Sheaths Used With Polymer Scaffold

• US 20120324696A1
• Filed: 06/21/2011
• Published: 12/27/2012
• Est. Priority Date: 06/21/2011
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Liu, Annie P., Phillips, Jason, Johnson, Mark C., Yribarren, Travis, Speck, Marc L., Lord, Brenna Hearn, Beer, Jeremy, Saville, Steve
• Granted Patent: US 8,852,257 B2
• Time in Patent Office: Days
• US Class Current: 29/428
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2/97 the outer sleeve being splittable
• 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: A61M 2025/1081 having sheaths or the like for covering the balloon but not forming a permanent part of the balloon, e.g. retractable, dissolvable or tearable sheaths
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: Y10T 29/49826 Assembling or joining
• CPC Class Codes: Y10T 29/49863 with prestressing of part

Abstract

A medical device includes a polymer scaffold crimped to a catheter having an expansion balloon. A sheath pair is placed over the crimped scaffold after crimping to reduce recoil of the crimped polymer scaffold and maintain scaffold-balloon engagement relied on to hold the scaffold to the balloon when the scaffold is being delivered to a target in a body. The sheath pair is removed by a health professional before placing the scaffold within the body.

Claims

1. A method for assembling a scaffold-balloon catheter, comprising:

providing a balloon-catheter having a scaffold crimped to the balloon; and

constraining the crimped scaffold including placing the crimped scaffold within a protecting portion, and then placing the scaffold and protecting portion within a constraining portion, wherein the protecting portion and constraining portion are integral portions of a sheath;

wherein the scaffold is configured for being passed through the body of a patient only after the sheath is removed from the crimped scaffold.

2. The method of claim 1, wherein the protecting portion includes a first and second half, each disposed between the crimped scaffold and the constraining portion, and extending parallel to each other and a substantial portion of the length of the scaffold, and the first half is connected to the constraining portion and the second half is not connected to the constraining portion.

3. The method of claim 2, wherein the first half includes a hinge, and wherein the placing the scaffold and protecting portion within the constraining portion includes articulating the constraining portion about the hinge and placing the articulated constraining portion over the protecting portion and crimped scaffold.

4. The method of claim 1, wherein the protecting portion includes braided wires.

5. An apparatus, comprising:

a catheter assembly having a distal end and including a scaffold comprising a polymer crimped to a balloon;

a sheath disposed over the scaffold, the sheath applying a radial inward force on the crimped scaffold to limit recoil of the scaffold, the sheath comprising

a protecting portion having a distal end,

a constraining portion disposed over the protecting portion, and

a connector portion connecting the protecting portion and constraining portion;

wherein the apparatus is configured for being passed through the body of a patient only after the sheath is removed.

6. The apparatus of claim 5, wherein the protecting portion and constraining portion comprise a unitary piece of flexible polymer material, and wherein the connector portion is deformed into, or shaped as a loop having one end at the constraining portion and the other end at the protecting portion such that the distal end of the protecting portion may be received within a proximal end of the constraining portion.

7. The apparatus of claim 5, wherein an extension of the constraining portion is disposed distally of the catheter distal end and the protecting portion distal end.

8. The apparatus of claim 7, wherein the constraining and protecting portions are configured so that the sheath is capable of being removed from the scaffold by the following steps:

pulling the extension distally to withdraw only the constraining portion from the scaffold and protecting portion,

after the constraining portion has been displaced distally, continuing to pull the constraining portion distally to place the connector portion in tension and thereby cause the connector portion to withdraw the protecting portion from the scaffold.

9. The apparatus of claim 5, wherein the protecting portion includes a first and second portion disposed over at least a substantial portion of the scaffold, the first and second portions configured for deflecting radially away from the scaffold when the constraining portion is removed from the scaffold.

10. The apparatus of claim 9, wherein the first portion is connected to a proximal end of the constraining portion.

11. The apparatus of claim 5, wherein the protecting portion includes braided wires.

12. The apparatus of claim 5, wherein an inner surface of the constraining portion and/or an outer surface of the protecting portion in contact with the inner surface includes ridges, rings, or nubs, or is roughened to reduce frictional resistance to sliding motion.

13. The apparatus of claim 12, wherein the constraining portion includes embedded wires for forming the ridges or rings over the inner surface.

14. A method for assembling a scaffold-balloon catheter, comprising:

providing a balloon-catheter having a scaffold crimped to the balloon; and

constraining the crimped scaffold using a two-piece sheath, including placing the crimped scaffold within a protecting portion of the sheath, then placing a constraining portion of the sheath over the protecting portion;

wherein the scaffold is configured for being passed through the body of a patient only after the constraining portion and protecting portion are removed from the crimped scaffold.

15. The method of claim 14, wherein the protecting portion can be configured between a closed and open portion, the constraining step including

placing the crimped scaffold within the protecting portion configured in the open position, and

sliding the constraining portion over the protecting portion to configure the protecting portion from the open to the closed position to thereby constrain the crimped scaffold.

16. The method of claim 15, wherein the two-piece sheath further includes a handling portion connected to the protecting portion, wherein the constraining portion is slid between the handling portion and the protecting portion to configure the protecting portion from the open to the closed position.

17. The method of claim 14, wherein the protecting portion includes half-cylinders spring biased to form the open position and the constraining portion is a cylindrical body of flexible material including a space formed through a center of the body for receiving the half-cylinders, such that when the half-cylinders are received within the space the body applies a compressive radial force bringing the half-cylinders together to form the closed position, which surrounds the crimped scaffold.

18. The method of claim 14, wherein the constraining step includes heat shrinking the constraining portion over the protecting portion.

19. An apparatus, comprising:

a catheter assembly having a distal end and including a scaffold comprising a polymer crimped to a balloon;

a two-piece sheath disposed over the scaffold, the sheath applying a radial inward force on the crimped scaffold to limit recoil of the scaffold, the sheath comprising

a protecting portion, and

a constraining portion disposed over the protecting portion;

wherein the apparatus is configured for being passed through the body of a patient only after the two-piece sheath is removed.

20. The apparatus of claim 19, wherein the protecting portion further includes half cylinders spring biased to form an open position, and the constraining portion is a cylindrical volume surrounding and applying a radial inward force on the half cylinders so that the half cylinders apply a radial inward force on the crimped scaffold.

21. The apparatus of claim 20, wherein the two-piece sheath further includes a handling portion connected to the protecting portion by a link, wherein the handling portion surrounds the constraining portion.

22. The apparatus of claim 21, wherein the two-piece sheath is configured so that the two-piece can be removed from the scaffold by the following steps:

the constraining portion, disposed between the handling portion and protecting portion, is removed to cause the half cylinders to form the open portion, and

removing the protecting portion from the scaffold using the handling portion.

23. The apparatus of claim 19, wherein the protecting portion consists of two unattached longitudinal tabs having a proximal end disposed proximal of the scaffold and configured for removing the constraining portion by pulling the tabs radially outward to thereby cause the constraining portion to be pushed off of a distal end of the scaffold.

24. The apparatus of claim 19, wherein an inner surface of the constraining portion in contact with an outer surface of the protecting portion includes at least one of ridges, rings, or nubs formed over the inner surface, or the inner surface is roughened to reduce frictional resistance to sliding motion of the constraining sheath over the protecting portion.