Curved Sheath Tip for Vascular Filter Centering
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Solution Overview
Problem
Existing vascular filters face challenges in being accurately centered within curved or tortuous vena cava anatomies during implantation, which complicates both placement and subsequent removal, due to potential misalignment and increased tissue ingrowth at the retrieval end.
Innovation Solution
A delivery system comprising a sheath with a Pebax material and a pusher with a curved tip, where the pusher's different stiffness causes the sheath tip to curve, allowing for better centering of the filter within the vessel, and a ferrule to separate vessel engaging hooks during delivery, facilitating more precise placement and easier removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a straight delivery system is used, then the filter can be delivered through the vessel, but the filter cannot be accurately centered in curved or tortuous vena cava anatomies
Solution Approach 1:
The delivery system employs a curved pusher that can be inserted through a straight sheath, allowing the pusher to dynamically adapt to the curved anatomy of the vena cava while the sheath remains relatively straight for easy access. This dynamic configuration enables the filter to be accurately centered in curved vessels without compromising delivery accessibility.
Solution Approach 2:
The curved pusher acts as an intermediary element between the straight sheath and the filter, transferring the filtering function while adapting to the curved vessel anatomy. The pusher's curved tip allows it to navigate tortuous paths and position the filter centrally, while the straight sheath provides a simple access route.
2Reliability
If the filter is placed against the vessel wall for stability, then the filter is secured, but the retrieval end becomes difficult to access for removal
Solution Approach 1:
The filter is divided into distinct segments including a proximal end with retrieval features and a distal end with different anchoring characteristics. This segmentation allows the proximal end to remain accessible for retrieval while the distal end provides stable anchoring against the vessel wall, resolving the contradiction between stability and retrievability.
3Ease of manufacture
If traditional filters are used in curved vena cava, then placement is possible, but tissue ingrowth increases at the retrieval end making removal difficult
Solution Approach 1:
Different portions of the filter are designed with different properties: the distal end has features optimized for anchoring and filtering, while the proximal end has a smoother surface and different geometry that minimizes tissue ingrowth and maintains accessibility. This local differentiation allows effective placement while preventing harmful tissue overgrowth at the retrieval site.
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 ensures improved centered delivery and placement of vascular filters, reducing tissue ingrowth at the retrieval end, thereby simplifying filter removal and minimizing complications.
Implementation Method 1
the pusher's different stiffness causes the sheath tip to curve
Data Source
Figure 1
Figure 1A~1B
Figure 1C
AI summary
A method of implanting a vessel filter by a femoral approach comprising the steps of providing a delivery sheath with a substantially straight distal tip and inserting a curved device into the sheath to move the sheath to a second configuration. In the second position, the distal tip of the sheath is curved at an angle to a longitudinal axis of the sheath. The method further comprises the step of rotating the sheath and pusher so a distal opening of the sheath has a more centered position within the vessel.