Self-Closing Implantable Valve Member for False-Lumen Occlusion
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Solution Overview
Problem
Existing implantable medical devices fail to effectively prevent backflow into a false lumen of dissection, particularly after treating aortic dissection, due to incomplete sealing at downstream tears in the false lumen wall.
Innovation Solution
An implantable medical device featuring an elongate support member with a flexible tubular valve member and resilient members that self-close upon deployment, using shape-memory materials like nitinol wire to ensure complete occlusion of the false lumen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional candy plug is used to occlude the false lumen, then the upstream end of the false lumen is closed, but backflow from downstream tears in the false lumen wall cannot be prevented
Solution Approach 1:
The device divides the occlusion function into two segments: the stent graft handles the upstream end occlusion, while the separate candy plug with valve element handles the downstream tear occlusion. This segmentation allows each component to address specific flow paths independently, preventing backflow from downstream tears that would occur with a single conventional plug design.
Solution Approach 2:
The candy plug acts as an intermediary device positioned within the false lumen to block downstream tears. The valve element within the candy plug serves as a mediator that selectively allows flow in one direction while preventing backflow, thereby completing the occlusion function that conventional plugs cannot achieve.
2Ease of operation
If the valve member is kept open during deployment, then the device can be installed, but the false lumen remains vulnerable to backflow
Solution Approach 1:
The valve element is designed with dynamic characteristics, being held open by a wire during deployment for ease of installation, then automatically closing when the wire is removed. This dynamic behavior transitions the valve from an open state during operation to a closed state during deployment, ensuring backflow prevention is activated only when needed.
Solution Approach 2:
The valve element performs self-service by automatically closing when the deployment wire is removed, eliminating the need for manual intervention to seal the false lumen. The spring mechanism provides self-closing action that ensures reliable backflow prevention without requiring additional operational steps.
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 device effectively prevents backflow into the false lumen by self-closing, facilitating thrombosis and reducing strain on the dissection, thereby minimizing the risk of rupture.
Implementation Method 1
The at least one elongate resilient member may be at least one shape-memory material member. The at least one shape-memory material member may be at least one pre-coiled nitinol wire.
Data Source
AI summary
An implantable medical device for preventing backflow into a false lumen of dissection includes an elongate support member, an elongate flexible tubular valve member having a length, a proximal end, and an open distal end. At least one elongate resilient member extends at least partially along the length of the elongate flexible tubular valve member, the at least one elongate resilient member having a proximal end distal to the elongate support member, a distal end proximal to the open distal end of the elongate flexible tubular valve member, an elongated configuration, and a coiled configuration. The at least one elongate resilient member is unattached to the elongate support member. The at least one elongate resilient member, upon release from a constraining force, is configured to move from the elongated configuration to the coiled configuration thereby closing the open distal end of the elongate flexible tubular valve member.