Custom-length self-expanding stent delivery systems with stent bumpers

• US 20050288763A1
• Filed: 09/17/2004
• Published: 12/29/2005
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: JW Medical Systems Ltd
• Original Assignee: XTENT, Inc.
• Inventors: Andreas, Bernard, Grainger, Jeffry J.
• Granted Patent: US 7,300,456 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 2/958 Inflatable balloons for placing 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
• CPC Class Codes: A61F 2/97 the outer sleeve being splittable
• CPC Class Codes: A61F 2002/826 more than one stent being applied sequentially
• CPC Class Codes: A61F 2002/9505 having retaining means other than an outer sleeve, e.g. male-female connector between stent and instrument
• CPC Class Codes: A61F 2002/9511 the retaining means being filaments or wires
• CPC Class Codes: A61F 2002/9583 Means for holding the stent on the balloon, e.g. using protrusions, adhesives or an outer sleeve
• CPC Class Codes: A61F 2002/9665 with additional retaining means

Abstract

Custom-length self-expanding stent delivery systems and methods enable precise control of prosthesis position during deployment. The stent delivery systems carry multiple stent segments and include a stent bumper for helping control the axial position of the stent segments during deployment. This enables the deployment of multiple prostheses at a target site with precision and predictability, preventing stent segment recoil and ejection from the delivery device and thus eliminating excessive spacing or overlap between prostheses. In particular embodiments, the prostheses of the invention are deployed in stenotic lesions in coronary or peripheral arteries or in other vascular locations.

Claims

1. A catheter system for delivery of a stent to a body lumen comprising:

a stent delivery catheter comprising;

a sheath having a first lumen;

a shaft extending through the first lumen and slidable relative to the sheath;

a stent bumper mounted to the shaft distally of the sheath and movable from a contracted shape to an expanded shape; and

a plurality of self-expanding stent segments carried within the first lumen in a collapsed configuration, the stent segments being adapted to resiliently expand from the collapsed configuration to an expanded configuration,

wherein the stent segments are deployable from the first lumen so as to expand into the expanded configuration, the stent bumper being configured to engage a first stent segment during deployment thereof to maintain its position relative to an adjacent stent segment disposed proximal to the first stent segment.

2. A system as in claim 1, wherein the stent bumper in the expanded shape has an outer diameter sized to contact an inner wall of the body lumen.

3. A system as in claim 1, wherein at least a portion of the stent bumper includes a lubricious surface for contacting one or more of the stent segments.

4. A system as in claim 1, wherein the stent bumper comprises an inflatable balloon.

5. A system as in claim 4, wherein the catheter further includes an inflation lumen in the shaft in fluid communication with the inflatable balloon.

6. A system as in claim 4, wherein the balloon is adapted to be deflated, positioned within the deployed first stent segment, and re-inflated to the expanded shape.

7. A system as in claim 6, wherein the balloon in the expanded shape is adapted to further expand the deployed first stent segment.

8. A system as in claim 4, wherein the balloon comprises an elongate balloon having an axial length at least as long as two stent segments.

9. A system as in claim 8, further comprising an inner sheath disposed over the balloon, wherein the inner sheath is retractable to expose a portion of the balloon to allow it to be inflated from the contracted shape to the expanded shape.

10. A system as in claim 9, wherein the balloon is adapted to be expanded within one or more deployed stent segments to further expand the segments.

11. A system as in claim 8, wherein the axial length of the elongate balloon is between 20 mm and 250 mm.

12. A system as in claim 1, wherein the stent bumper is selected from the group consisting of an expandable basket, a plurality of expandable blades, rods or petals, an expandable disk and a proximal portion of a nosecone at the distal end of the shaft.

13. A system as in claim 1, wherein the stent segments are made of a material selected from the group consisting of Nitinol, other superelastic alloys, stainless steel, cobalt chromium, other resilient metals and polymers.

14. A system as in claim 1, wherein each of the stent segments has a length of between 3 mm and 30 mm.

15. A system as in claim 1, wherein the plurality of stent segments comprises between 2 and 50 segments.

16. A system as in claim 1, further comprising a pusher slidably disposed over the shaft, proximal to the stent segments, for advancing the stent segments relative to the sheath or holding the stent segments in place while the sheath is retracted.

17. A method of delivering a stent toga body lumen comprising:

positioning a stent delivery catheter in the body lumen, the delivery catheter carrying at least first and second stent segments;

expanding a stent bumper on the delivery catheter;

releasing the first stent segment from the delivery catheter into the body lumen proximal to the stent bumper, the first stent segment self-expanding into an expanded configuration in the body lumen, wherein the stent bumper engages the first stent segment during expansion thereof to maintain its position relative to the delivery catheter; and

releasing the second stent segment from the delivery catheter into the body lumen adjacent to the first stent segment.

18. A method as in claim 17, wherein expanding the stent bumper comprises inflating a balloon.

19. A method as in claim 18, further comprising, before releasing the second stent segment:

deflating the balloon;

positioning the deflated balloon within the expanded first stent segment; and

inflating the balloon, wherein the balloon engages the second stent segment during expansion thereof to maintain its position relative to the delivery catheter and the first segment.

20. A method as in claim 19, wherein inflating the balloon within the first segment further expands the first segment.

21. A method as in claim 19, further comprising:

deflating the balloon;

positioning the deflated balloon within the expanded second stent segment; and

inflating the balloon, wherein the balloon engages a third stent segment during expansion thereof to maintain its position relative to the delivery catheter and the first and second segments.

22. A method as in claim 18, further comprising, before expanding the balloon, exposing a portion of the balloon from the distal end of an inner sheath disposed over the balloon.

23. A method as in claim 18, further comprising, before releasing the second stent segment:

exposing an additional portion of the balloon from the distal end of the inner sheath, the additional portion disposed within the expanded first stent segment; and

inflating the balloon, wherein the balloon engages the second stent segment during expansion thereof to maintain its position relative to the delivery catheter and the first segment.

24. A method as in claim 23, wherein inflating the additional portion of the balloon further expands the expanded first stent segment.

25. A method as in claim 17, wherein expanding the stent bumper comprises expanding a basket of resilient polymer or metal mesh.

26. A method as in claim 17, wherein expanding the stent bumper comprises releasing one or more shape-memory members from constraint.

27. A method as in claim 25, wherein the shape-memory member(s) are selected from the group consisting of blades, rods, petals and rings.

28. A method as in claim 17, wherein releasing each stent segment comprises:

maintaining an axial position of the stent segments relative to the delivery catheter using a pusher member of the catheter; and

retracting an outer sheath disposed over the stent segments.

29. A method as in claim 17, wherein releasing each stent segment comprises:

maintaining an axial position of an outer sheath disposed over the stent segments relative to the delivery catheter; and

advancing the stent segments out of a distal end of the sheath using a pusher member of the catheter.