conditions such as severe calcification, and navigating a delivery catheter through tortuous and stenosed vasculature, while ensuring atraumatic introduction and support for deployment.
Innovation Solution
A delivery catheter system with a distal portion for insertion into the anatomy, featuring a stent-valve accommodation region with dual sheaths that translate in opposite directions to reduce distal extension, a stent holder for axial restraint, and a flexible stem portion with nested tubes for torque transmission, allowing for precise control and rotation of the stent-valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the delivery catheter is made large enough to accommodate the stent-valve, then the stent-valve can be delivered and deployed, but the catheter becomes difficult to navigate through tortuous and stenosed vasculature
Solution Approach 1:
The delivery catheter is divided into multiple functional segments: a flexible distal portion for navigation through vasculature, a mid-portion with controlled flexibility for force transmission, and a proximal portion for operator control. This segmentation allows each segment to be optimized for its specific function while working together as a complete system.
Solution Approach 2:
Different portions of the catheter have different flexibility characteristics tailored to their specific functions. The distal portion is made highly flexible for navigating tortuous vasculature, while the mid-portion has controlled flexibility to transmit deployment forces, and the proximal portion provides structural support for operator manipulation.
2Ease of operation
If the catheter is made soft and flexible for atraumatic introduction and ease of navigation, then the catheter can navigate tortuous vasculature easily, but it reduces the ability to provide support for force applied from the proximal end
Solution Approach 1:
The catheter is segmented into distinct flexibility zones: a soft distal portion for navigation, a mid-portion with intermediate flexibility for force transmission, and a stiff proximal portion for operator control. This allows the catheter to be soft where needed for navigation while maintaining strength where needed for force application.
Solution Approach 2:
The catheter exhibits spatially varying mechanical properties, with the distal portion being highly flexible for atraumatic navigation, the mid-portion having controlled flexibility to transmit forces effectively, and the proximal portion being structurally robust for operator manipulation and force application.
3Volume of moving object
If the delivery catheter is made small for easier navigation, then the catheter can pass through stenosed vasculature, but it affects the reliability and accuracy of stent-valve deployment
Solution Approach 1:
The catheter is designed with segmented flexibility characteristics that allow a smaller overall profile for navigation while maintaining adequate support capabilities. The distal portion is small and flexible for passage through stenosed vasculature, while the proximal and mid-portions provide the necessary structural support for reliable deployment.
Solution Approach 2:
The catheter has locally optimized mechanical properties where the distal portion is small and highly flexible for navigating through constricted vasculature, while the proximal and mid-portions maintain sufficient stiffness and strength to ensure reliable and accurate stent-valve deployment.
4Strength
If the catheter is made stiff to provide support for force application, then the catheter can traverse the existing valve effectively, but it reduces the ability to navigate tortuous vasculature
Solution Approach 1:
The catheter is divided into flexibility zones where the distal portion is soft and flexible for navigating tortuous vasculature, while the proximal and mid-portions are stiffer to provide the necessary support for force application during valve traversal and stent-valve deployment.
Solution Approach 2:
The catheter exhibits spatially varying stiffness characteristics, with the distal portion being soft and flexible for easy navigation through tortuous vasculature, while the proximal and mid-portions are structurally reinforced to provide adequate support for force application during the deployment procedure.
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
Enables precise and controlled deployment of stent-valves in challenging anatomical conditions, reducing the risk of damage to heart tissue and improving the reliability and accuracy of valve placement, while facilitating easier withdrawal of the catheter.
Implementation Method 1
a flexible stem portion with nested tubes for torque transmission, allowing for precise control and rotation of the stent-valve
Data Source
AI summary
A delivery catheter for a stent valve, the delivery catheter having a distal portion insertable into an anatomy, the distal portion comprising an accommodation region for accommodating a stent-valve for delivery into the anatomy, the delivery catheter further comprising at least one sheath that is translatable between a closed position for at least partly closing the accommodation region and an open position for at least partly opening the accommodation region.