Prosthetic Heart Valve Delivery Handle for Precise Single-Handed Positioning
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Solution Overview
Problem
Existing delivery devices for prosthetic heart valves face challenges such as large crimp profiles that hinder advancement through vasculature, difficulty in precise positioning, and cumbersome control mechanisms, often requiring both hands and prone to jamming or kinking.
Innovation Solution
A delivery apparatus with a handle portion and elongated shafts, featuring a gear assembly that converts longitudinal motion to rotational motion for precise positioning, and a steering assembly with a rotatable member and pull wire for flexible control, allowing single-handed operation and accurate placement of the prosthetic valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a prosthetic valve has a relatively large profile in the compressed state, then the valve structure can be more robust and easier to manufacture, but the physician's ability to advance the valve through the femoral artery or vein is inhibited
Solution Approach 1:
The delivery device is divided into multiple segments including a compressible valve body, a delivery catheter, and a compression mechanism. The valve is segmented into a crimped configuration for delivery and an expanded configuration for implantation, allowing it to pass through small vasculature while maintaining structural integrity at the implantation site.
Solution Approach 2:
The valve's physical parameters (diameter, volume) are changed between two states: a compressed crimped state for delivery through the vasculature and an expanded functional state for implantation. This parameter transformation enables the valve to overcome the contradiction between size for advancement and size for structural robustness.
2Length of moving object
If the delivery device is relatively long for transfemoral delivery, then the valve can be delivered through the vasculature, but the physician's ability to position the valve precisely at the desired implantation site is inhibited due to unwanted movement caused by forces applied to the handle
Solution Approach 1:
A wire or stylet is introduced as an intermediary element within the delivery catheter to provide a stable rail for the valve. This intermediary structure allows the valve to be positioned precisely at the implantation site while the long delivery catheter can be maneuvered through the vasculature, separating the functions of delivery and positioning.
Solution Approach 2:
The mechanical coupling between the handle and the distal tip is replaced or supplemented with a wire-based control system. This substitution allows independent control of the valve position from the handle location, reducing unwanted movement transmission over the long device length while maintaining precision at the implantation site.
3Force
If known delivery devices require two hands for positioning control, then sufficient force can be applied to control the valve, but the ease of operation is reduced and control mechanisms can become jammed or kinked
Solution Approach 1:
A wire or stylet acts as an intermediary transmission element that conveys control forces from the proximal handle to the distal valve with mechanical advantage. This intermediary mechanism amplifies the force applied by a single hand, enabling sufficient control force without requiring two hands, while reducing the risk of jamming by eliminating the need for complex multi-handed control mechanisms.
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, single-handed control and positioning of prosthetic heart valves, reducing the risk of jamming and kinking, and facilitating delivery through smaller vasculature profiles for a wider patient population.
Implementation Method 1
The handle portion comprises a control member movable longitudinally with respect to the handle portion, the control member engaging a gear assembly operable to convert longitudinal motion of the control member to rotational motion of the gear assembly
Implementation Method 2
The shaft comprises a proximal end portion coupled to the handle portion and a distal end portion configured to mount a prosthetic heart valve in a radially compressed state
Data Source
AI summary
A delivery apparatus for implanting a radially compressible and expandable prosthetic heart valve in a native heart valve of the heart includes a handle portion and a balloon catheter assembly comprising an elongated balloon catheter shaft extending from the handle portion. The balloon catheter shaft includes a proximal end portion coupled to the handle portion and a distal end portion. The balloon catheter assembly further includes a balloon coupled to the distal end portion and configured to mount a prosthetic heart valve in a radially compressed state. A two-piece protective cover encapsulates the balloon, and the cover includes separable first and second cover portions defining a cavity shaped to accommodate the balloon. The cavity includes a distal portion, a proximal portion, and a central portion, and an internal wall that reduces an inner diameter of the cavity between the distal portion and the central portion.