GB2513921A

GB2513921A - Vena cava filter with stabilising arcs

Info

Publication number: GB2513921A
Application number: GB1308479.3A
Authority: GB
Inventors: Matthew Mccarthy
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-05-11
Filing date: 2013-05-11
Publication date: 2014-11-12
Also published as: GB201308479D0

Abstract

A blood vessel filter, particularly for the inferior vena cava, which anchors to the vessel wall using arcs 20 at the end of the legs 21 to prevent tipping of the filter or movement within the blood vessel. The filter legs 21 and arcs 20 can be retracted away from the wall 22 using the hook 26. Pulling the hook 26 relative to the hub 25 pulls on flexible material 28 connecting the arcs on the legs to the hook and allows collapse of the device towards the centre, and thus retrieval of the device from the blood vessel.

Description

IVC Filter With Stabilising Arcs This invention relates to a vena cava filter which resists tipping or migration within a blood vessel.

Vena cava filters are devices which trap blood clots (emboli) and prevent their passage along a vessel. They are typically deployed in the inferior vena cava to prevent clots from reaching the lungs and causing a pulmonary embolism. These filters may be permanent or temporary (retrievable).

In the case of temporary filters it is common that the filter migrates or tilts within the vessel prior to retrieval. This change in position makes safe retrieval of the device more difficult or impossible. The invention disclosed proposes the use of arcs at the end of each leg to stabilise the device and prevent this unwanted movement.

Preferably the device includes a mechanism to disengage the arcs from the vessel wall prior to device retrieval.

Preferably the arcs articulate with the device legs to allow for variations in the vessel wall.

The invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 shows a vena cava filter which has tilted within the vessel Figure 2 shows a cross-section of an embodiment of the invention with stabilising arcs Figure 3 shows a 3D view of an embodiment of the invention with stabilising arcs Figure 4 shows an embodiment of the invention with disengagement apparatus Figure 5 shows an embodiment of the invention collapsed for retrieval In figure 1 a vena cava filter 10 has tilted within the vessel 11 causing the retrieval hook 12 to become lodged against the vessel wall 11.

In figure 2 arc 20 attaches to leg 21. The attachment point 24 may be articulated or fixed.

Alternatively the leg 21 and arc 20 may be fashioned from one piece of material. Each arc engages with the vessel wall 22 at both ends 23 of its length The device may have a number of the leg-arc assemblies around a central hub 25. The top point of the arc 23 prevent the device from tipping and keep the central hub 25 equidistant from the vessel wall 22.

In figure 3 an embodiment of the invention can be seen. Four legs 21 are mounted to a central hub 25. An arc 30 is attached to each leg 21 and provides engagement points 23 to anchor the device to the vessel wall.

In figure 4 a variant of the invention is seen which includes a provision for disengaging the anchor points 23 from the vessel wall 22. In this embodiment a central tube 27 is mounted to the underside of the central point 25. A hook 26 runs through the central hub 25 and into the central tube 27. The curved portion of the hook being above the hub. The bottom of the hook 26 is attached to the arc 20 by a flexible material 28. A vertical force on hook 26 is translated into a horizontal force on the arc 20 via the flexible material 28. This disengages the anchor points 23 from the vessel wall 22 and makes the overall diameter of the device smaller to enable the device to be fed inside a catheter for retrieval. Depending on the particular embodiment of the invention there may be a number of strands of the flexible material 28 and these may attach to the arc 20 anywhere along its length. Alternatively the flexible material 28 can attach to the leg 21. The end of the central tube 27 may be bevelled or rounded to allow smooth movement of the flexible material 28. Alternatively the flexible material may pass through holes in the wall of the central tube 27.

In figure 5 the legs 21 and arcs 20 have been brought towards the central tube 27 using the hook 26 and flexible material 28. Excess force on the flexible material 28 is prevented using a wider section of the hook 26 which engages with the underside of the central hub when the legs are fully retracted. The anchor points 23 have disengaged from the wall of the vessel 22 with a movement perpendicular to the wall. This minimises trauma to the vessel.