Flared coronary artery bypass grafts

• US 6,821,295 B1
• Filed: 06/26/2000
• Issued: 11/23/2004
• Est. Priority Date: 06/26/2000
• Status: Expired due to Term

• Current Assignee: Thoratec LLC
• Original Assignee: Thoratec LLC
• Inventors: Farrar, David J.
• Primary Examiner(s): Woo, Julian W.
• Application Number:
  US09/604,114
• Time in Patent Office: 1,611 Days
• Field of Search: 623/1.1, 623/1.15, 623/1.16, 623/1.3, 623/1.31, 623/1.49
• US Class Current: 623/1.31
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61L 27/40 Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: C08L 75/00 Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers

Abstract

A bypass graft includes a tubular portion having an internal tubular diameter and a first end and a second end. The tubular portion has a central axis. A flared portion has an adjoining end, wherein the adjoining end of the flared portion is integrally formed on and is substantially concentric with the second end of the tubular portion, and a flared end, wherein the flared end has a flared end internal diameter, such that the internal flared end diameter is greater than the internal tubular diameter. The flared portion includes a circumferential skirt for surgical attachment of the graft to a patient'"'"'s blood vessel. A method for manufacturing a bypass graft, includes the steps of providing a mandrel having a tubular portion and a flared end with a flared end central axis; forming a layer of polyurethane over the mandrel; drying the layer of polyurethane on the mandrel; forming a skirt edge around the flared end of the mandrel to form an opening at a predetermined angle to the flared end central axis; forming a second edge around the tubular portion of the mandrel, and removing the graft from the mandrel.

Claims

1. A bypass graft comprising:

a tubular portion configured to extend and to form a conduit between at least a pair of blood vessels and having an internal tubular diameter, a first end, a second end opposite the first end, and a central axis; and

at least one flared portion having an adjoining end and a compliant flared end formed to facilitate anastomosis, wherein said adjoining end is integrally formed on and is substantially concentric with said second end, and said adjoining end has a diameter not less than said internal tubular diameter, wherein said at least one flared portion comprises an interior surface formed, such that said flared end has a flared end internal diameter, such that said internal flared end diameter is greater than said internal tubular diameter;

whereby said at least one flared portion comprises a circumferential skirt adapted for surgical attachment of said graft to one of said blood vessels, wherein said graft is formed without intervening seams or overlap wherein at least said flared portion comprises a plurality of layers.

2. The graft of claim 1, wherein said graft is made from a polymer selected from the group consisting of polyether urethanes, polycarbonate urethanes, polyester urethanes, silicone polyether urethanes, silicone polycarbonate urethanes, and PHMO polyurethanes.

3. The graft of claim 2, wherein said polyether urethane comprises a polyether urethane-urea.

4. The graft of claim 3, wherein said polyether urethane-urea further comprising an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

5. The graft of claim 3, wherein said polyether urethane-urea is end-capped with dibutylamine.

6. The graft of claim 1, wherein said graft comprises:

an inner first micro-porous layer of polyether urethane-urea comprising about 1% to about 5% by weight of an additive formed by condensing MDI, polydimethylsiloxane, and 1,4-butanediol;

a second nonporous layer of polyether urethane-urea comprising about 1% to about 5% by weight of said additive; and

a third porous layer of a polyether urethane-urea comprising about 1% to about 5% of said additive.

7. The graft of claim 6, wherein said first layer is contiguous with said second layer.

8. The graft of claim 6, wherein said second layer is contiguous with said third layer.

9. The graft of claim 6, wherein said first layer contains pores having an average diameter of less about 38 microns.

10. The graft of claim 6, wherein said third layer contains pores having an average diameter less than about 38 microns.

11. The graft of claim 1, wherein said flared end has a flared end central axis, which is at an oblique angle to said central axis of said tubular portion.

12. The graft of claim 11, wherein said graft is made a polyether urethane-urea and said polyether urethane-urea further comprises an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

13. The graft of claim 1, wherein said circumferential skirt is oriented for attaching at an acute angle to said blood vessel.

14. The graft of claim 13, wherein said graft is made from a polyether urethane-urea and said polyether urethane-urea further comprises an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

15. The graft of claim 1, wherein said flared end has a flared end central axis, which is parallel to said central axis of said tubular portion.

16. The graft of claim 15, wherein said graft is made from a polyether urethane-urea and said polyether urethane-urea further comprises an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

17. The graft of claim 1 wherein said circumferential skirt is elongated.

18. The graft of claim 17, wherein said graft is made from a polyether urethane-urea and said polyether urethane-urea further comprises an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

19. The graft of claim 1, wherein said graft comprises reinforcing member wound around and substantially concentric with said tubular portion.

20. The graft of claim 19, wherein said graft is made from a polyether urethane-urea and said polyether urethane-urea further comprises an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

21. The graft of claim 1, wherein said flared end is asymmetrically flared with respect to said central axis of said tubular portion, such that said skirt has a substantially elliptically-shaped circumference.

22. The graft of claim 21, wherein said graft is made from a polymer selected from the group consisting of polyether urethanes, polycarbonate urethanes, polyester urethanes, silicone polyether urethanes, silicone polycarbonate urethanes, and PHMO polyurethanes.

23. The graft of claim 22, wherein said polyurethanes comprise a polyether urethane-urea.

24. The graft of claim 23, wherein said polyether urethane-urea further comprising an additive in the amounts in a range of about 1% to about 5% by weight, said additive formed by condensing a combination of MDI, polydimethylsiloxane, and 1,4-butanediol.

25. The graft of claim 23, wherein said polyether urethane-urea is end-capped with dibutylamine.

26. The graft of claim 21, wherein said graft comprises:

an inner first micro-porous layer of polyether urethane-urea comprising about 1% to about 5% by weight of an additive formed by condensing MDI, polydimethylsiloxane, and 1,4-butanediol;

a second nonporous layer of polyether urethane-urea comprising about 1% to about 5% by weight of said additive; and

a third porous layer of a polyether urethane-urea comprising about 1% to about 5% of said additive.

27. The graft of claim 26, wherein said first layer is contiguous with said second layer.

28. The graft of claim 26, wherein said second layer is contiguous with said third layer.

29. The graft of claim 26, wherein said first layer contains pores having an average diameter of less about 38 microns.

30. The graft of claim 26, wherein said third layer contains pores having an average diameter of less than about 38 microns.

31. A graft of claim 21, wherein said skirt comprises an opening for attaching said skirt at an acute angle to said blood vessel.

32. The graft of claim 21, wherein the flared end comprises an elliptically-shaped opening, which is oriented at an oblique angle to said central axis of said tubular portion.

33. The graft of claim 21, wherein said circumferential skirt is elongated.

34. A method for manufacturing a bypass graft, comprising the steps of:

providing a mandrel having a tubular portion and a flared end bulb with a flared end central axis;

forming at least one layer of polyurethane over said mandrel;

drying said at least one layer of polyurethane, on said mandrel;

forming a skirt edge around said flared end bulb of said mandrel to form an opening at a predetermined angle to said flared end central axis;

forming a second edge around said tubular portion of the mandrel; and

removing said graft from said mandrel.

35. The method of claim 34, further comprising the steps of:

providing a first source of polyurethane comprising polymeric solids and sodium chloride particles, such that said sodium chloride particles are in an amount equal to about 1400% by weight of said polymeric solids;

applying a first layer of said source of polyurethane over said mandrel; and

leaching said sodium chloride particles from said first layer to form pores.

36. The method of claim 34, further comprising the steps of:

providing a third source of polyurethane comprising polymeric solids and sodium chloride particles, such that said sodium chloride particles are in an amount equal to about 600% by weight of said polymeric solids;

applying a third layer of said third source of polyurethane over said mandrel; and

leaching said sodium chloride particles from said third layer to form pores.

37. The method of claim 34, further comprising the steps of:

wrapping said graft with a reinforcing means; and

securing said reinforcing means by applying a polyurethane layer thereover.

38. The method of claim 34, wherein the step of forming at least one layer of polyurethane over said mandrel comprises drawing said mandrel through said source of polyurethane.

39. The method of claim 38, wherein the step of forming at least one layer of polyurethane comprises repeatedly drawing said mandrel through said source of polyurethane.

40. The method of claim 34, further comprising the step of forming said skirt edge and controlling a length of said graft by applying a mask to said mandrel to limit exposure of the surface of said mandrel to said source of polyurethane.

41. The method of claim 40, further comprising the step of cutting the flared end of said graft subsequent to removal of said mandrel to impart an asymmetrical opening on said graft.

42. The method of claim 34, wherein the step of forming at least one layer of polyurethane over said mandrel comprises dipping said mandrel into said source of polyurethane.

43. The method of claim 42, wherein the step of forming at least one layer of polyurethane comprises repeatedly dipping said mandrel through said source of polyurethane.

44. The method of claim 42, further comprising the step of controlling a length of said graft by limiting a depth to which said mandrel is dipped into said source of polyurethane.

45. The method of claim 43, further comprising the step of forming said skirt edge and controlling a length of said graft by applying a mask to said mandrel to limit exposure of the surface of said mandrel to said source of polyurethane.

46. The method of claim 42, further comprising the step of cutting the flared end of said graft subsequent to removal of said mandrel to impart an asymmetrical opening on said graft.

47. The method of claim 34, wherein the step of forming at least one layer of polyurethane over said mandrel comprises spraying said source of polyurethane onto said mandrel.

48. The method of claim 47, wherein the step of forming at least one layer of polyurethane comprises repeatedly spraying said source of polyurethane onto said mandrel.

49. The method of claim 47, further comprising the step of forming said skirt edge and controlling a length of said graft by applying a mask to said mandrel to limit exposure of the surface of said mandrel to said source of polyurethane.

50. The method of claim 47, further comprising the step of forming said skirt edge and controlling a length of said graft by directing a sprayed stream of said source of polyurethane onto a selected portion of said mandrel.

51. A bypass graft produced in accordance with the method of claim 34.

52. A bypass graft comprising:

a tubular portion configured to extend and to form a conduit between at least a pair of blood vessels and having an internal tubular diameter, a first end, a second end opposite the first end, and a central axis; and

a first flared portion and a second flared portion, each having an adjoining end and a compliant flared end formed to facilitate anastomosis, wherein said adjoining end is integrally formed on and is substantially concentric with said first end and said second end, respectively, and said adjoining end has a diameter not less than said internal tubular diameter, wherein each of said flared portions comprises an exterior surface formed, such that said flared end has a flared end internal diameter, such that said internal flared end diameter is greater than said internal tubular diameter;

whereby each of said flared portions comprises a circumferential skirt adapted for surgical attachment of said graft to one of said blood vessels, wherein said graft is formed without intervening seams or overlap wherein each of at least said flared portions comprises a plurality of layers.