Cardiovascular stent and retrieval apparatus

• US 5,643,309 A
• Filed: 01/25/1995
• Issued: 07/01/1997
• Est. Priority Date: 03/25/1993
• Status: Expired due to Fees

• Current Assignee: Hemodynamics, Inc.
• Original Assignee: Hemodynamics, Inc.
• Inventors: Myler, Richard, Hammerslag, Julius G.
• Primary Examiner(s): Buiz, Micheal
• Assistant Examiner(s): MULCARE, NANCY C
• Application Number:
  US08/378,059
• Time in Patent Office: 888 Days
• Field of Search: 606/191, 606/194-195, 606/198, 604/96, 604/104, 623/1, 623/12
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• 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 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2002/9528 for retrieval of stents
• CPC Class Codes: A61F 2210/0019 operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers

Abstract

Disclosed is a removable cardiovascular stent, an apparatus for the retrieval of the stent and a method for removal of the stent. The removable stent includes radially inwardly extending engagement members for contacting an extraction catheter. The extraction catheter includes a tubular body and an axially moveable guidewire, each adapted to grasp the engagement members of the tubular stent. The stent is elongated in an axial direction thereby reducing the cross-sectional area of the stent. The stent can be removed directly, or can fit within the tubular body of the extraction catheter for atraumatic removal from the treatment location.

Claims

1. A tubular stent for implantation within a body lumen such as by dilatation using a dilatation balloon, said stent configured to reversibly radially expand from a first insertion diameter to a second, enlarged implanted diameter, and to radially reduce from the second, enlarged diameter to a smaller, extraction diameter, upon axial elongation thereof, said stent comprising a tubular wall of lattice elements having interstitial spaces therebetween, said stent having a proximal end, a distal end and a central lumen extending axially therethrough, at least one radially inwardly extending engagement member coupled to said tubular body and distinct from the lattice wall for engaging a removal catheter, and an outer polymer jacket substantially entirely covering the radially outward most surface of the latticed, tubular body and its interstitial spaces, for minimizing adhesion between the stent and the wall of the body lumen during a period of implantation within the body lumen.

2. A tubular stent as in claim 1, wherein said engagement member is at the proximal end.

3. A tubular stent as in claim 2, wherein the diameter of the stent in the implanted configuration is smaller at the proximal end than at the central region thereof.

4. A tubular stent as in claim 2, further comprising at least one engagement member at the distal end for engaging a removal catheter.

5. A tubular stent as in claim 4, wherein said at least one engagement member comprises two or more radially inwardly extending hooks at each of the proximal and distal ends for engaging a removal catheter.

6. A tubular stent as in claim 1, wherein said jacket is provided with a plurality of pores for expressing medication to the wall of the body lumen.

7. A method of treating a preselected site in a body lumen, comprising the steps of:

positioning a reversibly expandable stent at said preselected site, said stent comprising a tubular wall having at least one proximal and one distal engagement member connected to and extending radially inwardly from the tubular wall;

radially enlarging said stent from a first, reduced diameter to a second, enlarged diameter to support said body lumen;

permitting the enlarged stent to remain at the preselected site for a sufficient body lumen treating period of time;

engaging the proximal and distal engagement members extending radially inwardly from the wall of the expanded stent;

elongating said stent by axially separating the proximal and distal engagement members to reduce the cross-sectional area of said stent from said second, enlarged diameter to an area which is less than the cross-sectional area of said body lumen at said treatment site; and

thereafter removing said stent.

8. A method as in claim 7, further comprising the step of inhibiting adhesion between the stent and the body lumen following said radially enlarging step, by first providing an outer polymer cover over the stent.

9. A removable cardiovascular stent, comprising:

a tubular body with a lattice wall having a plurality of openings between adjacent lattice elements, said tubular body having a proximal and distal end wherein said lattice enables the radial expansion and contraction of said tubular body; and

at least two radially inwardly extending engagement members coupled to and distinct from said lattice wall for engaging a removal catheter.

10. The removable cardiovascular stent of claim 9, further comprising an outer polymer layer on the stent for minimizing adhesion between the stent and the vascular wall.

11. The removable cardiovascular stent of claim 10, wherein the outer polymer layer is the radially outward most surface of an elastic polymer jacket enclosing the stent.

12. The removable cardiovascular stent of claim 10, wherein the outer polymer layer comprises an elastic polymer.

13. The removable cardiovascular stent of claim 12, wherein the polymer layer comprises latex.

14. The removable cardiovascular stent of claim 9, wherein the engagement members are spaced axially apart from one another and adapted to cooperate with the lattice structure so that axial displacement of one of said engagement members away from the other of said engagement members causes a reduction in the cross sectional area of the stent.