Method and apparatus for thermal spray processing of medical devices

• US 7,201,940 B1
• Filed: 06/12/2001
• Issued: 04/10/2007
• Est. Priority Date: 06/12/2001
• Status: Expired due to Term

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Kramer, Pamela A.
• Primary Examiner(s): MIGGINS, MICHAEL C
• Application Number:
  US09/880,514
• Time in Patent Office: 2,128 Days
• Field of Search: 427/189, 427/191, 427/192, 427/199, 427/202, 427/205, 427294-296, 427/427
• US Class Current: 427/189
• CPC Class Codes: A61L 2300/416 Anti-neoplastic or anti-proliferative or anti-restenosis or anti-angiogenic agents, e.g. paclitaxel, sirolimus
• CPC Class Codes: A61L 2300/42 Anti-thrombotic agents, anticoagulants, anti-platelet agents
• CPC Class Codes: A61L 2300/606 Coatings
• CPC Class Codes: A61L 2420/02 Methods for coating medical devices
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61L 29/106 Inorganic materials other than carbon
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61L 31/082 Inorganic materials
• CPC Class Codes: A61L 31/088 Other specific inorganic materials not covered by A61L31/084 or A61L31/086
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 31/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: B05B 7/0006 Spraying by means of explosions
• CPC Class Codes: B05B 7/203 the material to be sprayed having originally the shape of a wire, rod or the like
• CPC Class Codes: B05B 7/205 the material to be sprayed being originally a particulate material
• CPC Class Codes: B05B 7/224 the material having originally the shape of a wire, rod or the like
• CPC Class Codes: B05B 7/226 : the material being originally a particulate material
• CPC Class Codes: C23C 24/04 : Impact or kinetic deposition of particles
• CPC Class Codes: C23C 28/00 : Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/028 : Including graded layers in composition or in physical properties, e.g. density, porosity, grain size
• CPC Class Codes: C23C 28/321 : with at least one metal alloy layer
• CPC Class Codes: C23C 28/322 : only coatings of metal elements only
• CPC Class Codes: C23C 28/34 : including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
• CPC Class Codes: C23C 28/3455 : with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
• CPC Class Codes: C23C 28/36 : including layers graded in composition or physical properties
• CPC Class Codes: C23C 4/12 : characterised by the method of spraying
• CPC Class Codes: Y10T 428/12021 : having composition or density gradient or differential porosity
• CPC Class Codes: Y10T 428/12292 : Workpiece with longitudinal passageway or stopweld material [e.g., for tubular stock, etc.]
• CPC Class Codes: Y10T 428/12299 : Workpiece mimicking finished stock having nonrectangular or noncircular cross section
• CPC Class Codes: Y10T 428/13 : Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1376 : Foam or porous material containing
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article

Abstract

The invention relates to devices for the treatment of heart disease and particularly to endo-arterial prostheses, which are commonly called stents. More particularly, the invention relates to methods of manufacturing and coating stents utilizing thermal spray processing (TSP). In one aspect the invention involves the use of TSP for the manufacture of fine grained tubing for subsequent use as a stent or other tubular or ring-based implant, or the manufacture of intermediate sized tubing that may then be drawn to final size tubing and for the coating of a stent. An average grain size of less than 64 microns is achieved by the invention resulting in a stent having an annular wall average thickness of about eight or more grains.

Claims

1. A method of coating a medical device, comprising:

providing a medical device;

providing a coating material containing a metal alloy; and

applying the coating material to the medical device by cold spray thermal processing wherein powder particles are introduced into a high pressure gas where both the gas and particles enter a supersonic jet which is directed against the medical device, wherein the thickness of the coating containing a metal alloy is varied around the diameter or along the length of the medical device and wherein the medical device is selected from the group consisting of a stent, guide wires, lead tips, catheters and markers.

2. The method of claim 1, further comprising varying the thickness of the metal alloy coating along a length of the medical device.

3. The method of claim 1, wherein providing the medical device comprises forming the medical device into a stent.

4. The method of claim 1, wherein the coating material further comprises ceramic material.

5. The method of claim 1, wherein the coating material comprises a composite material.

6. The method of claim 1, wherein polymers are coated onto the medical device.

7. The method of claim 1, further comprising heat treating the coating formed from the thermal spray-forming of the metal alloy to grow the grain size of the coating.

8. The method of claim 1, further comprising swaging the medical device after thermally spray-forming material onto the medical device.

9. The method of claim 1, wherein the medical device is drawn after the coating is formed.

10. The method of claim 1, wherein the medical device is annealed after the coating is formed.

11. The method of claim 1, wherein the medical device is heated for post-processing after the coating is formed.

12. The method of claim 1, wherein after the coating is formed, the medical device is post processed in a traveling ring furnace where the material is melted and resolidified as the ring travels the length of the medical device.

13. The method of claim 1, further comprising processing the medical device in a vacuum and under high mechanical pressure so as to sinter the material forming the coating.

14. The method of claim 1, wherein after the coating is formed, an outer diameter of the medical device is post processed through centerless grinding.

15. The method of claim 1, wherein after the coating is formed, an outer diameter of the medical device is post processed by drawing to reduce the coating thickness.

16. The method of claim 1, wherein after the coating is formed, an inner diameter of the medical device is post processed by boring for improving both dimension and surface roughness.