Thermoelastic and superelastic NI-TI-W alloy

• US 8,974,517 B2
• Filed: 04/21/2014
• Issued: 03/10/2015
• Est. Priority Date: 12/28/2000
• Status: Expired due to Fees

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Pelton, Brian Lee, Boylan, John F.
• Primary Examiner(s): Iwamaye, Andrew
• Assistant Examiner(s): Coburn, Leslie
• Application Number:
  US14/257,839
• Publication Number:
  US 20140243947A1
• Time in Patent Office: 323 Days
• Field of Search: 623 118- 119
• US Class Current: 623/1.19
• 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 2/90 characterised by a net-like or mesh-like structure
• 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 2/962 having an outer sleeve
• CPC Class Codes: A61F 2002/91516 the meander having a change in frequency along the band
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2210/0019 operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61L 2400/16 Materials with shape-memory or superelastic properties
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 31/18 Materials at least partially X-ray or laser opaque
• CPC Class Codes: C22C 19/03 based on nickel
• CPC Class Codes: C22F 1/006 Resulting in heat recoverable alloys with a memory effect
• CPC Class Codes: Y10S 623/90 Stent for heart valve
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

A radiopaque nitinol stent for implantation in a body lumen is disclosed. The stent is made from a superelastic alloy such as nickel-titanium or nitinol, and includes a ternary element including tungsten. The added tungsten in specified amounts improve the radiopacity of the nitinol stent comparable to that of a stainless steel stent of the same strut pattern coated with a thin layer of gold. Furthermore, the nitinol stent has improved radiopacity yet retains its superelastic and shape memory behavior and further maintains a thin strut/wall thickness for high flexibility.

Claims

1. An endoprosthesis delivery system comprising:

a delivery sheath and an endoprosthesis disposed within the delivery sheath, the endoprosthesis comprising;

a tubular-shaped body, the body including a nickel-titanium superelastic alloy, and the alloy further includes a ternary element including tungsten, wherein the tubular-shaped body includes a nickel-titanium-tungsten tubing having an austenite finish temperature of −

15 degrees C. to 0 degrees C.

2. The endoprosthesis delivery system of claim 1, wherein the endoprosthesis delivery system is configured to be passed through a body lumen over a guidewire.

3. The endoprosthesis delivery system of claim 1, wherein the atomic percent of the tungsten is greater than or equal to 5 and less than or equal to 12.

4. The endoprosthesis delivery system of claim 1, wherein the atomic percent of the nickel is 50.8, the atomic percent of the tungsten is 10, and a balance is the atomic percent of titanium.

5. The endoprosthesis delivery system of claim 1, wherein the superelastic alloy includes a stress-induced martensite phase.

6. The endoprosthesis delivery system of claim 1, wherein the atomic percent of the nickel is 50.8 and the atomic percent of the titanium is a maximum of approximately 40.

7. The endoprosthesis delivery system of claim 1, wherein an austenite finish temperature (A_f) of the superelastic alloy in the endoprosthesis is greater than or equal to zero and less than or equal to 30 degrees C.

8. The endoprosthesis delivery system of claim 1, wherein the tubular-shaped body includes raw tubing having an austenite finish temperature (A_f) of greater than or equal to −

15 degrees C. and less than or equal to 0 degrees C.

9. The endoprosthesis delivery system of claim 1, wherein the endoprosthesis has a greater radiopacity than a 316L stainless steel endoprosthesis coated with 4.7 μ

m of gold.

10. An endoprosthesis delivery system comprising:

a delivery sheath;

a delivery catheter configured to be disposed within the delivery sheath; and

an endoprosthesis disposed adjacent to a distal end of the delivery catheter, the endoprosthesis comprising;

a tubular-shaped body wherein the body includes a nickel-titanium superelastic alloy with a ternary element including tungsten, said alloy exhibiting a stress-strain curve that approximates the idealized stress-strain curve of binary nickel-titanium, wherein the body is radiopaque and the tubular-shaped body includes a pattern with struts no greater than 0.0046 inch in width.

11. The endoprosthesis delivery system of claim 10, wherein the atomic percent of the tungsten is greater than or equal to 5 and less than or equal to 12.

12. The endoprosthesis delivery system of claim 10, wherein the atomic percent of the nickel is 50.8, the atomic percent of the tungsten is 10, and a balance is the atomic percent of titanium.

13. The endoprosthesis delivery system of claim 10, wherein the superelastic alloy includes a stress-induced martensite phase.

14. The endoprosthesis delivery system of claim 10, wherein the atomic percent of the nickel is 50.8 and the atomic percent of the titanium is a maximum of approximately 40.

15. The endoprosthesis delivery system of claim 10, wherein the superelastic alloy in the tubular-shaped body has an austenite finish temperature (A_f) of greater than or equal to zero and less than or equal to 30 degrees C.

16. The endoprosthesis delivery system of claim 10, wherein the tubular-shaped body includes raw tubing having an austenite finish temperature (A_f) of greater than or equal to −

15 degrees C. and less than or equal to 0 degrees C.

17. An endoprosthesis delivery system comprising:

a delivery sheath;

a delivery catheter configured to be disposed within the delivery sheath; and

an endoprosthesis disposed on the deliver catheter, the endoprosthesis comprising;

a tubular-shaped body wherein the body includes a nickel-titanium superelastic alloy with a ternary element including tungsten, wherein the nickel-titanium superelastic alloy includes;

30 to 52 atomic percent titanium,

5 to 12 atomic percent tungsten, and

a balance of nickel;

wherein the tubular-shaped body is formed from a nickel-titanium-tungsten tubing having an austenite finish temperature (A_f) of −

15 degree C. to 0 degree C., wherein the body is radiopaque.

18. The endoprosthesis delivery system of claim 17, wherein the nickel-titanium superelastic alloy includes 50.8 atomic percent nickel, 10 atomic percent tungsten, and a balance of titanium.

19. The endoprosthesis delivery system of claim 17, wherein the tubular-shaped body includes a strut pattern with struts no greater than 0.0046 inch in width.

20. The endoprosthesis delivery system of claim 17, wherein the superelastic alloy includes a stress-induced martensite phase.

21. The endoprosthesis delivery system of claim 17, wherein an austenite finish temperature (A_f) of the superelastic alloy in the tubular-shaped body of the endoprosthesis is greater than or equal to zero and less than or equal to 30 degrees C.

22. An endoprosthesis delivery system comprising:

a delivery sheath and an endoprosthesis disposed within the delivery sheath, the endoprosthesis comprising;

a tubular-shaped body including;

an atomic percent of nickel of 50.8,

an atomic percent of tungsten greater than or equal to 5 and less than or equal to 12, and

a balance of titanium

wherein the tubular-shaped body has an active austenite finish temperature A_f defined by −

15 degree C.≦

active A_f≦

0 degree C.

23. The endoprosthesis delivery system of claim 22, wherein the tubular-shaped body includes 50.8 atomic percent nickel, 10 atomic percent tungsten, and a balance of titanium.

24. The endoprosthesis delivery system of claim 22, wherein the tubular-shaped body includes a strut pattern having struts and each strut has a cross-sectional area of less than 0.000021 in².