Embolic filter

• US 6,558,405 B1
• Filed: 08/29/2000
• Issued: 05/06/2003
• Est. Priority Date: 08/29/2000
• Status: Active Grant

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: McInnes, Peter R.
• Primary Examiner(s): TRUONG, KEVIN THAO
• Application Number:
  US09/650,278
• Time in Patent Office: 980 Days
• Field of Search: 606/200, 606/127, 606/114, 606/159, 606/1
• US Class Current: 606/200
• CPC Class Codes: A61F 2/013 Distal protection devices, i.e. devices placed distally in combination with another endovascular procedure, e.g. angioplasty or stenting
• CPC Class Codes: A61F 2002/018 made from tubes or sheets of material, e.g. by etching or laser-cutting
• CPC Class Codes: A61F 2230/0006 circular
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61M 25/104 used for angioplasty

Abstract

An intravascular filter for capturing embolic particles entrained in blood flowing in an arterial vessel during an interventional procedure. The filter is intended to be used as a primary filtering device in conjunction with interventional treatment procedures such as balloon angioplasty and/or stenting. The filter may also be used as a secondary filtering device in conjunction with suction in atherectomy and other interventional procedures. The filter is capable of capturing embolic particles at least as small as 150 microns in diameter, thereby increasing the safety of balloon angioplasty and stenting. The filter includes a spring-like expandable strut assembly and a filtering medium composed of a plurality of complex passageways. The filter assembly is compressible to an initial low profile delivery diameter and is expandable to a larger deployed diameter.

Claims

1. A filter device for capturing embolic particles released into a body lumen of a patient, comprising:

an expandable strut assembly, the expandable strut assembly having a plurality of expandable struts adapted to move between a collapsed position and an expanded position;

a filtering element having an inlet face and an outlet face and including a plurality of layers of depth filter material for capturing embolic particles;

the filtering element being attached to the expandable strut assembly and being movable with the struts to expand and contact the wall of the body lumen, wherein blood flows through the filtering element to trap embolic particles released in the body lumen.

2. The filter device of claim 1, wherein the expandable strut assembly comprises:

a proximal hollow cylindrical collar;

a distal hollow cylindrical collar; and

wherein the struts are joined to the proximal collar and taper radially outwardly from the proximal collar to from a proximal truncated cone section and continue longitudinally to form an elongated cylindrical section and taper radially inwardly to join the distal collar forming a distal truncated cone section.

3. The filter device of claim 2, further comprising:

a rotatable shaft member having a proximal end and a distal end; and

wherein the proximal collar of the expandable strut assembly is rotatably affixed to the shaft member and the distal collar is movable longitudinally along the shaft member.

4. The filter device of claim 3, wherein:

the proximal collar is mounted between a pair of stop elements which prevent longitudinal movement of the proximal collar relative to the shaft member while permitting the filtering assembly to be rotatable on the shaft member.

5. The filter device of claim 4, wherein:

at least one of the stop elements is made from a radiopaque material.

6. The filter device of claim 2, wherein:

the strut assembly is made from a segment of tubing, portions of which are selectively removed to form each of the struts of the assembly.

7. The filter device of claim 1, wherein:

the expandable struts are self-expanding.

8. The filter device of claim 1, wherein:

the depth filter material is an open cell, porous polymer foam.

9. The filter device of claim 1, wherein:

the layers of depth filtering material are open cell foam, each layer of open cell foam having a different filter density.

10. The filter device of claim 1, wherein:

the filtering element includes a top layer and a bottom layer with a plurality of layers of depth filters therebetween, each subsequent lower layer having a filter density greater than the adjacent upper layer.

11. The filter device of claim 1, wherein:

the depth filter material is formed from a material selected from the group consisting of polyurethane, polyester, PTFE, and polyethylene.

12. The filter device of claim 1, wherein:

the depth filter material is formed from a felted polymer material.

13. The filter device of claim 12, wherein:

the felted material is made from about 1 denier to about 3 denier polymer fibers.

14. The filter device of claim 12, wherein:

the felted material has a density of about 8 ounces per square yard.

15. The filter device of claim 1, wherein:

the depth filter material is felt from an adjacent layer, where each layer of felt has a different density.

16. The filter device of claim 15, wherein:

the filter element includes a top felt layer and a bottom felt layer with a plurality of felt layers therebetween, each subsequent lower felt layer having a density greater than the adjacent upper layer.

17. The filter device of claim 16, wherein:

the filter element is made from a material selected from the group consisting of polyurethane, polyester, PTFE, and polyethylene.

18. The filter device of claim 1, wherein:

at least one layer of depth filter material has a different filter density than the other layers of depth filter material.

19. The filter device of claim 18, wherein:

the layers of the depth filter material are aligned adjacent to each other to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic particles.

20. The filter device of claim 18, wherein:

the layers of the depth filter material are aligned behind each other in a longitudinal direction to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic particles.

21. The filter device of claim 1, wherein:

each layer of depth material is formed from filtering media creating a multiplicity of meandering passageways of particular pore size through which an embolic particle of smaller size must pass through in order to bypass the particular depth filter layer.

22. A filter device for capturing embolic particles released into a body lumen of a patient, comprising:

an inner shaft member having a proximal end and a distal end;

an expandable strut assembly having a proximal collar and a distal collar and a plurality of expandable struts connected therebetween, one of the collars being attached to the inner shaft member;

a filtering element having an inlet face and an outlet face and having a plurality of layers for capturing embolic material; and

the filtering element being attached to the expandable strut assembly and being movable with the struts to expand to contact the wall of the body lumen, wherein blood flows through the filtering element and any embolic debris entrained in the blood is captured by the filter.

23. The filter device of claim 22, wherein:

the expandable struts of the strut assembly are adapted to move between a collapsed position and an expanded position.

24. The filter device of claim 22, wherein:

the proximal collar of the expandable strut assembly is rotatably affixed to the shaft member and the distal collar is rotatable and movable longitudinally along the shaft member.

25. The filter device of claim 22, further including:

an outer tubular member connected to the proximal collar wherein relative motion between the outer tubular member and the inner shaft member creates an axial force for moving the expandable struts between the collapsed and expanded positions.

26. The filter device of claim 22, wherein:

the proximal collar is mounted between a pair of stop elements for preventing longitudinal movement of the proximal collar relative to the inner shaft member while permitting the filtering assembly to be rotatable on the inner shaft member.

27. The filter device of claim 26, wherein:

at least one of the stop elements is made from a radiopaque material.

28. The filter device of claim 22, wherein:

at least one layer for capturing embolic material has a different filter density than the other layers for capturing embolic material.

29. The filter device of claim 28, wherein:

the layers for capturing embolic material are aligned adjacent to each other to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic material.

30. The filter device of claim 28, wherein:

the layers for filtering embolic material are aligned behind each other in a longitudinal direction to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic material.

31. The filter device of claim 22, wherein:

each layer of depth material is formed from filtering media creating a multiplicity of meandering passageways of particular pore size through which an embolic particle of smaller size must pass through in order to bypass the particular depth filter layer.

38. The filter device of claim 28, wherein:

at least one layer of depth filter material has a different filter density than the other layers of depth filter material.

39. The filter device of claim 38, wherein:

the layers of the depth filter material are aligned adjacent to each other to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic particles.

40. The filter device of claim 38, wherein:

the layers of the depth filter material are aligned behind each other in a longitudinal direction to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic particles.

32. A filter device for capturing embolic materials released into a body lumen of a patient, comprising:

an inner shaft member having a proximal end and a distal end;

a filtering element having an inlet space and an outlet space and a plurality of layers of depth filter material for capturing embolic material, each layer of depth material being formed from filtering media which creates a multiplicity of meandering passageways of particular pore size through which an embolic particle of smaller size must pass through in order to bypass the particular depth filter layer; and

means attached near the distal end of the inner shaft member and the filtering element to open the inlet space within the body lumen.

33. The filter device of claim 32, wherein:

the layers of depth filtering material are open cell foam, each layer of open cell foam having a different filter density.

34. The filter device of claim 32, wherein:

the depth filter is an open cell, porous polymer foam.

35. The filter device of claim 32, wherein:

the depth filter material is formed from a material selected from the group consisting of polyurethane, polyester, PTFE, and polyethylene.

36. The filter device of claim 32, wherein:

the depth filter material is formed from a felted polymer material.

37. The filter device of claim 32, wherein:

the filtering element includes a top layer and bottom layer of depth filtering material with a plurality of layers of depth filters therebetween, each subsequent lower layer having a filter density greater than the adjacent upper layer, the top layer being located at the inlet space of the filtering element.

41. A filter device for capturing embolic particles released into a body lumen of a patient, comprising:

a shaft member;

an expandable strut assembly having a proximal collar and a plurality of expandable struts connected thereto, the proximal collar being mounted between a pair of stop elements located on the shaft member which prevent longitudinal movement of the proximal collar on the shaft member while permitting the expandable strut assembly to be rotatable on the shaft member; and

a filtering element having a first filter and a second filter for capturing embolic particles, the filtering element being attached to the expandable strut assembly and movable with the struts to expand with the body lumen, wherein body fluid which may have embolic particles entrained therein flows initially through the first filter and subsequently through the second filter for filtering at least some of the embolic particles present in the body fluid.

42. The filter device of claim 41, wherein:

the first filter has a different filter density than the second filter.

43. The filter device of claim 42, wherein:

the first filter is aligned adjacent to the second filter to form a composite filtering element having areas with different filtering densities for filtering different sizes of embolic particles.

44. The filter device of claim 41, wherein:

the second filter is aligned behind the first filter in a longitudinal direction to form the composite filtering element having areas with different filtering densities for filtering different sizes of embolic particles.

45. The filter device of claim 42, wherein:

the filtering element includes another filter disposed between the first filter and the second filter which has a different filter density than the first filter and the second filter.

46. The filter device of claim 42, wherein:

the second filter has a filter density greater than the first filter.

47. The filter device of claim 41, wherein:

the expandable struts are self-expanding.

48. The filter device of claim 41, wherein:

at least one of the stop elements is made from a radiopaque material.

49. The filter device of claim 41, wherein:

the shaft member is a guide wire.

50. The filter device of claim 41, wherein:

the first filter and the second filter are depth filters.

51. The filter device of claim 50, wherein the depth filters are made from an open cell, porous polymer foam.

52. The filter device of claim 50, wherein:

the first filter has a different filter density than the second filter.

53. The filter device of claim 50, wherein:

each layer of depth material is formed from filtering media creating a multiplicity of meandering passageways of particular pore size through which an embolic particle of smaller size must pass through in order to bypass the particular depth filter layer.