Funnel-trap IVC Filter Retrieval with Heatset Braid
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Solution Overview
Problem
Current temporary Inferior Vena Cava (IVC) filter retrieval systems face difficulties in capturing filters due to unstable placement and orientation, especially under constant blood flow and the presence of blood clots, which complicates recapture.
Innovation Solution
A 'funnel-trap' type retrieval device with a heatset braid, preferably made of superelastic nickel-titanium alloy, featuring a distal rim and a proximal aperture, creates a pocket to securely capture the filter's enlarged end, with optional locking mechanisms and crossing members to entangle hooks, facilitating retrieval even when the filter is off-angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hook-like feature is used for filter capture, then the filter can be captured with a snare loop, but the retrieval becomes difficult when the filter is tilted or off-kilter due to unstable placement and blood flow disorientation
Solution Approach 1:
The retrieval system is divided into separate functional components: a delivery catheter with a funnel-shaped distal end for guiding and initial capture, and a separate snare loop for securing the hook feature. This segmentation allows each component to perform its specific function optimally, with the funnel providing stable guidance and the snare providing secure capture, thereby resolving the contradiction between ease of operation and capture reliability.
Solution Approach 2:
The funnel-shaped distal end of the delivery catheter acts as an intermediary structure between the operator and the filter. It provides a enlarged capture zone that guides the filter into proper orientation and facilitates stable capture even when the filter is initially tilted or off-kilter, thereby improving both ease of operation and capture reliability.
2Reliability
If the filter is placed in the IVC, then it can filter blood clots, but constant blood flow and clots can disorient the filter making recapture difficult
Solution Approach 1:
The funnel-shaped distal end of the delivery catheter is designed to perform preliminary guidance and stabilization of the filter during placement. By providing an enlarged capture zone and guiding structure, it ensures the filter is initially positioned correctly before blood flow can disorient it, thereby maintaining placement stability while facilitating future recapture.
Solution Approach 2:
The delivery catheter with its funnel-shaped distal end serves multiple functions: it delivers the filter to the IVC, guides the filter into proper orientation during placement, and provides a stable structure for recapture later. This multi-functionality resolves the contradiction by ensuring the same structure that enables reliable placement also facilitates ease of recapture.
3Ease of operation
If a snare loop is used to capture the filter hook, then the filter can be retrieved, but the procedure becomes complicated when the filter orientation is unstable
Solution Approach 1:
The retrieval system segments the capture function into two parts: the funnel-shaped distal end of the delivery catheter provides the first level of capture and guidance, while the snare loop provides the second level of secure capture. This segmentation simplifies the overall procedure by dividing complex capture tasks into manageable steps, reducing the complexity of using the snare loop alone.
Solution Approach 2:
The funnel-shaped structure serves as an intermediary that simplifies the capture process by providing a enlarged capture zone and guiding the filter into proper orientation before the snare loop is applied. This intermediary structure reduces the complexity of the snare loop operation by pre-positioning the filter for easier capture.
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 system improves the ease of filter retrieval by providing a stable and atraumatic mechanism for capturing and securing IVC filters, reducing the susceptibility to orientation issues and ensuring successful recapture, even in challenging conditions.
Implementation Method 1
heatset braid, possibly superelastic (SE) nickel-titanium alloy (Nitinol) braid
Implementation Method 2
heatset braid, preferably made of superelastic nickel-titanium alloy
Data Source
Figure 1A~3
Figure 4~7D
Figure 8~10
AI summary
Funnel-trap type delivery and/or retrieval devices for temporary Inferior Vena Cava (IVC) filters or other medical implants or foreign bodies are described. These may employ a locking sheath or a proximal-aperture capture feature or features for IVC filter (or other device) retrieval.