Heart Valve Delivery Sheath Control for Precise Aortic Deployment
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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 outward biasing force causing them to 'jump' out of the delivery sheath, and may not exert sufficient force for anchoring in 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 mechanism that allows controlled axial movement of the delivery sheath, combined with a valve-retaining mechanism, ensures precise deployment and anchoring of the prosthetic valve in the native aortic valve without extending into non-diseased areas.
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 outward biasing force causes the valve to jump out quickly from the sheath, making precise and controlled delivery difficult
Solution Approach 1:
The delivery sheath is pre-configured with a retention mechanism that engages with the prosthetic valve before deployment. This preliminary engagement allows the operator to control the valve's expansion sequence, preventing premature ejection while enabling controlled deployment when needed.
Solution Approach 2:
A delivery sheath acts as an intermediary between the operator and the self-expanding prosthetic valve. The sheath's retention mechanism mediates the interaction by providing controlled resistance to the valve's outward biasing force, enabling precise positioning before release.
2Reliability
If additional anchoring devices are added to the prosthetic valve stent, then the valve can resist migration in non-stenotic native valves, but the anchoring devices extend into non-diseased areas, complicating future interventions
Solution Approach 1:
The anchoring mechanism is designed to engage only with the diseased native valve tissue at the implantation site, not with healthy surrounding vasculature. This localized anchoring provides sufficient resistance to migration while preserving future intervention options by avoiding attachment to non-diseased areas.
Solution Approach 2:
The prosthetic valve system is segmented into functional components: the self-expanding stent for structural support, the valve leaflets for function, and a minimal anchoring feature integrated into the stent framework. This segmentation allows anchoring without requiring separate additional devices that would extend into healthy tissue.
3Force
If the prosthetic valve is made to expand quickly to apply sufficient anchoring force, then the valve can secure to calcified tissue, but the rapid expansion increases trauma risk and reduces control
Solution Approach 1:
The expansion process is divided into periodic stages: initial controlled expansion to establish positioning, followed by gradual progression to full expansion. This staged approach allows the tissue to accommodate the expanding valve progressively, reducing traumatic effects while achieving sufficient anchoring force.
Solution Approach 2:
The delivery system incorporates cushioning mechanisms that manage the expansion force before it reaches the tissue. The retention mechanism and controlled release system act as cushions, regulating the force transmission to prevent sudden traumatic expansion while ensuring adequate anchoring is achieved.
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, minimizing trauma and simplifying future interventions by anchoring primarily to the diseased native valve, reducing complications and facilitating easy removal.
Implementation Method 1
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
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.