Removeable embolus blood clot filter and filter delivery unit

• US 20050234503A1
• Filed: 06/10/2005
• Published: 10/20/2005
• Est. Priority Date: 09/25/1998
• Status: Active Grant

• Current Assignee: Adrian C. Ravenscroft, Stephen J. Kleshinski
• Original Assignee: Adrian C. Ravenscroft, Stephen J. Kleshinski
• Inventors: Ravenscroft, Adrian C., Kleshinski, Stephen J.
• Granted Patent: US 8,133,251 B2
• Time in Patent Office: Days
• 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 2/011 Instruments for their placement or removal
• CPC Class Codes: A61F 2002/016 made from wire-like elements
• CPC Class Codes: A61F 2220/0008 Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2230/005 Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2230/008 paraboloidal

Abstract

A blood clot filter which is collapsible toward a central longitudinal axis into a collapsed configuration for insertion into a blood vessel and which is radially expandable outwardly from the longitudinal axis to an expanded configuration for contact with the inner wall of the blood vessel at two longitudinal spaced locations. A first plurality of spaced, elongate arms, in the expanded configuration of the filter, curve outwardly away from the longitudinal axis toward the leading end of the filter to form a first filter basket and to center a hub at the trailing end of the filter within the vessel. A second plurality of spaced elongate legs angle outwardly away from the longitudinal axis toward the leading edge of the filter in the expanded configuration thereof to form a second filter basket opening toward the leading end. The ends of these legs include hooks to bend and straighten in response to withdrawal force.

Claims

1. A blood filter comprising:

a hub extending in a hub direction from a first hub end to a second hub end along a longitudinal axis;

a plurality of legs extending away from the second hub end along the longitudinal axis, each of the legs having a leg end proximate the hub and a hook proximate a distal end of the leg to retain the leg to a blood vessel wall; and

a plurality of arms extending away from the second hub end along the longitudinal axis, each of the arms having a first end and free end, the first end of each arm contiguous to a portion of the leg, the free end of each arm being closer to the body than the hook of each leg, the free end of each arm being spaced radially transverse to the longitudinal axis at substantially the same radial distance as the free end of another arm from the longitudinal axis.

2. The blood filter of claim 1, wherein the plurality of arm comprises at least four arms with four corresponding free ends disposed around the longitudinal axis to define a polygon about the longitudinal axis.

3. The blood filter of claim 1, wherein the plurality of arms comprises six arms with six free ends disposed on a generally circular perimeter about the longitudinal axis.

4. The blood filter of claim 3, wherein the hub comprises a generally cylindrical member that surrounds the leg ends of the legs and the first ends of the arms.

5. The blood filter of claim 3, wherein the hub comprises a generally cylindrical member having an inner surface contiguous to portions of the leg ends of the legs and the first ends of the arms.

6. The blood filter of claim 3, wherein the plurality of arms comprises at least four arms disposed over generally equal angular intervals and the plurality of legs comprises at least four legs disposed over generally equal angular intervals.

8. The blood filter of claim 3, wherein each of the arms comprises a portion disposed between the first end and the free end so that at least two arms are disposed diametrically with respect to the longitudinal axis and approximate a generally planar cross-section of an inverted cup.

9. The blood filter of claim 8, wherein the free ends of the at least two arms define a diameter smaller than a diameter defined by terminal ends of the hook of at least two legs disposed diametrically with respect to the longitudinal axis.

10. The blood filter of claim 8, wherein the portion comprises an inner arm portion and an outer arm portion located further away from the longitudinal axis than the inner arm portion, the inner arm portion extending at a first angle less than a second angle of the outer arm portion.

11. The blood filter of claim 10, wherein the second angle comprises about forty-five degrees with respect to the longitudinal axis.

12. The blood filter of claim 10, wherein each of the legs comprises an inner leg portion and an outer leg portion, the outer leg portion located further away from the longitudinal axis than the inner leg portion.

13. The blood filter of claim 12, wherein the inner leg portion extends at a first angle less than a second angle of the outer leg portion.

14. The blood filter of claim 13, wherein the second angle comprises about forty-five degrees with respect to the longitudinal axis.

15. The blood filter of one of claims 3 or 14, wherein the legs and arms comprise a metal alloy.

16. The blood filter of claim 15, wherein the metal alloy comprises an alloy selected from a group consisting of stainless steel, titanium, Nitinol, Elgiloy, and combinations thereof.

7. The blood filter of claim 7, wherein the angular interval comprises about 60 degrees about the longitudinal axis.

17. A filter to be placed in a flow of blood through a vessel, the vessel having a wall, the filter comprising:

a hub extending in a hub direction from a first end to a second end along a longitudinal axis;

a plurality of legs extending away from the second end of the hub along the longitudinal axis, each of the legs having a leg end proximate the hub, a hook proximate a distal end of the leg, and inner and outer leg portions disposed between the leg end, the inner leg portion extending at a first angle with respect to the longitudinal axis, the outer leg portion extending at a second angle different from the first angle; and

a plurality of arms extending away from the hub along the longitudinal axis, each of the arms having an inner arm portion and an outer arm portion, the inner arm portion extending at a third angle with respect to the longitudinal axis and the outer arm portion extending at a fourth angle with respect to the longitudinal axis different from the third angle.

18. The blood filter of claim 17, wherein the plurality of legs and plurality of arms extend from the hub along the hub direction.

19. The blood filter of claim 18, wherein at least one of the arm having a portion contiguous to a portion of at least one leg.

20. The blood filter of claim 17, wherein at least one of the arms and at least one of the legs comprise a shape memory material.

21. The blood filter of any one of claims 17 to 20, wherein the shape memory material is selected from a group consisting of plastic, super-elastic metal, Titanium, stainless steel, Nitinol, Elgiloy and combinations thereof.

22. The blood filter of any one of claims 17 to 20, wherein each hook comprises a barb configured to engage the wall of the vessel.

23. The blood filter of claim 22, wherein the hook comprises an arcuate profile having cross-sections along a substantial portion of the hook being less than the cross-section of each leg to permit the arcuate profile to be transformed into a generally linear profile.

24. A filter to be placed in a flow of blood through a vessel, the vessel having a wall, the filter comprising:

a hub extending along a longitudinal axis between first and second ends;

a set of first members projecting from the hub, each of the first members including a hook spaced along the longitudinal axis from the hub, and each hook being spaced radially from the longitudinal axis a first distance; and

a set of second members projecting from the hub and having a portion of at least one second member contiguous to a portion of at least one first member, each of the second members including a tip being spaced along the longitudinal axis from the hub, and each tip being spaced radially from the longitudinal axis a second distance less than the first distance.

25. The filter of claim 24, wherein the first and second members project from the second hub end.

26. The filter of claim 25, wherein the first and second members project from the second hub end along a direction from the first end to the second end of the hub.

27. The filter of claim 25, wherein each of the first members projects between a pair of the second members, and each of the second members projects between a pair of the first members.

28. The filter of claim 25, wherein the hooks are tangent to a virtual plane orthogonal to the longitudinal axis to define a first circle having a radius equal to the first distance, and the tips are tangent to a virtual plane orthogonal to the longitudinal axis to define a second circle having a radius equal to the second distance, the first and second circles being concentric about the longitudinal axis.

29. The filter of claim 25, wherein each of the hooks are tangent to a virtual plane orthogonal to the longitudinal axis to define a first circle having a radius equal to the first distance, and the tips are tangent to a virtual plane orthogonal to the longitudinal axis to define a second circle having a radius equal to the second distance, the first and second circles coaxial about the longitudinal axis.

30. The filter of claim 25, wherein each hook comprises a barb configured to engage the wall of the vessel.

31. The filter of claim 25, wherein each of the first members comprises a first segment extending substantially parallel to the longitudinal axis, a second segment extending tangentially with respect to the respective hook, and an intermediate segment extend between and obliquely coupled to each of the respective first and second segments.

32. The filter of claim 31, wherein each first, second and intermediate segment extend linearly.

33. The filter of claim 32, wherein each of the second segments extends obliquely with respect to the long axis at a first angle, and each of the intermediate segments extends obliquely with respect to the long axis at a second angle less than the first angle.

34. The filter of claim 33, wherein the intermediate segments define a cone having a first apex located along the longitudinal axis proximate the hub.

35. The filter of claim 24, wherein at least one of the arms and at least one of the legs comprise a shape memory material.

36. The filter of any one of claims 24 to 35, wherein the shape memory material is selected from a group consisting of plastic, superelastic metal, Titanium, stainless steel, Nitinol, Elgiloy and combinations thereof.

37. The filter of any one of claims 24 to 35, wherein each hook comprises a barb configured to engage the wall of the vessel.

38. The filter of claim 37, wherein the hook comprises an arcuate profile having cross-sections along a substantial portion of the hook being less than the cross-section of each leg to permit the arcuate profile to be transformed into a generally linear profile.

39. A filter to be placed in a flow of blood through a vessel, the filter comprising:

a hub disposed along a longitudinal axis;

at least one anchor projecting from the hub, the at least one anchor member including a hook that penetrates a wall of the blood vessel, the hook being spaced along the longitudinal axis from the hub, and spaced a first radial distance from longitudinal axis; and

at least one locator projecting from the hub, the at least one locator having at least a portion proximate a tip that engages the wall of the vessel, the tip being spaced along the longitudinal axis from the hub, and spaced a second radial distance from the longitudinal axis, the second radial distance being less than the first radial distance.

40. The filter of claim 39, wherein the first and second members project from the second hub end.

41. The filter of claim 40, wherein the first and second members project from the second hub end along a direction from the first end to the second end of the hub.

42. The filter of claim 41, wherein each of the first members projects between a pair of the second members, and each of the second members projects between a pair of the first members.

43. The filter of claim 41, wherein the hooks are tangent to a virtual plane orthogonal to the longitudinal axis to define a first circle having a radius equal to the first distance, and the tips are tangent to a virtual plane orthogonal to the longitudinal axis to define a second circle having a radius equal to the second distance, the first and second circles being concentric about the longitudinal axis.

44. The filter of claim 41, wherein the hooks are tangent to a virtual plane orthogonal to the longitudinal axis to define a first circle having a radius equal to the first distance, and the tips are tangent to a virtual plane orthogonal to the longitudinal axis to define a second circle having a radius equal to the second distance, the first and second circles coaxial about the longitudinal axis.

45. The filter of claim 41, wherein each hook comprises a barb configured to engage the wall of the vessel.

46. The filter of claim 41, wherein each of the first members comprises a first segment extending substantially parallel to the longitudinal axis, a second segment extending tangentially with respect to the respective hook, and an intermediate segment extend between and obliquely coupled to each of the respective first and second segments.

47. The filter of claim 46, wherein each first, second and intermediate segment extend linearly.

48. The filter of claim 47, wherein each of the second segments extends obliquely with respect to the long axis at a first angle, and each of the intermediate segments extends obliquely with respect to the long axis at a second angle less than the first angle.

49. The filter of claim 48, wherein the intermediate segments define a cone having a first apex located along the longitudinal axis proximate the hub.

50. The filter of claim 39, wherein at least one of the arms and at least one of the legs comprise a shape memory material.

51. The filter of any one of claims 39 to 50, wherein the shape memory material is selected from a group consisting of plastic, super-elastic metal, Titanium, stainless steel, Nitinol, Elgiloy and combinations thereof.

52. The filter of any one of claims 39 to 50, wherein each hook comprises a barb configured to engage the wall of the vessel.

53. The filter of claim 52, wherein the hook comprises an arcuate profile having cross-sections along a substantial portion of the hook being less than the cross-section of each leg to permit the arcuate profile to be transformed into a generally linear profile.

54. A filter delivery system to deliver a blood filter in a blood vessel, the system comprising:

a blood filter including;

a hub disposed along a longitudinal axis;

at least one anchor projecting from the hub, the at least one anchor member including a hook that penetrates a wall of the blood vessel, the hook being spaced along the longitudinal axis from the hub, and spaced a first radial distance from longitudinal axis; and

at least one locator projecting from the hub and contiguously engaging a portion of at least one anchor, the at least one locator having at least a portion proximate a tip that engages the wall of the vessel, the tip being spaced along the longitudinal axis from the hub, and spaced a second radial distance from the longitudinal axis, the second radial distance being less than the first radial distance; and

a delivery unit including;

a first end coupled to a pusher pad via an elongate pusher, the elongate pusher having first, second, and third sections of different cross-sections between the first end and the pusher pad;

a slotted spline disposed between any two of the first, second, and third sections, the slotted spline having a plurality of grooves extending along the longitudinal axis, the slotted spline having a reduced cross-section proximate the elongate pusher, and each of the plurality of grooves receiving a portion of each of the plurality of legs of the filter.

55. The system of claim 54, wherein the first end of the delivery unit comprises a handle.

56. The system of claim 55, wherein the third section comprises a flexible wire having a smaller cross-section than the first and second cross-sections to assist in centering the filter in the blood vessel.

57. The system of claim 55, wherein the elongate pusher comprises a Nitinol wire.

58. The system of claim 57, wherein the slotted spline is located at distance from the pusher pad less than a length of a leg of the filter.

59. The system of claim 58, wherein the delivery unit further comprises a delivery tube surrounding a portion of the slotted spline.

60. The system of claim 57, wherein the hub comprises first and second ends spaced apart along the longitudinal axis, the at least one locator and anchor projecting from the second end of the hub in substantially the same direction along the longitudinal axis.

61. A method of recovering a blood filter implanted in a blood vessel, the blood filter having a plurality of legs that extend from a hub and radially spaced about a longitudinal axis, each of the legs having a hook coupled to a wall of the blood vessel, the hook having a curved profile, the method comprising:

deforming the hook of each of the legs from the curved profile towards a generally straight profile; and

forcing the plurality of legs to move towards the longitudinal axis.

62. The method of claim 61, wherein the deforming comprises applying a force greater than 70 grams to each leg in a direction along the longitudinal axis towards the hub to separate the hook of the blood filter from the wall of the blood vessel.

63. The method of claim 62, wherein the applying comprises applying a force greater than 420 grams to the hub to separate the hooks of the blood filter from the wall of the blood vessel of about 28 millimeters.

64. The method of claim 63, wherein the deforming comprises bending each of the hooks toward a generally straight configuration to release a tip of the hook from the blood vessel wall.