Percutaneous Valve Prosthesis Supra-Annular Fixation
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Solution Overview
Problem
Current percutaneous heart valve replacement technologies face challenges such as lack of deployment control, large cross-sectional delivery profile, inadequate fixation, poor radial strength, and leakage issues, which increase procedural complexity and risk, and do not effectively address the need for maximal valve area or long-term durability.
Innovation Solution
A heart valve prosthesis comprising a cylindrical valve cage stent with a superior rim and an elastic, compressible multi-leaflet valve, where the valve is detachably connected to the stent using memory metal frames and tissue covers, providing active fixation and minimizing leakage through a supra-annular implantation and attachment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a balloon-expandable stent integrated with a bioprosthetic valve is used for percutaneous replacement, then the procedure can be performed under local anesthesia without open-heart surgery, but there is very little control over deployment which endangers coronary ostia and mitral valve
Solution Approach 1:
The stent is designed with expandable and collapsible properties, allowing it to be compressed for delivery through a catheter and then expanded at the target site. This dynamic transformation enables percutaneous access while providing controlled deployment through mechanical actuation mechanisms that allow the operator to control the timing and extent of expansion.
Solution Approach 2:
A delivery catheter system serves as an intermediary device that holds the compressed stent during navigation and then facilitates controlled expansion at the target site. The catheter system provides the mechanical interface through which the operator can control deployment, thereby resolving the contradiction between percutaneous access and deployment control.
2Strength
If a robust stainless steel stent is used to fabricate the tri-leaflet pericardial valve, then the valve structure is durable, but the cross-sectional delivery profile becomes relatively large making retrograde delivery challenging
Solution Approach 1:
The stent valve is designed to be nested within a delivery catheter in a compressed state. The stent structure allows it to be collapsed into a small profile for delivery while maintaining its robust construction for durability once deployed. This nesting capability enables the valve to pass through the catheter in a compressed configuration and then expand to its full functional size at the implantation site.
Solution Approach 2:
The stent transitions from a compressed, low-profile state during delivery to an expanded, high-strength state at the implantation site. This dynamic transformation allows the same structure to satisfy both the small delivery profile requirement and the durability requirement in different phases of the procedure.
3Stability of the object's composition
If radial force is used to hold the stent in position, then fixation is achieved, but sufficient dilation can cause damage to the annulus and the device cannot treat aortic regurgitation
Solution Approach 1:
The stent is designed with non-uniform structural characteristics, with enhanced radial strength in specific regions to provide secure fixation while maintaining appropriate compliance in other areas to prevent annular damage. The stent structure includes features such as varied strut thickness or density in different zones to optimize both fixation and tissue protection.
Solution Approach 2:
The stent combines materials or structural configurations that provide different mechanical properties in different regions, allowing simultaneous achievement of strong fixation and annular protection. The composite design enables the stent to exert controlled radial force that secures positioning without causing excessive dilation or damage to the native annulus.
4Strength
If the valve and stent materials are made bulky to ensure durability, then the structural strength is improved, but the cross-sectional delivery profile increases significantly
Solution Approach 1:
The valve and stent are designed to nest within each other and within the delivery catheter in a compressed configuration. The structural strength is maintained through the inherent material properties and geometric design of the stent framework, while the nested arrangement allows the entire assembly to be delivered through a catheter with a manageable profile.
Solution Approach 2:
The valve-stent assembly transitions from a compressed, low-profile state during delivery to an expanded, high-strength state at implantation. The dynamic transformation allows the structure to have small cross-sectional area during delivery while achieving large structural strength once deployed in its functional configuration.
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
The solution enables precise, controlled deployment with improved radial strength, reduced leakage, and maximal valve area, allowing for safer and more effective percutaneous heart valve replacement with enhanced durability and ease of valve exchange if needed.
Implementation Method 1
a valve frame made from a memory metal
Implementation Method 2
an elastic and compressible, multi-leaflet valve including a valve frame made from a memory metal and a tissue cover
Data Source
AI summary
A method for delivering a heart valve prosthesis to a native valve annulus comprises expanding an expandable frame at the native valve annulus and positioning a replacement heart valve within the expandable frame. The expandable frame preferably includes a first anchoring portion that is positioned on a first side of the native valve annulus and a second anchoring portion that is positioned on a second side of the native valve annulus. The first anchoring portion engages tissue on the first side of the native valve annulus and the second anchoring portion engages tissue on the second side of the native valve annulus for securing the expandable frame to the native valve annulus. The replacement heart valve comprises a plurality of leaflets for replacing the function of the native valve.