Interwoven dual sinusoidal helix stent

• US 5,913,896 A
• Filed: 07/03/1997
• Issued: 06/22/1999
• Est. Priority Date: 11/28/1995
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Boyle, William J., Shy, James M., Wong, Rosalinda A.
• Primary Examiner(s): Prebilic, Paul B.
• Assistant Examiner(s): Koh, Choon P.
• Application Number:
  US08/887,585
• Time in Patent Office: 719 Days
• Field of Search: 623/1, 623/11, 623/12, 623/901, 606/108, 606/191, 606/192, 606/194, 606/195, 606/198, 128/898
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

A method and apparatus for a radially expandable stent for implantation within a body vessel, comprising a first and second wire having a series of alternating peaks and valleys. The valleys of the first wire are braided with the peaks of the second wire forming a braided region with the interwoven first and second wire being wound into a continuous helix having a hollow cylindrical shape. The peaks of the first wire of the continuous helix may be welded to the adjacent valleys of the second wire of the continuous helix. The peaks and valleys of the first wire may symmetrically intersect with the peaks and valleys of the second wire to form a uniform series of crossings thereby permitting even expansion of the first and second wires. The proximal end of the first wire may be attached to the proximal end of the second wire. The distal end of the first wire may be attached to the distal end of the second wire. A means within the interwoven first and second wires of the continuous helix may be included for expansion thereof.

Claims

1. A radially expandable stent for implantation within a body vessel, comprising:

a first wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

a second wire having a preformed series of peaks alternating with valleys therein each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

the first wire being interwoven with the second wire such that each valley of the first wire is interwoven with one respective peak of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter; and

the interwoven first and second wires being wound into a continuous helix having a hollow cylindrical shape.

2. The stent according to claim 1 wherein the first and second wires are formed of a biocompatible metal that can be plastically deformed at low to moderate stress levels.

3. The stent according to claim 1 wherein the first and second wires are formed of a biocompatible clad metal having a radiopaque material covered with a higher strength material.

4. The stent according to claim 1 wherein the first and second wires are formed of MP-35N with at least 33% tantalum by volume.

5. The stent according to claim 1 wherein the first and second wires are formed of a stainless steel alloy 316 with greater than 25% tantalum by volume.

6. The stent according to claim 1 having a means within the interwoven first and second wires of the continuous helix for expanding the interwoven first and second wires of the continuous helix.

7. The stent according to claim 1 wherein at least one peak of the first or second wire of the continuous helix is welded to an adjacent valley of the first or second wire of the continuous helix.

8. The stent according to claim 1 wherein the first and second wires are formed of a biocompatible clad metal having a radiopaque material covered with a higher strength material.

9. A radially expandable stent for implantation within a body vessel, comprising:

a first wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

a second wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

the first wire being interwoven with the second wire such that each valley of the first wire is interwoven with one respective peak of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter;

the interwoven first and second wires being wound into a continuous helix having a hollow cylindrical shape; and

the peaks and valleys of the first wire symmetrically intersecting with the peaks and valleys of the second wire to form a uniform series of crossings thereby permitting even expansion of the first and second wires.

10. The stent according to claim 9 wherein the first and second wires are formed of a biocompatible metal that can be plastically deformed at low to moderate stress levels.

11. The stent according to claim 9 wherein the first and second wires are formed of a biocompatible clad metal having a radiopaque material covered with a higher strength material.

12. The stent according to claim 9 wherein the first and second wires are formed of MP-35N with at least 33% tantalum by volume.

13. The stent according to claim 9 wherein the first and second wires are formed of a stainless steel alloy 316 with greater than 25% tantalum by volume.

14. The stent according to claim 9 having a means for expanding the first and second wires.

15. The stent according to claim 9 wherein at least one peak of the first or second wire of the continuous helix is welded to an adjacent peak of the first or second wire of the continuous helix.

16. The stent according to claim 9 wherein the first and second wires are formed of a biocompatible clad alloy having a radiopaque material covered with a higher strength material.

17. A radially expandable stent for implantation within a body vessel, comprising:

a first wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

a second wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

the first wire being interwoven with the second wire such that each valley of the first wire is interwoven with one respective peak of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter;

the interwoven first and second wires being wound into a continuous helix having a hollow cylindrical shape; and

the proximal end of the first wire being attached to the proximal end of the second wire, and the distal end of the first wire being attached to the distal end of the second wire.

18. A method for making a stent body for implantation within a body vessel comprising:

preforming a first wire into a sinusoidal wave pattern having a series of peaks alternating with valleys, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

preform a second wire into a sinusoidal wave pattern having a series of peaks alternating with valleys, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

interweaving the first wire with the second wire such that each valley of the first wire is braided with one respective peak of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter; and

winding the interwoven first and second wires on a cylindrical mandrel into a continuous helix having a cylindrical shape such that the alternating peaks and valleys are retained.

19. The method of claim 18 comprising a further step of attaching the proximal end of the first wire to the proximal end of the second wire;

and

attaching the distal end of the first wire to the distal end of the second wire.

20. The method of claim 18 comprising a further step of interweaving the first wire with the second wire such that the peaks and valleys of the first wire symmetrically intersect with the peaks and valleys of the second wire to form a uniform series of crossings thereby permitting even expansion of the first and second wires.

21. The method of claim 18 including a further step of welding at least one peak of the first or second wire of the continuous helix to an adjacent valley of the first or second wire of the continuous helix.

22. The method of claim 18 including a further step of having a means within the interwoven first and second wires of the continuous helix for expanding the interwoven first and second wires of the continuous helix.

23. The method of claim 18 including a further step of flattening the first outer diameter of one or more braids using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter.

24. A radially expandable stent for implantation within a body vessel, comprising:

a first wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

a second wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

the first wire being interwoven with the second wire such that at least a pair of immediately adjacent peaks of the first wire are interwoven with at least a pair of respective counterpart immediately adjacent valleys of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter; and

the interwoven first and second wires being wound into a continuous helix having a hollow cylindrical shape.

25. A radially expandable stent for implantation within a body vessel, comprising:

a first wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

a second wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

the first wire being interwoven with the second wire such that at least a pair of immediately adjacent peaks of the first wire are interwoven with at least a pair of respective counterpart immediately adjacent valleys of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter;

the interwoven first and second wires being wound into a continuous helix having a hollow cylindrical shape; and

the peaks and valleys of the first wire symmetrically intersecting with the peaks and valleys of the second wire to form a uniform series of crossings thereby permitting even expansion of the first and second wires.

26. A radially expandable stent for implantation within a body vessel, comprising:

a first wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

a second wire having a preformed series of peaks alternating with valleys therein, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

the first wire being interwoven with the second wire such that at least a pair of immediately adjacent peaks of the first wire are interwoven with at least a pair of respective counterpart immediately adjacent valleys of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter;

the interwoven first and second wires being wound into a continuous helix having a hollow cylindrical shape; and

the proximal end of the first wire being attached to the proximal end of the second wire, and the distal end of the first wire being attached to the distal end of the second wire.

27. A method for making a stent body for implantation within a body vessel comprising:

preforming a first wire into a sinusoidal wave pattern having a series of peaks alternating with valleys, each peak and valley being connected by a substantially straight segment, the first wire having a proximal end and a distal end;

preforming a second wire into a sinusoidal wave pattern having a series of peaks alternating with valleys, each peak and valley being connected by a substantially straight segment, the second wire having a proximal end and a distal end;

interweaving the first wire with the second wire such that at least a pair of immediately adjacent peaks of the first wire are braided with at least a pair of respective immediately adjacent valleys of the second wire with each interweaving forming a braid, the braid having a first outer diameter, the first outer diameter of one or more braids are flattened using a means whereby a wall thickness of the braid is reduced resulting in a second outer diameter of the braid which is less than the first outer diameter; and

winding the interwoven first and second wires on a cylindrical mandrel into a continuous helix having a cylindrical shape such that the alternating peaks and valleys are retained.