Stent with variable properties

• US 20020138133A1
• Filed: 05/20/2002
• Published: 09/26/2002
• Est. Priority Date: 11/09/1999
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Lenz, Jason T., Stinson, Jonathan Swift
• Granted Patent: US 7,226,475 B2
• Time in Patent Office: Days
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/852 Two or more distinct overlapping stents
• 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 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/9155 Adjacent bands being connected to each other
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2250/0029 differing in bending or flexure capacity
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: A61F 2250/0063 Nested prosthetic parts
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body

Abstract

A stent having variable thickness with improved radiopacity, MRI compatibility, radial stiffness, and flexibility and to the method of making such stents.

Claims

1. A method of making a stent having variable thickness comprising the steps of:

providing a first tubular member having cut-out regions;

providing a second tubular member; and

assembling said first tubular member over said second tubular member or said second tubular member over said first tubular member to form a layered stent preform.

2. The method of claim 1 further comprising the step of fixing said first and said second tubular members together.

3. The method of claim 2 wherein said fixing step includes welding, machining, brazing, co-rolling or co-drawing.

4. The method of claim 2 wherein said assembling and said fixing steps are simultaneous.

5. The method of claim 1 wherein said first tubular member is fitted over said second tubular member.

6. The method of claim 1 further comprising a step of cutting a desired pattern in said layered tubular preform.

7. The method of claim 1 wherein said first tubular member and said second tubular member are formed of the same material.

8. The method of claim 1 wherein said first tubular member is formed of a different material than said second tubular member.

9. The method of claim 1 wherein said first tubular member and said second tubular member are formed from shape memory materials, noble metals, transition metals, alloys thereof, polymers, and mixtures thereof.

10. The method of claim 1 wherein said first tubular member and said second tubular member are formed from nitinol, stainless steel, titanium, tantalum, platinum, gold, cobalt, chromium, molybdenum, niobium, any alloys thereof, and mixtures thereof.

11. The method of claim 1 wherein the thickness of said first tubular member or said second tubular member is varied over the surface.

12. The method of claim 1 wherein said second tubular member has cut-out regions which align with the cut-out regions of said first tubular member.

14. The stent of claim 13 wherein said first tubular member is assembled over said second tubular member.

15. The stent of claim 12 wherein said second tubular member has cut-out regions which substantially align with said cut-out regions of said first tubular member.

16. The stent of claim 12 wherein said first tubular member and said second tubular member are formed of the same material.

17. The stent of claim 12 wherein said first tubular member is stainless steel and said second tubular member is selected from the group consisting of tantalum, platinum, niobium, cobalt, chromium, molybdenum, titanium, nickel, vanadium, aluminum, and alloys thereof.

18. The stent of claim 12 wherein said first tubular member or said second tubular member or both, are formed of an alloy of titanium-nickel, cobalt-chromium, titanium-chromium, cobalt-chromium-molybdenum or titanium-aluminum-vanadium.

19. The stent of claim 12 wherein the wall thickness of said first tubular member or said second tubular member is variable.

20. The stent of claim 12 wherein said first tubular member and said second tubular member are formed from shape memory materials, noble metals, transition metals, alloys thereof, polymers, and mixtures thereof.

21. The stent of claim 12 wherein said first tubular member and said second tubular member are formed from nitinol, stainless steel, titanium, tantalum, platinum, gold, cobalt, chromium, molybdenum, niobium, any alloys thereof, and mixtures thereof.

13. A stent having variable thickness comprising a first tubular member having cut-out regions and a second tubular member having a thin walled construction said first tubular member assembled over said second tubular member or said second tubular member assembled over said first tubular member.

22. A method of manufacturing a stent from a tubular member said stent having radiographic contrast, comprising the steps of:

selecting a pattern which is an oval, a protuberance or a honeycomb pattern;

forming said pattern in said tubular member.

23. The method of claim 22 wherein said pattern is formed by laser or chemical etching.

24. A stent formed according to the method of claim 22.

26. The stent of claim 25 wherein said strut has variable thickness along the periphery.

27. The stent of claim 25 wherein said polygonal outer surface is a hexagon or an octagon.

28. The stent of claim 27 having a substantially uniform circular inner surface.

30. The method of claim 29 further comprising the step of cutting a stent pattern in said polygonal stent preform.

31. The method of claim 29 wherein said polygonal stent preform has a relatively even inner surface after the removing step.

32. The method of claim 29 wherein said stent has variable wall thickness around the circumference of said stent.

33. The method of claim 29 wherein said polygonal stent preform is a hexagon or an octagon.

34. The method of claim 29 wherein said method further comprises the steps of:

placing said polygonal stent preform on a rotating mechanism;

rotating said tubular member; and

pressing a machining tool against the inner surface of said tubular member.

35. The method of claim 34 wherein material is removed from said polygonal stent preform in a relatively uniform circular pattern.

36. The method of claim 29 further comprising the steps of:

positioning said polygonal stent preform in a rotatable collet fixture relative to a laser; and

rotating said polygonal stent preform relative to said laser.

37. The method of claim 36 wherein said laser removes material from said inner surface of said polygonal stent preform in a substantially uniform circular pattern.

39. The stent of claim 38 wherein said first sections are stainless steel, shape memory material or a metal alloy.

40. The stent of claim 39 wherein said second sections comprise gold, tantalum, platinum, or a mixture thereof.

41. The stent of claim 38 wherein said first sections and said second sections are joined by welding, brazing, bonding, drawing or rolling.

25. A stent with struts said stent having variable wall thickness around the circumference formed from a stent preform having a polygonal outer surface.

29. A method of forming a stent from a polygonal stent preform comprising the steps of:

providing a polygonal stent preform having an inner surface; and

removing material from said inner surface of said polygonal stent preform.

38. A stent formed from a tubular member comprising a plurality first and second sections said first sections formed from a first material and said second sections formed from a second more radiopaque material said first sections joined to said second sections end to end.