LONGITUDINALLY FLEXIBLE STENT

• US 20080215133A1
• Filed: 03/05/2008
• Published: 09/04/2008
• Est. Priority Date: 03/01/2000
• Status: Active Grant

• Current Assignee: Medinol Limited (Medinol USA Incorporated)
• Original Assignee: Medinol Limited (Medinol USA Incorporated)
• Inventors: Richter, Jacob
• Granted Patent: US 8,202,312 B2
• Time in Patent Office: Days
• US Class Current: 623/1.16
• 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 2002/91508 the meander having a difference in amplitude along the band
• 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

Abstract

An intravascular stent especially suited for implanting in curved arterial portion. The stent retains longitudinal flexibility after expansion. The stent is formed of intertwined meander patterns forming triangular cells. The cells are adapted to provide radial support, and also provide longitudinal flexibility after expansion. The cells also provide increase coverage of a vessel wall. The stent has a reduced crimped profile due to the differing lengths of adjacent structural members within the cells, resulting in loops which are not aligned around the circumference of the stent. Also, this stent may contain a second type of square cells, which are adapted predominately to minimize flaring of the stent ends and to provide additional stiffness.

Claims

1. A stent for holding open a blood vessel comprising:

a plurality of first loop containing sections arranged generally in a circumferential direction and spaced apart from one another, loops in said first loop containing sections occurring at a first frequency, and wherein the loops in the first loop containing sections are staggered around the circumference of the stent;

a plurality of second loop containing sections, loops in said second loop containing sections occurring at a second frequency that is higher than said first frequency, said second loop containing sections consecutively alternating and periodically coupled to said first loop containing sections along a longitudinal axis of the stent, wherein said second loop containing sections provide longitudinal flexibility of the stent, and wherein the loops in the second loop containing sections are staggered around the circumference of the stent.

2. The stent according to claim 1, wherein said first loop containing sections have two cycles for every three cycles of said second loop containing sections to form one cell.

3. The stent according to claim 1, wherein the alternate joining of said second loop containing sections to said longitudinally neighboring sections of said first loop containing sections is circumferentially offset.

4. The stent according to claim 1, wherein said first loop containing sections and said second loop containing sections form a plurality of cells.

5. The stent according to claim 4, wherein each of said cells encompass about the same area.

6. The stent according to claim 4, wherein each of the cells is substantially symmetrical about a line parallel to said longitudinal axis of the stent.

7. The stent according to claim 1, wherein the relative width of each of said first loop containing sections is such that when said stent is crimped for insertion into a lumen of a blood vessel, each of said second loop containing sections are crimpable to essentially the same diameter as each of said first loop containing sections.

8. The stent according to claim 1, wherein flexibility is provided by a selected material making up the second loop containing sections.

9. The stent according to claim 1, wherein said first loop containing sections and said second loop containing sections have struts, said first loop containing sections have wider struts than struts of said second loop containing sections.

10. The stent according to claim 9, wherein, while flexing, the struts of said second loop containing sections have maximal strain that is lower than an elastic limit of the stent.

11. An expandable stent consisting essentially of:

a plurality of first circumferential bands containing a pattern of loops at a first frequency wherein the loops of the first circumferential bands are staggered;

a plurality of second circumferential bands containing a pattern of loops at a second frequency higher than said first frequency, said second circumferential bands consecutively alternating with said first circumferential bands along a longitudinal axis of the stent and periodically coupled thereto to form cells, and wherein the loops of the second circumferential bands are staggered.

12. The stent according to claim 11, wherein each of the first circumferential bands have loops which are disposed out of phase relative to one another.

13. The stent according to claim 11, wherein the alternate joining of said second circumferential bands to said longitudinally neighboring sections of said first circumferential bands is circumferentially offset.

14. The stent according to claim 13, wherein said first circumferential bands have two cycles for every three cycles of said second circumferential bands to form at least one cell.

15. The stent according to claim 11, wherein said first circumferential bands and said second circumferential bands form a plurality of cells.

16. The stent according to claim 15, wherein each of said cells encompass about the same area.

17. The stent according to claim 15, wherein each of the cells is substantially symmetrical about a line parallel to said longitudinal axis of the stent.

18. The stent according to claim 11, wherein said first circumferential bands and said second circumferential bands have struts, said first circumferential bands have wider struts than struts of said second circumferential bands.

19. The stent according to claim 11, wherein, while flexing, the struts of said second circumferential bands have maximal strain that is lower than an elastic limit of the stent.

20. A stent comprising:

a plurality of first circumferential bands containing a pattern of loops at a first frequency and wherein the loops in the first circumferential bands are staggered;

a plurality of second circumferential bands containing a pattern of loops at a second frequency higher than said first frequency, consecutively alternating with said first circumferential bands and periodically coupled to form cells such that said first circumferential bands are joined together through said second circumferential bands without connection directly between said first circumferential bands,

wherein the loops of the first circumferential bands are out of phase with each other, each cell including two cycles of the first circumferential band and three cycles of the second circumferential band.

21. The stent according to claim 20 wherein the loops of the second circumferential band are staggered.

22. The stent according to claim 20, wherein said first circumferential bands and said second circumferential bands form a plurality of cells.

23. The stent according to claim 22, wherein each of said cells encompass about the same area.

24. The stent according to claim 22, wherein each of the cells is substantially symmetrical about a line parallel to said longitudinal axis of the stent.

25. The stent according to claim 20, wherein flexibility is provided by a selected material comprising the second circumferential bands.

26. The stent according to claim 20, wherein said first circumferential bands and said second circumferential bands have struts, said first circumferential bands have wider struts than struts of said second circumferential bands.

27. The stent according to claim 20, wherein, while flexing, the struts of said second circumferential bands have maximal strain that is lower than an elastic limit of the stent.

28. A uniform flexible expandable stent comprising a plurality of enclosed flexible spaces, each of the plurality of enclosed flexible spaces consisting essentially of a plurality of triangular cells, each triangular cell including:

a) a first member having a first end and a second end;

b) a second member having a first end and a second end;

c) a third member having a first end and a second end;

d) a fourth member having a first end and a second end;

the first end of the first member communicating with the first end of the second member, the second end of the second member communicating with the second end of the third member, and the first end of the third member communicating with the first end of the fourth member;

e) the first member and the second member with the curved portion at their ends forming a first loop;

f) the third member and the fourth member with the curved portion at their ends forming a second loop;

g) a fifth member having a first end and a second end;

h) a sixth member having a first end and a second end;

i) a seventh member having a first end and a second end;

j) an eighth member having a first end and a second end;

k) a ninth member having a first end and a second end; and

l) a tenth member having a first end and a second end;

the first end of the fifth member coupled to the second end of the first member, the second end of the fifth member communicating with the second end of the sixth member, the first end of the sixth member communicating with the first end of the seventh member, the second end of the seventh member communicating with the second end of the eighth member, the first end of the eighth member communicating with the first end of the ninth member, the second end of the ninth member communicating with the second end of the tenth member, and the first end of the tenth member coupled to the second end of the fourth member;

m) the fifth member and the sixth member with the curved portion at their ends forming a third loop;

n) the seventh member and the eighth member with the curved portion at their ends forming a fourth loop; and

o) the ninth member and the tenth member with the curved portion at their ends forming a fifth loop, such that the first and the fourth members are joined together through the fifth, the sixth, the seventh, the eighth, the ninth and the tenth members without connection directly between first and fourth members;

p) the first and second members are different lengths;

the second and third members are different lengths;

third and fourth members are different lengths;

the fifth and sixth members are different lengths;

the sixth and seventh members are different lengths;

the seventh and eighth members are different lengths;

the eighth and ninth members are different lengths; and

wherein the ninth and tenth members are different lengths.

29. The stent according to claim 28 wherein the loops are staggered.

30. The stent according to claim 28, wherein each of said first member, said second member, said third member and said fourth member have a wider members than each of said third member, said fourth member, said fifth member, said sixth member, said seventh member, said eighth member, said ninth member and said tenth member.

31. A multicellular stent having a distal end and a proximal end comprising:

a plurality of bands of square cells, each square cell including a first loop disposed generally longitudinally opposite a second loop, and a first pair of connecting members joined to the legs of the first and second loops, wherein one connecting member is larger than the other;

a plurality of bands of triangular cells, each triangular cell comprising a first loop containing section, the first loop containing section arranged generally in the circumferential direction, the loops in said first loop containing section occurring at a first frequency;

a second loop containing section, the second loop containing section arranged generally in the circumferential direction, the loops in said second loop containing section occurring at a second frequency; and

a third loop containing section, the loops in said third loop containing section occurring at said second frequency that is higher than said first frequency, said third loop containing section is joined to said first and said second loop containing sections forming a band of triangular cells;

said stent having a band of square cells at said distal end and a band of square cells at said proximal end.

32. A stent according to claim 31 wherein two bands of cells at the proximal end are square cells and two bands of cells of the distal end are square cells.