MEDICAL DEVICES INCLUDING HARDENED ALLOYS

• US 20080091267A1
• Filed: 03/29/2007
• Published: 04/17/2008
• Est. Priority Date: 10/13/2006
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation), CRS Holding of America, LLC
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Stinson, Jonathan S., Cambronne, Matthew, Gleixner, Richard A., Heilmann, James E., Frank, Richard B.
• Granted Patent: US 7,780,798 B2
• Time in Patent Office: Days
• US Class Current: 420/108
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: Y10S 623/924 Material characteristic

Abstract

Medical devices, such as endoprostheses, and methods of making the devices are disclosed. The endoprostheses comprise a tubular member capable of maintaining patency of a bodily vessel. The tubular member includes a mixture of at least two compositions, where the presence of the second composition gives the mixture a greater hardness than that of the first composition alone. The first composition includes less than about 25 weight percent chromium, less than about 7 weight percent molybdenum, from about 10 to about 35 weight percent nickel, and iron. The second composition is different from the first and is present from about 0.1 weight percent to about 5 weight percent of the mixture.

Claims

1. An endoprosthesis, comprising a tubular member capable of maintaining patency of a bodily vessel, the tubular member comprising a mixture comprising a first composition and a second composition within the first composition, the first composition comprising less than about 25 weight percent chromium, less than about 7 weight percent molybdenum, from about 10 to about 35 weight percent nickel, and iron, the second composition being different from the first composition and being present from about 0.1 weight percent to about 5 weight percent of the mixture, wherein the mixture has a hardness greater than a hardness of the first composition.

2. The endoprosthesis of claim 1, wherein the mixture comprises particles comprising the second composition.

3. The endoprosthesis of claim 2, wherein the particles have an average width from about 10 nm to about 500 nm.

4. The endoprosthesis of claim 1, wherein the second composition comprises a moiety selected from the group consisting of NiTi, Ni—

Al, Ni—

Nb, Fe—

Nb, Ni—

Ta, Fe—

Ta, Pt—

Ir, Pt—

Au, Cr—

Pt, Pt—

Cu, Pt—

Ti, Pt—

Al, Ni—

Cu, and Fe—

Cu.

5. The endoprosthesis of claim 4, wherein said moiety is selected from the group NiTi₂, NiTi, Ni₃Ti, NiAl₃, Ni₂Al₃, Ni₅Al₃, Ni₃Al, Ni₈Nb, Ni₃Nb, Ni₆Nb₇, Fe₂Nb, FeNb, Ni₈Ta, Ni₃Ta, Ni₂Ta, NiTa, NiTa₂, Fe₂Ta,FeTa, Pt—

Ir, PtAu₃, PtAu, Pt₃Au, Cr₃Pt, CrPt, CrPt₃, PtCu₃, PtCu, Pt₅Cu₃, Pt₃Cu, Ni—

Cu, and Fe—

Cu.

6. The endoprosthesis of claim 1, wherein the mixture has a hardness of from about 95 Rockwell B to about 50 Rockwell C.

7. The endoprosthesis of claim 1, wherein the mixture comprises less than about 2,000 ppm of carbon, nitrogen, and/or oxygen.

8. The endoprosthesis of claim 1, wherein the mixture further comprises particles comprising a third composition different from the first and second compositions.

9. The endoprosthesis of claim 1, wherein the tubular member comprises substantially entirely of the mixture.

10. The endoprosthesis of claim 1, wherein less than the entire tubular member comprises the mixture.

11. The endoprosthesis of claim 1, wherein the tubular member comprises a band, and an elongated portion extending from the band, at least one of the band and the elongated portion comprising the mixture.

12. The endoprosthesis of claim 1, wherein the band has a yield strength lower than a yield strength of the elongated portion.

13. The endoprosthesis of claim 1, wherein the first composition further comprises a first element selected from the group consisting of platinum, iridium, gold, tantalum, hafnium, tungsten, palladium, rhodium, lead, and silver.

14. The endoprosthesis of claim 13, wherein the first composition comprises from about 1 to about 40 weight percent of the first element.

15. The endoprosthesis of claim 1, wherein the endoprosthesis comprises a stent.

16. The endoprosthesis of claim 1, wherein the tubular member comprises multiple layers, at least one of the layers comprising the mixture.

17. The endoprosthesis of claim 1, wherein the tubular member comprises a wall thickness from about 0.0020 inch to about 0.0030 inch.

18. A medical device, comprising a mixture comprising a first composition and a second composition within the first composition, the first composition comprising less than about 25 weight percent chromium, less than about 7 weight percent molybdenum, from about 10 to about 35 weight percent nickel, and iron, the second composition being different from the first composition and is present from about 0.1 weight percent to about 5 weight percent of the mixture, wherein the mixture has a hardness greater than a hardness of the first composition.

19. The medical device of claim 18, wherein the mixture comprises particles comprising the second composition.

20. The medical device of claim 19, wherein the particles have an average width from about 10 nm to about 500 nm.

21. The medical device of claim 18, wherein the second composition comprises a moiety selected from the group consisting of NiTi, Ni—

Al, Ni—

Nb, Fe—

Nb, Ni—

Ta, Fe—

Ta, Pt—

Ir, Pt—

Au, Cr—

Pt, Pt—

Cu, Pt—

Ti, Pt—

Al, Ni—

Cu, and Fe—

Cu.

22. The medical device of claim 21 wherein said moiety is selected from the group consisting of group NiTi₂, NiTi, Ni₃Ti, NiAl₃, Ni₂Al₃, Ni₅Al₃, Ni₃Al, Ni₈Nb, Ni₃Nb, Ni₆Nb₇, Fe₂Nb, FeNb, Ni₈Ta, Ni₃Ta, Ni₂Ta, NiTa, NiTa₂, Fe₂Ta,FeTa, Pt—

Ir, PtAu₃, PtAu, Pt₃Au, Cr₃Pt, CrPt, CrPt₃, PtCu₃, PtCu, Pt₅Cu₃, Pt₃Cu, Ni—

Cu, and Fe—

Cu.

23. The medical device of claim 18, wherein the mixture has a hardness of from about 95 Rockwell B to about 50 Rockwell C.

24. The medical device of claim 18, wherein the mixture comprises less than about 2,000 ppm of a carbon, nitrogen, oxygen, or combination thereof.

25. The medical device of claim 18, wherein the mixture further comprises particles comprising a third composition different from the first and second compositions.

26. The medical device of claim 18, wherein the first composition comprises a 300 series stainless steel.

27. The medical device of claim 26, wherein the first composition further comprises a first element selected from the group consisting of platinum, iridium, gold, tantalum, hafnium, tungsten, palladium, rhodium, lead, and silver.

28. The medical device of claim 27, wherein the first composition comprises from about 1 to about 40 weight percent of the first element.

29. The medical device of claim 18, wherein the first composition further comprises a first element selected from the group consisting of platinum, iridium, gold, tantalum, hafnium, tungsten, palladium, rhodium, lead, and silver.

30. The medical device of claim 29, wherein the first composition comprises from about 1 to about 40 weight percent of the first element.

31. The medical device of claim 18, in the form of an endoprosthesis.

32. The medical device of claim 18, in a form selected from the group consisting of a wire, a cutting element configured to be supported by a medical balloon, and an orthopedic implant.

33. A method of making a medical device, the method comprising:

forming a second composition in a first metallic composition to provide a mixture having a hardness greater than a hardness of the first metallic composition; and

including the mixture in at least a portion of the medical device.

34. The method of claim 33, wherein forming the second composition comprises precipitating the second composition.

35. The method of claim 33, wherein the mixture comprises particles comprising the second composition.

36. The method of claim 35, wherein the particles have an average width from about 10 nm to about 500 nm.

37. The method of claim 33, wherein the second composition comprises a moiety selected from the group consisting of NiTi, Ni—

Al, Ni—

Nb, Fe—

Nb, Ni—

Ta, Fe—

Ta, Pt—

Ir, Pt—

Au, Cr—

Pt, Pt—

Cu, Pt—

Ti, Pt—

Al, Ni—

Cu, and Fe—

Cu.

38. The method of claim 37 wherein said moiety is selected from the group consisting of group NiTi₂, NiTi, Ni₃Ti, NiAl₃, Ni₂Al₃, Ni₅Al₃, Ni₃Al, Ni₈Nb, Ni₃Nb, Ni₆Nb₇, Fe₂Nb, FeNb, NisTa, Ni₃Ta, Ni₂Ta, NiTa, NiTa₂, Fe₂Ta,FeTa, Pt—

Ir, PtAu₃, PtAu, Pt₃Au, Cr₃Pt, CrPt, CrPt₃, PtCu₃, PtCu, Pt₅Cu₃, Pt₃Cu, Ni—

Cu, and Fe—

Cu.

39. The method of claim 33, wherein the mixture has a hardness of from about 95 Rockwell B to about 50 Rockwell C.

40. The method of claim 33, wherein the mixture comprises less than about 2,000 ppm of a carbon, nitrogen, oxygen, or combination thereof.

41. The method of claim 33, further comprising forming in the mixture particles comprising a third composition different from the first and second compositions.

42. The method of claim 33, wherein the first composition comprises a 300 series stainless steel.

43. The method of claim 42, wherein the first composition further comprises a first element selected from the group consisting of platinum, iridium, gold, tantalum, hafnium, tungsten, palladium, rhodium, lead, and silver.

44. The method of claim 43, wherein the first composition comprises from about 1 to about 40 weight percent of the first element.

45. The method of claim 33, wherein the first composition further comprises a first element selected from the group consisting of platinum, iridium, gold, tantalum, hafnium, tungsten, palladium, rhodium, lead, and silver.

46. The method of claim 45, wherein the first composition comprises from about 1 to about 40 weight percent of the first element.

47. The method of claim 33, wherein the medical device comprises an endoprosthesis.

48. The method of claim 33, wherein the medical device is selected from the group consisting of a wire, a cutting element configured to be supported by a medical balloon, and an orthopedic implant.

49. A precipitation hardenable stainless steel alloy that provides a unique combination of strength and radiopacity, said alloy comprising in weight percent, about:

50. The precipitation hardenable stainless steel alloy as set forth in claim 49 wherein the alloy contains at least about 15% platinum and not more than about 20% chromium.

51. The precipitation hardenable stainless steel alloy as set forth in claim 49 wherein the alloy contains at least about 1.5% titanium and at least about 0.5% aluminum.

52. The precipitation hardenable stainless steel alloy as set forth in claim 49 wherein the alloy contains at least about 0.5% molybdenum.

53. The precipitation hardenable stainless steel alloy as set forth in claim 49 wherein the alloy contains at least about 15% nickel.

54. The precipitation hardenable stainless steel alloy as set forth in claim 49 wherein the alloy contains not more than about 40% nickel.

55. The precipitation hardenable stainless steel alloy as set forth in any one of claim 49-54 wherein the alloy contains about 0.025% max. phosphorus, about 0.75% max. silicon, about 0.010% max. sulfur, about 0.07% max. vanadium, and about 0.2% max selenium.