FLARED STENTS AND APPARATUS AND METHODS FOR DELIVERING THEM

• US 20070073388A1
• Filed: 08/22/2006
• Published: 03/29/2007
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Incept LLC
• Original Assignee: Incept LLC
• Inventors: Dreher, James, Krolik, Jeffrey, Kim, Eliot
• Granted Patent: US 10,092,429 B2
• Time in Patent Office: Days
• US Class Current: 623/1.310
• 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 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/30322 differing in surface structures
• CPC Class Codes: A61F 2002/821 Ostial stents
• 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 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2230/005 Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0026 differing in surface structures
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: A61M 25/1002 characterised by balloon shape A61M25/1006, A61M25/1009 take precedence

Abstract

Flared stents are disclosed, and apparatus and methods for delivering such stents into a bifurcation between a main vessel and a branch vessel. The stent includes a first tubular portion a second flaring portion that may be flared radially outwardly to contact the ostium. The stent may include variable mechanical properties along its length. The stent may be delivered using a catheter including proximal and distal ends, the stent overlying first and second balloons on the distal end. During use, the catheter is advanced through an ostium into the branch to place the stent within the branch. The first balloon is expanded to flare the stent to contact a wall of the ostium, thereby causing the stent to migrate partially into the ostium. The second balloon is expanded to filly expand the stent within the ostium and branch.

Claims

1. An apparatus for locating an ostium of a body lumen, comprising:

an elongate member comprising a proximal end, a distal end sized for introduction into a body lumen, and a longitudinal axis extending therebetween;

a first expandable member on the distal end of the elongate member, the first expandable member being expandable from a contracted condition to an enlarged condition, the first expandable member comprising a distal surface, a proximal surface, and an intermediate region between the proximal and distal surfaces in the enlarged condition; and

a prosthesis comprising first and second portions on the distal end of the elongate member such that the distal surface of the first expandable member extends both beneath the first portion of the prosthesis and adjacent the prosthesis such that, when the first expandable member is expanded to the enlarged condition, the distal surface flares the first portion of the prosthesis and a portion of the distal surface of the first expandable member extends beyond the prosthesis to provide a tapered surface.

2. The apparatus of claim 1, further comprising a second expandable member on the distal end of the elongate member, the second expandable member being expandable from a contracted condition to an enlarged condition, the second portion of the prosthesis overlying at least a portion of the second expandable member such that, when the second expandable member is expanded to the enlarged condition, the second expandable member expands at least the second portion of the prosthesis.

3. The apparatus of claim 1, further comprising a stop on the distal end of the elongate member adjacent the second portion of the prosthesis, the stop comprising a proximal surface that contacts the second portion of the prosthesis to prevent distal migration of the prosthesis when the first expandable member is expanded.

4. The apparatus of claim 2, wherein the first expandable member overlies a portion of the second expandable member.

5. The apparatus of claim 2, wherein the second expandable member comprises a proximal portion that extends beneath the distal surface of the first expandable member and a distal portion that extends distally beyond the distal surface of the first expandable member, the second portion of the prosthesis overlying the distal portion of the second expandable member.

6. An apparatus for locating an ostium of a body lumen, comprising;

an elongate member comprising a proximal end, a distal end sized for introduction into a body lumen, and a longitudinal axis extending therebetween;

first and second expandable members on the distal end of the elongate member, the first and second expandable members being independently expandable from one another between a contracted condition and an enlarged condition; and

a tubular prosthesis comprising a first portion overlying a portion of the first expandable member and a second portion overlying a portion of the second expandable member,

wherein the first expandable member comprises a distal surface, a proximal surface, and an intermediate region between the proximal and distal surfaces in the enlarged condition, the first portion of the prosthesis covering a portion of the distal surface such that, when the first expandable member is expanded to the enlarged condition, the distal surface flares the first portion of the prosthesis and a portion of the distal surface of the first expandable member extends beyond the prosthesis to provide an exposed tapered surface.

7. The apparatus of claim 6, further comprising a stop on the distal end of the elongate member adjacent the second portion of the prosthesis, the stop comprising a proximal surface that contacts the second portion of the prosthesis to prevent distal migration of the prosthesis when the first expandable member is expanded.

8. A method for delivering a stent within an ostium communicating from a main body lumen to a branch body lumen, comprising:

directing a distal end of an elongate member into the main body lumen with a prosthesis carried on the distal end in a contracted condition;

advancing the distal end of the elongate member through the ostium into the branch body lumen until the prosthesis is disposed within the branch body lumen;

expanding a first expandable member on the distal end of the elongate member such that a tapered distal surface of the first expandable member contacts a wall of the branch body lumen, thereby causing the prosthesis to migrate at least partially towards the ostium; and

expanding the prosthesis such that a first portion of the prosthesis is disposed within the ostium and a second portion of the prosthesis is disposed within the branch body lumen.

9. The method of claim 8, wherein expanding the first expandable member causes the tapered distal surface of the first expandable member to at least partially flare the first portion of the prosthesis.

10. The method of claim 8, wherein the prosthesis is expanded by expanding a second expandable member on the distal end of the elongate member.

11. The method of claim 10, wherein the second portion of the prosthesis is expanded to dilate the branch body lumen when the second expandable member is expanded.

12. The method of claim 9, wherein a stop on the distal end of the elongate member prevents distal migration of the prosthesis as the first portion of the prosthesis is flared.

13. The method of claim 8, further comprising positioning the distal end of the elongate member such that the first portion of the prosthesis is disposed adjacent the ostium.

14. The method of claim 13, further comprising monitoring markers on the distal end of the elongate member to facilitate positioning the first portion of the prosthesis adjacent the ostium.

15. The method of claim 13, wherein expanding the first expandable member causes the prosthesis to migrate such that the first portion moves from being adjacent the ostium at least partially into the ostium.

16. A stent, comprising:

a tubular member comprising first and second ends defining a longitudinal axis therebetween, and a plurality of cells disposed between the first and second ends, the tubular member being expandable from a contracted condition to an enlarged condition, the first end having a larger cross-section than the second end in the enlarged condition;

wherein the tubular member comprises a first set of cells disposed at the first end, and a second set of cells disposed adjacent the first set of cells, the first and second sets of cells having first and second axial lengths, respectively, in the contracted condition, the first axial length being substantially shorter than the second axial length.

17. The stent of claim 16, wherein the tubular member further comprises a third set of cells adjacent the second set of cells, the third set of cells having a third axial length in the contracted condition that is substantially shorter than the second axial length.

18. The stent of claim 16, wherein the tubular member comprises a plurality of cells between the second set of cells and the second end of the tubular member, each of the plurality of cells having an axial length in the contracted condition that is substantially shorter than the second axial length.

19. The stent of claim 16, wherein the first set of cells comprises a plurality of struts that extend generally axially in the contracted condition, the first set of cells being deformed as the tubular member is directed to the enlarged condition such that the plurality of struts extend generally circumferentially around the first end of the tubular member.

20. A stent, comprising:

a tubular member comprising first and second ends defining a longitudinal axis therebetween, and a plurality of cells disposed between the first and second ends, the tubular member being expandable from a contracted condition to an enlarged condition, the first end having a larger cross-section than the second end in the enlarged condition;

wherein the tubular member comprises a first set of cells disposed at the first end, the first set of cells comprising a plurality of struts that extend generally axially in the contracted condition, the first set of cells being deformed as the tubular member is directed to the enlarged condition such that the plurality of struts extend generally circumferentially around the first end of the tubular member.

21. The stent of claim 20, wherein the tubular member comprises a second set of cells adjacent the first set of cells, the second set of cells configured to flare outwardly as the tubular member is directed to the enlarged condition such that the first end of the tubular member is larger than the second end of the tubular member.

22. A stent configured to be expanded from a contracted condition to an enlarged condition, comprising:

a first end portion configured to flare outwardly when the stent is expanded from the contracted condition to the enlarged condition;

a second intermediate portion adjacent the first portion; and

a third end portion adjacent the second portion opposite the first portion, wherein at least two of the first, second, and third portions have different mechanical properties.

23. The stent of claim 22, wherein the first portion is configured for providing greater luminal support than the third portion in the enlarged condition.

24. The stent of claim 23, wherein the second portion has a greater flexibility characteristic than the first and third portions.

25. The stent of claim 22, wherein the third portion has a length that is greater than the first and second portions.

26. The stent of claim 22, wherein the first portion comprises a first band of cells including struts that deform from an axial to a circumferential orientation when the stent is expanded from the contracted condition to the enlarged condition, thereby enhancing a luminal support characteristic of the first portion in the enlarged condition.

27. The stent of claim 22, wherein the different mechanical properties are provided by varying at least one of the following along a length of the stent:

length of axial struts, thickness of struts, material hardness, number of zigzags extending around a circumference of the stent, intermittency of links between adjacent bands of cells, and shape of links between adjacent bands of cells.