STENT WITH ANCHORS TO PREVENT VULNERABLE PLAQUE RUPTURE DURING DEPLOYMENT

• US 20080015685A1
• Filed: 07/11/2007
• Published: 01/17/2008
• Est. Priority Date: 12/22/2003
• Status: Active Grant

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Feezor, Christopher, Cox, Daniel
• Granted Patent: US 8,475,518 B2
• Time in Patent Office: Days
• US Class Current: 623/1.16
• CPC Class Codes: A61F 2/848 having means for fixation to the vessel wall, e.g. barbs
• CPC Class Codes: A61F 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members
• 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 2002/91516 the meander having a change in frequency along the band
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0054 V-shaped

Abstract

A stent for implantation in a body lumen for protecting from rupture a fibrous cap in order to treat vulnerable plaque. One embodiment of the stent achieves staged expansion through stronger and weaker circumferential regions, and includes optional anchors positioned at the circumferential transition between the stronger and weaker regions. During the first stage expansion, the weaker region expands moving the anchors laterally apart. The anchors straddle the fibrous cap and embed into the vessel wall. The second stage expansion of the stent exerts gentler stresses by the weaker region against the fibrous cap while the stronger region exerts greater stresses on the remainder of the vessel wall to open the vessel.

Claims

1. An intravascular stent, comprising:

a plurality of rings having undulating struts with peaks and valleys, and aligned along a common longitudinal axis to define a tube having a circumference;

a link interconnecting adjacent rings;

a first region spanning an arc along the circumference and axially along the length of the stent;

a second region, excluding the first region, spanning the circumference and axially along the length of the stent, wherein the struts in the second region are larger in size than the struts in the first region;

an anchor disposed parallel to the longitudinal axis of plurality of rings at a transition between the first region and the second region; and

reinforcing members with peaks and valleys that subtend the peaks of the struts in the first region, wherein the reinforcing members limit the expansion of the first region of the stent.

2. The stent of claim 1, wherein the anchor includes a spine that is coupled to outer surface of the link, and the anchor includes a cutting edge that projects outward from the link.

3. The stent of claim 2, wherein the anchor includes sides that are convex, concave, or flat.

4. The stent of claim 1, wherein the anchor has a height between about 50 microns and about 100 microns.

5. The stent of claim 1, further comprising a first anchor and a second anchor each disposed parallel to the longitudinal axis of the plurality of rings, and the first anchor being about 90 degrees apart from the second anchor.

6. The stent of claim 1, wherein the reinforcing members include ends that are aligned along a plane perpendicular to the longitudinal axis of the plurality of rings.

7. The stent of claim 1, wherein the struts in the first region have greater flexibility than the struts in the second region.

8. The stent of claim 1, wherein the struts in the first region have less hoop strength than the struts in the second region.

9. The stent of claim 1, wherein the stent further comprises a plurality of anchors that are aligned lengthwise parallel to the longitudinal axis of the stent and a gap is located lengthwise between adjacent anchors.

10. The stent of claim 1, wherein the link includes an undulating portion along a length thereof located between adjacent rings.

11. The stent of claim 1, wherein the link includes an undulating portion along a length thereof located between struts of one ring.

12. The stent of claim 1, wherein the stent when expanded includes an asymmetrical circular cross-sectional shape wherein the first region is less arcuate than the second region.

13. The stent of claim 1, wherein at least a portion of the stent includes a coating of a drug or therapeutic agent.

14. An intravascular stent, comprising:

a plurality of rings having undulating struts with peaks and valleys, and aligned along a common longitudinal axis to define a tube having a circumference;

a first region spanning an arc along the circumference and axially along the length of the stent;

a second region, excluding the first region, spanning the circumference and axially along the length of the stent, wherein the struts in the first region have greater flexibility than the struts in the second region;

a first series of links interconnecting each pair of adjacent rings, the links of the first series positioned at a first interface between the first region and the second region, which is substantially parallel to the longitudinal axis of the stent;

a second series of links interconnecting each pair of adjacent rings, the links of the second series positioned at a second interface between the first region and the second region, which is substantially parallel to the longitudinal axis of the stent; and

a plurality of anchors disposed along the first series of links and the second series of links;

wherein the stent is expandable from a crimped state to an expanded state, and in the expanded state the struts in the first region straighten out to be substantially perpendicular to the longitudinal axis of the stent to increase vessel wall coverage of the first region.

15. The stent of claim 14, wherein the first series of links is less than 180 degrees apart from the second series of links when the stent is in the expanded state.

16. The stent of claim 15, wherein the first series of links is about 90 degrees apart from the second series of links when the stent is in the expanded state.

17. The stent of claim 14, wherein the plurality of anchors each include a spine, and the spine is coupled to the links such that the width of the spine is nearly equivalent to the width of the links.

18. The stent of claim 14, wherein the plurality of anchors each include a spine, and the spine is coupled to the links such that the width of the spine is less than the width of the links.

19. A method of implanting a stent within a vessel including vulnerable plaque, comprising:

positioning a cylindrical stent in a crimped state within a lumen near a target area including vulnerable plaque, the stent including a first region spanning an arc along the circumference and axially along the length of the stent, and a second region, excluding the first region, spanning the circumference and axially along the length of the stent, and the stent also including anchors positioned along a first transition and a second transition each disposed between the first region and the second region along lines substantially parallel to the longitudinal axis of the stent;

aligning the first region of the stent to substantially overly the vulnerable plaque of the vessel;

visualizing the alignment of the stent within the vessel using guidance equipment;

expanding the first region until nearly fully deployed and the anchors are embedded into the vessel wall proximate to and on opposite sides of the vulnerable plaque; and

expanding the second region of the stent after nearly fully deploying the first region until the second region of the stent is fully deployed.

20. The method of claim 19, wherein expanding the first region, the first transition and second transition are spread apart by greater than about 180 degrees.

21. The method of claim 19, wherein expanding the second region until it is fully deployed, the first transition and second transition are spread apart by about 90 degrees.

22. The method of claim 19, wherein positioning a cylindrical stent within the lumen, the stent includes cylindrical rings with struts, and the struts in the first region are weaker than the struts in the second region.