Endovascular Stent-Graft with Eversion Structure for Time-Differential Deployment
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Solution Overview
Problem
Accurately positioning and deploying a stent-graft within a body lumen, particularly in high-pressure areas like the thoracic aorta, while minimizing disruption to blood flow during deployment, poses challenges due to the need for precise maneuverability and reduced fluid flow disruption.
Innovation Solution
A time-differential deployment method and apparatus using a tubular endovascular device with segmented stent and graft structures and an eversion structure that allows for sequential expansion and fluid flow, allowing for partial deployment to maintain blood flow during the process, including a method where the device is collapsed and deployed in stages with a constraining sheath, and the eversion structure permits lateral fluid flow during interim periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent-graft is deployed within a body lumen using conventional techniques, then the stent-graft can be positioned at the target site, but blood flow disruption occurs during deployment
Solution Approach 1:
The device is divided into multiple deployable segments (first device segment, second device segment, intermediate device segment) that can be deployed sequentially rather than all at once. This allows blood flow to be maintained through undeployed segments during the deployment process, reducing overall blood flow disruption while achieving accurate positioning of each segment.
Solution Approach 2:
The device incorporates dynamic elements including hinge joints that allow rotation and movement of segments relative to each other, and an eversion structure that can transition between deployed and undeployed states. This dynamic capability enables the device to adapt its configuration during deployment to maintain blood flow while achieving final positioning.
2Stress or pressure
If a stent-graft is deployed in high-pressure areas like the thoracic aorta, then the device must withstand higher blood flow rates and pressure, but maneuverability and placement become more difficult
Solution Approach 1:
The device is segmented into multiple sections that can be deployed independently and positioned with greater precision in high-pressure environments. Each segment can be controlled separately, improving maneuverability during deployment while the complete structure is designed to withstand thoracic aorta pressure conditions.
Solution Approach 2:
The device structure changes its physical parameters during deployment - transitioning from a compressed delivery configuration to an expanded functional configuration. The hinge joints and eversion structure allow the device to adapt its shape and rigidity parameters to navigate high-pressure areas during deployment, then maintain structural integrity once deployed.
3Reliability
If the eversion structure is deployed to restrict lateral fluid flow, then blood flow control is improved, but the deployment process becomes more complex
Solution Approach 1:
The eversion structure is designed to be nested within the device body during delivery and deployment. It can be inverted or everted from a compressed state within the catheter to an expanded functional state at the target site. This nested configuration reduces deployment complexity by allowing the structure to self-organize during the deployment sequence while still achieving the desired fluid flow control function.
Data Source
AI summary
A tubular first device segment has longitudinally spaced proximal and distal first segment ends. The first device segment includes a first segment lumen. A tubular second device segment has longitudinally spaced proximal and distal second segment ends and a second segment lumen. A tubular eversion structure is located longitudinally intermediate the first and second device segments. The eversion structure has longitudinally spaced proximal and distal eversion ends separated by a tubular eversion structure wall. One of the proximal and distal eversion ends is attached to the first device segment and the other of the proximal and distal eversion ends is attached to the second device segment. At least a portion of the eversion structure wall is configured for selective intussusception into at least one of the first segment lumen, the second segment lumen, and another portion of the eversion structure wall.