Zirconium oxide and zirconium nitride coated stents

• US 5,649,951 A
• Filed: 06/06/1995
• Issued: 07/22/1997
• Est. Priority Date: 07/25/1989
• Status: Expired due to Fees

• Current Assignee: Smith & Nephew Richards Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Richards Incorporated (Smith & Nephew PLC)
• Inventors: Davidson, James A.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/470,682
• Time in Patent Office: 777 Days
• Field of Search: 606/191, 606/192, 606/198
• US Class Current: 606/198
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/2448 D-shaped rings
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• 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 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/30107 using materials or accessories for preventing galvanic or electrolytic corrosion
• CPC Class Codes: A61F 2210/0009 using materials or accessories for preventing galvanic or electrolytic corrosion
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2310/00089 Zirconium or Zr-based alloys
• CPC Class Codes: A61F 2310/00634 Coating made of zirconium oxide or hydroxides
• CPC Class Codes: A61F 2310/00892 Coating made of zirconium nitride
• CPC Class Codes: A61L 27/047 Other specific metals or alloys not covered by A61L27/042 - A61L27/045 or A61L27/06
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: A61L 29/02 Inorganic materials
• CPC Class Codes: A61L 29/106 : Inorganic materials other than carbon
• CPC Class Codes: A61L 31/02 : Inorganic materials
• CPC Class Codes: A61L 31/022 : Metals or alloys
• CPC Class Codes: A61L 31/088 : Other specific inorganic materials not covered by A61L31/084 or A61L31/086
• CPC Class Codes: A61L 33/027 : Other specific inorganic materials not covered by A61L33/022 or A61L33/025

Abstract

Stents fabricated from a substrate of a low modulus metal coated with blue to black zirconium oxide or zirconium nitride. The coating provides enhanced thrombogenicity, biocompatibility, blood compatibility, corrosion-resistance, friction and microfretting resistance, durability, and electrical insulation, where applicable. The coatings may be applied to low modulus metallic substrates by physical or chemical vapor deposition as well as other ion-beam assisted methods. Preferably, however, for optimizing attachment strength, the stents are fabricated from zirconium or zirconium-containing alloys and the coatings are formed by oxidizing or nitriding through an in situ method that develops a coating from and on the metal surface of the stent, without need for depositing a coating on the metal surface.

Claims

1. An expandable stent for supporting a tubular conduit of a living body from collapsing inward, the stent comprising:

(a) a radially outwardly expandable substantially cylindrical stent body of a low elastic modulus metallic composition for insertion in a tubular conduit of a living body, the stent body having a longitudinal bore therethrough for receiving a means for expanding the body radially outwardly and outer surfaces exposed to body fluid and body tissue when the stent is in use;

(b) a corrosion-resistant, biocompatible, hemocompatible, durable, stable coating selected from the group consisting of zirconium oxides, ranging in color from blue to black, and zirconium nitrides, ranging in color from yellow to orange;

said coating disposed on surfaces of the stent body exposed to body fluid and body tissue when the stent is in use; and

(c) anchoring means for engaging the tubular conduit and anchoring the stent body in a radially outward expanded position thereby supporting the tubular conduit from collapsing inward.

2. The stent of claim 1, wherein the coating is from about 0.1 to about 20 microns thick.

3. The stent of claim 1, wherein the stent body comprises a metal selected from the group consisting of zirconium and zirconium-containing alloys.

4. The stem of claim 3, wherein the stem body further includes a sub-surface zone containing diffused oxygen and the coating comprises diffusion-bonded blue to black zirconium oxides.

5. The stent of claim 4, wherein the coating is from about 0.1 to about 20 microns thick.

6. The stent of claim 1, wherein the stent body further comprises a second coating selected from the group consisting of antibiotics and anticoagulants, wherein said second coating is applied over said corrosion-resistant, biocompatible, hemocompatible, durable, stable coating.

7. The stem of claim 1 further comprising a silver-containing overlay coating over the corrosion-resistant, biocompatible, hemocompatible, durable, stable coating.

8. The stent of claim 1 further comprising overlay coatings over the coating, said overlay coatings selected from the group consisting of amorphous diamond-like carbon, cubic zirconia, and white tetragonal zirconia.

9. The stent of claim 1 further comprising a boronated overlay coating over the corrosion-resistant, biocompatible, hemocompatible, durable, stable coating.

10. The stent of claim 1 wherein the radially outwardly expandable substantially cylindrical stent body of a low elastic modulus metallic composition comprises a wire mesh of a low elastic modulus metallic composition.

11. The stent of claim 10, wherein the wire mesh further comprises the anchoring means.

12. The stent of claim 1, wherein the anchoring means are barbs disposed on an outer surface of the stent body.