Vena cava filter

• US 5,836,969 A
• Filed: 07/28/1997
• Issued: 11/17/1998
• Est. Priority Date: 10/01/1993
• Status: Expired due to Term

• Current Assignee: Lifescreen Sciences LLC (Acacia Research Corporation)
• Original Assignee: Boston Scientific Corporation
• Inventors: Kim, Hannah S., Sandock, David L., Nott, Sepideh H.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): LEWIS, WILLIAM W
• Application Number:
  US08/901,126
• Time in Patent Office: 477 Days
• Field of Search: 606/1, 606/108, 606/191, 606/194, 606/195, 606/198, 606/200, 623/1, 623/17, 623/12, 128/898, 128/899
• US Class Current: 606/200
• CPC Class Codes: A61F 2/0103 With centering means
• CPC Class Codes: A61F 2/0105 Open ended, i.e. legs gathered only at one side
• CPC Class Codes: A61F 2002/016 made from wire-like elements
• CPC Class Codes: A61F 2002/018 made from tubes or sheets of material, e.g. by etching or laser-cutting
• CPC Class Codes: A61F 2002/8483 Barbs
• CPC Class Codes: A61F 2230/005 Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2230/0078 hyperboloidal
• CPC Class Codes: A61F 2230/008 paraboloidal

Abstract

A vascular filter comprises an emboli-capturing portion having a set of helical filter-wires joined at a central region and extending in a given direction along the blood vessel in a diverging relationship to the axis of the filter, the wires terminating in free ends constructed to engage the walls of said vessel. A major mid-portion of the length of the free ended wires are of generally helical form, cooperatively related to form an effective emboli capturing array. Anchoring is accomplished by a separate assembly formed of struts and anchoring devices. A parallelogram supporting strut assembly and other means for providing linear engagement with the wall of the vena cava are shown. The parallelogram structure is shown to have filter capability by itself as well.

Claims

1. A vascular filter for placement in a blood vessel for preventing the movement of emboli in the blood stream of a human, the filter including a set of filter-wires that diverge from a central region in a generally upstream direction along the blood vessel when implanted forming an emboli-capturing array, the filter wires having portions that engage the vessel wall, and an anchoring assembly defined by at least one set of struts joined centrally with said set of filter-wires, portions of said anchoring assembly constructed and arranged to engage the wall of said blood vessel in a manner anchoring said filter in position, the region of said anchoring being spaced downstream from the region of contact of said set of filter wires with said vessel wall, wherein said anchoring assembly comprises anchoring formations distributed about said filter, said anchoring formations being mounted on parallelogram-like supports arranged to adapt to the walls of vessels over a range of sizes while maintaining substantially the same attitude with respect to the wall of the vessel.

2. The vascular filter of claim 1 wherein each of said anchoring formations is supported and disposed for engagement with the wall of said blood vessel and comprises at least one pointed projection constructed to engage wall tissue and anchor the strut thereto.

3. The filter of claim 1 wherein wall-engaging formations supported by said struts are constructed and arranged to maintain generally linear contact with the vessel walls.

7. The filter of claim 1, 3 or 6 wherein said parallelogram-like supports are constructed and arranged to move between expanded and collapsed condition without change in the overall length of the filter.

9. The filter of claim 1, 5 or 8 wherein said struts are of rectangular transverse cross-section, the thin dimension of said strut cross-section being arranged in the redial direction.

20. The filter of claim 1, 5, 10, or 15 wherein a surface treatment is included on said struts or wires that enhances their effectiveness.

21. The filter of claim 20 wherein said surface treatment comprises a biocompatible polymeric coating.

22. The filter of claim 20 wherein said surface treatment comprises a metal coating.

4. A vascular filter for placement in a blood vessel for preventing the movement of emboli in the blood stream of a human, the filter including a set of filter-wires that diverge from a central region in a generally upstream direction along the blood vessel when implanted forming an emboli-capturing array, the filter wires having portions that engage the vessel wall, and an anchoring assembly defined by at least one set of struts joined centrally with said set of filter-wires, portions of said anchoring assembly constructed and arranged to engage the wall of said blood vessel in a manner anchoring said filter in position, the region of said anchoring being spaced from the region of contact of said set of filter wires with said vessel wall, said anchoring assembly including anchoring formations each of which is supported and disposed for engagement with the wall of said blood vessel, each of said anchoring formations comprising at least a pair of pointed projections, the projections of said pair being oriented in opposite directions along the blood vessel, each anchoring portion being angled to penetrate into wall tissue, said pair of projections being effective to resist dislodgement of said strut in either direction along said vessel.

5. A vascular filter for placement in a blood vessel for preventing the movement of emboli in the blood stream of a human, the filter including a set of filter-wires that diverge from a central region in a generally upstream direction along the blood vessel when implanted forming an emboli-capturing array, the filter wires having portions that engage the vessel wall, and an anchoring assembly defined by at least one set of struts joined centrally with said set of filter-wires, portions of said anchoring assembly constructed and arranged to engage the wall of said blood vessel in a manner anchoring said filter in position, the region of said anchoring being spaced from the region of contact of said set of filter wires with said vessel wall, said filter-wires of said set being helically configured and arranged, conforming generally to an imaginary cone, to form an effective clot capturing array that can radially expand and contract to adapt to vessels of different sizes.

6. The filter of claim 5 wherein said anchoring assembly comprises anchoring formations distributed about said filter, said anchoring formations being mounted on parallelogram-like supports arranged to adapt to the walls of vessels over a range of sizes while maintaining substantially the same attitude with respect to the wall of the vessel.

8. The filter of claim 5 wherein said filter wires are of round cross-section.

10. A vascular filter for placement in a blood vessel for preventing the movement of emboli in the blood stream of a human, the filter comprising an emboli-capturing portion having a set of filter-wires that diverge from a central region in a given direction along the blood vessel, the wires terminating in free ends constructed to contact the wall of said vessel, at least a major mid-portion of the length of said free ended wires being of generally helical form conforming generally to an imaginary cone, cooperatively related to form an effective emboli-capturing array.

11. The filter of claim 5 or 10 wherein said filter wires are comprised of elastic metal of round cross-section, and said struts are comprised of flat strip-form material arranged with the direction of thickness of the strip oriented radially.

12. The filter of claim 5 or 10 wherein said filter-wires are comprised of elastic material, said helical wires being cooperatively related, upon compaction, to elastically straighten and to meet closely with each other, enabling collapse into a small size, and enabling radial compaction of said set of filter wires into an introducer catheter of about 9 French or less outer diameter for insertion into a blood vessel, said wires, when released from said catheter into the blood vessel, constructed to expand to form said effective emboli-capturing array.

13. The filter of claim 5 or 10 constructed for placement in blood vessels over a range of sizes, wherein portions of said wires adjacent to said free ends are relatively straight, enabling, substantially, end-contact of said wires with the walls of said blood vessel over said range of vessel sizes.

14. The filter of claim 5 or 10 wherein all of said wires in said set are curved in the same general helical direction.

15. A vascular filter for placement in a blood vessel for preventing the movement of emboli in the blood stream of a human, the filter including:

a set of filter-wires that diverge from a central region in a generally upstream direction along the blood vessel when implanted forming an emboli-capturing array, the filter wires having portions that engage the vessel wall; and

an anchoring assembly defined by at least one set of struts joined centrally with said set of filter-wires, portions of said anchoring assembly constructed and arranged to engage the wall of said blood vessel in a manner anchoring said filter in position, the region of said anchoring being spaced from the region of contact of said set of filter wires with said vessel wall;

wherein the struts extend from said central joining region a distance that is short relative to the distance said filter-wires extend from the central region, and diverge in the same general direction as said filter-wires but at a greater angle relative to the longitudinal axis of the filter, the spacing of the regions of contact of said filter-wires and said struts with the vascular wall being selected to stabilize said filter in said vessel in a generally centered relationship.

16. The filter of claim 15 wherein outer, wall-engaging formations supported by said struts are constructed and arranged to maintain generally linear contact with the vessel wall.

17. The filter of claim 16 wherein said wall-engaging formations are linear elements, each of said linear elements being supported at one end by a respective strut of said set, and the other end of each of said linear elements being joined to and supported by a respective strut of a second set of struts of said assembly.

18. The filter of claim 17 wherein each of said linear elements comprises an integral extension of at least one of the respective supporting struts.

19. The filter of claim 17 wherein said struts in said second set are centrally joined at a location spaced axially from the region at which said first set of struts are joined, and are arranged to provide effectively parallelogram-like support to said linear wall-engaging elements to assure substantially linear contact thereof with the vessel wall over a range of sizes of the vessel.

23. A vascular filter for placement in blood vessels for preventing the movement of emboli in the blood stream of a human, said filter including an anchoring assembly wherein said anchoring assembly comprises anchoring formations distributed radially about an axis of said filter, said anchoring formations mounted on closed-loop parallelogram-like supports arranged to adapt to the walls of vessels over a range of sizes.

24. The vascular filter of claim 23 wherein outer wall-engaging elements are constructed and arranged to make generally linear contact with the vessel wall, one end of each of said wall-engaging elements being joined to and supported by a strut of a first set of struts, and the other end of each of said wall-engaging elements being joined to and supported by a respective strut of a second set of struts wherein said second set of struts are centrally joined at a location spaced axially from the region at which said first set of struts are joined, and are arranged to provide effectively parallelogram-like support to said outer, linear wall-engaging elements.

25. The vascular filter of claim 24 wherein each said linear wall-engaging element comprises an integral extension of at least one of the respective supporting struts.

26. The vascular filter of claim 23 wherein each of said parallelogram-like supports comprises a pair of struts that are coupled to the filter at spaced-apart locations along said filter axis.

27. The vascular filter of claim 23 further comprising a filtering portion formed from a set of filter-wires constructed and arranged to form an emboli-capturing array.

28. The vascular filter of claim 27 wherein said filtering portion comprises a set of filter-wires that diverge from a central region in a generally upstream direction along the blood vessel when implanted forming an emboli-capturing array.

29. The vascular filter of claim 28 wherein said filter-wires terminate in free ends.