Flexible stent

• US 6,203,569 B1
• Filed: 06/27/1997
• Issued: 03/20/2001
• Est. Priority Date: 01/04/1996
• Status: Expired due to Fees

• Current Assignee: Bandula Wijay
• Original Assignee: Bandula Wijay
• Inventors: Wijay, Bandula
• Primary Examiner(s): Isabella, David J.
• Assistant Examiner(s): Koh, Choon P.
• Application Number:
  US08/883,801
• Time in Patent Office: 1,362 Days
• Field of Search: 623/1, 623/11, 623/12, 623/1.15, 623/1.16, 623/1.17
• US Class Current: 623/1.15
• 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 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: A61F 2250/0071 breakable or frangible

Abstract

A stent is disclosed which comprises generally of ring having, in the preferred embodiment, crossties that have flexibility by having at least one bend. The rings themselves have predetermined stress-relieving points to predispose, by stress relief, particular segments of each ring to bend upon application of an expansion force such as by a balloon or by other means. In the preferred embodiment, the individual rings have notches, reducing the cross-sectional areas at particular locations adjacent reversing bends such that upon radial expansion, bending occurs at these reduced cross-sectional areas to prevent stress from accumulating at the reversing bends.

Claims

1. A stent comprising:

a plurality of rings arranged in general alignment to define a cylindrical shape, each ring comprises a singular elongated wire member having discrete reversing bends which do not intersect with other reversing bends and at least two cross-sectional areas identified by at least one cross-sectional change location, said wire member forming an undulating pattern;

at least one crosstie connecting adjacent rings said crosstie disposed in general alignment with a longitudinal axis defined by said rings, said crosstie having at least one bend formed therein;

the cross-sectional area of said wire member changes adjacent at least one of said reversing bends;

said wire member which comprises each said rings, when expanded radially outwardly, bends at said cross-sectional change location adjacent said reversing bends; and

said reversing bends remain generally aligned to said cylindrical shape defined by said rings after radial expansion due to bending at said cross-sectional change locations.

11. The stent of claim 1, further comprising:

a plurality of non-overlapping crossties each having at least two bends.

12. The stent of claim 11, wherein:

said bends define at least two slope changes in said crossties.

13. The stent of claim 12, wherein:

each crosstie connects a reversing bend in one of said rings to the next adjacent circumferentially offset reversing bend on an adjacent ring.

14. The stent of claim 1, wherein:

said at least one crosstie comprises at least two reversing bends located remotely from said end of said crosstie.

2. A stent, comprising:

a plurality of rings arranged in general alignment to define a cylindrical shape, each ring comprises a singular elongated wire member having discrete reversing bends which do not intersect with other reversing bends, and at least two cross-sectional areas defined by at least one cross-sectional change location, said wire member forming an undulating pattern;

at least one crosstie connecting adjacent rings said crosstie disposed in general alignment with a longitudinal axis defined by said rings, said crosstie having at least one bend formed therein;

said wire member having at least one straight section between said reversing bends;

the cross sectional area of said wire member changes in said straight section and adjacent said reversing bends;

said wire member which comprises each said rings, when expanded radially outwardly, bends at said cross-sectional change location adjacent said reversing bends; and

said reversing bends remain generally aligned to said cylindrical shape defined by said rings after radial expansion due to bending at said cross-sectional change locations.

3. A stent, comprising:

a plurality of rings arranged in general alignment to define a cylindrical shape, each ring comprises a singular elongated wire member having discrete reversing bends which do not intersect with other reversing bends, said wire member forming an undulating pattern, said wire member having at least one cross-sectional area;

at least one crosstie connecting adjacent rings said crosstie disposed in general alignment with a longitudinal axis defined by said rings, said crosstie having at least one bend formed therein;

the wire member is formed having a notch wherein the cross-sectional area of the wire member changes at a notch location;

said notch is located adjacent at least one of said reversing bends.

4. The stent of claim 3, wherein:

said change in cross-section is accomplished by opposed notches.

18. The stent of claim 3, wherein:

said wire-like member has straight sections between said reversing bends;

said straight sections have a smaller cross-sectional area than the cross-sectional area through said reversing bends.

5. A stent, comprising:

a plurality of rings arranged in general alignment to define a cylindrical shape, each ring comprises a singular elongated wire member having reversing bends forming an undulating pattern;

at least one crosstie connecting adjacent rings wherein said crosstie is disposed in general alignment with a longitudinal axis defined by said rings; and

said wire member is formed having a notch adjacent at least one of said reversing bends which defines a change in cross-sectional area.

6. The stent of claim 5, wherein:

said change in cross-sectional area is accomplished by opposed notches.

7. A stent, comprising:

a plurality of rings arranged in general alignment to define a cylindrical shape, each ring comprises a singular elongated wire member having discrete reversing bends which do not intersect with other reversing bends, said wire member forming an undulating pattern; and

having at least two cross-sectional areas identified by at least one cross-sectional change location; and

at least one cross-tie having said connecting adjacent rings said crosstie disposed in general alignment with a longitudinal axis defined by said rings, said crosstie having at least one bend formed between said ends to allow said crosstie to flex as said rings expand while remaining within the confines of said cylindrical shape; and

the cross-sectional area of said wire member changes adjacent at least one of said reversing bends.

8. The stent of claim 7, wherein:

said wire member changes cross-section adjacent each said reversing bend.

9. The stent of claim 8, wherein:

said wire member changes cross-section on both sides of each said reversing bend.

10. The stent of claim 7, wherein:

said wire member which comprises said rings, when said rings are expanded radially outwardly, bends at said cross-sectional change location adjacent said reversing bends.

15. The stent of claim 7 wherein:

said at least one crosstie comprises at least two reversing bends located remotely from said ends of said crosstie; and

said bends define a turn of no less than about 90°

.

16. The stent of claim 15, wherein:

said crosstie having a first end offset circumferentially from a second end.

17. The stent of claim 15, wherein that portion of said crossties extending between said first and second ends and up to said bends of said crosstie are in substantial longitudinal alignment with the longitudinal axis of said cylindrical shape.

20. The stent of claim 9, wherein:

said straight section has a smaller cross-sectional area than the cross-sectional area through an adjacent said reverse bend.

19. A stent, comprising:

a plurality of rings arranged in general alignment to define a cylindrical shape, each ring comprises a singular elongated wire member having discrete reversing bends which do not intersect with other reversing bends;

said wire member forming an undulating pattern and having at least one cross-section;

at least one crosstie connecting adjacent rings said crosstie disposed in general alignment with a longitudinal axis defined by said rings, said crosstie having at least one bend formed therein; and

said wire member having at least one straight section between said reversing bends;

the cross-section of said wire member changes in said straight section and adjacent said reversing bends.

21. The stent of claim 19, wherein:

said wire member changes cross-section adjacent each said reversing bend.

22. The stent of claim 19, wherein:

said wire member changes cross-section on both sides of each said reversing bend.

23. The stent of claim 19, wherein:

said wire member which comprises said rings, when said rings are expanded radially outwardly, bends at said cross-sectional change location adjacent said reversing bends.

24. A stent of claim 19, further comprising:

a plurality of non-overlapping crossties each having at least two bends.

25. The stent of claim 24, wherein:

said bends define at least two slope changes in said crossties.

26. The stent of claim 25, wherein:

each crosstie connects a reversing bend in one of said rings to the next adjacent circumferentially offset reversing bend on an adjacent ring.