Clad composite stent

• US 5,628,787 A
• Filed: 06/07/1995
• Issued: 05/13/1997
• Est. Priority Date: 01/19/1993
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Schneider Electric SE
• Inventors: Mayer, David W.
• Primary Examiner(s): Isabella, David
• Assistant Examiner(s): Black, John M.
• Application Number:
  US08/480,121
• Time in Patent Office: 706 Days
• Field of Search: 623/1, 623/10, 623/11, 623/12, 623/66, 607/129, 174/251, 174/254, 174/107, 174/102 C, 174/126.4
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• 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 2220/0016 with sharp anchoring protrusions, e.g. barbs, pins, spikes
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2310/00029 Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/082 Inorganic materials
• CPC Class Codes: A61L 31/18 Materials at least partially X-ray or laser opaque
• CPC Class Codes: A61M 25/0009 Making of catheters or other medical or surgical tubes
• CPC Class Codes: B21C 1/00 Manufacture of metal sheets, metal wire, metal rods, metal tubes by drawing
• CPC Class Codes: B21F 45/008 of medical instruments, e.g. stents, corneal rings medical science A61
• CPC Class Codes: Y10S 623/924 Material characteristic
• CPC Class Codes: Y10T 428/12819 Group VB metal-base component
• CPC Class Codes: Y10T 428/12875 Platinum group metal-base component

Abstract

A body compatible stent is formed of multiple filaments arranged in two sets of oppositely directed helical windings interwoven with one another in a braided configuration. Each of the filaments is a composite including a central core and a case surrounding the core. In the more preferred version, the core is formed of a radiopaque and relatively ductile material having a linear attenuation coefficient of at least 25 cm^-1 at 100 KeV, e.g. tantalum or platinum. The outer case is formed of a relatively resilient material, e.g. a cobalt/chromium based alloy. Favorable mechanical characteristics of the stent are determined by the case, while the core enables in vivo imaging of the stent. Alternative composite filaments employ an intermediate barrier layer between the case and core formed for example of tantalum, niobium or platinum. To improve compatibility, a biocompatible cover layer can surround the case. The cover layer incorporates at least one of the following: tantalum, platinum, iridium, stainless steel, niobium and titanium. Yet another alternative composite filament features a radiopaque case surrounding a structural core.

Claims

1. A body compatible device comprising:

an elongate filament substantially uniform in lateral cross-section over a length of the filament and including an elongate cylindrical core and an elongate tubular case surrounding the core substantially over said length and concentric with the core; and

a further layer surrounding the core and concentric with the core and the case;

wherein one of said core and case is constructed of a first material having a yield strength of at least 150,000 psi at 0.2 percent offset, and the other of said core and case is constructed of a second material being more radiopaque and at least as ductile as the first material, and having a linear attenuation coefficient at 100 KeV of at least 25 cm^-1.

2. The device of claim 1 wherein:

the first material forms the case.

3. The device of claim 2 wherein:

said further layer forms a barrier layer between the core and the case.

4. The device of claim 3 wherein:

said barrier layer consists essentially of at least one of the following constituents;

tantalum, niobium, and platinum.

5. The device of claim 2 wherein:

said further layer provides a body compatible cover layer surrounding and covering the case.

6. The device of claim 5 wherein:

said cover layer consists essentially of at least one of the following constituents;

tantalum, platinum, iridium, stainless steel, niobium, and titanium.

7. The device of claim 1 wherein:

the first material forms the core.

8. The device of claim 7 wherein:

the further layer forms a barrier layer between the core and the case.

9. The device of claim 7 wherein:

the further layer forms a body compatible cover layer surrounding and covering the case.

10. A body compatible device comprising:

an elongate filament substantially uniform in lateral cross-section over a length thereof, said filament including an elongate cylindrical core, an elongate tubular case surrounding the core, and a barrier layer surrounding the core and disposed between the core and the case; and

wherein one of said core and said case is constructed of a first material having a yield strength of at least 150,000 psi at 0.2% offset, and the other of said core and said case is constructed of a second material being more radiopaque and at least as ductile as the first material.

11. The device of claim 10 wherein:

the first material forms the case.

12. The device of claim 10 wherein:

said barrier layer consists essentially of at least one of the following constituents;

tantalum, niobium, and platinum.

13. The device of claim 10 wherein:

the first material forms the core.

14. The device of claim 10 further including:

a body compatible cover layer surrounding and covering the case.

15. The device of claim 14 wherein:

said cover layer consists essentially of at least one of the following;

tantalum, platinum, iridium, stainless steel, niobium, and titanium.