Expandable Left Atrial Appendage Closure for Constrained Delivery
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Solution Overview
Problem
Existing medical devices for closing the left atrial appendage in patients with atrial fibrillation are inadequate in effectively preventing thrombi formation and migration, leading to stroke or heart attack risks.
Innovation Solution
A left atrial appendage closure device with an expandable framework of struts that transitions through various positions, allowing it to conform to the complex geometry of the left atrial appendage, anchored by anchoring members and sealed with an occlusive element to prevent thrombi from entering the bloodstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the expandable framework is fully constrained by the delivery sheath, then the device can be safely delivered through the vasculature, but the device cannot assume its functional configuration for occlusion
Solution Approach 1:
The expandable framework is nested within the delivery sheath in a compressed delivery configuration, allowing safe passage through the vasculature. Upon deployment, the framework expands from the sheath into its functional occlusive configuration, transitioning from a constrained nested state to an expanded functional state.
2Volume of moving object
If the struts form acute angles opening inwardly, then the framework can compress to fit within the delivery sheath, but the framework may not adequately engage the left atrial appendage geometry
Solution Approach 1:
The struts are designed with dynamic geometry that changes during deployment. In the compressed state, acute angles allow the framework to fit within the delivery sheath. During expansion, the struts transition to form obtuse angles opening outwardly, enabling adequate engagement with the left atrial appendage geometry and ensuring reliable occlusion.
3Reliability
If the framework expands to fully unconstrained position, then the device can effectively occlude the left atrial appendage, but the device cannot be delivered through the catheter
Solution Approach 1:
The framework is segmented into multiple struts that can be independently positioned and angled. This segmentation allows the overall structure to be compressed into a compact form for delivery while maintaining the capability to expand into an effective occlusive configuration upon deployment.
Data Source
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AI summary
A left atrial appendage closure device may include an expandable framework having a plurality of struts joined at a proximal and distal hub. When the framework is fully constrained in a first position, a first segment of struts extends distally from the distal hub parallel to a central longitudinal axis to a first bend and a second segment of struts extends from the first bend proximally. A first amount of the framework is unconstrained in a second position, where the first segment extends distally from the distal hub parallel to the central longitudinal axis to the first bend, the second segment extends from the first bend proximally and radially outward to a second bend, a third segment of struts extends from the second bend proximally and radially inward to a third bend, and a fourth segment of struts extends from the third bend proximally to within the delivery sheath.