Vena Cava Filter Retrieval System with Expandable Mesh
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Solution Overview
Problem
Conventional vena cava filters become permanently anchored in the vessel wall due to ingrowth of intimal cells, making retrieval difficult, and there is a risk of emboli dislodgement during removal, which is undesirable.
Innovation Solution
A retrieval system comprising an access sheath, an intermediate tube with a radially expandable mesh, and a retrieval device that captures the filter by expanding the mesh to engage the vessel wall and securely grasp the filter, allowing for safe removal while capturing emboli.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter is deployed in the vena cava to filter thrombi, then the filtering effectiveness is improved, but the filter becomes anchored to the vessel wall due to intimal cell ingrowth, making retrieval difficult
Solution Approach 1:
The retrieval system performs preliminary action by deploying the expandable mesh and retrieval member before the filter becomes permanently anchored. The system is introduced through the delivery sheath, expanded to engage the filter, and secures it for retrieval before intimal cell ingrowth makes removal impossible
Solution Approach 2:
The retrieval system is divided into separate functional components: an access sheath for delivery, an expandable mesh for engagement, and a retrieval member for securing the filter. This segmentation allows each component to perform its specific function independently, enabling effective retrieval while maintaining filtering capability during the procedure
2Stability of the object's composition
If the filter becomes off-centered or tilted in the vessel, then the filter may engage the vessel wall along its length, but this causes endothelialization and permanent implantation, reducing retrieval time window
Solution Approach 1:
The retrieval system incorporates dynamic components including an expandable mesh that can adapt to the filter's position and orientation, and a retrieval member that can be adjusted to engage the filter hub regardless of tilting. This dynamic capability allows retrieval even when the filter has become off-centered or tilted in the vessel
Solution Approach 2:
The expandable mesh acts as an intermediary between the retrieval member and the filter. It provides a flexible engagement surface that can accommodate misaligned or tilted filters, transferring the retrieval force evenly and preventing additional vessel wall engagement during the retrieval process
3Ease of operation
If conventional retrieval methods are used on an ingrown filter, then retrieval may become more difficult, but there is a risk that trapped emboli may become dislodged and re-enter the bloodstream
Solution Approach 1:
The expandable mesh converts the potential harm of filter ingrowth into a benefit by providing a large surface area for engagement. The mesh can engage the filter struts and hub even when embedded in tissue, distributing retrieval forces to minimize emboli dislodgement while successfully extracting the ingrown filter
Solution Approach 2:
The retrieval system provides beforehand cushioning by using the compliant expandable mesh to absorb and distribute retrieval forces. This cushioning effect protects trapped emboli from sudden movements or sharp forces that could cause dislodgement, while still enabling effective retrieval of the anchored filter
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
Enables efficient and safe retrieval of vena cava filters by preventing ingrowth and minimizing the risk of emboli dislodgement, allowing for the removal of filters that have become permanently anchored.
Implementation Method 1
a first mesh member coupled to the intermediate tube and being biased radially outward to define a concave shape with a concavity facing the distal direction
Implementation Method 2
a retrieval device having an elongate shape and having proximal and distal ends, and a retrieval member coupled thereto
Data Source
AI summary
A retrieval system for a medical device includes an access sheath, a clot catch with an attached mesh, and a filter catch having an attached retrieval member. The filter catch is translatable within clot catch, and the clot catch is translatable within the access sheath. The mesh is expandable into engagement with a body vessel during retrieval of the medical device. The mesh captures emboli that are dislodged during retrieval of the device. The device is captured by the clot catch during retrieval, and the clot catch is subsequently captured by the access sheath. The system can further include an inner sheath translatable within the clot catch, with the inner sheath capturing the medical device and the clot catch capturing the inner sheath.