Conical stent

• US 6,533,810 B2
• Filed: 09/04/2001
• Issued: 03/18/2003
• Est. Priority Date: 11/27/1995
• Status: Expired due to Term

• Current Assignee: Boston Scientific Corporation
• Original Assignee: Schneider (Europe) GmbH (Boston Scientific Corporation)
• Inventors: Gianotti, Marc, Hofmann, Eugen, Hankh, Susanne
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): PHAN, HIEU
• Application Number:
  US09/946,403
• Publication Number:
  US 20020032479A1
• Time in Patent Office: 560 Days
• Field of Search: 623/1.1, 623/1.11, 623/1.12, 623/1.13, 623/1-4-, 623/1.3, 623/1.31
• US Class Current: 623/1.16
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2250/0037 differing in height or in length
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: D04C 1/06 Braid or lace serving particular purposes
• CPC Class Codes: D10B 2509/06 Vascular grafts; stents

Abstract

The stent comprises a flexible self-expandable braided tubular wall having a proximal segment having an outer diameter, and a distal segment having an outer diameter smaller than the outer diameter of the proximal segment. An intermediate segment is formed between proximal and distal segments, which forms a truncated cone of which the base is forming the proximal end of the intermediate segment and of which the top is forming the distal end of the intermediate segment. A covering layer is arranged within the tubular wall.

Claims

1. A body insertable stent, including:

a flexible self-expandable tubular wall incorporating at least one truncated conical segment disposed about a longitudinal axis;

wherein the truncated conical segment has a distal end with a distal end diameter, and a proximal end with a proximal end diameter larger than the distal end diameter; and

wherein a radial force of the tubular wall increases in the proximal direction along the at least one truncated conical segment.

2. The stent of claim 1 wherein:

a flexibility of the tubular wall increases in the distal direction along the at least one truncated conical segment.

3. The stent of claim 1 wherein:

the tubular wall further includes a proximal segment disposed about the longitudinal axis proximally of the truncated conical segment.

4. The stent of claim 3 wherein:

the proximal segment is cylindrical and has a proximal segment diameter substantially equal to the proximal end diameter.

5. The stent of claim 3 wherein:

the tubular wall further includes a distal segment disposed about the longitudinal axis distally of the truncated conical segment.

6. The stent of claim 5 wherein:

the distal segment is cylindrical and has a distal segment diameter substantially equal to the distal end diameter.

7. The stent of claim 5 wherein:

the proximal segment has a proximal segment diameter substantially equal to the proximal end diameter, the distal segment has a distal segment diameter substantially equal to the distal end diameter, and the proximal segment diameter and distal segment diameters are selected to facilitate a placement of the tubular wall at a junction of the esophagus with the stomach.

8. The stent of claim 1 wherein:

the flexible self-expandable tubular wall is formed of at least one strand of a resilient material.

9. The stent of claim 8 wherein:

the at least one strand of a resilient material comprises a spring steel wire.

10. The stent of claim 8 wherein:

the at least one strand of a resilient material comprises at least a first strand wound helically in a first direction, and a second strand wound helically in a second direction different than the first direction.

11. The stent of claim 10 wherein:

the first and second strands are wound in opposite directions.

12. The stent of claim 11 wherein:

the first and second strands form a steep angle with respect to the longitudinal axis, and the steep angle varies along the truncated conical segment in the longitudinal direction.

13. The stent of claim 12 wherein:

the steep angle increases in the proximal direction.

14. The stent of claim 1 wherein:

the tubular wall is radially contractible through application of force to pull the proximal and distal ends away from one another, and further is adapted to radially self-expand in response to a release of said force.

15. The stent of claim 1 further including:

an elastic covering layer extended along the truncated conical segment.

16. The stent of claim 15 wherein:

the elastic covering layer surrounds the tubular wall.

17. The stent of claim 15 wherein:

the elastic covering layer is disposed within the tubular wall.

18. The stent of claim 15 wherein:

the tubular wall further includes a proximal segment disposed proximally of the truncated conical segment, and a distal segment disposed distally of the truncated conical segment; and

the elastic covering is extended distally of the truncated conical segment along at least a portion of the distal segment.

19. The stent of claim 18 wherein:

the elastic covering extends proximally of the truncated conical segment along at least a portion of the proximal segment.

20. A process for forming a truncated conical segment in a radially expandable and radially contractible prosthesis, including:

providing a mandrel having a mandrel segment that forms a truncated cone;

providing a tubular structure having a proximal end and a distal end, radially contractible by moving the proximal and distal ends away from one another;

positioning the tubular structure in surrounding relation to the mandrel, with a portion of the tubular member aligned with said mandrel segment; and

with the tubular structure so positioned, radially contracting the tubular structure about the mandrel, thereby causing said portion of the tubular structure to engage the mandrel segment and assume a truncated conical shape substantially conforming to the mandrel segment.

21. The process of claim 20 further including:

with said portion of the tubular structure engaging and substantially conforming to the mandrel segment, heating the tubular structure to cause the portion of the tubular structure to retain said truncated conical shape.

22. The process of claim 20 wherein:

said radially contracting the tubular structure about the mandrel comprises moving the proximal and distal ends of the tubular structure away from one another.

23. The process of claim 22 wherein:

said moving the proximal and distal ends away from one another comprises applying an axial force to pull the proximal and distal ends away from one another against an elastic restoring force.

24. A body insertable prosthesis, including:

a flexible, self-expandable braided tubular wall comprising a proximal segment having a proximal segment diameter adapted to provide a sufficiently high radial force to substantially prevent migration of the stent in a body passageway;

a distal segment having a distal segment diameter less than the proximal segment diameter; and

an intermediate segment disposed about a longitudinal axis between the proximal and distal segments, having a distal end with a distal end diameter substantially equal to the distal segment diameter, and a proximal end having a proximal end diameter substantially equal to the proximal segment diameter;

wherein the proximal segment is adapted to exert a first level of radial force therealong, the distal segment is adapted to exert a second level of force therealong less than the first level of radial force, and wherein the intermediate segment is adapted to exert radial force at a level that increases in the proximal direction therealong, to provide a transition in radial force between the proximal segment and the distal segment.

25. The stent of claim 24 wherein:

the intermediate segment incorporates at least one truncated conical portion disposed about the longitudinal axis.

26. The stent of claim 25 wherein:

the flexible self-expandable tubular wall is formed of at least one strand of a resilient material.

27. The stent of claim 26 wherein:

the at least one strand of a resilient material comprises at least a first strand wound helically in a first direction, and a second strand wound helically in a second direction different from the first direction.

28. The stent of claim 27 wherein:

the first and second strands are wound in opposite directions.

29. The stent of claim 28 wherein:

the first and second strands form a steep angle with respect to the longitudinal axis and the steep angle increases along the truncated conical portion in the proximal direction.

30. The stent of claim 24 wherein:

a flexibility of the tubular wall increases in the distal direction along the intermediate segment.

31. The stent of claim 24 wherein:

the proximal segment diameter and the distal segment diameter are selected to facilitate a placement of the tubular wall at a junction of the esophagus with the stomach.