RADIOPAQUE SUPER-ELASTIC INTRAVASCULAR STENT

• US 20090177268A1
• Filed: 01/07/2008
• Published: 07/09/2009
• Est. Priority Date: 01/07/2008
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Micrus Endovascular LLC (Johnson & Johnson)
• Inventors: Lundkvist, Andre S., Watson, David A.
• Granted Patent: US 8,623,071 B2
• Time in Patent Office: Days
• US Class Current: 623/1.220
• CPC Class Codes: A61B 17/12118 for positioning in conjunction with a stent
• CPC Class Codes: A61B 2017/00526 Methods of manufacturing
• CPC Class Codes: A61F 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: B23P 13/00 Making metal objects by operations essentially involving machining but not covered by a single other subclass making specific objects B23P15/00
• CPC Class Codes: Y10T 29/4998 Combined manufacture including applying or shaping of fluent material

Abstract

The intravascular stent is formed from a composite wire includes an inner core of radiopaque metal, a polymer layer coaxially disposed about the inner core, and an outer metal layer coaxially disposed about the polymer layer. The intermediary polymer layer acts as a barrier material between the inner core and the outer sheath, so that the inner core and outer sheath may be made of dissimilar metallic layers, and the intermediary polymer layer will prevent a galvanic reaction between the inner core and the peripheral metal layer. The intravascular stent has ends flared radially outwardly to prevent radially and longitudinally inward deformation of the ends of the stent when the stent is disposed in a desired location in a patient'"'"'s vasculature.

Claims

1. A generally tubular intravascular stent having opposing first and second ends, said intravascular stent comprising:

a plurality of end loop portions at the opposing first and second ends of the stent, and an intermediate tubular body portion formed of a plurality of intermediate circumferential loops between the plurality of end loop portions, said intermediate tubular body portion having a first diameter, an enlarged first end and an enlarged opposing second end, said enlarged first and second ends having a second diameter greater than the first diameter of the intermediate tubular body portion.

2. The intravascular stent of claim 1, wherein a plurality of said end loop portions flare radially outward with respect to the intermediate tubular body portion of the stent.

3. The intravascular stent of claim 1, wherein said plurality of end loop portions and said plurality of intermediate circumferential loops of said intermediate tubular body portion are formed from a single spirally wound composite wire.

4. The intravascular stent of claim 3, wherein said composite wire has a first free end and a second free end placed in close proximity to each other, and further comprising a short segment of heat shrink tubing capturing said first and second free ends together to prevent the free ends of the composite wire from extending away from the body of the stent.

5. The intravascular stent of claim 1, wherein said intravascular stent takes on a linear shape when stretched, without the ends shrinking to a diameter less than the diameter of the central body of the stent.

6. The intravascular stent of claim 3, wherein said composite wire comprises:

an elongated inner core having a selected length and formed from a radiopaque metal;

an intermediate polymer layer coaxially disposed immediately adjacent to and surrounding the inner core; and

an outer metal layer coaxially disposed immediately adjacent to and surrounding the polymer layer.

7. The intravascular stent of claim 6, wherein the radiopaque metal is selected from the group consisting of platinum, tantalum, gold, and combinations thereof.

8. The intravascular stent of claim 6, wherein the inner core is cylindrical.

9. The intravascular stent of claim 6, wherein the inner core is disposed centrally along a longitudinal axis of the composite wire.

10. The intravascular stent of claim 6, wherein the polymer layer is formed from a polymer selected from the group consisting of polytetrafluoroethylene, poly-para-xylylene, a fluorine substituted poly-para-xylylene, and combinations thereof.

11. The composite wire of claim 6, wherein the outer metal layer is formed of a superelastic alloy.

12. The intravascular stent of claim 6, wherein the outer metal layer is formed of nitinol.

13. The intravascular stent of claim 6, wherein the inner core and outer sheath are made of dissimilar metals.

14. The intravascular stent of claim 6, wherein the composite wire is formed as a cylindrical wire.

15. A cylindrical mandrel, comprising:

a cylindrical main body having first and second opposing ends and a longitudinal axis;

a first set of four orthogonally arranged pegs extending from the cylindrical main body at the first end of the cylindrical main body;

a second set of four orthogonally arranged pegs extending from the cylindrical main body at the second end of the cylindrical main body;

a first conical end cap mounted to said first end of said cylindrical main body; and

a second conical end cap mounted to the second end of the cylindrical main body.

16. The mandrel of claim 15, wherein said first and second conical end caps have conically tapered surfaces forming a tapered angle at the first and second ends of the cylindrical main body.

17. The mandrel of claim 16, wherein said tapered angle is about 30°

with respect to the longitudinal axis of the cylindrical main body.

18. A method for forming an intravascular stent, comprising:

a) providing a cylindrical mandrel including a cylindrical main body having first and second opposing ends and a longitudinal axis, a first set of four orthogonally arranged pegs extending from the cylindrical main body at the first end of the cylindrical main body, a second set of four orthogonally arranged pegs extending from the cylindrical main body at the second end of the cylindrical main body, a first conical end cap mounted to said first end of said cylindrical main body, and a second conical end cap mounted to the second end of the cylindrical main body;

b) winding a single composite wire about a first peg of the first set of pegs at the first end of the cylindrical mandrel to form a first end loop portion at the first end of the stent, and thereafter transitioning to form an intermediate circumferential loop;

c) winding the composite wire about a first peg of the second set of pegs at the second end of the cylindrical mandrel to form a first end loop portion at the second end of the stent, and thereafter transitioning to form an intermediate circumferential loop; and

d) repeating steps b) and c) alternatingly, beginning with one of steps b) and c), to continue sequentially to form a plurality of intermediate circumferential loops between a plurality of end loop portions at the opposing first and second ends of the cylindrical mandrel.