Stents with multi-layered struts

• US 20010044652A1
• Filed: 06/14/2001
• Published: 11/22/2001
• Est. Priority Date: 10/14/1999
• Status: Abandoned Application

• Current Assignee: United Stenting Incorporated
• Original Assignee: United Stenting Incorporated
• Inventors: Moore, Brian Edward
• Application Number:
  US09/882,466
• Publication Number:
  US 20010044652A1
• Time in Patent Office: Days
• US Class Current: 623/1.16
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2220/0041 using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped

Abstract

An endoluminal prosthetic device comprising axially repeating rings made up in turn of unit cells. The unit cells themselves are made up of circumferentially repeating patterns of multilayered strut members to form the ring. The rings may be axially connected to form a stent or an expandable housing for housing other medical device inserts. The multilayered struts, created by recessed slots cut from various regions in the strut members, permit improved radiopacity, increased flexibility during insertion stage into a lumen and better post-expansion conformability to the longitudinal shape of the body lumen, while providing increased rigidity and strain tolerance once the device has been expanded, as well as improved expansion ratio and fatigue characteristics. Variations on slot placement, length, orientation and shape with respect to the centerline of the strut members permit the optimization of a stent'"'"'s strength, rigidity, strain and related mechanical properties. This approach reconciles competing needs for an expandable device to be low-profile and flexible enough to facilitate navigation through a tortuous body lumen so as to avoid causing lumen trauma prior to stent expansion and still achieve the expansion ratio and possess the needed radial strength to obtain and maintain lumen patency. Apertures placed in the struts further enable an easy and reliable point of attachment of an insert by means of sewing, stitching or riveting.

Claims

1. A unit cell to be used in a stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said unit cell comprising a plurality of continuous strut members arranged to define a unit cell pattern, wherein said unit cell pattern is arranged in a circumferentially repeating construction defining a radially expandable tubular structure, each of said strut members comprising a plurality of regions, said plurality of regions including:

at least one hinge region; and

a plurality of lateral regions, each of said lateral regions in connection with said hinge region; and

at least one recess disposed in at least one of said plurality of continuous strut members.

2. A unit cell according to

claim 1

, wherein each of said at least one recess is a slot.

3. A unit cell according to

claim 2

, wherein said slot is at least one continuous, longitudinal slot.

4. A unit cell according to

claim 2

, wherein said slot comprises a plurality of discrete slots.

5. A unit cell according to

claim 2

, wherein the longitudinal axis of each of said slots is positioned asymmetrically with respect to the centerline of said at least one of said plurality of regions.

6. A unit cell according to

claim 2

, wherein the longitudinal axis of each of said slots is positioned substantially equidistant between opposing edges of said at least one of said plurality of regions.

7. A unit cell according to

claim 1

, further comprising at least one unit cell interconnect region, said interconnect region including a proximal end in connection with said at least one hinge region, and a distal end.

8. A unit cell according to

claim 7

wherein said at least one unit cell interconnect region is substantially elongate.

9. A unit cell according to

claim 1

, further comprising at least one unit cell interconnect region, said interconnect region including a proximal end in connection with at least one of said plurality of lateral regions, and a distal end.

10. A unit cell according to

claim 9

, wherein said at least one unit cell interconnect region is substantially elongate.

11. A unit cell according to

claim 1

, wherein said unit cell is bistable.

12. A ring to be used in a stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said ring comprising a plurality of continuous strut members arranged to define a unit cell pattern, wherein said unit cell pattern is arranged in a circumferentially repeating construction defining a radially expandable tubular structure configured to expand from a first state into a second state, each of said strut members comprising a plurality of regions, said plurality of regions including:

at least one hinge region;

a plurality of lateral regions, each of said lateral regions in connection with said hinge region; and

at least one recess disposed in at least one of said at least one hinge region or said plurality of lateral regions such that, upon completion of expansion of said unit cell to said predetermined expansion ratio, said tubular structure said first state becomes said tubular structure said second state with a reduced level of strain in said strut members compared to a similar expansion ratio were no said recess present.

13. A ring according to

claim 12

, wherein said at least one recess is a slot.

14. A ring according to

claim 13

, further comprising an aperture disposed within at least one of said plurality of regions to facilitate attachment of an insert.

15. A ring according to

claim 13

, wherein said slot is at least one continuous, longitudinal slot.

16. A ring according to

claim 13

, wherein said slot comprises a plurality of discrete slots.

17. A ring according to

claim 16

, wherein each of said plurality of said discrete slots is positioned adjacent at least one lateral hinge point in said hinge region.

18. A ring according to

claim 14

, wherein the longitudinal axis of each of said slots is positioned asymmetrically with respect to the centerline of said at least one of said plurality of regions.

19. A ring according to

claim 14

, wherein the longitudinal axis of each of said slots is positioned substantially equidistant between opposing edges of said at least one of said plurality of regions.

20. A ring according to

claim 13

, further comprising at least one unit cell interconnect region, said interconnect region including a proximal end in connection with said at least one hinge region, and a distal end.

21. A ring according to

claim 20

, wherein said at least one unit cell interconnect region is substantially elongate.

22. A ring according to

claim 17

, further comprising at least one unit cell interconnect region, said interconnect region including a proximal end in connection with at least one of said plurality of lateral regions, and a distal end.

23. A ring according to

claim 22

, wherein said at least one unit cell interconnect region is substantially elongate.

24. A ring according to

claim 17

, wherein said members are bistable.

25. A ring to be used in a stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said ring defining an axial dimension and a radial dimension and comprising:

a plurality of continuous strut members arranged to define a unit cell pattern, wherein said unit cell pattern is arranged in a circumferentially repeating construction defining a tubular structure configured to expand in said radial dimension, each of said strut members comprising a plurality of regions, said plurality of regions including;

at least one hinge region;

a plurality of lateral regions angularly offset from said axial dimension, each of said lateral regions in connection with said at least one hinge region;

at least one substantially elongate interconnect region; and

at least one slot disposed in at least one of said plurality of continuous strut members;

a first state of said tubular structure, defining a first diameter; and

a second state of said tubular structure, defining a second diameter, wherein said second diameter is greater than said first diameter by an amount defined by a predetermined expansion ratio, such that, upon completion of expansion of said unit cell to said predetermined expansion ratio, said tubular structure said first state becomes said tubular structure said second state with a reduced level of strain in said strut members compared to a similar expansion ratio were no said recess present.

26. A ring according to

claim 25

, wherein the longitudinal axis of each of said slots is positioned asymmetrically with respect to the centerline of said at least one of said plurality of regions.

27. A ring according to

claim 25

, wherein the longitudinal axis of each of said slots is positioned substantially equidistant between opposing edges of said at least one of said plurality of regions.

28. A ring according to

claim 25

, wherein said at least one slot is at least one continuous, longitudinal slot.

29. A ring according to

claim 28

, wherein said continuous, longitudinal slot is disposed substantially within said at least one hinge region.

30. A ring according to

claim 29

, wherein said continuous, longitudinal slot further includes an additional widened portion adjacent a central hinge of said hinge region.

31. A ring according to

claim 28

, wherein said continuous, longitudinal slot is disposed substantially within said at least one lateral region.

32. A ring according to

claim 25

, wherein said slots are a plurality of discrete slots.

33. A ring according to

claim 32

, wherein said plurality of discrete slots are disposed substantially within said at least one hinge region.

34. A ring according to

claim 25

, wherein said at least one interconnect region includes a proximal end in connection with said at least one hinge region, and a distal end.

35. A ring according to

claim 25

, wherein said at least one interconnect region includes a proximal end in connection with said plurality of lateral regions, and a distal end.

36. A ring according to

claim 25

, wherein said members are bistable.

37. A stent for inserting into an anatomical lumen, comprising a plurality of axially repeating unit cells, each unit cell comprising:

a plurality of continuous strut members arranged to define a pattern, wherein said pattern is arranged in a circumferentially repeating construction defining a radially expandable tubular structure, each of said strut members comprising a plurality of regions, said plurality of regions including;

a hinge region;

a plurality of lateral regions, each of said lateral regions in connection with said hinge region; and

at least one recess disposed in at least one of said plurality of continuous strut members;

a first state of said tubular structure, defining a first diameter; and

a second state of said tubular structure, defining a second diameter, wherein said second diameter is greater than said first diameter by an amount defined by a predetermined expansion ratio, such that, upon completion of expansion of said unit cell to said predetermined expansion ratio, said tubular structure said first state becomes said tubular structure said second state with a reduced level of strain in said strut members compared to a similar expansion ratio were no said recess present.

38. A stent according to

claim 37

, wherein each of said at least one recess is a slot.

39. A stent according to

claim 38

, wherein a longitudinal axis of each of said slots is positioned substantially equidistant between opposing edges of said at least one of said plurality of regions.

40. A stent according to

claim 38

, wherein a longitudinal axis of each of said slots is positioned asymmetrically with respect to the centerline of said at least one of said plurality of regions.

41. A stent according to

claim 38

, wherein said slot is at least one continuous, longitudinal slot.

42. A stent according to

claim 41

, wherein said continuous, longitudinal slot is disposed substantially within said at least one lateral region.

43. A stent according to

claim 41

, wherein said continuous, longitudinal slot is disposed substantially within said at least one hinge region.

44. A stent according to

claim 43

, wherein said continuous, longitudinal slot further includes an additional widened portion adjacent a central hinge of said hinge region.

45. A stent according to

claim 38

, wherein said slot comprises a plurality of discrete slots.

46. A stent according to

claim 39

, wherein each of said plurality of said discrete slots is positioned adjacent at least one lateral hinge point in said hinge region.

47. A stent according to

claim 37

, further comprising at least one substantially elongate unit cell interconnect region, said interconnect region including a proximal end in connection with said hinge region, and a distal end.

48. A stent according to

claim 37

, further comprising at least one substantially elongate unit cell interconnect region, said interconnect region including a proximal end in connection with said lateral region, and a distal end.

49. A stent according to

claim 37

, wherein said members are bistable.

50. A stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said stent comprising:

a plurality of continuous strut members arranged to define a unit cell pattern, wherein said unit cell pattern is arranged in a circumferentially repeating construction defining a radially expandable tubular structure, each of said strut members comprising a plurality of regions, said plurality of regions including;

at least one hinge region;

a plurality of lateral regions angularly offset from said axial dimension, each of said lateral regions in connection with said at least one hinge region;

at least one substantially elongate interconnect region; and

at least one slot disposed in at least one of said plurality of continuous strut members;

a first state of said tubular structure, defining a first diameter; and

a second state of said tubular structure, defining a second diameter, wherein said second diameter is greater than said first diameter by an amount defined by a predetermined expansion ratio, such that, upon completion of expansion of said unit cell to said predetermined expansion ratio, said tubular structure said first state becomes said tubular structure said second state with a reduced level of strain in said strut members compared to a similar expansion ratio were no said recess present.

51. A stent according to

claim 50

, wherein said at least one interconnect region includes a proximal end in connection with said at least one hinge region, and a distal end.

52. A stent according to

claim 50

, wherein said at least one interconnect region includes a proximal end in connection with said plurality of lateral regions, and a distal end.

53. A stent according to

claim 50

, wherein the longitudinal axis of each of said slots is positioned asymmetrically with respect to the centerline of said at least one of said plurality of regions.

54. A stent according to

claim 50

, wherein the longitudinal axis of each of said slots is positioned substantially equidistant between opposing edges of said at least one of said plurality of regions.

55. A stent according to

claim 50

, wherein said at least one slot is at least one continuous, longitudinal slot.

56. A stent according to

claim 55

, wherein said continuous, longitudinal slot is disposed substantially within said lateral region.

57. A stent according to

claim 55

, wherein said continuous, longitudinal slot is disposed substantially within said hinge region.

58. A stent according to

claim 55

, wherein said continuous, longitudinal slot further includes an additional widened portion adjacent a central hinge of said hinge region.

59. A stent according to

claim 50

, wherein said at least one slot comprises a plurality of discrete slots.

60. A stent according to

claim 50

, wherein said members are bistable.

61. An expandable medical device configured for use as a housing for intraluminal inserts, said expandable medical device including a first state defining a first diameter and a second state defining a second diameter, wherein said second diameter is greater than said first diameter by an amount defined by a predetermined expansion ratio, said expandable medical device comprising:

a plurality of continuous strut members arranged to define a generally repeating pattern, wherein said generally repeating pattern is arranged such that each of said continuous strut members comprise a plurality of regions, said plurality of regions including;

a hinge region;

a plurality of lateral regions, each of said lateral regions in connection with said hinge region;

an interconnect region to connect said generally repeating pattern with an adjacent repeating pattern; and

at least one slot disposed in at least said hinge region or said plurality of lateral regions.

62. An expandable medical device according to

claim 61

, further comprising at least one aperture disposed in at least one of said plurality of regions to facilitate the attachment of said expandable medical device to said insert.

63. An expandable medical device according to

claim 62

, wherein said insert is selected from the group consisting of graft material, drug release device, valves, occlusion device and filters.

64. An expandable medical device according to

claim 62

, wherein said attachment to said insert material is configured to be accomplished through the use of materials from the group consisting of stitches, sewing wire and rivets.

65. A method of expanding an expandable housing, comprising:

configuring a length of generally tubular, expandable housing defined by a substantially lengthwise axial dimension and a radial dimension, said expandable housing configured to expand from a first state of said tubular structure defining a first diameter to a second state of said tubular structure defining a second diameter such that said second diameter is greater than said first diameter by an amount defined by a predetermined expansion ratio, said expandable housing possessive of a repeating unit cell, each of which comprises a plurality of continuous strut members, each defining a plurality of regions, said plurality of regions including;

a hinge region;

a plurality of lateral regions, each of said lateral regions in connection with said hinge region; and

at least one slot disposed in at least one of said plurality of continuous strut members;

placing said expandable housing in a predetermined location; and

expanding said expandable housing such that said housing changes from said first state into said second state.

66. A method according to

claim 65

, wherein prior to said step of placing said expandable housing in a predetermined location, said method further comprises the additional steps of:

inserting a catheter into an inner wall of said expandable housing; and

providing a conduit for the introduction of an expansion fluid into said catheter, said conduit in fluid communication with an external fluid pressure supply.

67. A method according to

claim 66

, wherein after said step of expanding said expandable housing such that said housing changes from said first state into said second state, said method further comprises the additional steps of:

deflating said catheter; and

withdrawing said deflated catheter from said expandable housing.

68. A method according to

claim 65

, wherein said expandable housing is self-expanding from said first state into said second state.

69. A method according to

claim 68

, wherein sometime prior to said step of expanding said expandable housing such that said housing changes from said first state into said second state, said method further comprises the additional step of restraining said expandable housing.

70. A method according to

claim 68

, wherein sometime prior to said step of expanding said expandable housing such that said housing changes from said first state into said second state, said method further comprises the additional step of separating said expandable housing from said restraint.

71. A method according to

claim 65

, wherein said slots are defined by a series of discrete slots positioned substantially equidistant between opposing edges of said strut members.

72. A method according to

claim 65

, wherein said slots are defined by a series of discrete slots positioned asymmetrically with respect to the centerline of said strut members.

73. A method according to

claim 65

, wherein said slots are defined by longitudinal and continuous slots throughout an entire length of at least one of a hinge region, a lateral region, or an interconnect region of each of said strut members, said slots positioned substantially equidistant between opposing edges of said strut members.

74. A method according to

claim 65

, wherein said slots are longitudinal and continuous throughout an entire length of at least one of a hinge region, a lateral region, or an interconnect region of each of said strut members, said slots positioned asymmetrically with respect to the centerline of said strut members.

75. A method according to

claim 65

, further comprising the steps of:

placing at least one aperture in at least one of said plurality of regions; and

attaching an insert to said expandable housing via said at least one aperture.

76. A method according to

claim 75

, wherein said attaching is accomplished through the use of materials from the group consisting of stitches, sewing wire or rivets.

77. A method according to

claim 76

, wherein said insert is selected from the group consisting of graft material, occlusion device, drug release device, valves and filters.

78. A method according to

claim 65

, wherein said lateral members are angularly offset relative to said axial dimension of said expandable housing

79. A method according to

claim 65

, wherein at least some of said slots or some of said lateral regions are non-prismatic in shape.

80. A bistable unit cell to be used in a stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said unit cell comprising:

a solid elongate strut member;

a slotted elongate strut member capable of a first bistable state and a second bistable state, wherein said slotted elongate strut member is nested with said solid elongate strut member in said first bistable state, and expanded away from said solid elongate strut member in said second bistable state;

a plurality of axially spaced hinge members, each defined by joined adjacent ends of said solid elongate strut member and said slotted elongate strut member, said plurality of axially spaced hinge members defining an elongate aperture configured as a curvilinear slot in said first bistable state and as an expanded opening in said second bistable state.

81. A bistable ring to be used in a stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said bistable ring comprising:

a plurality of circumferentially repeating unit cells, each of said unit cells comprising;

a solid elongate strut member;

a slotted elongate strut member capable of a first bistable state and a second bistable state, wherein said slotted elongate strut member is nested with said solid elongate strut member in said first bistable state, and expanded away from said solid elongate strut member in said second bistable state; and

a plurality of axially spaced hinge members, each defined by joined adjacent ends of said solid elongate strut member and said slotted elongate strut member, said plurality of axially spaced hinge members defining an elongate aperture configured as a curvilinear slot in said first bistable state and as an expanded opening in said second bistable state; and

an interconnect region disposed between adjacent bistable unit cells such that said adjacent bistable unit cells are configured to cooperatively expand when said bistable ring expands from said first bistable state into said second bistable state.

82. A bistable stent for inserting into an anatomical lumen and expandable upon insertion into said lumen, said bistable stent comprising:

a plurality of axially aligned bistable rings, each of said bistable rings formed by a plurality of interconnected unit cells arranged in a circumferentially repeating pattern, each of said unit cells comprising;

a solid elongate strut member;

a slotted elongate strut member capable of a first bistable state and a second bistable state, wherein said slotted elongate strut member is nested with said solid elongate strut member in said first bistable state, and expanded away from said solid elongate strut member in said second bistable state; and

a plurality of axially spaced hinge members, each defined by joined adjacent ends of said solid elongate strut member and said slotted elongate strut member, said plurality of axially spaced hinge members defining an elongate aperture configured as a curvilinear slot in said first bistable state and as an expanded opening in said second bistable state;

a first interconnect region disposed between adjacent bistable unit cells such that said adjacent bistable unit cells are configured to cooperatively expand when said bistable ring expands from said first bistable state into said second bistable state; and

a second interconnect region disposed between axially adjacent hinge members such that said plurality of axially aligned bistable rings are connected together to form said bistable stent.