Curved nitinol stent for extremely tortuous anatomy

• US 20030187497A1
• Filed: 03/26/2003
• Published: 10/02/2003
• Est. Priority Date: 06/02/2000
• Status: Abandoned Application

• Current Assignee: John F. Boylan, Mark G. Wholey
• Original Assignee: John F. Boylan, Mark G. Wholey
• Inventors: Wholey, Mark G., Boylan, John F.
• Application Number:
  US10/397,487
• Publication Number:
  US 20030187497A1
• Time in Patent Office: Days
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2002/9665 with additional retaining means
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers

Abstract

A stent for use in a curved body lumen is disclosed. The stent is made from a superelastic alloy such as nickel titanium or nitinol, and optionally includes a ternary element. The superelastic alloy has a low temperature phase or martensitic phase and a high temperature phase or an austenitic phase. In the high temperature phase, the stent has a curve along the length that closely matches the curve of the vessel in the patient'"'"'s anatomy. When deployed in the curved vessel of the patient, the heat set curve of the stent closely conforms to the curvature in the vessel and minimizes trauma and stress to the vessel.

Claims

1. A stent for use in a curved body lumen, comprising:

a cylindrically-shaped stent having a diameter and a unitary length greater than the diameter;

the stent including a superelastic alloy, the superelastic alloy having a high temperature phase and a low temperature phase;

the cylindrically-shaped stent having an expanded configuration in the high temperature phase and a compressed configuration in the low temperature phase; and

wherein the cylindrically-shaped stent in the expanded configuration of the high temperature phase induces a bend along the length thereof that substantially conforms to the curved body lumen.

2. The stent of claim 1, wherein the stent includes a directional radiopaque marker.

3. The stent of claim 1, wherein the superelastic alloy includes a nickel titanium alloy with at least 30 to 52 percent titanium, and a ternary element that is selected from the group of elements consisting of palladium, platinum, chromium, iron, cobalt, vanadium, manganese, boron, copper, aluminum, tungsten, tantalum, or zirconium.

4. The stent of claim 1, wherein the superelastic alloy includes at least 30 to 52 percent titanium, at least 38 percent nickel, and up to 10 percent of a ternary element selected from the group of elements consisting of palladium, platinum, chromium, iron, cobalt, vanadium, manganese, boron, copper, aluminum, tungsten, tantalum, or zirconium.

5. A stent for use in a curved body lumen, comprising:

a cylindrically-shaped stent including a superelastic alloy, wherein the stent has a unitary construction of a length that is greater than a diameter;

the superelastic alloy having a low temperature phase that induces a first shape to the stent, and a high temperature phase that induces a second shape with a bend along the length of the stent; and

wherein the bend substantially conforms to the curved body lumen.

6. The stent of claim 5, wherein the high temperature phase corresponds to an austenitic phase and the low temperature phase corresponds to a martensitic phase.

7. The stent of claim 5, wherein the stent in the second shape includes a plurality of bends along the length thereof.

8. The stent of claim 5, wherein the length of the stent is sufficient to prevent stent migration.

9. The stent of claim 5, wherein the superelastic alloy includes nickel and titanium.

10. The stent of claim 5, wherein the stent includes a radiopaque marker.

11. The stent of claim 5, wherein the superelastic alloy includes a nickel titanium alloy with at least 30 to 52 percent titanium, and a ternary element that is selected from the group of elements consisting of palladium, platinum, chromium, iron, cobalt, vanadium, manganese, boron, copper, aluminum, tungsten, tantalum, or zirconium.

12. The stent of claim 5, wherein the stent in the first shape has a straight length and in the second shape has a bend along the length.

13. The stent of claim 5, wherein the stent in the second shape includes a bend of greater than 90 degrees.

14. The stent of claim 5, wherein the stent in the second shape includes a bend extending in at least two dimensions.

15. The stent of claim 5, wherein the stent in the second shape includes a bend having compound curves.

16. A method for providing a stent for use in a curved body lumen, comprising:

providing a cylindrically-shaped stent including a superelastic alloy, wherein the stent has a unitary construction of a length that is greater than a diameter;

providing the superelastic alloy to have a low temperature phase conferring a first shape to the stent and a high temperature phase conferring a second shape to the stent; and

heat setting the stent to include a bend in the second shape that substantially conforms to the curved body lumen.

17. The method for providing a stent for use in a curved body lumen of claim 16, wherein providing the superelastic alloy includes providing a nickel and titanium alloy.

18. The method for providing a stent for use in a curved body lumen of claim 16, wherein the method further comprises providing directional radiopaque markers on the stent.

19. The method for providing a stent for use in a curved body lumen of claim 16, wherein the stent in the second shape includes a bend of greater than 90 degrees.

20. The method for providing a stent for use in a curved body lumen of claim 16, wherein the stent in the second shape includes a bend extending in at least two dimensions.

21. The method for providing a stent for use in a curved body lumen of claim 16, wherein the stent in the second shape includes a bend having compound curves.