Retrievable Filter With Segmented Stent And Locking Mechanism
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Solution Overview
Problem
Current blood filtration units, particularly temporary filters, face challenges with long-term implantation and retrievability, as they often lead to complications such as venous stasis and difficulty in safe removal due to endothelialization, limiting their effectiveness in managing prolonged risk of embolism.
Innovation Solution
A long-term retrievable, permanent filter design featuring a stent that engages the vessel walls and becomes incorporated by endothelial tissue, coupled with a filter and a locking mechanism allowing for releasable attachment, enabling both long-term filtration and easy retrieval or permanent placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If temporary filters are used without hooks for securing to the vessel wall, then the filter can be removed more easily, but the filter may migrate within the vessel during the implantation period
Solution Approach 1:
The filter device is divided into two independent parts: a stent portion that remains permanently implanted to provide anchoring, and a filter portion that can be retrieved. This segmentation allows the stent to provide stable positioning while the filter can be removed independently, resolving the contradiction between ease of removal and position stability.
Solution Approach 2:
The stent acts as an intermediary component between the vessel wall and the filter. It provides the anchoring function that would otherwise require hooks on the filter, while allowing the filter itself to remain free of permanent attachment structures, enabling easy retrieval.
2Reliability
If barbs or anchors are used to secure the filter to the vessel wall, then the filter remains in place, but removal becomes difficult and may injure the vessel wall
Solution Approach 1:
By separating the anchoring function (stent with barbs) from the filtering function (filter portion), the design allows the stent to provide secure attachment while the filter portion can be retrieved without removing the stent, eliminating the injury risk associated with removing anchored filters.
Solution Approach 2:
The filter portion is extracted as a separate, removable component from the anchoring structure. This allows the filtering function to be temporarily provided and then removed without affecting the permanent stent anchor, avoiding vessel wall injury during removal.
3Adaptability or versatility
If tethered temporary filters are used with a tethering catheter, then the filter can be retrieved, but there is potential for septic complications from the catheter exiting the neck or groin
Solution Approach 1:
The tethering catheter is completely removed from the system. Instead of using a catheter that exits through the skin (creating infection risk), the filter is deployed self-expanding and self-attaching to the stent, with retrieval achieved through a different mechanism that does not require a long-term external catheter.
Solution Approach 2:
The retrieval function is achieved through a simplified mechanism (snare through jugular vein) rather than copying the tethering catheter approach. This alternative retrieval method eliminates the need for a catheter exiting through the neck or groin, removing the source of septic complications.
4Reliability
If the filter is left in place permanently, then continuous filtration is provided, but the risk of venous stasis due to caval occlusion increases
Solution Approach 1:
The filter system transitions from a static permanent implant to a dynamic system where the filter portion can be retrieved after a predetermined period. This dynamic approach allows continuous filtration during the high-risk period while enabling removal to prevent long-term complications like venous stasis.
Solution Approach 2:
The filter provides periodic protection rather than permanent implantation. It is implanted for a specific duration (e.g., 6 weeks) corresponding to the high-risk period for embolism, then retrieved. This periodic action maintains filtration reliability during the critical period while avoiding long-term harmful effects.
Data Source
AI summary
A filter may have an apical hub and a plurality of divergent legs. A first attachment member may be separate from, but attached to the second end of at least one of the plurality of divergent legs. A second attachment member may be separate from, but attached to a stent. The first and second attachment members may be separate from, but attachable to one another to releasably attach the filter to the stent. One of the first attachment member and the second attachment member may include an attachment wire that is positioned in a lumen of a tubular member or one of the first attachment member and the second attachment member may comprise a cannula. In some implementations, an upward motion applied to the retrieval connection member may disengage at least one attachment wire of the first attachment member from the second attachment member.