METHOD OF LOADING A STENT INTO A SHEATH

• US 20100049297A1
• Filed: 08/21/2009
• Published: 02/25/2010
• Est. Priority Date: 08/21/2008
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Dorn, Juergen
• Granted Patent: US 9,833,349 B2
• Time in Patent Office: Days
• US Class Current: 623/1.110
• CPC Class Codes: A61F 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• 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 2/97 the outer sleeve being splittable
• CPC Class Codes: A61F 2002/9511 the retaining means being filaments or wires
• CPC Class Codes: A61P 35/00 Antineoplastic agents

Abstract

A method of loading a self-expanding stent into a delivery sheath configured to retain the stent in a radially compressed pre-deployment configuration, including the steps of radially compressing the stent from a relaxed outside diameter d0 to a compressed outside diameter d1, providing a loading sheath with an inner diameter d2, where d0>d2>d1, translating the stent relative to the sheath, whereby the stent is accommodated within the lumen of the loading sheath, providing a delivery sheath with an inner diameter d3, where d0>d3>d2, advancing the loading sheath, containing the stent, into the lumen of the delivery sheath, and deploying the stent into the lumen of the delivery sheath.

Claims

1. A method of loading a self-expanding stent into a delivery sheath configured to retain the stent in a radially compressed pre-deployment configuration, comprising the steps of:

i) radially compressing the stent from a relaxed outside diameter d0 to a compressed outside diameter d1;

ii) providing a loading sheath with an inner diameter d2, where d0>

d2>

d1;

iii) translating the stent relative to the sheath, whereby the stent is accommodated within the lumen of the loading sheath;

iv) providing a delivery sheath with an inner diameter d3, where d0>

d3>

d2;

v) advancing the loading sheath, containing the stent, into the lumen of the delivery sheath; and

vi) deploying the stent into the lumen of the delivery sheath.

2. The method according to claim 1, wherein the step of deploying the stent into the lumen of the delivery sheath is effected by withdrawing the loading sheath while restraining the stent from relative axial movement out of the lumen of the delivery sheath.

3. The method according to claim 1, further comprising the step of, with the stent within the lumen of the delivery sheath, imposing lengthwise strain on the sheath, to draw down the inner diameter of the delivery sheath to a diameter d4 which is less than d3.

4. The method according to claim 1, wherein the delivery sheath is one which can be parted along a line extending axially the full length of the stent to allow the stent to push the material of the longitudinally parted sheath out of the way during radial expansion of the stent that occurs as the stent deploys into a bodily lumen.

5. The method according to claim 1, wherein the sheath is made of PET.

6. The method according to claim 1, wherein the sheath prior to said strain has a wall thickness of approximately 20 μ

m.

7. The method according to claim 1, wherein the sheath exhibits a strain initiation zone from which the strain spreads out, progressively along the length of the sheath.

8. The method according to claim 7, including the step of positioning the strain initiation zone between the opposing ends of the stent.

9. The method according to claim 8, wherein the strain initiation zone is located mid-way between the stent ends.

10. The method according to claim 7, wherein the strain initiation zone comprises a portion of the sheath that exhibits a reduced wall thickness.

11. The method according to claim 1, wherein a tool is used to advance the stent into the sheath, the tool having a portion that extends along at least a part of the length of the lumen of the stent.

12. The method according to claim 11, wherein the tool is removed from the stent before the step of drawing down the sheath is completed.

13. The method according to claim 1, including a step of introducing into the lumen of the stent a component of a catheter delivery system for said stent before the step of drawing down the sheath is completed.

14. The method according to claim 1, including a step of providing within the lumen of the sheath, prior to drawing down said sheath onto the stent, a splitter that lies between the stent and the drawn down sheath, which splitter is capable when actuated of splitting the sheath to permit the stent to deploy.

15. The method according to claim 1, in which a tool is used to impose the strain on the sheath, the tool comprising first and second sheath grippers, one to grip each opposite end of the sheath, beyond the respective end of the stent inside the sheath.

16. The method according to claim 15, wherein at least one of the sheath grippers grips the sheath all around the circumference of the sheath.

17. The method according to claim 16, in which at least one of the grippers exhibits a high friction grip surface to contact the sheath, which grip surface is of a silicone rubber material.

18. The method according to claim 1, in which the sheath drawn down over the stent exhibits an outside diameter of not more than 6 French (2 mm).