Cardiovascular stent and retrieval apparatus

• US 5,474,563 A
• Filed: 02/25/1994
• Issued: 12/12/1995
• Est. Priority Date: 03/25/1993
• Status: Expired due to Fees

• Current Assignee: Hemodynamics, Inc.
• Original Assignee: Julius G. Hammerslag, Richard Myler
• Inventors: Hammerslag, Julius G., Myler, Richard
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): MULCARE, NANCY C
• Application Number:
  US08/201,632
• Time in Patent Office: 655 Days
• Field of Search: 606/108, 606/191, 606/194, 606/195, 606/198, 604/96, 604/104, 623/1
• US Class Current: 606/108
• 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 2220/005 using adhesives
• 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 retrievable elastomeric stent, an apparatus for the insertion/retrieval of the stent and a method for insertion/retrieving the stent. The removable stent includes at least one proximal and at least one distal engagement element to allow the insertion/retrieval catheter to engage the stent for the application of axial force. The insertion/retrieval catheter includes a tubular body and an axially moveable guidewire, each adapted to engage the engagement elements of the tubular stent. When elongated in an axial direction, the stent is reduced in cross-sectional area. The stent can then be removed directly, or can fit within the tubular body of the extraction catheter for atraumatic removal from the treatment location. Further disclosed are configurations of the engagement elements to allow more precise manipulation of body lumen stents.

Claims

1. A tubular stent for implantation within a body lumen, said stent configured to reversibly radially self-expand from a first insertion diameter to a second, enlarged vessel-supporting implanted diameter, and to radially reduce from the second, enlarged vessel-supporting diameter to a smaller, retrieval diameter upon axial elongation thereof, said stem comprising a unitary tube formed of an elastomeric material and having a proximal end, a distal end and a central lumen extending axially therethrough, and at least a first engagement element near the proximal end and at least a second engagement element near the distal end, said engagement elements adapted to engage a catheter for manipulating the stent.

2. A tubular stent as in claim 1, wherein said elastomeric material comprises latex.

3. A tubular stent as in claim 1, wherein said first engagement element comprises an aperture extending through at least a portion of the wall of the stent.

4. A tubular stent as in claim 1, comprising at least three first engagement elements and at least three second engagement elements.

5. A tubular stent as in claim 1, wherein at least one of said engagement elements comprises an aperture through the wall of the stent, said aperture having a noncircular configuration with the long axis extending generally parallel to the longitudinal axis of the stent.

6. A tubular stent as in claim 5, wherein said stent further comprises a reinforcing means surrounding the aperture for minimizing the risk of tearing the wall of the stent when the aperture is engaged by a catheter.

7. A tubular stent as in claim 6, wherein said reinforcing means comprises a generally grommet shaped element having a first end on the radially inwardly directed surface of the stent and a second end on the radially outwardly facing wall of the stent.

8. A tubular stent as in claim 7, wherein said reinforcing means further comprises a first flange on the first end thereof extending generally along the interior surface of the tubular stent, and a second flange on the second end thereof extending generally along the exterior surface of the tubular stent.

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

selecting a site to be treated in a body lumen;

providing an elastomeric unitary tubular body, having a proximal end, a distal end, and central lumen extending therethrough;

axially elongating the tubular body to reduce its diameter from a first, native vessel-supporting diameter to a second, reduced diameter;

positioning the tubular body at said preselected site; and

permitting the first end and second end to move axially towards each other under resilient forces stored in said elastomeric unitary tubular body, thereby permitting the tubular body to self-expand its diameter from the second, reduced diameter towards the first, native vessel-supporting diameter at said preselected site.

10. A method of removing an elastomeric tubular stent from an installation site in a body lumen, comprising the steps of:

identifying an elastomeric tubular stent positioned within a body lumen, said stent having a proximal and a distal end, wherein said stent comprises at least a first aperture near the proximal end and at least a second aperture near the distal end, wherein each of said apertures is reinforced by a grommet shaped element having a first end on the radially inward directed surface of the stent and a second end on the radially outward facing wall of the stent;

positioning a stent retrieval catheter within said tubular stent, such that engagement means on the distal end of the retrieval catheter are aligned with the apertures on the stent;

engaging the tubular stent with the catheter;

manipulating the catheter to cause an axial elongation of said stent, thereby reducing the radial diameter of the stent;

maintaining an axial elongation force on the stent sufficient to overcome the radially enlarging bias imparted by the elastomeric material of the stent; and

removing said catheter and said stent from the body lumen.

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

positioning a self-expanding axially elongated unitary tubular stent at the preselected site;

allowing the axially elongated stent to contract axially, thereby permitting the stent to self-expand radially from a first, reduced cross-sectional area to a second, enlarged vessel-supporting native cross-sectional area;

permitting the enlarged stent to remain at the preselected site for a sufficient treatment period;

axially elongating the stent to overcome the self expanding radial outward bias and to reduce the cross-sectional area of the stent from the second, enlarged vessel-supporting native cross-sectional area to an area which is less then the cross-sectional area of the body lumen at the treatment site; and

thereafter removing the stent.

12. A self-expanding tubular stent for implantation within a body lumen, 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, retrieval diameter upon axial elongation thereof, said stent comprising a tubular elastomeric material and having a proximal end, a distal end and a central lumen extending axially therethrough, and at least a first engagement element near the proximal end and at least a second engagement element near the distal end, said engagement elements adapted to engage a catheter for manipulating the stent where at least one of said engagement elements comprises an aperture through the wall of the stent, said aperture having a noncircular configuration with the long axis extending generally parallel to the longitudinal axis of the stent, and where said aperture is surrounded by reinforcing means for minimizing the risk of tearing the wall of the stent when the aperture is engaged by a catheter, and where said reinforcing means comprise a generally grommet shaped element having a first end on the radially inwardly directed surface of the stent and a second end on the radially outwardly facing wall of the stent, and a first flange on the first end thereof extending generally along the interior surface of the tubular stent, and a second flange on the second end thereof extending generally along the exterior surface of the tubular stent.