Adjustable Heart Valve Sizer with Protective Cover
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Solution Overview
Problem
Current heart valve sizing methods are time-consuming, inaccurate, and prone to entanglement with heart structures during minimally invasive surgeries, leading to potential tissue damage and increased risks of embolization and paravalvular leaks.
Innovation Solution
An adjustable force-based heart valve sizer with a sizer cover that expands and contracts to prevent entanglement, allowing smooth access and removal from valvular and sub-valvular spaces, using an elastomeric or shape-memory alloy material to guard against chordae tendineae and other structures, and a clutch mechanism to control radial expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sizer discs are used to measure valve annulus, then multiple sizers need to be tried sequentially, but this increases surgery time and reduces efficiency
Solution Approach 1:
The sizer is designed with a single device that can determine multiple valve sizes through radial expansion. The sizer includes an expandable frame structure that can be adjusted to different diameters, allowing one sizer to replace multiple conventional sizer discs. The surgeon can expand the sizer to different sizes by adjusting the radial position of the frame segments, eliminating the need to insert multiple separate sizers sequentially.
2Measurement precision
If dimensionally large sizers are used to accurately gauge valve sizes, then insertion through minimally invasive incisions becomes difficult, but smaller sizers may not provide accurate tactile feedback
Solution Approach 1:
The sizer employs a dynamic structure that can change its dimensions. The frame segments can radially expand from a compressed delivery profile to a full sizing profile. During insertion through minimally invasive incisions, the sizer maintains a compact profile. Once positioned in the valve annulus, the sizer can be expanded to provide accurate tactile feedback for sizing determination.
Solution Approach 2:
The sizer frame segments are designed to nest within each other during delivery. The expandable structure allows the sizer to be collapsed into a small profile for insertion through small incisions, then expanded to full size for accurate valve annulus measurement. This nesting capability enables the sizer to pass through minimally invasive access points while maintaining full sizing capability.
3Measurement precision
If sizer is pushed past the annulus to determine tight fit, then accurate sizing can be achieved, but chordae tendineae may become entangled with the sizer
Solution Approach 1:
A protective cover is provided that surrounds the sizer frame segments. This cover acts as an intermediary barrier between the sizer and the chordae tendineae. The cover prevents direct contact and entanglement of the chordae with the sizer structure while still allowing the sizer to expand and contact the valve annulus for accurate sizing determination.
Solution Approach 2:
The protective cover is made of a flexible material that can accommodate the radial expansion of the sizer frame. The flexible cover conforms to the expanded sizer shape while providing a smooth outer surface that prevents chordae tendineae from catching or entangling with the sizer structure during insertion and sizing operations.
4Measurement precision
If excessive force is exerted to determine tight fit size, then accurate sizing may be achieved, but tissue damage can occur
Solution Approach 1:
The sizer incorporates a force sensing mechanism that provides feedback to the surgeon about the force being exerted on the valve annulus. This feedback allows the surgeon to determine the appropriate tight fit size without applying excessive force. The system can detect when sufficient contact force is achieved and alert the surgeon, preventing tissue damage while ensuring accurate sizing.
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 quick, accurate sizing of the heart valve annulus with reduced surgery time and minimized risk of complications, ensuring precise replacement valve selection and smooth surgical procedures.
Implementation Method 1
The sizer cover is made from an elastomeric material configured to expand and contract in response to conversion of the sizing element between its radially-retracted and radially-expanded configurations
Implementation Method 2
The sizer cover comprises a woven basket made of shape-memory alloy wires configured to expand and contract in response to conversion of the sizing element between its radially-retracted and radially-expanded configurations
Data Source
AI summary
A heart valve sizer and sizer cover are provided for determining the size of a heart valve annulus. The valve sizer can include a handle, a shaft extending distally from the handle, a sizing element coupled to the distal end of the shaft, the sizing element being movable between a first retracted position and a second expanded position, and a sizer cover. The sizer cover can be formed from a continuous sheet of material configured to surround at least a portion of the sizing element of the heart valve sizer so as to guard against entanglement of the sizing element with structures of a human heart.