Expandable Centering Member for Vascular Filter Placement
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Solution Overview
Problem
Existing vascular filters face challenges in centered placement and removal due to tortuous vena cava anatomy, with prior solutions either complicating the filter design or requiring invasive modifications to the delivery system, which can lead to inconsistent placement and increased difficulty in filter retrieval.
Innovation Solution
An expandable centering member is integrated into the delivery system, allowing for movable centering wires or structures that ensure the filter is accurately positioned within the vessel, facilitating both initial placement and later removal by maintaining the filter's centering during deployment and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the delivery system uses a straight catheter for filter insertion, then the filter can be delivered through the vessel, but the filter cannot be properly centered in tortuous vena cava anatomy
Solution Approach 1:
The catheter is designed with a flexible, dynamically adjustable curvature that can adapt to tortuous vena cava anatomy while maintaining delivery capability. The catheter's flexible structure allows it to conform to curved vessel paths, enabling proper filter centering even in challenging anatomical configurations.
Solution Approach 2:
The catheter incorporates a pre-formed or adjustable curved configuration that matches the natural curvature of the vena cava. This curved design allows the delivery system to navigate tortuous anatomy and position the filter centrally within the vessel, resolving the contradiction between maintaining straight-line delivery and adapting to curved vessel geometry.
2Reliability
If the filter is placed against the vessel wall for anchoring, then the filter is securely positioned, but the retrieval end becomes difficult to access for removal
Solution Approach 1:
The filter is divided into distinct functional segments: an anchoring portion with legs that engage the vessel wall for secure positioning, and a separate retrieval end that remains accessible. This segmentation allows the filter to be firmly anchored while maintaining easy access to the retrieval end through the delivery catheter's lumen, resolving the contradiction between secure anchoring and retrieval accessibility.
Solution Approach 2:
The delivery catheter serves as an intermediary that facilitates both anchoring and retrieval. During implantation, it guides the filter to the target site; during retrieval, it provides a pathway to access and remove the filter even when the anchoring portion is embedded in the vessel wall. This intermediary structure resolves the access problem without compromising anchoring security.
3Manufacturing precision
If the filter length is increased to provide centering structure, then the filter can be centered in the vessel, but the available space in the inferior vena cava is exceeded
Solution Approach 1:
The centering function is extracted from the filter body and transferred to the delivery catheter system. The catheter incorporates features such as a curved distal end or positioning mechanisms that actively center the filter within the vessel during deployment. This extraction allows the filter itself to remain compact and space-efficient while achieving accurate centering through the delivery system's design.
Solution Approach 2:
The delivery catheter acts as an intermediary that provides the centering function without requiring the filter to be longer. The catheter's geometry or positioning features enable precise filter placement and centering during delivery, allowing the filter to maintain its compact dimensions while achieving accurate positioning in the limited space of the inferior vena cava.
Data Source
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AI summary
An implantation system for a vascular implant comprises a sheath (20, 120) having a longitudinal axis, a lumen formed therein and a distal opening (26, 124). A pusher (30, 130, 230, 260) is positioned within the sheath, the pusher adapted to contact a vascular implant to deliver the implant from the sheath. A sheath centering structure (40, 140, 240, 270) includes an elongated portion (43, 143) and a plurality of arms (43, 44, 143, 144) extending from a distal portion of the elongated portion, the arms movable from a reduced profile position to an expanded position to move the sheath away from a vessel wall to a more centered position. The centering structure is movable relative to the pusher.