Stent-graft with bioabsorbable structural support

• US 6,626,939 B1
• Filed: 12/18/1997
• Issued: 09/30/2003
• Est. Priority Date: 12/18/1997
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Burnside, Diane K., Chouinard, Paul F., Stinson, Jonathan S.
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US08/993,985
• Time in Patent Office: 2,112 Days
• Field of Search: 623/1, 623/12, 623/1.38, 623/1.5, 623/1.51, 623/1.53, 606/194, 606/192
• US Class Current: 623/1.38
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/885 comprising a coil including a plurality of spiral or helical sections with alternate directions around a central axis
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2/9661 the proximal portion of the stent or stent-graft is released first
• 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 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2250/0068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61L 31/042 Polysaccharides
• CPC Class Codes: A61L 31/044 Collagen
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/148 Materials at least partially resorbable by the body
• CPC Class Codes: C08L 1/02 Cellulose; Modified cellulose
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: C08L 67/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C08L67/06 takes precedence
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: C08L 75/00 Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 77/00 : Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 85/02 : containing phosphorus
• CPC Class Codes: D04C 1/06 : Braid or lace serving particular purposes

Abstract

The invention relates to a stent-graft with a bioabsorbable structure and a permanent graft for luminal support and treatment of arterial fistulas, occlusive disease, and aneurysms. The bioabsorbable structure is formed from braided filaments of materials such as PLA, PLLA, PDLA, and PGA and the graft is formed from materials such as PET, ePTFE, PCU or PU.

Claims

1. A stent-graft comprising:

a tubular annealed structure formed of a plurality of filaments, each filament comprising bioabsorbable material and having an average diameter in the range of about 0.15 mm to about 0.6 mm;

wherein said filaments include a first set of the filaments wound helically about an axis of the tubular structure and having a first common direction of winding, and a second set of the filaments wound helically about the axis and having a second common direction of winding, whereby the filaments of the second set cross the filaments of the first set at an axially directed angle; and

wherein the filaments have tensile strengths and tensile moduli whereby the tubular structure is radially compressible and radially self-expandable; and

a compliant graft cooperating with at least a portion of the tubular structure to form a stent-graft adapted to be disposed in a body lumen.

2. The stent-graft of claim 1 wherein:

the first and second sets of filaments are adapted to cooperate to provide an initial radial force to a vessel wall when the stent-graft is implanted in the body lumen and further are adapted to bioabsorb over time in-vivo to cause a decrease in the radial force to the vessel wall, and the graft is adapted to remain in the body lumen.

3. The stent-graft of claim 1 wherein:

said graft is permanent.

4. The stent-graft of claim 1 wherein:

said graft is compliant and tends to conform to the tubular structure as the tubular structure radially expands and contracts.

5. The stent-graft of claim 1 wherein each of the first and second sets of filaments ranges from about 5 filaments to about 18 filaments.

6. The stent-graft of claim 1 wherein each of the first and second sets of filaments ranges from about 5 filaments to about 18 filaments.

7. The stent-graft of claim 1 wherein the axially directed angle when in a free radially expanded state after being annealed but before being loaded on a delivery device is between about 120 degrees and about 150 degrees.

8. The stent-graft of claim 1 wherein:

the stent-graft is adjustable between a nominal state and a radially-reduced state.

9. The stent-graft of claim 1 wherein:

the structure is formed in a generally elongated shape, and is radially compressible and self-expandable.

10. The stent-graft of claim 1 further including:

an adhesive for bonding the bioabsorbable structure and the graft.

11. The stent-graft of claim 1 wherein:

the filaments are made of a bioabsorbable material selected from the group consisting of;

poly (alpha-hydroxy acid), PGA, PLA, PLLA, PDLA, polycaprolactone, polydioxanone, polygluconate, polylactic acid-polyethylene oxide copolymers, modified cellulose, collagen, poly (hydroxybutyrate), polyanhydride, polyphosphoester, poly (amino acids), and combinations thereof, and the graft is made of a polymer selected from the group consisting of;

PET, ePTFE, PCU, and PU.

12. The stent-graft of claim 1 wherein:

the filaments are substantially uniform in cross-section and in length.

13. The stent-graft of claim 1 wherein:

the graft comprises a plurality of interwoven components selected from the group of components consisting of;

fibers, mono-filaments, multi-filaments, and yarns.

14. The stent-graft of claim 1 wherein:

the graft is one of the structures selected from the group of structures consisting of;

a film, a sheet, and a tube.

15. The stent-graft of claim 1 wherein:

the graft is adapted to form a composite wall with body tissue in the body lumen.

16. The stent-graft of claim 1,wherein:

the stent-graft is adapted to be permeated with body tissue.

17. The stent-graft of claim 1 wherein:

the stent-graft provides structural support to a body lumen for less than about three years.

18. The stent-graft of claim 1 wherein:

the graft is disposed on at least one of the inside and outside surfaces of the structure.

19. The stent-graft of claim 1 wherein:

the graft and the filaments are interbraided.

20. The stent-graft of claim 1 further comprising:

at least one radiopaque marker for facilitating a visualization of the structure.

21. The stent-graft of claim 1 wherein:

the graft defines a first braid angle and the structure defines a second braid angle, wherein the difference between the first braid angle and the second braid angle is less than about five degrees.

22. The stent-graft of claim 1 wherein:

the structure and the graft cooperate to provide a common longitudinal length over which the structure and graft are bonded together.

23. The stent-graft of claim 1 wherein:

each of the filaments has a substantially solid and substantially uniform cross-section.

24. The stent-graft of claim 1 wherein:

each filament has a tensile strength of from about 276 MPa (40 ksi) to about 827 MPa (120 ksi), and a tensile modulus from about 2758 MPa (400,000 psi) to about 13790 MPa (2,000,000 psi).

25. The stent-graft of claim 1 wherein:

each filament has a tensile strength of from about 103 MPa (15 ksi) to about 827 MPa (120 ksi), and a tensile modulus from about 1379 MPa (200,000 psi) to about 13790 MPa (2,000,000 psi).

26. The stent-graft of claim 25 wherein:

the graft layer is disposed on an inside surface of the structural layer.

27. The stent-graft of claim 25 wherein:

the structural layer and the graft layer are;

bonded together.

28. The stent-graft of claim 25 wherein:

the structural layer is comprised of a plurality of structural filaments braided together.

29. The stent-graft of claim 28 wherein:

the graft layer is comprised of a plurality of graft filaments, and the graft filaments and the structural filaments are interbraided.

30. The stent-graft of claim 25 wherein:

the graft layer is adapted to form a composite wall with body tissue at the treatment site.

31. The stent-graft of claim 25 wherein:

the graft layer is disposed on an outside surface of the structural layer.