Transcatheter Heart Valve Delivery Resheathing Lock Mechanism
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Solution Overview
Problem
Conventional delivery systems for self-expanding prosthetic heart valves face challenges in controlling partial deployment and repositioning, as they often result in accidental full deployment before verifying the valve's optimal position, making it difficult to resheathe and reposition the valve.
Innovation Solution
A delivery device with an operating handle and catheter assembly featuring a carriage assembly and resheathing locks that allow for controlled partial deployment and repositioning of the valve, using a combination of locks and a deployment actuator to manage the movement of the distal sheath and valve deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional delivery systems are used for self-expanding valves, then the valve can be deployed, but it is difficult to control partial deployment and the valve may accidentally deploy fully before verifying optimal position
Solution Approach 1:
The delivery system is segmented into multiple functional components: a distal sheath for containing the valve, a carriage assembly for controlled movement, and a resheathing lock mechanism with multiple lockable positions. This segmentation allows independent control of each function, enabling precise partial deployment where the valve can be stopped at intermediate positions without accidental full deployment.
Solution Approach 2:
The system performs preliminary actions by allowing the valve to be partially deployed and secured at an intermediate position before final deployment. The resheathing lock can be engaged at the first intermediate position to temporarily secure the valve in a partially deployed state, enabling position verification and adjustment before committing to full deployment.
2Ease of operation
If the valve is partially deployed for position verification, then repositioning becomes possible, but the valve expands to a diameter larger than the sheath making resheathing impossible or difficult
Solution Approach 1:
The system employs a nested structure where the distal sheath can be re-sheathed over the partially deployed valve. The carriage assembly is designed to receive and secure the distal sheath at intermediate positions, creating a nested configuration that enables resheathing and repositioning without requiring the valve to be fully collapsed.
Solution Approach 2:
The system provides dynamic control through the resheathing lock mechanism that can be engaged or disengaged at different stages. The carriage assembly can move between locked and unlocked states, allowing the operator to dynamically adjust the deployment state and perform resheathing operations when needed, rather than having a fixed deployment path.
3Manufacturing precision
If the distal sheath is moved to an intermediate condition for partial deployment, then controlled positioning is achieved, but the mechanism becomes more complex
Solution Approach 1:
The carriage assembly serves multiple functions: it moves the distal sheath to intermediate positions for partial deployment, secures the sheath in locked positions, and enables resheathing operations. This multi-functionality reduces the need for separate mechanisms for each operation, managing complexity while achieving precise valve placement control.
Data Source
AI summary
A delivery device for a collapsible heart valve includes an operating handle, including a frame defining a movement space therein, a carriage assembly moveable within the movement space, and a first resheathing lock having a locked position and an unlocked position. The delivery device further includes a catheter assembly, including a first shaft around which a valve-receiving compartment is defined, the first shaft being fixedly connected to one of the frame or the carriage assembly, and a distal sheath operatively connected to the carriage assembly. The distal sheath is moveable between a closed condition adapted to maintain the valve in the compartment and an open condition adapted to fully deploy the valve. With the resheathing lock in the locked position, the distal sheath is unable to move to the open condition to fully deploy the valve.