Transcatheter Mitral Valve with Nested Collapsible Frame
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Solution Overview
Problem
Developing a percutaneously delivered prosthetic mitral valve has been challenging due to the complex and uneven anatomy of the mitral valve, which has hindered successful replacement and treatment of mitral valve stenosis and insufficiency, unlike the successful percutaneous treatment of aortic valves.
Innovation Solution
A prosthetic heart valve with a collapsible wire frame combining a stent and wire mesh parts, designed for self-expansion and anchoring, along with leaflets made of natural or synthetic materials, which can switch positions in response to blood flow, is deployed using a delivery system that allows for precise placement and retrieval, addressing the anatomical complexities and providing stabilization and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a percutaneous delivery system is used for mitral valve replacement, then patient eligibility is expanded to include those with high surgical risk, but the device must navigate complex and uneven mitral valve anatomy which increases device complexity
Solution Approach 1:
The prosthetic valve is divided into distinct functional components: a frame structure with anchoring elements, leaflets for valve function, and a delivery system with separate positioning and deployment mechanisms. This segmentation allows each component to be optimized independently for its specific function while being delivered through a percutaneous approach, expanding patient eligibility without proportionally increasing overall device complexity.
Solution Approach 2:
The prosthetic valve components are nested within the delivery system catheter during delivery. The frame is collapsed within the catheter, with leaflets positioned within the frame structure. This nested configuration enables percutaneous delivery through small access points while maintaining all necessary functional elements, allowing treatment of high-risk patients who would otherwise be ineligible for surgery.
2Manufacturing precision
If the prosthetic valve frame is designed for self-expansion and anchoring, then deployment precision is improved, but the frame structure becomes more complex requiring both stent and wire mesh parts
Solution Approach 1:
The frame structure merges two different structural approaches: a stent component providing radial support and expansion force, and a wire mesh component providing flexibility and conformability to the irregular mitral valve annulus. This combination enables self-expansion and secure anchoring in the complex mitral valve anatomy while maintaining deployment precision through the complementary functions of each structural element.
Solution Approach 2:
Different portions of the frame structure have different properties: the stent portions provide rigid radial support at critical anchoring zones, while the wire mesh portions provide flexibility and conformability in regions requiring adaptation to uneven anatomy. This local differentiation of structural quality enables precise deployment and secure anchoring without requiring the entire frame to be uniformly complex.
3Reliability
If the delivery system allows for recapture and removal of the endoprosthesis, then safety is improved, but the control mechanism complexity increases with multiple control knobs and shaft assemblies
Solution Approach 1:
The delivery system is designed with multi-functional components that can perform multiple operations. The control knobs and shaft assemblies enable progression through different deployment stages: initial positioning, partial deployment, complete deployment, and recapture if needed. This universal control mechanism handles all operational scenarios including the safety function of recapture and removal, eliminating the need for separate specialized mechanisms for each function.
Solution Approach 2:
The delivery system transitions from a constrained delivery state to an expanded functional state through controlled mechanical transitions. The control mechanism dynamically adjusts the level of constraint on the prosthetic valve, allowing progression from fully sheathed to partially deployed to fully deployed states. This dynamic control enables safe recapture by reversing the deployment sequence, providing operational flexibility without requiring entirely separate systems for each state.
Data Source
AI summary
A prosthetic heart valve for transcatheter delivery that includes a collapsible and expandable inner stent, a plurality of valve leaflets supported within the inner stent, a collapsible and expandable outer frame having a lower radial strength than the inner stent for conforming to a shape of a native heart valve, a sealing material attached to the outer frame, and a plurality of anchors extending radially outwardly of the outer frame. The inner stent includes an atrial end and a ventricular end. The outer frame surrounds at least a portion of the atrial end of the inner stent and extends towards the ventricular end of the inner stent. The outer frame includes an atrial end having a larger dimension than that of the ventricular end of the inner stent.