Porous synthetic vascular grafts with oriented ingrowth channels

• US 20020169499A1
• Filed: 07/02/2002
• Published: 11/14/2002
• Est. Priority Date: 11/23/1998
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zilla, Peter Paul, Bezuidenhout, Deon
• Granted Patent: US 7,033,388 B2
• Time in Patent Office: Days
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2250/0031 made from both resorbable and non-resorbable prosthetic parts, e.g. adjacent parts
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/32 with annular openings, e.g. for forming tubular articles
• CPC Class Codes: B29C 53/587 having a non-uniform wall-structure, e.g. with inserts, perforations, locally concentrated reinforcements
• CPC Class Codes: B29C 53/665 Coordinating the movements of the winding feed member and the mandrel
• CPC Class Codes: B29K 2075/00 Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/045 with open cells
• CPC Class Codes: B29K 2105/06 containing reinforcements, fillers or inserts
• CPC Class Codes: B29K 2105/101 Oriented
• CPC Class Codes: B29L 2031/7534 Cardiovascular protheses
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A vascular prosthesis is constructed from a structure having interconnected, helically oriented channel-porosity to allow oriented ingrowth of connective tissue into a wall of the prosthesis. The prosthesis can have a small internal diameter of 6 mm or less. Several different methods can be used to produce the prosthesis, including a fiber winding and extraction technique, a melt extrusion technique, and a particle and fiber extraction technique using either a layered method or a continuous method. Furthermore, mechanical properties of the prosthesis are matched with mechanical properties of the host vessel, thereby overcoming problems of compliance mismatch.

Claims

1. A vascular graft prosthesis comprising:

an elastomeric polymeric tubular structure having a wall; and

interconnecting, helically oriented channels in the tube wall;

wherein at least 75% of the channels have diameters within 10 μ

m of one another.

2. The vascular graft prosthesis of claim 1 wherein the tubular structure has an internal diameter in a range of 1-20 mm.

3. The vascular graft prosthesis of claim 1 wherein the tubular structure has an internal diameter in a range of 2-6 mm.

4. The vascular graft prosthesis of claim 1 wherein the diameters of the channels are in a range of 10-300 μ

m.

5. The vascular graft prosthesis of claim 1 wherein the diameters of the channels are in a range of 40-110 μ

m.

6. The vascular graft prosthesis of claim 1 wherein the elastomeric polymeric tubular structure comprises polyurethane.

7. The vascular graft prosthesis of claim 1 wherein the elastomeric polymeric tubular structure comprises a segmented aliphatic polyurethane.

8. The vascular graft prosthesis of claim 1 wherein the elastomeric polymeric tubular structure comprises a material selected from the group consisting of Pellethane, Chronoflex, Hydrothane, Estane, Elast-Eon, Texin, Biomer, Surethane, Corethane, Carbothane, Techoflex, Tecothane and Biospan.

9. The vascular graft prosthesis of claim 1 further comprising reinforcing fibers in the elastomeric polymeric tubular structure.

10. The vascular graft prosthesis of claim 9 wherein the reinforcing fibers comprise a non-elastic, non-degradable material.

11. The vascular graft prosthesis of claim 9 wherein the reinforcing fibers comprise an elastic, non-degradable material.

12. The reinforcing fibers of claim 10 further comprising an elastic, non-degradable material.

13. The reinforcing fibers of claim 10 further comprising a material degradable in vivo.

14. The reinforcing fibers of claim 11 further comprising a material degradable in vivo.

15. The reinforcing fibers of claim 12 further comprising a material degradable in vivo.

16. The vascular graft prosthesis of claim 9 wherein the reinforcing fibers have diameters in a range of 10 to 100 micrometers.

17. The vascular graft prosthesis of claim 1 wherein at least 85% of the channels have diameters within 10 μ

m of one another.

18. The vascular graft prosthesis of claim 1 wherein at least 95% of the channels have diameters within 10 μ

m of one another.

19. The vascular graft prosthesis of claim 1 wherein substantially all of the channels have diameters within 10 μ

m of one another.

20. An aortic valve prosthesis comprising:

an elastomeric polymeric tubular structure having a wall; and

interconnecting, helically oriented channels in the tube wall;

wherein at least 75% of the channels have diameters within 10 μ

m of one another.

21. A method of making a prosthesis comprising the steps of:

assembling a mandrel in a winding device;

coating an extractable fiber with a coating solution, wherein the coating solution comprises a graft material dissolved in a graft material solvent;

winding the extractable fiber onto the mandrel;

solidifying the coating solution; and

extracting the fiber from the graft material.

22. The method of claim 21 further comprising the step of winding a non-extractable, reinforcing fiber onto the mandrel simultaneously with the extractable fiber.

23. The method of claim 21 wherein solidifying the coating solution is accomplished by precipitating the graft material in a precipitation solvent.

24. The method of claim 21 wherein solidifying the coating solution is accomplished by drying the graft material solvent in the coating solution.

25. The method of claim 21 wherein the mandrel has a diameter about equal to an internal diameter of the vascular graft prosthesis.

26. The method of claim 21 wherein the diameter of the mandrel is in a range of 1-20 mm.

27. The method of claim 21 wherein the diameter of the mandrel is in a range of 2-6 mm.

28. The method of claim 21 wherein the fiber has a diameter in a range of 10-300 μ

m.

29. The method of claim 21 wherein the fiber has a diameter in a range of 40-110 μ

m.

30. The method of claim 21 wherein the fiber comprises a polymer.

31. The method of claim 21 wherein the graft material comprises a thermoplastic elastomer.

32. The method of claim 21 wherein the graft material comprises a polyurethane.

33. The method of claim 21 wherein the coating solution further comprises extractable beads.

34. An aortic valve prosthesis made according to the method of claim 21.

35. A vascular graft prosthesis made according to the method of claim 21.

37. The method of claim 36 wherein a blowing agent is used to extrude the molten polymer.

38. The method of claim 37 wherein the blowing agent comprises a physical blowing agent.

39. The method of claim 37 wherein the blowing agent comprises a chemical blowing agent.

40. The method of claim 37 wherein the blowing agent comprises physical and chemical blowing agents.

41. The method of claim 36 wherein the polymer comprises a polyurethane.

42. The method of claim 36 wherein the polymer further comprises reinforcing fibers.

43. An aortic valve prosthesis made according to the method of claim 36.

44. A vascular graft prosthesis made according to the method of claim 36.

46. The method of claim 45 wherein the diameter of the mandrel is in a range of 1-20 mm.

47. The method of claim 45 wherein the diameter of the mandrel is in a range of 2-6 mm.

48. The method of claim 45 wherein the thickness of the vascular graft prosthesis is in a range of 0.1-5 mm.

49. The method of claim 45 wherein the thickness of the vascular graft prosthesis is in a range of 0.4-1.5 mm.

50. The method of claim 45 wherein the fiber has a diameter in a range of 10-300 μ

m.

51. The method of claim 45 wherein the fiber has a diameter in a range of 40-110 μ

m.

52. The method of claim 45 wherein the fiber comprises a polymer.

53. The method of claim 45 wherein the graft material comprises a thermoplastic elastomer.

54. The method of claim 45 wherein the graft material comprises a polyurethane.

55. The method of claim 45 further comprising the step of winding a non-extractable, reinforcing fiber onto the paste simultaneously with the winding of the extractable fiber.

56. The method of claim 45 wherein the graft material is precipitated from the graft material solution and the fiber is extracted from the graft material simultaneously.

57. An aortic valve prosthesis made according to the method of claim 45.

58. A vascular graft prosthesis made according to the method of claim 45.

60. The method of claim 59 wherein the diameter of the mandrel is in a range of 1-20 mm.

61. The method of claim 59 wherein the diameter of the mandrel is in a range of 2-6 mm.

62. The method of claim 59 wherein the thickness of the vascular graft prosthesis is in a range of 0.1-5 mm.

63. The method of claim 59 wherein the thickness of the vascular graft prosthesis is in a range of 0.4-1.5 mm.

64. The method of claim 59 wherein the fiber has a diameter in a range of 10-300 μ

m.

65. The method of claim 59 wherein the fiber has a diameter in a range of 40-110 μ

m.

66. The method of claim 59 wherein the fiber comprises a polymer.

67. The method of claim 59 wherein the graft material comprises a thermoplastic elastomer.

68. The method of claim 59 wherein the graft material comprises a polyurethane.

69. The method of claim 59 further comprising the step of winding a non-extractable, reinforcing fiber onto the paste simultaneously with the depositing of the layers of paste and the winding of the extractable fiber.

70. The method of claim 59 wherein the graft material is precipitated from the graft material solution and the fiber is extracted from the graft material simultaneously.

71. An aortic valve prosthesis made according to the method of claim 59.

36. A method of making a prosthesis comprising the steps of:

extruding a molten polymer, wherein the polymer comprises chopped strands of soluble fibers; and

annealing and reticulating the polymer to effect an open-cell structure.

45. A method of making a prosthesis comprising the steps of:

preparing a paste comprising a graft material solution and an extractable filler;

depositing a layer of the paste onto a mandrel, wherein the mandrel has a diameter about equal to a desired inside diameter of the vascular graft prosthesis;

winding an extractable fiber onto the layer of paste;

successively depositing additional layers of the paste and winding the extractable fiber onto each layer of the paste until a desired thickness of the vascular graft prosthesis is achieved;

precipitating graft material from the graft material solution; and

extracting the fiber from the graft material.

59. A method of making a prosthesis comprising the steps of:

preparing a paste comprising a graft material solution and an extractable filler;

depositing a layer of the paste onto a mandrel, and simultaneously winding an extractable fiber onto the mandrel, until a desired thickness of the vascular graft prosthesis is achieved, wherein the mandrel has a diameter about equal to a desired inside diameter of the vascular graft prosthesis;

precipitating graft material from the graft material solution; and

extracting the fiber from the graft material.

72. A vascular graft prosthesis made according to the method of claim 59.