METHOD OF LOADING A STENT INTO A SHEATH

• US 20110060397A1
• Filed: 05/08/2009
• Published: 03/10/2011
• Est. Priority Date: 05/09/2008
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Dorn, Jürgen
• Granted Patent: US 9,687,370 B2
• 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 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• CPC Class Codes: A61F 2/97 the outer sleeve being splittable

Abstract

There is disclosed herein a method of loading a self-expanding stent (10) into a delivery sheath (12) that is by itself strong enough to preserve the stent in a radially compressed pre-deployment configuration, comprising the steps of: (i) compressing the stent (10) to a relatively small diameter; (ii) providing a loading sheath (18) with an inner diameter d1; (iii) with the stent (10) exhibiting an outside diameter of d2, where d2<d1, providing relative translational movement between the stent (10) and the loading sheath (18), whereby the stent is accommodated within the lumen of the loading sheath (18); (iv) advancing the loading sheath (18), containing the stent (10), into the lumen (16) of the delivery sheath (12); and {v} deploying the stent into the lumen (16) of the delivery sheath (12), by withdrawing the loading sheath (18) while restraining the stent (10) from axial movement out of the lumen (16) of the delivery sheath (12).

Claims

1. A method of loading a self-expanding stent into a delivery sheath that is by itself strong enough to preserve the stent in a radially compressed pre-deployment configuration, comprising the steps of:

i) compressing the stent to a relatively small diameter;

ii) providing a loading sheath with an inner diameter d1;

iii) with the stent exhibiting an outside diameter of d2, where d2<

d1, providing relative translational movement between the stent and the loading sheath, whereby the stent is accommodated within the lumen of the loading sheath;

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

v) deploying the stent into the lumen of the delivery sheath, by withdrawing the loading sheath while restraining the stent from axial movement out of the lumen of the delivery sheath.

2. 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 d3 which is less than d1.

3. Method according to claim 1, in which 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 the radial expansion of the stent that occurs as the stent deploys into a bodily lumen.

4. Method according to claim 1, wherein the sheath is of PET.

5. Method according to claim 2, wherein the sheath prior to said strain has a wall thickness of the order of 30 μ

m.

6. Method according to claim 2, wherein the sheath exhibits a strain initiation zone from which the strain spreads out, progressively along the length of the sheath.

7. Method according to claim 6, including the step of positioning the strain initiation zone between the opposing ends of the stent.

8. Method according to claim 7, wherein the strain initiation zone is located mid-way between the stent ends.

9. Method according to claim 6, wherein the strain initiation zone comprises a portion of the sheath that exhibits a reduced wall thickness.

10. Method according to claim 1, in which a tool is used to advance the stent into the sheath, which tool has a portion that extends along at least a part of the length of the lumen of the stent.

11. Method according to claim 10, in which said tool is removed from the stent, before the step of drawing down the sheath is completed.

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

13. 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.

14. Method according to claim 2, wherein 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.

15. Method according to claim 14, wherein at least one of the sheath grippers grips the sheath all around the circumference of the sheath.

16. Method according to claim 15, 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.

17. 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).