Prosthetic Heart Valve Delivery for Controlled Sheath Release
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Solution Overview
Problem
Existing prosthetic heart valves, particularly self-expanding ones, face challenges in precise and controlled deployment due to their tendency to 'jump' out of the delivery sheath, and may not anchor sufficiently to non-stenotic native valves, often requiring additional anchoring devices that can complicate future interventions.
Innovation Solution
A delivery apparatus with a rotatable second shaft and a sheath retaining ring system, allowing controlled axial movement of the delivery sheath via thread engagement, and a valve-retaining mechanism to secure the prosthetic valve during deployment, minimizing the need for additional anchoring devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a self-expanding prosthetic valve is advanced from the delivery sheath, then the valve expands to its functional size, but the valve tends to jump out very quickly from the end of the sheath due to outward biasing force
Solution Approach 1:
The delivery sheath is designed with a tapered distal end that gradually reduces in diameter, creating a gradual transition zone that allows the self-expanding valve to expand in a controlled manner as it exits the sheath. This preliminary shaping action prevents sudden expansion and jumping while maintaining precise delivery control.
Solution Approach 2:
The tapered distal end of the delivery sheath acts as an intermediary structure between the compressed valve and the final expanded position. This intermediate geometry provides a transition zone that mediates the expansion process, allowing controlled deployment without direct sudden contact between the fully expanded valve and the sheath opening.
2Reliability
If additional anchoring devices are added to the prosthetic valve to prevent migration, then anchoring force is improved, but the device complexity increases and future interventions are complicated
Solution Approach 1:
The stent structure is designed to perform multiple functions simultaneously: it provides structural support for the valve, enables self-expansion, and provides anchoring through its interaction with the aortic wall. This multi-functional design eliminates the need for separate anchoring devices while maintaining anchoring stability.
Solution Approach 2:
The anchoring function is merged with the stent structure itself. The stent's radial expansion and apposition to the aortic wall combines support and anchoring functions in a single integrated component, reducing overall device complexity while ensuring reliable anchoring.
3Reliability
If anchoring devices extend into non-diseased areas of the vasculature to secure the valve, then anchoring force is improved, but trauma risk and complications in future interventions increase
Solution Approach 1:
The stent is designed with varying radial strength and expansion characteristics along its length, with the distal portion providing anchoring in the diseased aortic tissue while the proximal portion maintains a lower profile. This local differentiation allows anchoring stability without extending rigid structures into non-diseased vasculature, minimizing trauma risk.
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 and controlled deployment of prosthetic heart valves, reducing the risk of trauma and simplifying future interventions by ensuring adequate anchoring to the native valve without extending into non-diseased areas.
Implementation Method 1
The second shaft is rotatable relative to the first shaft but is fixed against axial movement relative to the first shaft. The distal end portion of the second shaft has an outer surface comprising external threads or grooves. A sheath retaining ring is disposed on the threads or grooves of the second shaft and is fixed against rotational movement relative to the distal end portion of the second shaft. The second shaft is configured to be rotatable relative to the first shaft such that rotation of the second shaft causes the sheath retaining ring to move axially along the threads or grooves, thereby moving the sheath axially relative to the first and second shafts to deploy a prosthetic valve contained within the sheath.
Data Source
Figure 1~2
Figure 3~4
Figure 5A
AI summary
Certain embodiments of the present disclosure provide a prosthetic valve (10) (e.g., prosthetic heart valve) and a valve delivery apparatus (100) for delivery of the prosthetic valve to a native valve site via the human vasculature. The delivery apparatus is particularly suited for advancing a prosthetic heart valve through the aorta (i.e., in a retrograde approach) for replacing a diseased native aortic valve. The delivery apparatus in particular embodiments is configured to deploy a prosthetic valve from a delivery sheath in a precise and controlled manner at the target location within the body.