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

• US 7,455,737 B2
• Filed: 08/25/2003
• Issued: 11/25/2008
• Est. Priority Date: 08/25/2003
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Boismier, Dennis A., Crank, Justin M.
• Primary Examiner(s): WYSZOMIERSKI, GEORGE P
• Application Number:
  US10/647,619
• Publication Number:
  US 20050049690A1
• Time in Patent Office: 1,919 Days
• Field of Search: 148/402, 148/902, 623/1.18, 623/1.19, 623/924
• US Class Current: 148/402
• 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. An embolic protection filter, comprising:

an elongate shaft;

a filter coupled to the shaft, the filter including a filter loop and a filter membrane coupled to the filter loop;

wherein the filter loop includes a nickel-titanium alloy; and

wherein the filter loop includes a first portion that includes a linear elastic nickel-titanium alloy and wherein at least one localized area of flexibility is defined in the filter loop by selectively heating an intermediate portion of the filter loop to a temperature sufficient to induce superelasticity in the filter loop and define a super elastic nickel-titanium alloy second portion of the filter loop.

2. An embolic protection filter, comprising:

an elongate shaft;

a filter coupled to the shaft, the filter including a linear elastic member having a linear elastic region and a localized superelastic region;

wherein the localized superelastic region is formed by heating an intermediate portion of the linear elastic member to a temperature sufficient to form the localized superelastic region within the linear elastic member, wherein the linear elastic member defines a filter leg.

3. The medical device of claim 2, wherein the linear elastic member has only one localized superelastic region.

4. The medical device of claim 2, wherein the localized superelastic region comprises an articulation region.

5. The medical device of claim 2, wherein the localized superelastic region is formed by heating to a temperature that is at least as high as a final austenitic temperature of a material forming the linear elastic member.

6. The medical device of claim 2, wherein the linear elastic member is formed of a linear elastic nickel-titanium alloy and the localized superelastic region comprises, after the heating step, a superelastic nickel-titanium alloy.