Delivery system for self-expanding stent, a method of using the delivery system, and a method of producing the delivery system

• US 20060184226A1
• Filed: 02/16/2005
• Published: 08/17/2006
• Est. Priority Date: 02/16/2005
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Austin, Michael
• Granted Patent: US 7,918,880 B2
• Time in Patent Office: Days
• US Class Current: 623/1.110
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/9517 handle assemblies therefor
• CPC Class Codes: A61F 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• CPC Class Codes: A61F 2002/9665 with additional retaining means
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body

Abstract

A medical appliance is provided that includes an outer sheath adapted to enclose a self-expanding stent in an inner space before deployment of the self-expanding stent and an inner sheath arranged between the outer sheath and the self-expanding stent before deployment of the self-expanding stent. The inner sheath includes longitudinal slits that extend from a distal end of the medical appliance to the proximal end. The longitudinal slits form a plurality of inner sleeve tails. The medical appliance also includes an actuator adapted to move the outer sheath with respect to the inner sheath during deployment of the self-expanding stent. The actuator is adapted to cause the outer sheath to move proximally. A method of deploying a self-expanding stent is provided. A method of loading a delivery mechanism is provided.

Claims

1. A medical appliance, comprising:

an outer sheath adapted to enclose a self-expanding stent in an interior space before deployment of the self-expanding stent;

an inner sheath enclosed within the outer sheath and adapted to be arranged about proximally adjacent to the self-expanding stent before deployment of the self-expanding stent; and

a plurality of extensions coupled to a distal end of the inner sheath, the extensions adapted to be arranged between the outer sheath and the self-expanding stent before deployment of the self-expanding stent.

2. The medical appliance of claim 1, wherein the extensions comprise longitudinal slits of the inner sheath forming a plurality of inner sleeve tails, the inner sleeve tails extending from a distal end of the outer sheath to a distal end of the inner sheath.

3. The medical appliance of claim 2, wherein at least the longitudinal slits of the inner sheath are biodegradable and detachable from the medical appliance.

4. The medical appliance of claim 1, wherein the extensions comprise a plurality of wires, the wires extending from a distal end of the outer sheath to a distal end of the inner sheath.

5. The medical appliance of claim 4, further comprising:

a molded tip coupled to a catheter and arranged distal of the outer sheath and the self-expanding stent before deployment;

wherein the catheter is adapted to position the medical appliance in a lumen; and

wherein the molded tip includes a respective annular space for housing an end of each of the plurality of wires.

6. The medical appliance of claim 4, wherein the wires comprise stainless steel wires.

7. The medical appliance of claim 4, wherein each of the wires is attached at a distal end to another of the wires to form a wire loop.

8. The medical appliance of claim 4, wherein the wires are roll-flattened to reduce a radial displacement of the wires.

9. The medical appliance of claim 1, further comprising an actuator adapted to move the outer sheath with respect to the inner sheath during deployment of the self-expanding stent, the actuator adapted to cause the outer sheath to move proximally.

10. The medical appliance of claim 1, further comprising the self-expanding stent.

11. The medical appliance of claim 10, wherein a rate of expansion of the self-expanding stent includes a delay.

12. The medical appliance of claim 10, wherein the self-expanding stent comprises a coating including a bioactive agent.

13. The medical appliance of claim 10, wherein:

the medical appliance is deployed in a lumen of a human body; and

the coating of the self-expanding stent releases the bioactive agent.

14. The medical appliance of claim 1, wherein, during deployment, the outer sheath is moved proximally with respect to the inner sheath and the plurality of extensions allows the self-expanding stent to expand.

15. The medical appliance of claim 14, wherein the plurality of extensions is retracted after the outer sheath has moved proximally and the self-expanding stent has expanded to fill a lumen.

16. The medical appliance of claim 14, further comprising an expandable pusher adapted to abut the self-expanding stent in a contracted state and oppose a proximal shear force during deployment.

17. The medical appliance of claim 16, wherein the expandable pusher fits flush with an inside diameter of the inner sheath.

18. The medical appliance of claim 16, wherein the expandable pusher is adapted to:

expand when the self-expanding stent has expanded;

abut the self-expanding stent in an expanded state; and

oppose a further proximal shear force during retraction of the plurality of extensions.

19. A method of deploying a self-expanding stent, comprising:

inserting an outer sheath into a lumen of a body, the outer sheath coupled to a catheter, the outer sheath enclosing an inner sheath and a plurality of extensions, the plurality of extensions coupled to a distal end of the inner sheath and enclosing the self-expanding stent; and

activating an activator to move the outer sheath relative to the inner sheath and the plurality of extensions, the outer sheath moving proximally, the plurality of extensions allowing the self-expanding stent to expand to an edge of the lumen.

20. The method of claim 19, further comprising:

activating the activator to move the inner sheath relative to a pusher abutting the self-expanding stent, the inner sheath and the plurality of extensions moving proximally with respect to the self-expanding stent.

21. The method of claim 19, further comprising:

retracting the catheter.

22. A method of loading a delivery mechanism, comprising:

inserting an inner sheath into an outer sheath, the inner sheath comprising a tube having a plurality of longitudinal slits bounded at least distally by a circumferential ring, the outer sheath coupled to a catheter, the catheter including an activation mechanism adapted to move the outer sheath proximally with respect to an expandable pusher; and

detaching each of the longitudinal slits from each other of the longitudinal slits at a distal end of the inner sheath.

23. The method of claim 22, wherein the detaching operation comprises severing the circumferential ring at each of the longitudinal slits to extend each longitudinal slit to a distal edge of the inner sheath.

24. The method of claim 22, wherein the detaching operation comprises severing a cylindrical end portion of at least the inner sleeve so that each longitudinal slit extends to a distal edge of the inner sheath.

25. The method of claim 22, wherein the expandable pusher is adapted to abut the inner sheath when the outer sheath moves proximally with respect to the expandable pusher.

26. The method of claim 25, wherein the activation mechanism comprises a dual action activator, a first activation adapted to move the outer sheath proximally with respect to the expandable pusher, a second activation adapted to move the inner sheath proximally with respect to the expandable pusher.

27. The method of claim 22, further comprising:

contracting a self-expanding stent; and

inserting the self-expanding stent into the inner sheath.

28. The method of claim 27, wherein:

the contracting of the self-expanding stent and the inserting of the self-expanding stent into the inner sheath are performed before the inserting of the inner sheath in the outer sheath and the detaching of each of the longitudinal slits; and

the inserting of the inner sheath into the outer sheath further comprises inserting the self-expanding stent and the inner sheath into the outer sheath.

29. The method of claim 28, wherein the contracting of the self-expanding stent and the inserting of the self-expanding stent into the inner sheath are performed after the inserting of the inner sheath in the outer sheath and the detaching of each of the longitudinal slits.