Single step shape memory alloy expansion

Patent metadata

Field	Value
Publication number	US-2016355912-A1
Application number	US-201615243620-A
Country	US
Kind code	A1
Filing date	Aug 22, 2016
Priority date	Sep 16, 2011
Publication date	Dec 8, 2016
Grant date	—

Abstract

Exposing nitinol to a shape setting temperature while the nitinol is in an unstrained or minimally strained condition. The nitinol is then substantially deformed in shape while at elevated temperature. After deformation, the nitinol remains at the elevated temperature for a time to shape set the material. The nitinol is then returned to approximately room temperature 20° C. by means of water quenching or air cooling for example.

First claim

What is claimed is:

1 . A method of forming a shape memory alloy (SMA) article, comprising:
providing a SMA article having an initial shape having an initial size, said SMA having a shape setting temperature; heating the SMA article to about said shape setting temperature; deforming the SMA article while at about its shape setting temperature to a final shape that is at least twice in size as the initial size; and cooling the SMA article while being constrained thereby substantially retaining said final shape.

2 . The method of claim 1 , wherein after deforming said SMA article, allowing said deformed SMA article to dwell at about its shape setting temperature.

3 . The method of claim 1 , wherein said SMA is nitinol.

4 . The method of claim 1 , wherein said shape setting temperature is about 300° C. to about 650° C.

5 . The method of claim 1 , wherein deforming said SMA article into said final shape is accomplished by application of an internal force.

6 . The method of claim 1 , wherein deforming said SMA article into said final shape is accomplished by application of an external force.

7 . The method of claim 1 , wherein deforming said SMA article into said final shape is accomplished by use of a tapered mandrel.

8 . The method of claim 1 , wherein said SMA article is shaped into a medical device.

9 . The method of claim 8 , wherein said medical device is an implantable medical device.

10 . The method of claim 9 , wherein said implantable medical device is selected from the group consisting of a stent, cardiac occluder, valve and an intraluminal filter.

11 . The method of claim 1 , wherein said SMA initial shape was formed by machining.

12 . The method of claim 11 , wherein said machining comprises laser cutting, water jet cutting, electrical discharge machining, and/or chemical etching.

13 . A medical device, comprising:
a shape memory alloy (SMA) article tailored to transition between a first, second and third state, wherein said SMA comprises a shape setting temperature; wherein;
the article in a first state comprises a first circumferential perimeter;
the article in a second state comprises multiple circumferential perimeters;
the article in a third state comprises a third circumferential perimeter that is at least twice in size as the first circumferential perimeter;
wherein each of said second state circumferential perimeters are larger than the first state circumferential perimeter and smaller than the third state circumferential perimeter; and wherein the shape memory alloy (SMA) article is kept at said shape setting temperature while transitioning between the first, second and third states.

14 . The medical device of claim 13 , wherein said shape setting temperature is about 300° C. to about 650° C.

15 . A device for deforming a shape memory alloy article, comprising:
a slotted elongated tube comprising;
i. a longitudinal axis and a first outer perimeter;
ii. the tube having a length, a through lumen and a wall;
iii. the lumen defining a first inner perimeter;
iv. the tube having at least two slots through the wall;
v. the slots being oriented essentially parallel to the tube longitudinal axis;
vi. the slots extending partially along the tube length;
an expansion mandrel comprising;
i. a first portion with an essentially constant first perimeter;
ii. a second tapered portion;
iii. the second tapered portion having a varying perimeter transitioning from the mandrel first perimeter to a larger second perimeter that is at least twice in size as the first outer perimeter;
iv. the mandrel first portion perimeter being dimensioned to be inserted into the lumen first inner perimeter of said slotted elongated tube; and
a shape memory alloy article surrounding at least a portion of said slotted elongated tube.

16 . The device of claim 15 , wherein said SMA is nitinol.

17 . The device of claim 15 , wherein said SMA article is a medical device.

18 . The device of claim 15 , wherein said medical device is selected from the group consisting of a stent, cardiac occluder, valve and an intraluminal filter.

19 . A device for deforming a shape memory alloy article, comprising:
a slotted elongated tube comprising;
i. a longitudinal axis and a first outer perimeter;
ii. the tube having a length, a through lumen and a wall;
iii. the lumen defining a first inner perimeter;
iv. the tube having at least two slots through the wall;
v. the slots being oriented essentially parallel to the tube longitudinal axis; and
vi. the slots extending partially along the tube length; and
an expansion mandrel comprising;
i. a first portion with an essentially constant first perimeter;
ii. a second tapered portion;
iii. the second tapered portion having a varying perimeter transitioning from the mandrel first perimeter to a larger second perimeter that is at least twice in size as the first outer perimeter;
iv. the mandrel first portion perimeter being dimensioned to be inserted into the lumen first inner perimeter of said slotted elongated tube; and
wherein the slotted elongated tube surrounds at least a portion of the expansion mandrel.

20 . The device of claim 19 , wherein the slotted elongated tube surrounds at least a portion of the expansion mandrel first portion.

21 . The device of claim 19 , wherein the slotted elongated tube surrounds at least a portion of the expansion mandrel second tapered portion.

22 . The device of claim 19 , wherein the expansion mandrel further comprises a third portion having an essentially constant second perimeter.

23 . The device of claim 19 , wherein the slotted elongated tube surrounds at least a portion of the expansion mandrel third portion.

Assignees

• Gore & Ass

Inventors

• Greene Joel M
• Lasley Christopher C

Classifications

• A61F2210/0014

  using shape memory or superelastic materials, e.g. nitinol · CPC title

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title

• A61F2/2418

  Scaffolds therefor, e.g. support stents · CPC title

• A61F2310/00023

  Titanium or titanium-based alloys, e.g. Ti-Ni alloys · CPC title

• A61F2/844

  folded prior to deployment · CPC title