STEEP-TAPER FLARED STENTS AND APPARATUS AND METHODS FOR DELIVERING THEM

• US 20070067011A1
• Filed: 08/22/2006
• Published: 03/22/2007
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Incept LLC
• Original Assignee: Incept LLC
• Inventors: Dreher, James, Krolik, Jeffrey, Kim, Eliot, Khosravi, Farhad
• Granted Patent: US 7,582,111 B2
• Time in Patent Office: Days
• US Class Current: 623/1.110
• 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

A stent includes a first portion including first and second bands of cells that flare outwardly when the stent is expanded from a contracted to a flared condition, and a second portion connected to the first portion by flexible connectors. During use, the stent is introduced into a main vessel in the contracted condition and positioned with the first portion adjacent an ostium and the second portion within a branch vessel extending from the ostium. The first portion is flared, causing first struts of the first set of cells to move from an axial towards a radial and partial circumferential orientation and causing second struts of the second set of cells to move from an axial towards a radial orientation. The stent is expanded further such that the second portion expands within the branch body lumen, and the first and second struts move towards a more circumferential orientation.

Claims

1. A stent comprising a tubular member including 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 stent comprising:

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

a second portion adjacent the first portion, the second portion connected to the first end portion by a plurality of connectors, the connectors being relatively flexible compared to the first end portion for accommodating the first end portion flaring outwardly.

2. The stent of claim 1, wherein the first end portion 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 plurality of connectors being connected to the second set of cells.

3. The stent of claim 2, the second set of cells comprising axial segments connected to curved segments, the curved segments having a lower yield strength than the axial segments.

4. The stent of claim 3, wherein the stent is expandable to an intermediate condition between the contracted and enlarged conditions, the axial segments extending generally radially outwardly in the intermediate condition.

5. The stent of claim 4, wherein a ratio of a diameter of the first end portion to the second end in the intermediate condition is between about two and five.

6. The stent of claim 4, wherein a ratio of a diameter of the first end portion to the second end in the enlarged condition is between about 1.1 and 1.8.

7. The stent of claim 2, wherein the first and second set of cells comprise axial segments having lengths substantially equivalent to one another.

8. The stent of claim 2, the first set of cells comprising segments that extend substantially axially in the contracted condition, the first end portion flaring such that the segments extend substantially circumferentially in the enlarged condition.

9. The stent of claim 1, wherein the connectors comprise curvilinear segments having a thickness and a width, at least one of the thickness and the width being thinner than segments comprising the first end portion.

10. A stent comprising a tubular member including 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 through an intermediate condition, the stent comprising:

a first end portion configured to flare outwardly when the stent is expanded from the contracted condition to the intermediate condition, the first end portion comprising a first set of cells at the first end and a second set of cells adjacent the first set of cells, the second set of cells comprising segments extending substantially axially in the contracted condition;

a second portion adjacent the first portion; and

a plurality of connectors connecting the second portion to the second set of cells of the first end portion, the connectors being relatively flexible such that the axial segments of the second set of cells assume a generally radially outward orientation in the intermediate condition;

wherein the first set of cells comprise a plurality of segments extending substantially axially in the contracted condition, the axial segments of the first set of cells assuming a generally circumferential orientation in the enlarged condition.

11. The stent of claim 10, wherein a ratio of a diameter of the first end portion to the second end in the intermediate condition is between about two and five.

12. The stent of clam 11, wherein a ratio of a diameter of the first end portion to the second end in the enlarged condition is between about 1.1 and 1.8.

13. An apparatus for treating an ostium communicating between a main body lumen and a branch body lumen, comprising:

an elongate member comprising a proximal end, a distal end sized for introduction into the main body lumen and the branch body lumen;

an expandable member on the distal end, the expandable member being expandable from a first collapsed configuration to a second flared configuration, and a third expanded configuration; and

a stent on the distal end over the expandable member, the stent comprising a first end portion and a second portion connected to the first end portion by a plurality of flexible connectors;

wherein, when the expandable member is expanded to the second configuration, the first end portion of the stent is expanded to a flared condition, and when the expandable member is expanded to the third configuration, the second portion is expanded radially outwardly and the first end portion is further expanded radially outwardly.

14. The apparatus of claim 13, wherein the expandable member comprises a first balloon underlying the first end portion of the stent and a second balloon underlying at least the second portion of the stent, the first balloon being expandable independent of the second balloon, the second configuration being defined by expansion of the first balloon.

15. The apparatus of claim 13, wherein the first end portion of the stent comprises:

a first set of cells disposed at the first end;

a second set of cells disposed adjacent the first set of cells, and

a plurality of flexible connectors connecting the second set of cells to the second portion of the stent.

16. The apparatus of claim 15, the second set of cells comprising struts connected to curved segments, the curved segments having a lower yield strength than the struts.

17. The apparatus of claim 16, wherein the struts are directed from a generally axial orientation towards a generally radially outward orientation when the expandable member is expanded to the second configuration.

18. The apparatus of claim 17, wherein the struts are directed from the generally radially outward orientation in the flared condition towards a circumferential orientation when the expandable member is expanded to the third configuration.

19. The apparatus of claim 15, wherein the first and second set of cells comprise axial segments having lengths substantially equivalent to one another.

20. The apparatus of claim 15, the first set of cells comprising struts that extend substantially axially when the stent is in a contracted condition, the first end portion flaring such that the struts are directed towards a circumferential orientation in the flared condition.

21. The apparatus of claim 15, wherein the connectors comprise curvilinear segments having a thickness and a width, at least one of the thickness and the width being thinner than segments comprising the first end portion.

22. A method for expanding a stent, comprising:

providing a stent on an expandable member, the stent comprising first and second ends, a first end portion including a first set of cells at the first end and a second set of cells adjacent the first set of cells, and a second portion connected to the first end portion; and

expanding the expandable member from a first collapsed configuration to a second flared configuration to flare the first end portion, thereby causing first struts of the first set of cells to move from a substantially axial orientation towards a radial and partial circumferential orientation and causing second struts of the second set of cells to move from a substantially axial orientation towards a radial orientation;

expanding the expandable member from the second configuration to a third enlarged condition, thereby causing the first and second struts to move towards a more circumferential orientation.

23. The method of claim 22, wherein the second set of cells are coupled to the second portion of the stent by a plurality of flexible connectors, the connectors accommodating radial movement of the second struts.

24. A method for delivering a stent within an ostium communicating between a main body lumen and a branch body lumen, the stent comprising first and second ends, a first end portion including a first set of cells at the first end and a second set of cells adjacent the first set of cells, and a second portion connected to the first end portion, the method comprising:

introducing the stent into the main body lumen with the stent in a contracted condition;

positioning the stent such that the first end portion is disposed adjacent the ostium and the second portion is disposed within the branch body lumen;

flaring the first end portion, thereby causing first struts of the first set of cells to move from a substantially axial orientation towards a radial and partial circumferential orientation and causing second struts of the second set of cells to move from a substantially axial orientation towards a radial orientation;

expanding the stent such that the second portion expands within the branch body lumen, and the first and second struts move towards a more circumferential orientation.