Radially expanding prostheses and systems for their deployment

• US 6,149,681 A
• Filed: 09/19/1997
• Issued: 11/21/2000
• Est. Priority Date: 09/20/1996
• Status: Expired due to Fees

• Current Assignee: Advanced Bypass Technologies, Inc.
• Original Assignee: Converge Medical, Inc.
• Inventors: Whayne, James G., Houser, Russell A., Fleischman, Sid D.
• Primary Examiner(s): Milano, Michael J.
• Application Number:
  US08/932,566
• Time in Patent Office: 1,159 Days
• Field of Search: 623/1, 623/11, 623/12, 623/1.12, 606/194, 606/195
• US Class Current: 623/1.12
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/2412 with soft flexible valve members, e.g. tissue valves shaped like natural valves check valves with flexible valve members in general F16K15/14
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/92 Stents in the form of a rolled-up sheet expanding after insertion into the vessel , e.g. with a spiral shape in cross-section
• CPC Class Codes: A61F 2/945 hardenable, e.g. stents formed in situ
• CPC Class Codes: A61F 2/954 for placing stents or stent-grafts in a bifurcation
• CPC Class Codes: A61F 2/962 having an outer sleeve
• 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 2002/065 Y-shaped blood vessels
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/9511 the retaining means being filaments or wires
• CPC Class Codes: A61F 2002/9528 for retrieval of stents
• CPC Class Codes: A61F 2210/0033 : electrically, e.g. heated by resistor
• CPC Class Codes: A61F 2210/0076 : multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2210/0085 : hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2220/0008 : Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2240/001 : Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0003 : having an inflatable pocket filled with fluid, e.g. liquid or gas
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2250/0067 : Means for introducing or releasing pharmaceutical products into the body

Abstract

A resilient graft construction incorporates a structural layer formed of a resilient body compatible metal or polymer, and a fluid impervious layer of graft material secured to the structural layer. The structural layer includes an elongate longitudinal primary section, and secondary sections extended transversely from opposite sides of the primary section. The secondary sections can be arranged in opposed pairs, or staggered. The secondary sections further can be tapered in width, thickness or both. The grafts can be constructed by stamping or otherwise severing structural layer patterns from a flat sheet of structural material, then thermally setting the structural layers when they are wrapped about a mandril to determine a relaxed-state curvature. Opposed longitudinal edges either can overlap one another or be spaced apart from one another in the relaxed state. According to one alternative, the structural layer alone functions as a stent. Other alternatives include circumferentially closed graft structures, one of which consists of a resilient graft material.

Claims

1. An intralumenally implantable prosthesis including:

a structural layer including a single elongate primary section extended in a longitudinal direction, the structural layer further including a plurality of secondary sections extended substantially transversally from the primary section and curved about an axis substantially parallel to the primary section, whereby the structural layer is thermally set so to conform, when in a substantially relaxed and fully deployed state, to a cylindrical shape having a predetermined radius,

wherein the secondary sections are flexible to allow a radial reduction of the structural layer to a reduced-radius delivery profile responsive to an external force, and wherein the structural layer requires a continued application of the external force to maintain the reduced-radius delivery profile and alternatively tends to return to the substantially relaxed and fully deployed state upon removal of the external force; and

a substantially continuous and compliant graft layer, supported by the structural layer, tending to conform to the shape of the structural layer, and substantially impervious to blood.

2. The prosthesis of claim 1 wherein:

each of the secondary sections converges in profile in a direction from a first end of the secondary segment adjacent the primary segment toward a second and opposite end of the secondary section.

3. The prosthesis of claim 1 wherein:

the structural layer when in the delivery profile is positionable at a treatment site along a tissue wall defining a body lumen, and radially expands into contact with the tissue wall segment upon release of the external force.

4. The prosthesis of claim 3 further including:

a heating component for heating at least a portion of the tissue near the treatment site while the support structure is in contact with the tissue wall.

5. The prosthesis of claim 4 wherein:

the heating means comprises at least one electrical heating element mounted adjacent the structural layer, and a means for providing an electrical current to the heating element to thermally bond the structural layer to the tissue wall segment.

6. The prosthesis of claim 1 wherein:

said secondary sections extend from opposite sides of the primary section, and opposed ones of the secondary sections overlap one another when the structural layer is in the relaxed state.

7. The prosthesis of claim 1 wherein:

the secondary members extend from opposite sides of the primary section, and respective ends of opposed second sections are spaced apart from one another when the structural layer is in the relaxed state.

8. The prosthesis of claim 1 additionally comprising:

an elongate and flexible delivery device having a proximal end and a distal end, intravascularly insertable by its distal end, to position the distal end at an intralumenal site while the proximal end remains outside of the body;

said delivery device including a prosthesis confining structure near the distal end of the device, for applying the external force to maintain the structural layer in the reduced-radius delivery profile; and

a control component operable from the proximal end of the device, for removing the external force to allow the structural layer to radially expand into contact with tissue at the site.

9. The system of claim 8 wherein:

the delivery device is a catheter, the confining structure includes a catheter wall defining a lumen extending at least along the distal end of the catheter and adapted to maintain the structural layer in the delivery state; and

the control component includes a means for moving the structural layer distally relative to the catheter, beyond the distal end to allow the structural layer to radially expand.

10. The system of claim 9 wherein:

the moving means includes a stylet adapted to engage a proximal end of the structural layer and either (i) move the structural layer distally while the catheter remains stationary;

or (ii) maintain the structural layer stationary while the catheter is proximately withdrawn.

11. The prosthesis of claim 1 further including:

a second substantially continuous and compliant graft layer supported by the structural layer, disposed adjacent the first graft layer and cooperating with the first graft layer to form at least one pocket containing at least one of;

a drug solution for diffusion into the tissue; and

a biocompatible foam adapted to solidify after said expansion into contact with the tissue.

12. The graft of claim 11 additionally comprising:

an elongate and flexible delivery device having a proximal end and a distal end, intravascularly insertable by its distal end, to position the distal end at an intralumenal site while the proximal end remains outside of the body;

said delivery device including first and second elongate stylets near the distal end of the device for applying the external force to maintain the structural layer in the reduced-radius delivery profile, the stylets being releasably coupled to proximal and distal ends of the structural layer, respectively;

the stylets being axially movable relative to one another so to axially elongate the structural layer and radially reduce the structural layer to the delivery profile;

the stylets additionally being axially movable to allow the structural layer to radially expand; and

a control component operable from the proximal end of the device for removing the external force to allow the structural layer to radially expand into contact with tissue at the site.

13. An intravascularly implantable graft, including:

a tubular graft body consisting essentially of an elastomer and self-supporting to have a predetermined radius when in a substantially relaxed and fully deployed state, said graft body having a continuous tubular wall substantially impervious to blood and other body fluids, said body being collapsible into a reduced-radius profile responsive to the application of an external force, and resiliently returning toward the substantially relaxed, fully deployed state upon removal of the external force.

14. The prosthesis of claim 13 wherein:

the graft body includes opposite flared end regions, each having a radius larger than the predetermined radius when the graft body is in the relaxed state.

15. An intraluminally implantable prosthesis, including:

a structural layer forming a framework curved about an axis and having a predetermined radius when in a relaxed state, adapted to undergo a radial compression to a reduced-radius delivery profile responsive to an external force, and tending to return to the relaxed state upon removal of the external force, said structural layer when in the delivery profile being positionable at a treatment site along a tissue wall defining a body lumen and adapted to radially expand into contact with the tissue wall segment upon release of the external force; and

a heating element supported by the structural layer, adapted for heating at least a portion of the tissue wall segment contiguous with the structural layer sufficiently to thermally bond the structural layer with respect to said portion of the tissue wall segment.

16. The prosthesis of claim 15 further including:

a means for providing an electrical current to the heating element to effect said heating, wherein the heating element is electrically conductive.

17. The prosthesis of claim 16 wherein:

the heating element comprises a plurality of elongate electrode strips fixed with respect to the structural layer, and disposed radially outward thereof.

18. The prosthesis of claim 16 further including:

an indifferent electrode coupled to the current source, said current source being an RF current source, wherein the indifferent electrode is positionable in spaced apart relation to the heating element.

19. The prosthesis of claim 16 further including:

a substantially continuous and compliant graft layer, supported by the structural layer, tending to conform to the shape of the structural layer, and substantially impervious to blood and other body fluids.

20. The prosthesis of claim 15 wherein:

the structural layer includes at least one elongate primary section extended in a direction parallel to the axis, and further includes a plurality of secondary sections extended substantially transversally from the at least one primary section and curved about the axis.

21. An intraluminal implantable graft including:

a compliant tubular body defining a lumen and having first and second ends;

a support structure attached to the tubular body, defining the shape of the tubular body, and having first and second support portions at the first and second ends, respectively; and

an electrode structure attached to the tubular body and having first and second electrode portions at the first and second ends, respectively.

22. The graft of claim 21 wherein:

said portions of the support structure are electrically conductive and provide said electrode portions.

23. The graft of claim 21 wherein:

the support structure is adapted to assume a delivery profile responsive to application of an external force to facilitate an intraluminal positioning thereof along a tissue wall defining a body lumen, and is radially expandable into contact with the tissue wall upon release of the external force.

24. The graft of claim 23 wherein:

the electrode structure is adapted to heat the tissue wall while the support structure is in contact therewith.

25. The graft of claim 23 wherein:

the electrode structure comprises at least one electrical heating element mounted adjacent the support structure, and a means for transmitting an electrical current to the heating element to facilitate a thermal securement of the tubular body and support structure to the tissue wall.

26. The graft of claim 21 wherein:

the tubular body includes at least two compliant graft layers supported by the support structure; and

the at least two compliant graft layers form at least one pocket adapted to contain at least one of;

a solution adapted for treatment of tissue at the treatment site;

an adhesive solution for enhancing bonding of the tubular body to tissue at the treatment site; and

a biocompatible, curable foam.

27. The graft of claim 26 wherein:

the at least two compliant graft layers have different porosities.

28. The graft of claim 27 wherein:

the at least two compliant graft layers comprise a substantially non-porous inner graft layer, and a substantially porous outer graft layer, thereby facilitating a selective diffusion of a solution contained in the at least one pocket at least primarily in the outward direction.

29. The graft of claim 26 wherein:

said at least one pocket is adapted to contain said solution for diffusion to the tissue at the treatment site, and said electrode structure includes an electrical element and means for transmitting an electrical current to the electrical element with an amplitude sufficient to cause electroporation of the tissue adjacent the electrical element.

30. The system of claim 26 wherein:

said power source is adapted to provide to the at least one electrode an electrical current of sufficient amplitude to cause electroporation of the tissue adjacent the at least one electrode.

31. A system for securing an implantable graft to a vessel, including:

a compliant graft;

at least one support structure attached to and supporting the graft;

at least one electrode attached to the graft adjacent the at least one support structure;

at least one electrical conductor;

a power source for providing an electrical current to the at least one electrode via the conductor sufficient to heat tissue adjacent the at least one electrode to thermally secure the graft and support structure with respect to said tissue; and

an electrical coupling of the conductor with the at least one electrode, adapted to facilitate a separation of the conductor from the at least one electrode after the graft and support structure have been so secured.

32. The system of claim 31 wherein:

the support structure comprises the electrode structure.

33. The system of claim 31 wherein:

the support structure is adapted to assume a delivery profile to facilitate deployment of the support structure and graft to a treatment site along a tissue wall defining a body lumen, and further is radially expandable into contact with the tissue wall.

34. The system of claim 31 further including:

an indifferent electrode electrically coupled to the power source and positionable in spaced-apart relation to the at least one electrode, wherein the power source comprises an RF generator.

35. The system of claim 31 wherein:

said electrical coupling of the conductor and the at least one electrode comprises a constriction adapted to undergo a breakdown when subjected to current of a predetermined amplitude, thereby to sever the conductor from the electrode.

36. The system of claim 31 wherein:

the graft includes at least two compliant graft layers supported by the support structure and cooperating to form at least one pocket adapted to contain at least one of;

a solution adapted for diffusion from the pocket to adjacent tissue to treat the adjacent tissue;

an adhesive solution to promote a bonding of the graft to the tissue; and

a biocompatible, curable foam.

37. An intralumenally implantable prosthesis including:

a structural layer including a single elongate primary section extended in a longitudinal direction, the structural layer further including a plurality of secondary sections extended substantially transversely from the primary section, the structural layer being thermally set so that when in a relaxed state the plurality of secondary sections are curved about an axis substantially parallel to the primary section to impart a substantially cylindrical shape to the structural layer;

wherein the structural layer self-expands from a reduced-radius delivery profile to an enlarged-radius deployment profile upon removal of an external force,

wherein each of the secondary sections converges in profile in a direction from a first end of the secondary segment adjacent the primary segment toward a second and opposite end of the secondary section; and

a substantially continuous and compliant graft layer, supported by the structural layer, tending to conform to the shape of the structural layer, and substantially impervious to blood.

38. The prosthesis of claim 37 wherein:

said structural layer is formed of a memory elastic material.

39. An intraluminal implantable graft including:

a self-supporting structural layer;

a first substantially continuous and compliant graft layer supported by the structural layer and tending to conform to the shape of the structural layer; and

a second substantially continuous and compliant graft layer, supported by the structural layer, tending to conform to the shape of the structural layer, and cooperating with the first graft layer to form a pocket containing at least one constituent selected from the group of constituents consisting of;

a solution adapted for treatment of tissue at a treatment site within a body lumen;

an adhesive solution for enhancing bonding of at least one of the graft layers to tissue at the treatment site; and

a biocompatible, curable foam.

40. The graft of claim 39 wherein:

one of said first and second graft layers is more porous than the other.

41. The graft of claim 39 further including:

at least one electrode attached to at least one of the first and second graft layers, and an electrical conductor electrically coupled to the at least one electrode.

42. The graft of claim 39 wherein:

the support layer is elastically deformable into a reduced-radius delivery profile responsive to application of an external force, and tends to radially enlarge upon removal of the external force.