WO1997014375B1

WO1997014375B1 - Vascular stent

Info

Publication number: WO1997014375B1
Application number: PCT/US1996/016789
Authority: WO
Filing date: 1996-10-18
Publication date: 1997-05-15

Abstract

A flexible stent is provided that has features to minimize recoil and facilitate anchoring of the stent in a vascular passage. The design features sharp angulated bends (8). Other features include a rounded cross section in the wire (1) or stent component. Another feature is the bending of the angulated bends (8) in a transverse plane to provide additional rigidity and an anchoring mechanism. Ties (3) are provided in alignment or in a staggered fashion, either semirigid or flexible, to allow the structure, which can be made of joined rings (20), or a helical arrangement, to be more flexible to accommodate bends in the vascular system. The ties (3) are also disclosed with a locking system involving bending the wire (1) as it is formed into a helix in combination with crosstie (60) with loops (96) which lock the stent in an expanded position.

Claims

AMENDED CLAIMS[received by the International Bureau on 3 April 1997 (03.04.97); original claims 3, 5, 11-13, 16, 21, 22, 25, 27 and 29-31 amended;' remaining claims unchanged (8 pages)]

1. A stent, comprising:

a radially flexible tubular structure made from a plurality of

windings about a longitudinal axis of a wire-like material, said wire-like material

incorporating shaφ first bends along its length;

at least one crosstie extending generally longitudinally to connect at

least one of said windings to another of said windings.

2. The stent of claim 1, wherein said at least one crosstie is formed to

be flexible to change its length in response to a bending force applied to said

tubular structure.

3. The stent of claim 1, further comprising:

at least one second bend formed adjacent said first bends, said first

bends disposing said wire-like material in a first plane while said second bend

alters at least one of said shaφ first bends out of said first plane and into an

intersecting plane where an apex is formed.

4. The stent of claim 3, wherein said second bend turns said apex

outwardly away from the longitudinal axis of said tubular structure.

27

5. The stent of claim 4, further comprising a plurality of second bends

wherein some of said second bends are in planes not parallel to other second

bends.

6. The stent of claim 1, wherein some of said first bends are oppositely

oriented with respect to said first bends on other windings.

7. The stent of claim 1, wherein at least some of said first bends are

similarly oriented between adjacent windings but are circumferentially out of

phase with other first bends on an adjacent winding.

8. The stent of claim 1, wherein at least some of said first bends are

similarly oriented between adjacent windings but are circumferentially in phase

with other first bends on an adjacent winding.

9. The stent of claim 7, wherein said at least one crosstie is formed to

be flexible to change its length in response to a bending force applied to said

tubular structure.

10. The stent of claim 8, wherein said at least one crosstie is formed to

be flexible to change its length in response to a bending force applied to said

tubular structure.

11. The stent of claim 7, further comprising a plurality of crossties

wherein at least one of said crossties between a first winding and a second

winding is circumferentially misaligned from said crossties which extend between

said second winding and a third winding.

12. The stent of claim 8, further comprising a plurality of crossties

wherein at least one of said crossties between a first winding and a second

said second winding and a third winding.

13. The stent of claim 3, wherein said shaφ first bends are formed by at

least a pair of wire-like segments approaching each other, said second bend is

disposed on each of said segments prior to said apex, with said shaφ first bends

defined by said approaching segments up to said second bend, said segments

beyond said second bend coming together to define a rounded configuration of

said apex.

29

14. The stent of claim 13, wherein at least one said second bend turns

said apex outwardly away from the longitudinal axis of said tubular structure.

15. The stent of claim 14, wherein each apex is turned away from said

longitudinal axis obliquely to said first bend.

16. The stent of claim 15, further comprising a plurality of second bends

wherein said second bends are disposed in intersecting planes.

17. The stent of claim 13, wherein said at least one crosstie is flexible to

change its length in response to a bending force applied to said tubular structure.

18. The stent of claim 13, wherein at least some of said first bends are

similarly oriented between adjacent windings but are circumferentially out of

phase with other first bends on an adjacent winding.

19. The stent of claim 13, wherein at least some of said first bends are

similarly oriented between adjacent windings but are circumferentially in phase

with other first bends on an adjacent winding.

30

20. The stent of claim 1, wherein said wire-like material has at least a

partially rounded cross-section.

21. The stent of claim 20, wherein said wire-like material is formed of a

metal which gives the stent a characteristic of a spring when formed into a tubular

structure.

22. The stent of claim 21, further comprising:

a delivery device comprising a retainer to hold the stent in a wound

reduced-diameter condition for insertion; and

said retainer releasable upon placement of said stent whereupon said

stent grows radially outwardly.

23. The stent of claim 20, wherein said wire-like material is formed of

an annealed metal which must be mechanically expanded for use of the stent.

24. The stent of claim 1, wherein said tubular structure is formed from

discrete rings of said wire-like material, secured to each other by a plurality of

crossties.

31

25. The stent of claim 1, wherein said tubular structure is formed from a

continuous spirally wound wire-like material further comprises a plurality of

crossties which connect said windings.

26. The stent of claim 2, wherein said tubular structure is formed from

crossties.

27. The stent of claim 2, wherein said tubular structure is formed from a

continuous spirally wound wire-like material further comprises a plurality of

crossties which connect said windings.

28. The stent of claim 3, wherein said tubular structure is formed from

crossties.

32

29. The stent of claim 3, wherein said tubular structure is formed from a

continuous spirally wound wire-like material further comprises a plurality of

crossties which connect said windings.

30. A stent, comprising:

a radially flexible tubular structure made from a plurality of

windings about a longitudinal axis of an undulating wire-like material, incorpo-

rating a plurality of undulations along its length;

at least one crosstie spanning a pair of said windings and fitting over

said undulations on at least one end of said crosstie in a manner so as to permit

relative movement between said end of said crosstie and said undulating wire-like

material which is thereby engaged.

31. The stent of claim 30, wherein:

said crosstie is formed having a loop extending around said undulat-

ing wire-like material at said end of said crosstie ;

said windings are radially expandable to a desired radial expansion,

facilitated by said relative movement as said loop allows movement therethrough

of said undulating wire-like material, whereupon attaining said desired radial

33 expansion of said windings, said loop is retained between said undulations to

minimize recoil.

32. The stent of claim 31, wherein said undulations are formed with

angled bends.

33. The stent of claim 31, wherein said undulations are formed with

rounded bends.

34