IVC Filter Retrieval Using Funnel-Trap Support Member
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Solution Overview
Problem
Current temporary Inferior Vena Cava (IVC) filters are challenging to retrieve due to instability and orientation issues within the IVC, exacerbated by blood flow and clots.
Innovation Solution
The introduction of a support member, such as a flower-shaped or J-hook design, interposed between braid layers of the IVC filter, providing stability and facilitating easier retrieval by creating a funnel trap mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a temporary IVC filter is placed with a hook-like feature for retrieval, then the filter can be captured and removed, but the filter becomes unstable and difficult to recapture when tilted or off-kilter due to blood flow and clots
Solution Approach 1:
The filter is divided into distinct functional segments: a stable anchoring mechanism (conical body with radiopaque markers) that ensures proper orientation, and a separate retrieval feature (hook-like structure) that can be captured. This segmentation allows the filter to maintain stability through the conical anchoring while preserving retrievability through the dedicated hook feature.
Solution Approach 2:
A snare loop acts as an intermediary tool between the operator and the filter's hook feature. The snare loop captures the hook-like retrieval feature, providing a mechanical connection that enables controlled removal of the filter without directly manipulating the filter itself, thus solving the difficulty of recapturing tilted filters.
2Reliability
If the filter is designed to avoid orientation issues, then stability may improve, but the device complexity increases and retrieval difficulty remains common
Solution Approach 1:
The filter employs an asymmetric conical body design with a wider distal end and a narrower proximal end. This asymmetric geometry, combined with radiopaque markers positioned at specific locations, provides inherent orientation stability by naturally aligning the filter along the IVC axis. The asymmetry ensures the filter settles in the correct orientation without requiring complex active control mechanisms.
Solution Approach 2:
The filter is pre-shaped with a conical configuration and pre-positioned radiopaque markers during manufacturing. This preliminary action of pre-forming the stable geometry and orientation features eliminates the need for complex post-implantation adjustments or active control systems, reducing device complexity while maintaining stability.
3Duration of action of stationary object
If constant blood flow and clots are present, then the filter remains in place, but the filter becomes disoriented and recapture becomes difficult
Solution Approach 1:
The hook-like retrieval feature is pre-formed and permanently attached to the filter during manufacturing, ensuring it remains accessible and properly positioned throughout the filter's implantation duration. This preliminary action of pre-positioning the retrieval feature ensures that even after prolonged exposure to blood flow and clots, the feature remains available for reliable recapture without becoming disoriented.
Data Source
AI summary
Apparatus and methods for retrieving a foreign body from a vasculature are provided. The devices can be Funnel-trap type retrieval devices. The devices can include a compressible support member extending from the distal end of an elongate shaft, the compressible support member having an expanded configuration, a compressed configuration, a plurality of independent elongate support elements that have a memory for the funnel-shaped expanded configuration, and a cover material that covers the compressible support member and forms a pocket configured for capturing the foreign body in the interior of the compressible support member.