Steep-taper flared stents and apparatus and methods for delivering them

• US 7,582,111 B2
• Filed: 08/22/2006
• Issued: 09/01/2009
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Incept LLC
• Original Assignee: Incept LLC
• Inventors: Khosravi, Farhad, Kim, Eliot, Dreher, James H., Krolik, Jeffrey A.
• Primary Examiner(s): McDermott; Corrine M
• Assistant Examiner(s): STEWART, JASON-DENNIS NEILKEN
• Application Number:
  US11/466,442
• Publication Number:
  US 20070067011A1
• Time in Patent Office: 1,106 Days
• Field of Search: 623/1.3, 623/1.31, 623/1.15
• US Class Current: 623/1.32
• 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 intermediate flared condition and to an enlarged condition, the stent comprising:

a first end portion that flares outwardly when the stent is expanded from the contracted condition to the enlarged condition, the first end portion comprising first and second bands including alternating axial segments and curved segments defining a serpentine pattern and coupled together such that, upon expansion from the contracted condition to the intermediate flared condition, first axial segments of the first band are directed from an orientation substantially parallel to the longitudinal axis to a generally radially outward orientation and, upon expansion to the enlarged condition, the first axial segments are directed to a substantially enclosed generally circumferential orientation and second axial segments of the second band are directed to a generally transverse orientation; 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 axial segments and curved segments of the first end portion for accommodating the first end portion flaring outwardly.

2. The stent of claim 1, wherein the curved segments of the first and second bands have a lower yield strength than the axial segments.

3. The stent of claim 1, 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.

4. The stent of claim 1, 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.

5. The stent of claim 1, wherein the axial segments of the first and second bands have lengths substantially equivalent to one another.

6. 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 the axial and curved segments of the first and second bands.

7. A stent comprising a tubular member including first and second ends defining a longitudinal axis therebetween and a plurality of circumferential bands 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 that flares outwardly when the tubular member is expanded from the contracted condition to the intermediate condition, the first end portion comprising a first band at the first end and a second band connected to the first band, the first and second bands comprising axial segments extending substantially parallel to the longitudinal axis and connected by curved segments in the contracted condition;

a second portion adjacent the first portion; and

a plurality of connectors extending from the second portion to the second band of the first end portion, the connectors being relatively flexible compared to the axial segments and curved segments of the first and second bands such that the axial segments of the second band assume a generally radially outward orientation in the intermediate condition;

wherein the curved segments of the first band bend to cause the axial segments of the first band to assume a substantially enclosed generally circumferential orientation defining the first end of the stent in the enlarged condition.

8. The stent of claim 7, 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.

9. The stent of claim 8, 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.

10. 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, and defining a longitudinal axis therebetween;

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, the first end portion comprising first and second circumferential bands, each band including alternating axial segments, extending substantially parallel to the longitudinal axis in the contracted configuration, and curved segments defining a serpentine pattern and coupled together such that, upon expansion to an intermediate condition, first axial segments of the first band are directed to a generally radially outward orientation and, upon expansion to an enlarged condition, the first axial segments are directed to a substantially enclosed generally circumferential orientation and second axial segments of the second band are directed to a generally transverse orientation;

wherein, when the expandable member is expanded to the second configuration, the first end portion of the stent is expanded to the intermediate condition while the second portion remains unexpanded, 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 to the enlarged condition.

11. The apparatus of claim 10, 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.

12. The apparatus of claim 10, wherein the plurality of flexible connectors connect the second band to the second portion of the stent.

13. The apparatus of claim 12, the curved segments having a lower yield strength than the first axial segments.

14. The apparatus of claim 12, wherein the first and second axial segments having lengths substantially equivalent to one another.

15. The apparatus of claim 12, wherein the connectors comprise curvilinear segments having a thickness and a width, at least one of the thickness and the width being thinner than the axial segments and curved segments of the first end portion.

16. 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, and defining a longitudinal axis therebetween, and 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, the first end portion comprising first and second circumferential bands, the first band defining a first end of the stent and the second band connected to the first band and the flexible connectors, each band comprising a serpentine pattern of axial elements alternately connected to curved elements extending around a circumference of the stent, the curved segments having a lower yield strength than the axial elements, adjacent curved elements of the first and second bands connected to one another, the axial elements of the first band directed from a generally axial orientation extending substantially parallel to the longitudinal axis towards a generally radially outward orientation when the expandable member is expanded from the first configuration to the second configuration and directed from the generally radially outward orientation towards a substantially enclosed circumferential orientation when the expandable member is expanded to the third configuration, the axial elements of the second band being directed from a generally axial orientation extending substantially parallel to the longitudinal axis towards a generally radially outward orientation when the expandable member is expanded from the first configuration to the second configuration, the second portion being expanded radially outwardly when the expandable member is expanded from the second configuration to the third configuration.

17. The apparatus of claim 16, 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 first configuration defined by the first and second balloons being in a collapsed condition, the second configuration defined by at least partial expansion of the first balloon, and the third configuration defined at least partially by expansion of the second balloon.

18. A stent comprising a tubular member including first and second ends defining a longitudinal axis therebetween, the tubular member being expandable from a contracted condition to an enlarged condition through an intermediate condition, the stent comprising:

a first end portion that flares outwardly when the tubular member is expanded from the contracted condition to the intermediate condition, the first end portion comprising a first circumferential band at the first end and a second circumferential band connected to the first band, each band comprising a serpentine pattern of axial elements alternately connected to curved elements extending around a circumference of the stent, the curved segments having a lower yield strength than the axial elements, adjacent curved elements of the first and second bands connected to one another, the axial elements of the first band directed from a generally axial orientation extending substantially parallel to the longitudinal axis towards a generally radially outward orientation when expanded from the contracted condition to the intermediate condition and directed from the generally radially outward orientation towards a substantially enclosed circumferential orientation when expanded from the intermediate condition to the enlarged condition, the axial elements of the second band directed from a generally axial orientation extending substantially parallel to the longitudinal axis towards a generally radially outward orientation when expanded from the contracted condition to the intermediate condition;

a second portion adjacent the first end portion and expandable radially outwardly; and

a plurality of connectors connecting the second portion to the second band of the first end portion, the connectors being relatively flexible compared to the axial elements and curved segments of the first and second bands to accommodate the axial elements of the second band being directed to the generally radially outward orientation.

19. The stent of claim 18, wherein the connectors have a thickness and a width, at least one of the thickness and the width being thinner than the axial elements and curved segments of the first and second bands.

20. The stent of claim 18, wherein curved segments of the first band adjacent curved segments of the second band are connected together by connectors that extend substantially parallel to the longitudinal axis.

21. The stent of claim 18, wherein curved segments of the first band adjacent curved segments of the second band are connected directly to one another.

22. The stent of claim 18, wherein the curved segments have a thickness and a width, at least one of the thickness and the width being thinner than the axial elements of the first and second bands.