Apparatus and methods for deploying self-expanding stents

• US 20080294230A1
• Filed: 05/24/2007
• Published: 11/27/2008
• Est. Priority Date: 05/24/2007
• Status: Abandoned Application

• Current Assignee: Cook Incorporated (Cook Group Incorporated)
• Original Assignee: Cook Incorporated (Cook Group Incorporated)
• Inventors: Parker, Fred T.
• Application Number:
  US11/805,803
• Publication Number:
  US 20080294230A1
• Time in Patent Office: Days
• US Class Current: 623/1.11
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/966 with relative longitudinal movement between outer sleeve and prosthesis, e.g. using a push rod

Abstract

Apparatus and methods are provided for improved deployment of self-expanding stents. One advantage of the improved delivery system is that energy storage within a portion of an outer sheath and/or an inner tube may be reduced during the deployment of the stent. In a first embodiment, the outer sheath and the inner tube may be coupled together using a plurality of engaging threaded members, such that circumferential rotation of the inner tube with respect to the outer sheath retracts the outer sheath to deploy the stent. In an alternative embodiment, a fluid reservoir may be provided between the inner tube and the outer sheath. A proximal sealing ring may be disposed annularly between the inner tube and the outer sheath, such that when the fluid reservoir is filled, the proximal sealing ring is urged proximally to engage and retract the outer sheath. Using these techniques, energy build-up in the outer sheath and/or inner tube may be substantially reduced and improved accuracy in deploying the stent may be achieved.

Claims

1. An apparatus for deploying a self-expanding stent, the apparatus comprising:

an outer sheath comprising proximal and distal regions;

an inner tube comprising proximal and distal regions being disposed substantially coaxially inside of the outer sheath;

a self-expanding stent comprising proximal and distal ends, the self-expanding stent positioned in a radially compressed state within the outer sheath at a location distal to the inner tube;

at least one fluid reservoir formed between the inner tube and the outer sheath; and

a fluid injectable into the fluid reservoir and suitable for imposing a pressure upon the outer sheath to retract the outer sheath when the inner tube is held longitudinally steady.

2. The apparatus of claim 1 further comprising a proximal sealing ring disposed annularly between the inner tube and the outer sheath at a proximal section of the fluid reservoir.

3. The apparatus of claim 2 further comprising a step disposed in the outer sheath at a location adjacent to the proximal sealing ring, wherein proximal advancement of the proximal sealing ring pushes against the step in the outer sheath to thereby cause retraction of the outer sheath.

4. The apparatus of claim 2 further comprising a distal sealing ring disposed annularly between the inner tube and the outer sheath at a distal region of the fluid reservoir.

5. The apparatus of claim 4 further comprising a protruding step formed in the inner tube, wherein the distal sealing ring is disposed proximal to the protruding step such that the distal sealing ring cannot move distally when the inner tube is held longitudinally steady.

6. The apparatus of claim 1 wherein a lumen is formed between inner and outer surfaces of the inner tube, the apparatus further comprising at least one aperture in the outer surface of the inner tube at a location overlying the fluid reservoir to enable fluid communication between the lumen and the fluid reservoir.

7. The apparatus of claim 1 wherein the outer sheath comprises inner and outer members disposed substantially adjacent to one another, the apparatus further comprising a coil member sandwiched between the inner and outer members along a portion of the distal region of the outer sheath.

8. An apparatus suitable for deploying a self-expanding stent, the apparatus comprising:

an outer sheath comprising proximal and distal regions;

a self-expanding stent comprising proximal and distal ends, and further comprising a compressed state and a radially expanded state, wherein the self-expanding stent is adapted to be disposed within the outer sheath and the outer sheath restrains the self-expanding stent in the compressed state;

at least one fluid reservoir disposed adjacent to an interior surface of the outer sheath;

at least one lumen in fluid communication with the fluid reservoir; and

a proximal sealing ring disposed within the outer sheath and disposed proximally from the proximal end of the self-expanding stent,

wherein the delivery of fluid to the fluid reservoir via the lumen is adapted to impose a pressure between the proximal sealing ring and the outer sheath to retract the outer sheath and permit deployment of the self-expanding stent.

9. The apparatus of claim 8 wherein the outer sheath comprises a step disposed adjacent to the proximal sealing ring, such that proximal advancement of the proximal sealing ring pushes against the step in the outer sheath to thereby cause retraction of the outer sheath.

10. The apparatus of claim 8 further comprising an inner tube disposed substantially coaxially inside of the outer sheath, wherein the fluid reservoir is disposed between the inner tube and the outer sheath.

11. The apparatus of claim 10 further comprising a distal sealing ring disposed annularly between the inner tube and the outer sheath within a distal section of the fluid reservoir.

12. The apparatus of claim 11 further comprising a protruding step formed in the inner tube, wherein the distal sealing ring is disposed proximal to the protruding step such that the distal sealing ring cannot move distally when the inner tube is held longitudinally steady.

13. The apparatus of claim 11 further comprising:

a stylet having proximal and distal ends; and

a disc member attached to the distal end of the stylet,

wherein the distal sealing ring is disposed proximal to the disc member and configured to abut the disc member when fluid is disposed in the fluid reservoir.

14. The apparatus of claim 10 wherein the lumen is formed between inner and outer surfaces of the inner tube, the apparatus further comprising at least one aperture disposed in the outer surface of the inner tube at a location overlying the fluid reservoir to enable fluid communication between the lumen of the inner tube and the fluid reservoir.

15. The apparatus of claim 10 wherein the lumen is formed within the inner surface of the inner tube.

16. The apparatus of claim 8 wherein the outer sheath comprises inner and outer members disposed substantially adjacent to one another, the apparatus further comprising a coil member sandwiched between the inner and outer members along a portion of the distal region of the outer sheath.

17. The apparatus of claim 8 wherein the proximal end of the outer sheath terminates just proximal to the self-expanding stent, such that the outer sheath spans less than fifty percent of an overall length of the inner tube.

18. An apparatus suitable for deploying a self-expanding stent, the apparatus comprising:

an outer sheath comprising proximal and distal regions and comprising at least one first threaded member;

an inner tube comprising proximal and distal regions and at least one second threaded member, wherein the inner tube is disposed substantially coaxially inside of the outer sheath; and

a self-expanding stent having proximal and distal ends, and further having a compressed state and a radially expanded state, wherein the self-expanding stent is adapted to be disposed within the outer sheath in the compressed state,

wherein rotation of the first threaded member with respect to the second threaded member is adapted to retract the outer sheath with respect to the inner sheath to permit deployment of the self-expanding stent.

19. The apparatus of claim 18 further comprising:

a protruding step formed in the inner tube and projecting in a radially outward direction, wherein the protruding step is disposed distal to the second threaded member; and

at least one washer disposed annularly between the outer sheath and the inner tube, and further disposed longitudinally between the protruding step of the inner tube and the proximal end of the stent.

20. The apparatus of claim 18 wherein the outer sheath comprises inner and outer members disposed substantially adjacent to one another, and further comprising a coil member sandwiched between the inner and outer members along a portion of the distal region of the outer sheath.