Steerable Catheter Pull Wire Actuation for Valve Delivery
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Solution Overview
Problem
Existing steerable catheters for delivering prosthetic valves to the heart face challenges in navigating through small vessels and tight bends, such as the aortic arch, due to complexity, cost, and instability issues, limiting their effectiveness and versatility.
Innovation Solution
A heart valve delivery system featuring a steerable section with a pull wire actuated by a rotational handle, integrated with a balloon catheter and a prosthetic valve, allowing for advancement through the vasculature while maintaining steerability and pushability, using a delivery sleeve assembly with a soft durometer Pebax® material for flexibility and a stainless steel hypotube for rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If spring bands are employed into a steerable catheter to provide stability, then the device gains stability, but the device complexity increases
Solution Approach 1:
The patent removes spring bands from the steerable catheter design, extracting the source of instability while eliminating device complexity. The catheter achieves stability through its structural design without requiring additional stabilizing components.
Solution Approach 2:
The steerable catheter is designed to be self-stabilizing through its inherent structural properties, eliminating the need for external spring bands. The catheter structure itself provides the necessary stability during navigation.
2Adaptability or versatility
If multiple connected segments are used to create a bent configuration for navigating tight bends, then the catheter can adapt to difficult vasculature, but the device complexity and cost increase
Solution Approach 1:
The catheter employs a dynamic bending mechanism that allows it to adapt to various vascular configurations. The catheter can change its shape from straight to bent as needed, providing navigation adaptability without requiring multiple rigid segments.
Solution Approach 2:
The catheter's physical parameters (shape, curvature) are made changeable to adapt to different vascular paths. By allowing the catheter to dynamically alter its configuration rather than using fixed segmented structures, the design achieves versatility while maintaining simplicity.
3Force
If the steerable section is made rigid for pushability, then the delivery system can be pushed through vasculature, but the ability to navigate bends is reduced
Solution Approach 1:
The delivery system is divided into distinct functional segments: a rigid pushable section for force transmission and a flexible steerable section for navigation. This segmentation allows the rigid portion to provide pushability while the flexible portion adapts to bends, resolving the contradiction between these two requirements.
Solution Approach 2:
Different portions of the catheter are assigned different mechanical properties - the proximal section is made rigid for pushability while the distal steerable section is made flexible for bending. This local differentiation of material properties allows simultaneous optimization of both pushability and navigation capability.
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 reliable and versatile navigation of the prosthetic valve to the native valve site, particularly around the aortic arch, without damaging the aorta, allowing for precise placement and deployment of the valve, enhancing the delivery system's pushability and control.
Implementation Method 1
The pull wire is actuated by a rotational handle assembly, wherein the rotational handle assembly is located proximal to the sleeve.
Implementation Method 2
the sleeve is formed of a polyether block amide, known as Pebax®, and comprises a soft durometer Pebax® near a distal end thereof
Implementation Method 3
using a delivery sleeve assembly with a soft durometer Pebax® material for flexibility and a stainless steel hypotube for rigidity
Data Source
AI summary
An assembly for delivering a prosthetic heart valve to a native heart valve is disclosed. The assembly includes a self-expanding prosthetic heart valve formed with an expandable metallic stent and a flexible valvular structure. The assembly also includes a delivery apparatus having a delivery sleeve. The delivery sleeve includes a selectively steerable section and a distal portion for retaining the prosthetic heart valve in a compressed state. A handle is coupled to a proximal end of the delivery sleeve and a pull wire extends from the handle to the steerable section of the delivery sleeve. The handle preferably includes a rotatable portion for actuating the pull wire and thereby selectively controlling a curvature of the steerable section during advancement through the patient's vasculature. In preferred embodiments, the steerable section includes a flexible metallic tubular portion formed with a plurality of circumferentially extending openings.