METHODS AND APPARATUS FOR LUMINAL STENTING

• US 20140200648A1
• Filed: 03/12/2013
• Published: 07/17/2014
• Est. Priority Date: 01/17/2013
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: HUYNH, Andy, FARHAT, Lawrence, NEWELL, Gabriel F.
• Granted Patent: US 9,295,571 B2
• Time in Patent Office: Days
• US Class Current: 623/1.11
• CPC Class Codes: A61B 2017/1205 Introduction devices
• CPC Class Codes: A61F 2/844 folded prior to deployment
• CPC Class Codes: A61F 2/966 with relative longitudinal movement between outer sleeve and prosthesis, e.g. using a push rod
• CPC Class Codes: A61F 2002/9534 for repositioning of stents
• CPC Class Codes: A61F 2002/9665 with additional retaining means
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol

Abstract

Described herein are flexible implantable devices or stents that can, for example, navigate tortuous vessels of the neurovasculature. The devices can also conform to the shape of tortuous vessels of the vasculature. In some embodiments, the devices can direct blood flow within a vessel away from an aneurysm or limit blood flow to the aneurysm. Methods and structures are provided for adjusting, along a length of the device, the porosity of the device while maintaining a cross-sectional dimension. In some embodiments, a distal stent cover covers the distal end of the device and reduces friction between the stent and an inner surface of a delivery device, such as a catheter.

Claims

1. A stent delivery system, comprising:

an elongate body having a lumen extending from a proximal portion to a distal portion of the body, the distal portion being configured to extend within a blood vessel;

a stent expandable from a compressed configuration, sized to be received within the body lumen, to an expanded configuration, the stent having a lumen and an inner surface extending from a proximal end to a distal end of the stent;

a core wire configured to extend through the body lumen and the stent lumen and having a distal region; and

an expandable member disposed along the core wire distal region, the expandable member being configured to facilitate the expansion of at least a portion of the stent to the expanded configuration by expanding and engaging the stent inner surface.

2. The system of claim 1, wherein the expandable member comprises first and second ends that are rotatably and slidably movable relative to the core wire.

3. The system of claim 1, further comprising at least one blocking member disposed along the core wire, the blocking member being configured to limit the movement of the expandable member relative to the core wire.

4. The system of claim 3, wherein the at least one blocking member comprises a fixed blocking member and a movable blocking member being slidable relative to the fixed blocking member, the fixed blocking member defining an outer profile that is sized greater than an inner profile of a lumen of the movable blocking member, the movable blocking member defining an outer profile that is sized greater than an inner profile of a lumen of an end of the expandable member, the movable blocking member being disposed between the end of the expandable member and the fixed blocking member, such that the end of the expandable member is blocked from sliding past the movable blocking member and the fixed blocking member.

5. The system of claim 3, wherein the at least one blocking member comprises a fixed blocking member and a movable blocking member.

6. The system of claim 3, wherein the at least one blocking member comprises a pair of fixed blocking members and a movable blocking member.

7. The system of claim 3, wherein the at least one blocking member is disposed along the core wire between expandable member first and second ends, the at least one blocking member having an outer cross-sectional profile that is greater than an inner cross-sectional profile of the lumens of the expandable member first and second ends.

8. The system of claim 7, wherein the at least one blocking member is a fixed blocking member that is fixed to the core wire.

9. The system of claim 1, wherein the expandable member comprises a plurality of filaments.

10. The system of claim 1, wherein the expandable member comprises a shape memory material.

11. The system of claim 1, wherein the expandable member self-expands when radially unrestrained by the elongate body.

12. The system of claim 1, further comprising a distal stent cover extending proximally from the distal region of the core wire and interposed between the outer surface of the stent and the inner surface of the elongate member.

13. The system of claim 12, wherein the distal stent cover comprises a folded region having (a) an outer layer configured to be urged against the inner surface of the elongate member and (b) an inner layer configured to contact the outer surface of the stent.

14. The system of claim 13, wherein the folded region is an inverted section of the distal stent cover where the distal stent cover folds within itself.

15. The system of claim 12, wherein the distal stent cover is coupled to the core wire.

16. The system of claim 12, wherein the distal stent cover is formed by one or more flaps of material.

17. The system of claim 12, wherein the distal stent cover comprises a lubricious material.

18. The system of claim 1, further comprising an atraumatic tip coil coupled to the distal region, wherein the distal stent cover is coupled to the tip coil.

19. The system of claim 18, wherein the distal stent cover is coupled to the tip coil by a shrink tube.

20. The system of claim 1, wherein the expandable member is positioned proximally of the stent proximal end when the stent is in the compressed configuration.

21. A method of deploying a stent in a vessel of a patient, comprising:

extending an elongate body within the vessel of the patient, the elongate body having an inner surface extending from a distal portion to a proximal portion of the elongate body;

extending within the elongate body a core assembly having an expandable member and an expandable stent having an inner surface and a distal end;

advancing, relative to and within the elongate body, the core assembly, wherein the stent and the expandable member are in a compressed configuration and the stent at least partially covers the expandable member; and

expanding the expandable member and engaging the stent inner surface with the expandable member when at least the distal end of the stent is expanded.

22. The method of claim 21, wherein the advancing the expandable member comprises permitting expansion of the distal end of the stent using the expandable member when radially unrestrained by the elongate body.

23. The method of claim 21, wherein expanding the expandable member comprises allowing the expandable member to self-expand or automatically expand when radially unrestrained by the elongate body.

24. The method of claim 21, further comprising axially moving the expandable member within a lumen of the stent to facilitate expansion of at least a portion of the stent.

25. The method of claim 24, wherein axially moving the expandable member comprises axially moving the expandable member in proximal and distal directions within the lumen of the stent.

26. The method of claim 24, wherein axially moving the expandable member comprises proximally withdrawing the expandable member within the stent lumen.

27. The method of claim 21, further comprising preventing the expandable member from moving axially beyond the stent distal end during stent expansion.

28. The method of claim 21, further comprising contacting a blocking member with an expandable member distal end to push the expandable member distally.

29. The method of claim 21, further comprising contacting a blocking member with an expandable member proximal end to withdraw the expandable member proximally.

30. The method of claim 21, further comprising advancing the core assembly out of the distal portion of the elongate body, such that a distal stent cover of the core assembly withdraws from the distal end of the stent as the stent expands.

31. The method of claim 30, wherein the distal stent cover of the stent is extended in the elongate body, such that a proximal portion of the distal stent cover is inverted to form a folded region having an outer layer configured to be urged against the member inner surface and an inner layer configured to contact the stent outer surface.

32. The method of claim 30, wherein when the distal stent cover withdraws from the distal end, the folded region unfurls from between the inner surface of the elongate member and the outer surface of the stent.