Stability Tube Sheath Design for Precise Heart Valve Deployment
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Solution Overview
Problem
Conventional transcatheter delivery systems for prosthetic heart valves face issues with unintended movement of the prosthesis due to friction between the introducer device and the delivery sheath, leading to incorrect positioning and potential complications during deployment.
Innovation Solution
A delivery device with a delivery sheath assembly, a handle, and an outer stability tube is used to isolate the delivery sheath from the introducer device, allowing for smooth retraction of the sheath and stable deployment of the prosthetic heart valve, utilizing a stent frame that self-expands from a compressed state to a natural arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the delivery sheath is retracted to deploy the self-expanding prosthetic heart valve, then the valve can be deployed, but friction between the introducer device and delivery sheath causes unintended movement of the prosthesis
Solution Approach 1:
A low-friction liner is introduced as an intermediary component between the delivery sheath and the introducer device. This liner acts as a mediator that reduces frictional forces, preventing the harmful transmission of movement from the delivery sheath retraction to the prosthetic valve, thereby maintaining positioning accuracy during deployment.
2Manufacturing precision
If the delivery sheath is held stationary during retraction, then positioning accuracy is maintained, but the friction force must be overcome by additional stabilizing structures
Solution Approach 1:
The low-friction liner serves as a mediating element that eliminates the need for complex stabilizing structures. By reducing friction at the interface between the delivery sheath and introducer device, the liner allows the delivery sheath to be held stationary during retraction without requiring additional stabilizing components, thus maintaining deployment precision while avoiding increased device complexity.
3Ease of operation
If the prosthetic valve is self-expanding, then deployment is simplified, but friction resistance during sheath retraction increases
Solution Approach 1:
The low-friction liner converts the harmful effect of friction resistance into a beneficial reduction of retraction force. By minimizing friction between the delivery sheath and introducer device, the liner ensures that the force required to retract the sheath and deploy the self-expanding valve is reduced, making the deployment process easier to control while maintaining the simplicity of self-expansion.
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
Ensures precise placement of the prosthetic heart valve by minimizing frictional interference, reducing the risk of misplacement and complications, and facilitating minimally invasive percutaneous implantation.
Implementation Method 1
a self-expanding stented prosthetic heart valve
Implementation Method 2
an outer stability tube that isolates the delivery sheath from the introducer device
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A device for percutaneous delivery of a stented prosthetic heart valve. The device includes a sheath, a handle, and an outer stability tube. The sheath includes a distal capsule and a proximal shaft. The handle has a housing maintaining an actuator mechanism that is coupled to the shaft. The actuator mechanism is configured to selectively move the shaft, and thus the capsule, relative to the housing. The stability tube is coupled to the housing and is coaxially received over the shaft such that the shaft is slidable relative to the stability tube. In a delivery state, the capsule encompasses the prosthetic valve. In a deployed state, the capsule is withdrawn from the prosthetic valve. The shaft slides relative to the stability tube in transitioning from the loaded state to the deployed state. When used with an introducer device, the stability tube frictionally isolates the sheath.