Stent and catheter assembly and method for treating bifurcations

• US 20080009932A1
• Filed: 07/07/2006
• Published: 01/10/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Cox, Daniel L., Wrolstad, David K., Pacetti, Stephen Dirk, Barbod, Leonard D., Ta, Diem Uyen, Hearn, Brenna K., Armstrong, Kenneth Kay, Kent, Darrin J., Wu, Caroline, Delgado, Jessie, Hatten, Thomas Ray
• Granted Patent: US 8,029,558 B2
• Time in Patent Office: Days
• US Class Current: 623/1.11
• CPC Class Codes: A61F 2/856 Single tubular stent with a side portal passage
• 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 2/954 for placing stents or stent-grafts in a bifurcation
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/067 modular
• CPC Class Codes: A61F 2002/91525 within the whole structure different bands showing different meander characteristics, e.g. frequency or amplitude
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2250/006 modular

Abstract

An improved stent design and stent delivery catheter assembly for repairing a main vessel and a side branch vessel forming a bifurcation. The stent includes rings aligned along a common longitudinal axis and connected by links, where the stent has one or more portals for aligning with and partially expanding into the opening to the side branch vessel. The stent is implanted at a bifurcation so that the main stent section is in the main vessel, and the portal section covers at least a portion of the opening to the side branch vessel. A second stent can be implanted in the side branch vessel and abut the expanded central section to provide full coverage of the bifurcated area in the main vessel and the side branch vessel. Radiopaque markers on the stent and on the tip of the delivery catheter assist in aligning the portal section with the opening to the side branch vessel.

Claims

1. A stent for treating a bifurcated vessel having a main vessel and a side branch vessel, comprising:

a cylindrical body having a proximal end, a distal end, and a plurality of rings;

each ring having a delivered diameter, an implanted diameter and a plurality of peaks and a plurality of valleys, the peaks and the valleys being connected by bar arms;

each ring being attached to an adjacent ring by more than one undulating link;

a portal section comprised of one or more rings; and

at least some of the bar arms connecting the peaks and the valleys of the one or more rings in the portal section have a length that is relatively longer than the bar arms connecting the peaks and the valleys of rings in a distal section of the stent.

2. The stent of claim 1, wherein two undulating links connect a portal ring to the adjacent ring distal to the portal ring.

3. The stent of claim 1, wherein at least two undulating links connect adjacent rings.

4. The stent of claim 1, wherein three undulating links connect adjacent rings except that two links connect a portal ring to the adjacent ring distal to the portal ring.

5. The stent of claim 2, wherein the two undulating links comprise undulating portions that point in a direction away from the portal section and transverse to a longitudinal axis of the stent, thereby creating a relatively larger portal section.

6. The stent of claim 1, wherein at least some of the bar arms in the rings of the portal section have a width that is less than a width of the bar arms in the rings not in the portal section.

7. The stent of claim 1, wherein the stent includes a proximal end ring, each of the peaks and the valleys of the proximal end ring having a radius that is greater than a radius of each of the peaks and the valleys of all of the other rings of the stent to improve stent retention and reduce flaring.

8. The stent of claim 1, wherein the stent is formed from a metal.

9. The stent of claim 8, wherein the metal is taken from the group of metals including stainless steel, titanium, nickel-titanium, cobalt-chromium, cobalt-chromium-vanadium, cobalt-chromium-tungsten, tungsten, gold, silver, platinum, and platinum-vanadium.

10. The stent of claim 1, wherein the stent is coated with at least one layer of containing a drug.

11. The stent of claim 1, wherein the stent is coated with a therapeutic agent.

12. The stent of claim 1, wherein the stent is coated with a primer material which adheres to the stent, the primer material being coated with a drug or therapeutic agent or a layer containing a drug or therapeutic agent.

13. The stent of claim 1, wherein the undulating links connecting adjacent rings in the portal section have undulating portions pointing toward the portal section.

14. The stent of claim 13, wherein the relatively longer bar arms connecting the peaks and the valleys of the one or more rings in the portal section are configured to move the undulating links in the portal section closer to the side branch vessel when the stent is expanded to the implanted diameter.

15. The stent of claim 1, wherein a proximal end ring includes W-shaped elements for increasing stent retention on a balloon catheter and to reduce flaring when the stent is expanded.

16. The stent of claim 1, wherein the undulating links in the portal section are substantially longer than the undulating links not in the portal section so that as the stent is expanded, the portal section will extend further into the side branch vessel.

17. The stent of claim 1, wherein the rings in the portal section are nested so that upon stent expansion the portal section will extend further into the side branch vessel.

18. The stent of claim 1, wherein a plurality of substantially straight links connect the portal section rings with the rings proximal to the portal section rings so that upon stent expansion, the portal section extends further into the side branch vessel.

19. The stent of claim 1, wherein the rings and undulating links have a constant radial thickness.

20. The stent of claim 1, wherein the rings and undulating links have variable radial thickness to vary the flexibility of the stent.

21. The stent of claim 1, wherein at least some of the bar arms connecting the peaks and the valleys of the rings in a proximal section have a length that is relatively longer than the bar arms connecting the peaks and the valleys of rings in the distal section of the stent.

22. The stent of claim 1, wherein there are more peaks and more valleys in each ring in a proximal section than in the distal section rings.

23. The stent of claim 1, wherein the location of the portal section on the stent can vary by increasing or decreasing the number of rings in a proximal section and/or the distal section.

24. The stent of claim 1, wherein the portal section is symmetric about a longitudinal axis of the stent thereby providing uniform crimping and expansion of the portal section.

25. The stent of claim 1, wherein a proximal section has a proximal end ring having peaks and valleys connected by bar arms, each of the peaks, the valleys and the bar arms of the proximal end ring having width greater than a width of the peaks, the valleys and the bar arms respectively of all of the other rings of the stent.

26. The stent of claim 1, wherein the stent is formed from a bioabsorbable polymer.

27. The stent of claim 1, wherein the stent is coated with a primer material which adheres to the stent, a drug or therapeutic agent being embedded in the primer.

28. A stent for treating a bifurcated vessel having a main vessel and a side branch vessel, comprising:

a cylindrical body having a proximal end and a distal end;

the cylindrical body having a proximal section, a distal section, and a portal section, wherein each of the sections is configured to be used with two balloons such that a first balloon extends through the proximal section and the distal section, and a second balloon extends through the proximal section and the portal section; and

the portal section having an expanded diameter greater than an expanded diameter of the proximal section and the distal section to thereby provide additional material to treat a bifurcated vessel, the portal section being configured to flare radially outwardly into contact with an opening to the side branch vessel and into at least a portion of the side branch vessel.

29. The stent of claim 28, wherein the cylindrical body has a plurality of rings aligned along a common longitudinal axis.

30. The stent of claim 29, wherein each of the proximal section, distal section, and portal section have at least one ring.

31. The stent of claim 29, wherein adjacent rings are connected by links.

32. The stent of claim 29, wherein the rings are connected by at least one link between adjacent rings.

33. The stent of claim 29, wherein at least some of the links have a straight segment.

34. The stent of claim 32, wherein at least some of the links have a curved segment.

35. The stent of claim 32, wherein at least some of the links have a straight segment and a curved segment.

36. The stent of claim 32, wherein at least some of the links have a non-linear segment.

37. The stent of claim 32, wherein the stent is formed from metal.

38. The stent of claim 37, wherein the metal is taken from the group of metals including stainless steel, titanium, nickel-titanium, cobalt-chromium, cobalt-chromium-vanadium, cobalt-chromium-tungsten, tungsten, gold, silver, platinum, or platinum iridium.

39. The stent of claim 28, wherein the stent is coated with at least one layer containing a drug.

40. The stent of claim 28, wherein the stent is coated with at least one layer containing a therapeutic agent.

41. The stent of claim 28, wherein at least a portion of the stent is coated with at least one layer containing a therapeutic agent.

42. The stent of claim 28, wherein at least a portion of the stent is coated with a primer material which adheres to the stent, the primer being coated with at least one layer of a therapeutic agent or drug or a layer containing a drug or therapeutic agent.

43. The stent of claim 28, wherein at least a portion of the portal section has a relatively higher degree of radiopacity than the proximal section and the distal section.

44. The stent of claim 28, wherein the at least a portion of the portal section is coated with a radiopaque material.

45. The stent of claim 28, wherein the stent comprises more than one portal section.

46. The stent of claim 28, wherein the portal section is symmetric about a longitudinal axis of the stent providing uniform crimping and expansion of the portal section.

47. The stent of claim 28, wherein the stent is formed from a bioabsorbable polymer.

48. The stent of claim 28, wherein the stent is coated with a primer material which adheres to the stent, a drug or therapeutic agent being embedded in the primer.

49. A stent for treating a bifurcated vessel having a main vessel and a side branch vessel, comprising:

a cylindrical body having a plurality of rings aligned along a common longitudinal axis, adjacent rings being connected by links;

the cylindrical body having a proximal section, a distal section, and a portal section;

a ring in the portal section having U-shaped elements comprised of peaks and valleys connected by first bar arms and second bar arms;

the first bar arms having a first length greater than a second length of the second bar arms so that the portal section has an increased area of expansion; and

the portal section ring being connected to an adjacent ring in the proximal section by two undulating links and to an adjacent ring in the distal section by two undulating links.

50. The stent of claim 49, wherein the undulating links have a curved portion extending transverse to a stent longitudinal axis.

51. The stent of claim 50, wherein the curved portion of the undulating links point away from a portal area in the portal section.

52. The stent of claim 49, wherein the rings in the proximal section and the distal section are connected by undulating links.

53. The stent of claim 52, wherein three undulating links attach adjacent rings in the proximal section and the distal section.

54. The stent of claim 53, wherein all of the undulating links in the distal section have a curved portion extending transverse to a stent longitudinal axis, the undulating portions all extending in the same circumferential direction.

55. A stent delivery balloon catheter, comprising:

a) an elongated shaft, having

i) a proximal section having a first inflation lumen;

ii) a bifurcated distal section having a first branch with a second inflation lumen within at least a portion thereof, and a second branch with a third inflation lumen within at least a portion thereof, the second and third inflation lumens each being in fluid communication with the first inflation lumen, the bifurcated distal section further having a secured portion along which the first and second branches are permanently secured together, and an unsecured portion proximally adjacent to the secured portion and along which the first and second branches are not secured together;

iii) an intermediate section joining the proximal and distal sections together, and having a fourth inflation lumen in fluid communication with the first, second, and third inflation lumens; and

iv) a joining wire lumen extending within the proximal section, the intermediate section, and the first branch, and a guidewire lumen extending within at least the intermediate section and the second branch; and

b) a first balloon on the first branch having an inflatable interior in fluid communication with the second inflation lumen, and a second balloon on the second branch having an inflatable interior in fluid communication with the third inflation lumen, and the inflatable interior of the first balloon and the inflatable interior of the second balloon are located distal to the secured portion of the bifurcated distal section;

c) a coupler secured to the second branch, located distal to the inflatable interior of the second balloon, and configured for releasably coupling the first and second branches together to form a coupled configuration;

d) a polymeric radiopaque distal tip marker surrounding a distal end section of the joining wire lumen, located distal to the inflatable interior of the first balloon, and formed of a blend of a polymeric material and radiopaque material; and

e) a stent releaseably mounted on the first and second balloons, located distal to the secured portion of the distal shaft section.

56. The catheter of claim 55, wherein the secured portion is formed at least in part by a tubular outer band member which constrains the first and second branches of the distal shaft section together.

57. The catheter of claim 56, wherein the tubular outer band member is adhesively bonded to the first and second branches.

58. The catheter of claim 55, wherein the secured portion is a first secured portion located approximately midway between a proximal end of one or both of the first and second balloons and a proximal end of the branched distal shaft section.

59. The catheter of claim 58, including a second secured portion at adjacent to and proximally spaced apart from the proximal end of one or both of the first and second balloons, such that the second secured portion is distally spaced apart from the first secured portion by an unsecured portion of the first and second branches of the distal shaft section.

60. The catheter of claim 55, wherein the secured portion is formed at least in part by a tubular outer band member of heat shrink tubing, heat shrunk around the first and second branches, and conforming to the underlying outer surfaces of the secured first and second branches such that the tubular outer band member has an hourglass shape.

61. The catheter of claim 55, wherein the first branch includes a soft distal tip member forming the distal end of the first branch, and having the joining wire lumen therein, and the polymeric radiopaque tip marker is an annular ring surrounding the soft distal tip member.

62. The catheter of claim 61, including a polymeric nonradiopaque outer sheath surrounding at least the proximal end of the soft distal tip member, and wherein the polymeric radiopaque tip marker has an inner surface secured to an outer surface of the outer sheath, and has a proximal end located distal to the distal end of the nonradiopaque sleeve, and a distal end located proximal to the distal end of the soft distal tip member.

63. The catheter of claim 55, wherein the polymeric radiopaque distal tip marker is a soft distal tip member forming the distal end of the first branch, and having the joining wire lumen therein.

64. The catheter of claim 55, wherein the polymeric radiopaque distal tip marker is located distal to a distal end of the first balloon.

65. The catheter of claim 55, including one or more balloon radiopaque metal markers on the catheter distal shaft section within the inflatable interiors of the balloon, of a different composition than the polymeric radiopaque distal tip marker.

66. The catheter of claim 65, wherein the polymeric radiopaque distal tip marker is longer than the radiopaque balloon markers.

67. A balloon catheter, comprising:

a) an elongated catheter shaft having a branched distal section with a first and a second branch configured for releasably coupling together to form a coupled configuration, an inflation lumen, and a joining wire lumen extending at least within the first branch of the branched distal section;

b) a first balloon on the first branch with an inflatable interior in fluid communication with the inflation lumen, and a second balloon on the second branch with an inflatable interior in fluid communication with the inflation lumen; and

c) a polymeric radiopaque distal tip marker surrounding a distal end section of the joining wire lumen, located distal to the inflatable interior of the first balloon, and formed of a blend of a polymeric material and radiopaque material.

68. The catheter of claim 67, including a stent releaseably mounted on at least one of the first and second balloons having a distal end located proximal to the polymeric radiopaque distal tip marker.

69. The catheter of claim 67, wherein the first branch has at least one secured portion along which the first branch is permanently secured to the second branch at a location spaced between a proximal end of the branched distal shaft section and a proximal end of the inflatable interiors of the first and second balloons.

70. The catheter of claim 67, including a joining guidewire disposed within the joining wire lumen, and within a guidewire locking mechanism located proximal to the catheter shaft, having a locked mode in which the catheter is releasably locked to the guidewire disposed within the joining wire lumen, and an unlocked mode in which the joining guidewire is slidably disposed within the joining wire lumen.

71. The catheter of claim 70, including a proximal adapter secured to a proximal end of the catheter shaft, having a port configured for connecting to a source of inflation fluid for inflating the first and second balloons, and the guidewire locking mechanism comprises a proximal fitting which is connected to the proximal adapter and which tightens onto the proximal adapter to place the guidewire locking mechanism in the locked mode.

72. The catheter of claim 71, wherein the guidewire locking mechanism comprises a radially collapsible slotted head of a collet member or of an inner extension of the proximal fitting, the slotted head being positioned within the proximal adapter when the proximal fitting is connected to the proximal adapter.

73. The catheter of claim 70, including a proximal adapter secured to a proximal end of the catheter shaft, having a port configured for connecting to a source of inflation fluid for inflating the first and second balloons, wherein the guidewire locking mechanism comprises a guidewire locking torque handle which reversibly engages the joining guidewire to provide a finger hold for manipulating the joining guidewire, and which, in the locked mode, is releaseably connected to a proximal fitting at a proximal end of the proximal adapter.

74. The catheter of claim 67, wherein the second branch has a fixed guidewire with a distal section permanently secured to a distal end section of the second branch, such that a section of the fixed guidewire located proximal to the second balloon extends directly within the inflation lumen of the second branch and not within a guidewire lumen of the catheter shaft.

75. A method of delivering a stent to a patient'"'"'s bifurcated blood vessel, comprising:

a) introducing within the patient'"'"'s blood vessel a stent delivery balloon catheter having

a proximal shaft section, an intermediate shaft section, and a bifurcated distal shaft section with a first branch and a second branch,

a first balloon with an inflatable interior in fluid communication with an inflation lumen in the first branch, and a second balloon with an inflatable interior in fluid communication with an inflation lumen in the second branch,

a coupler secured to the second branch, located distal to the inflatable interior of the second balloon, configured for reversibly coupling the first and second branches together to form a coupled configuration,

a polymeric radiopaque distal tip marker surrounding a distal end section of a lumen of the first branch, located distal to the inflatable interior of the first balloon, and formed of a blend of a polymeric material and radiopaque material, and

a stent releaseably mounted on the first and second balloons;

b) advancing the catheter within the patient'"'"'s blood vessel towards a opening of a side branch of the patient'"'"'s blood vessel, with the first and second branches of the catheter distal section in the coupled configuration;

c) fluoroscopically imaging the polymeric radiopaque distal tip marker to determine the alignment of the first branch balloon relative to the opening of the side branch of the patient'"'"'s blood vessel;

d) uncoupling the first and second branches to an uncoupled configuration; and

e) positioning the uncoupled first branch of the catheter within the side branch of the patient'"'"'s blood vessel, and expanding the stent.

76. The method of claim 75, including after c) and before d), adjusting the alignment of the first branch balloon relative to the side branch opening of the patient'"'"'s blood vessel while fluoroscopically imaging the polymeric radiopaque distal tip marker.

77. The method of claim 75, including after d) and before e), adjusting the alignment of the first branch balloon relative to the side branch opening of the patient'"'"'s blood vessel while fluoroscopically imaging the polymeric radiopaque distal tip marker.

78. The method of claim 75, wherein the catheter includes one or more radiopaque balloon markers which indicate the first and/or second balloon and which appear with a shape visually different than the polymeric radiopaque distal tip marker under fluoroscopy, such that the fluoroscopic imaging distinguishes the balloons markers from the polymeric radiopaque distal tip marker.

79. The method of claim 75, wherein the bifurcated distal section has a secured portion along which the first and second branches are permanently secured together, and an unsecured portion proximally adjacent to the secured portion and along which the first and second branches are not secured together, and e) comprises advancing the catheter, so that a distal tip of the uncoupled first branch advances radially away from the second branch into the side branch of the patient'"'"'s blood vessel and the first and second branches advance together at the secured portion.

80. The method of claim 75, wherein the catheter has a guidewire disposed within the joining wire lumen and within a guidewire locking mechanism located proximal to the catheter shaft, the guidewire locking mechanism having a locked mode in which the catheter is releasably locked to the guidewire disposed within the joining wire lumen, and an unlocked mode in which the guidewire is slidably disposed within the joining wire lumen, and including positioning the guidewire distal end distal to the distal end of the first branch and locking the catheter to the guidewire so that the guidewire is a fixed guidewire in the locked mode, and including advancing the catheter together with the fixed guidewire to the side branch opening of the patient'"'"'s blood vessel.

81. The method of claim 75, wherein the catheter has a joining guidewire disposed within the joining wire lumen and within a guidewire locking mechanism located proximal to the catheter shaft, the guidewire locking mechanism having a locked mode in which the catheter is releasably locked to the joining guidewire disposed within the joining wire lumen, and an unlocked mode in which the joining guidewire is slidably disposed within the joining wire lumen, wherein c) comprises unlocking the joining guidewire from the catheter and removing the joining guidewire from the coupler, and including after d) and before e) positioning the joining guidewire in the side branch of the patient'"'"'s blood vessel.

82. The method of claim 81, including a proximal adapter secured to a proximal end of the catheter shaft, having a port configured for connecting to a source of inflation fluid for inflating the first and second balloons, wherein the guidewire locking mechanism comprises a guidewire locking torque handle which reversibly engages the joining guidewire to provide a finger hold for manipulating the joining guidewire, and which is releaseably connected to a proximal fitting at a proximal end of the proximal adapter in the locked mode so that unlocking the joining guidewire from the catheter comprises disconnecting the proximal fitting from the proximal adapter, and including grasping the guidewire locking torque handle engaged on the joining guidewire, to position the joining guidewire in the side branch of the patient'"'"'s blood vessel.

83. The method of claim 75, wherein the second branch of the catheter has a fixed guidewire with a distal section permanently secured to a distal end section of the second branch, such that a section of the fixed guidewire located proximal to the second balloon extends directly within the inflation lumen of the second branch and not within a separate guidewire lumen, and including advancing the catheter together with the fixed guidewire to the side branch opening of the patient'"'"'s blood vessel.