Selective treatment of linear elastic materials to produce localized areas of superelasticity

• US 20050049690A1
• Filed: 08/25/2003
• Published: 03/03/2005
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Boismier, Dennis A., Crank, Justin M.
• Granted Patent: US 7,455,737 B2
• Time in Patent Office: Days
• US Class Current: 623/1.180
• CPC Class Codes: A61F 2/01 Filters implantable into blood vessels
• CPC Class Codes: A61F 2/0105 Open ended, i.e. legs gathered only at one side
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2250/0042 differing in shape-memory transition temperatures, e.g. in martensitic transition temperature, in austenitic transition temperature
• CPC Class Codes: C22F 1/006 Resulting in heat recoverable alloys with a memory effect
• CPC Class Codes: Y10S 148/902 having portions of differing metallurgical properties or characteristics

Abstract

Methods of selectively treating linear elastic materials to produce localized areas of superelasticity and/or shape-memory are disclosed. In an illustrative method, a linear elastic workpiece may be formed into a particular shape by cold-forming or other low-temperature process, and incorporated into a medical device such as an embolic protection filter, vena cava filter, stent or guidewire. A heat source may be used to apply thermal energy to selective areas of the workpiece, imparting superelasticity to the material.

Claims

1. A method of treating a linear elastic member to produce localized areas of superelasticity, comprising the steps of:

providing a member formed at least in part of a linear elastic material; and

selectively heat-treating a portion of the member to a temperature sufficient to induce superelasticity in the material.

2. The method of claim 1, wherein the step of selectively heat-treating a portion of the member comprises the steps of:

providing a heating source adjacent to the member; and

applying thermal energy to the member.

3. The method of claim 2, wherein said heat source is a laser heat source.

4. The method of claim 2, wherein said heat source is an induction heat source.

5. The method of claim 2, wherein said heat source is an infrared heat source.

6. The method of claim 1, wherein the step of selectively heat-treating a portion of the member includes heating the member for a period of about 5 to 60 minutes.

7. The method of claim 1, wherein the step of selectively heat-treating a portion of the member includes heating the member at or above the final austenitic temperature A_f of the material.

8. The method of claim 1, wherein the step of selectively heat-treating a portion of the member includes heating the member at or above the starting austenitic temperature A_s of the material.

9. The method of claim 1, wherein said linear elastic material is a linear elastic nickel-titanium alloy.

10. The method of claim 1, wherein said linear elastic material is selected from the group of alloys consisting of silver-cadmium, gold-cadmium, gold-copper-zinc, copper-aluminum-nickel, copper-gold-zinc, copper-zinc, copper-zinc-aluminum, copper-zinc-tin, copper-zinc-silicon, iron-beryllium, iron-nickel-titanium-cobalt, iron-platinum, indium-thallium, iron-manganese, nickel-titanium-cobalt, and copper-tin.

11. The method of claim 1, further comprising the step of imparting a shape-memory to the material.

12. A method of treating a linear elastic member to produce localized areas of superelasticity, comprising the steps of:

providing a member formed at least in part of a linear elastic material;

providing a heat source adjacent to the member; and

selectively applying thermal energy to one or more regions on the member at a temperature sufficient to induce superelasticity in the material.

13. The method of claim 12, wherein said heat source is a laser heat source.

14. The method of claim 12, wherein said heat source is an induction heat source.

15. The method of claim 12, wherein said heat source is an infrared heat source.

16. The method of claim 12, wherein the step of selectively heat-treating a portion of the member includes heating the member for a period of about 5 to 60 minutes.

17. The method of claim 12, wherein the step of selectively heat-treating a portion of the member to a sufficient temperature includes heating the member at or above the final austenitic temperature A_f of the material.

18. The method of claim 12, wherein the step of selectively heat-treating a portion of the member includes heating the member at or above the starting austenitic temperature A_s of the material.

19. The method of claim 12, wherein said linear elastic material is a linear elastic nickel-titanium alloy.

20. The method of claim 12, wherein said linear elastic material is selected from the group of alloys consisting of silver-cadmium, gold-cadmium, gold-copper-zinc, copper-aluminum-nickel, copper-gold-zinc, copper-zinc, copper-zinc-aluminum, copper-zinc-tin, copper-zinc-silicon, iron-beryllium, iron-nickel-titanium-cobalt, iron-platinum, indium-thallium, iron-manganese, nickel-titanium-cobalt, and copper-tin.

21. The method of claim 12, further comprising the step of imparting a shape-memory to the material.

22. A method of treating a linear elastic member to produce localized areas of superelasticity, comprising the steps of:

providing a member formed at least in part of a linear elastic material;

cold-forming the member at a temperature less than the starting austenitic temperature A_s of the material to impart a shape to the member;

providing a heat source adjacent to the shaped member; and

selectively applying thermal energy to one or more regions on the shaped member at a temperature sufficient to induce superelasticity in the material.

23. A medical device, comprising:

a linear elastic member having at least one localized area of flexibility formed by selectively heating at least a portion of the member to a temperature sufficient to induce superelasticity in the member.

24. The medical device of claim 23, wherein the linear elastic member defines a wire loop.

25. The medical device of claim 23, wherein the linear elastic member defines a filter leg.

26. The medical device of claim 23, wherein the linear elastic member defines a stent.

27. The medical device of claim 23, wherein the linear elastic member defines a core wire.