Expandable fluoropolymer device and method of making

• US 20020183716A1
• Filed: 04/22/2002
• Published: 12/05/2002
• Est. Priority Date: 01/25/1999
• Status: Active Grant

• Current Assignee: Atrium Medical Corporation (Getinge AB)
• Original Assignee: Atrium Medical Corporation (Getinge AB)
• Inventors: Martakos, Paul, Karwoski, Theodore, Herweck, Steve A., Gingras, Peter H.
• Granted Patent: US 7,637,886 B2
• Time in Patent Office: Days
• US Class Current: 604/509
• CPC Class Codes: A61L 29/041 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: B29C 2049/465 being incompressible
• CPC Class Codes: B29C 48/00 Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor extrusion blow-moulding B29C49/04
• 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 55/24 radial
• CPC Class Codes: B29K 2027/18 PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29L 2022/022 Balloons
• CPC Class Codes: B29L 2031/753 Medical equipment; Accessories therefor bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008
• CPC Class Codes: B32B 2305/026 Porous
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: Y10T 428/1376 Foam or porous material containing

Abstract

A radially expandable device having a body constructed of a generally inelastic, expanded fluoropolymer material is described. The body is deployable upon application of a radial expansion force from a reduced diameter, collapsed configuration to an expanded configuration having a pre-defined and fixed increased diameter. The body has a singular, unitary construction of generally homogenous material that is characterized by a seamless construction of expanded fluoropolymer material, such as expanded polytetrafluoroethylene (ePTFE), and is preferably constructed through an extrusion and expansion process. The body is further characterized by a microstructure of nodes interconnected by fibrils in which substantially all the nodes of the body are oriented generally perpendicularly to the longitudinal axis of the body. The monolithic construction of the body and the orientation of the nodes, perpendicular to the longitudinal axis of the body, yields a radially expandable device that predictably and dependably expands to a predefined, fixed maximum diameter that is generally independent of the expansion force used to radially expand the device. In addition, the microstructure of nodes interconnected by fibrils provides at least one predetermined flow rate of fluid therethrough over a range of fluid pressures.

Claims

1. A radially expandable device having a shaped form, comprising:

a body constructed of fluoropolymer material, the fluoropolymer material having a microstructure of nodes interconnected by fibrils;

wherein the body can receive a fluid through a fluid conduit to expand the body from a reduced diameter collapsed configuration to an increased diameter expanded configuration; and

wherein the microstructure of nodes interconnected by fibrils has a predetermined porosity suitable for regulating a flow of the fluid therethrough at a rate substantially independent of fluid pressures as the fluid is introduced for expansion of the body.

2. The device of claim 1, wherein the body is expandable to a pre-defined and fixed increased diameter that is generally independent of the expansion force used to expand the device to the expanded configuration.

3. The device of claim 2, wherein the body can achieve the pre-defined and fixed increased diameter prior to the fluid flowing through the microstructure of nodes interconnected by fibrils.

4. The device of claim 1, wherein the fluoropolymer material is expanded polytetrafluoroethylene (ePTFE).

5. The device of claim 1, wherein the body is tubular in shape and wherein the wall extends radially between an inner and an outer surface.

6. The device of claim 5, wherein the nodes are oriented such that spaces between the nodes form channels oriented and extending from the inner surface to the outer surface of the wall.

7. The device of claim 1, wherein the nodes are separated by an internodal distance, the internodal distance being approximately 1 μ

m-150 μ

m.

8. The device of claim 1, wherein the body is monolithic in construction.

9. The device of claim 1, wherein the fluid flowing through the through-pores has therapeutic characteristics.

10. The device of claim 1, wherein the predetermined porosity comprises a designated porosity for at least a portion of the body.

11. The device of claim 1, wherein the fluid comprises at least one of antioxidants, anti-hypertensive agents, anti-inflammatory agents, growth factor antagonists, anti-platelet agents, anti-coagulant agents, thrombolytic agents, drugs to alter lipid metabolism, ACE inhibitors, anti-proliferatives, anti-neoplastics, tissue growth stimulants, gasses, agents for promotion of hollow organ occlusion or thrombosis, agents for functional protein or factor delivery, agents for second messenger targeting, angiogenic agents, anti-angiogenic agents, agents for inhibition of protein synthesis, anti-infective agents, agents for gene delivery, agents for local tissue perfusion, nitric oxide donating derivatives, and contrast media.

12. The device of claim 1, wherein the fluid comprises at least one of a contrast agent and a dye.

13. The device of claim 1, wherein the fluid can flow through the microstructure of nodes interconnected by fibrils at a rate that will not injure a patient with hydraulic fluid forces.

15. The device of claim 14, wherein the body is expandable to a pre-defined and fixed increased diameter that is generally independent of the expansion force used to expand the device to the expanded configuration.

16. The device of claim 14, wherein the fluoropolymer material is expanded polytetrafluoroethylene (ePTFE).

17. The device of claim 14, wherein the body is tubular in shape and wherein the wall extends radially between an inner and an outer surface.

18. The device of claim 17, wherein the nodes are oriented such that spaces between the nodes form channels oriented and extending from the inner surface to the outer surface of the wall.

19. The device of claim 14, wherein the nodes are separated by an internodal distance, the internodal distance being approximately 1 μ

m-150 μ

m.

20. The device of claim 14, wherein the body is monolithic in construction.

21. The device of claim 14, wherein the fluid flowing through the through-pores has therapeutic characteristics.

22. The device of claim 14, wherein the predetermined porosity comprises a designated porosity for at least a portion of the body.

23. The device of claim 14, wherein the fluid comprises at least one of antioxidants, anti-hypertensive agents, anti-inflammatory agents, growth factor antagonists, anti-platelet agents, anti-coagulant agents, thrombolytic agents, drugs to alter lipid metabolism, ACE inhibitors, anti-proliferatives, anti-neoplastics, tissue growth stimulants, gasses, agents for promotion of hollow organ occlusion or thrombosis, agents for functional protein or factor delivery, agents for second messenger targeting, angiogenic agents, anti-angiogenic agents, agents for inhibition of protein synthesis, anti-infective agents, agents for gene delivery, agents for local tissue perfusion, nitric oxide donating derivatives, and contrast media.

24. The device of claim 14, wherein the fluid comprises at least one of a contrast agent and a dye.

25. The device of claim 14, wherein the fluid can flow through the microstructure of nodes interconnected by fibrils at a rate that will not injure a patient with hydraulic fluid forces.

27. The system of claim 26, wherein the body is expandable to a pre-defined and fixed increased diameter that is generally independent of the expansion force used to expand the device to the expanded configuration.

28. The system of claim 26, wherein the fluoropolymer material is expanded polytetrafluoroethylene (ePTFE).

29. The system of claim 26, wherein the body is tubular in shape and wherein the wall extends radially between an inner and an outer surface.

30. The system of claim 29, wherein the nodes are oriented such that spaces between the nodes form channels oriented and extending from the inner surface to the outer surface of the wall.

31. The system of claim 26, wherein the nodes are separated by an internodal distance, the internodal distance being approximately 1 μ

m-150 μ

m.

32. The system of claim 26, wherein the body is monolithic in construction.

33. The system of claim 26, wherein the fluid flowing through the through-pores has therapeutic characteristics.

34. The system of claim 26, wherein the predetermined porosity comprises a designated porosity for at least a portion of the body.

35. The system of claim 34, wherein the predetermined porosity further comprises at least two different designated porosities for at least two different portions of the body, such that the predetermined porosity is non-uniform.

36. The system of claim 26, wherein the fluid comprises at least one of antioxidants, anti-hypertensive agents, anti-inflammatory agents, growth factor antagonists, anti-platelet agents, anti-coagulant agents, thrombolytic agents, drugs to alter lipid metabolism, ACE inhibitors, anti-proliferatives, anti-neoplastics, tissue growth stimulants, gasses, agents for promotion of hollow organ occlusion or thrombosis, agents for functional protein or factor delivery, agents for second messenger targeting, angiogenic agents, anti-angiogenic agents, agents for inhibition of protein synthesis, anti-infective agents, agents for gene delivery, agents for local tissue perfusion, nitric oxide donating derivatives, and contrast media.

37. The system of claim 26, wherein guidewire is removably and replaceably coupled with the catheter.

38. The system of claim 26, wherein the fluid comprises at least one of a contrast agent and a dye.

39. The device of claim 26, wherein the fluid can flow through the microstructure of nodes interconnected by fibrils at a rate that will not injure the patient body with hydraulic fluid forces.

14. A radially expandable device, comprising:

a body constructed of fluoropolymer material, the fluoropolymer material having a microstructure of nodes interconnected by fibrils;

wherein the body can receive a fluid through a fluid conduit to expand the body from a reduced diameter collapsed configuration to an increased diameter expanded configuration; and

wherein the microstructure of nodes interconnected by fibrils has at least two different designated porosities for at least two different portions of the body, such that the at least two different designated porosities are suitable for regulating a flow of the fluid therethrough for at least two different rates substantially independent of fluid pressures as the fluid is introduced for expansion of the body.

26. A drug delivery system, comprising:

a radially expandable device having a shaped form, comprising;

a body constructed of fluoropolymer material, the fluoropolymer material having a microstructure of nodes interconnected by fibrils;

wherein the body can receive a fluid to expand the body from a reduced diameter collapsed configuration to an increased diameter expanded configuration; and

wherein the microstructure of nodes interconnected by fibrils has a predetermined porosity suitable for regulating a flow of the fluid therethrough at a rate substantially independent of fluid pressures as the fluid is introduced for expansion of the body;

a catheter coupled with the radially expandable device, the catheter suitable for introducing the fluid to expand the body; and

a guidewire suitable for positioning the device within a patient body.

40. A radially expandable device having a shaped form, comprising:

a body constructed of a fluoropolymer material, the body having a longitudinal axis and a wall having a thickness transverse to the longitudinal axis and formed of a microstructure of nodes interconnected by fibrils, such that the microstructure of nodes interconnected by fibrils has one or more predetermined porosities suitable for regulating a flow of fluid therethrough at one or more substantially constant flow rates for a range of fluid pressures;

wherein substantially all the nodes are oriented generally perpendicularly to the longitudinal axis of the body along at least a portion of the body, the body being deployable from a reduced diameter collapsed configuration to an increased diameter expanded configuration upon application of an expansion force.

41. The device of claim 40, wherein the body is expandable to a pre-defined and fixed increased diameter that is generally independent of the expansion force used to expand the device to the expanded configuration.

42. The device of claim 40, wherein the fluoropolymer material is expanded polytetrafluoroethylene (ePTFE).

43. The device of claim 40, wherein the body is tubular in shape and wherein the wall extends radially between an inner and an outer surface.

44. The device of claim 43, wherein the nodes are oriented such that spaces between the nodes form channels oriented and extending from the inner surface to the outer surface of the wall.

45. The device of claim 40, wherein the nodes are separated by an internodal distance, the internodal distance being approximately 1 μ

m-150 μ

m.

46. The device of claim 40, wherein the body is monolithic in construction.

47. The device of claim 40, wherein the fluid flowing through the through-pores has therapeutic characteristics.

48. The device of claim 40, wherein the one or more predetermined porosities comprise a designated porosity for at least a portion of the body.

49. The device of claim 48, wherein the one or more predetermined porosities further comprise at least two different designated porosities for at least two different portions of the body, such that the one or more predetermined porosities is non-uniform.

50. The device of claim 40, wherein the fluid comprises at least one of antioxidants, anti-hypertensive agents, anti-inflammatory agents, growth factor antagonists, anti-platelet agents, anti-coagulant agents, thrombolytic agents, drugs to alter lipid metabolism, ACE inhibitors, anti-proliferatives, anti-neoplastics, tissue growth stimulants, gasses, agents for promotion of hollow organ occlusion or thrombosis, agents for functional protein or factor delivery, agents for second messenger targeting, angiogenic agents, anti-angiogenic agents, agents for inhibition of protein synthesis, anti-infective agents, agents for gene delivery, agents for local tissue perfusion, nitric oxide donating derivatives, and contrast media.

51. The device of claim 40, wherein the fluid comprises at least one of a contrast agent and a dye.

52. The device of claim 40, wherein the fluid can flow through the microstructure of nodes interconnected by fibrils at a rate that will not injure a patient body with hydraulic fluid forces.

53. A method of manufacturing a radially expandable device, having a shaped form, the method comprising the steps of:

forming a tube of expanded fluoropolymer material having an initial diameter and microporous through-pores having one or more predetermined porosities suitable for regulating a flow of fluid therethrough at one or more substantially constant flow rates for a range of fluid pressures, the tube having an inlet;

applying a radial expansion force to the tube through the inlet to expand the tube from the initial diameter to a second diameter and to alter the geometry of the microporous through-pores, to thereby form the shaped form, the shaped form having a fine nodal structure conducive to radial expansion by a radial deployment force; and

removing the expansion force,

wherein the shaped form is radially expandable from a reduced diameter configuration to the second diameter upon application of the radial deployment force from a deployment mechanism within the shaped form as fluid permeates through the microporous through-pores and the rate at which fluid permeates through the microporous through-pores is substantially constant over a range of fluid pressures.

54. The method of claim 53, wherein the step of forming the tube the comprises the steps of:

creating a billet by blending a mixture of a fluoropolymer and a lubricant and compressing the mixture,

extruding the billet to form an extruded article having a longitudinal axis,

removing the lubricant from the extruded article,

expanding the extruded article to form the tube of expanded fluoropolymer material, and

heat setting the tube.

55. The method of claim 54, wherein the fluoropolymer is polytetrafluoroethylene (PTFE).

56. The method of claim 54, wherein the step of expanding the extruded article further comprises

bilaterally stretching the extruded article in two opposing directions along the longitudinal axis to yield an article which is substantially uniformly stretched over a major portion of its length and has a microstructure of nodes interconnected by fibrils.

57. The method of claim 56, wherein the step of expanding the extruded article includes

longitudinally stretching the extruded article from an initial length to a stretched length at a stretch rate.

58. The method of claim 57, further comprising selecting an amount of radial deployment force sufficient to radially expand the shaped form to the second diameter by varying a stretch ratio of the stretched length to the initial length.

59. The method of claim 58, further comprising selecting an amount of radial deployment force sufficient to radially expand the shaped form to the second diameter by varying the stretch rate.

60. The method of claim 53, wherein the second diameter to which the shaped form expands is a maximum diameter.

61. The method of claim 60, wherein the maximum diameter is independent the radial deployment force applied by the deployment mechanism.

62. The method of claim 53, wherein the deployment mechanism is the fluid.

63. The method of claim 53, wherein the step of applying a radial expansion force includes inserting a balloon into the tube, and expanding the balloon to apply the radial expansion force to the tube.

64. The method of claim 63, wherein the balloon is expanded by inflation with the fluid.

65. The method of claim 64, wherein the balloon is constructed of an inelastic material.

66. The method of claim 65, wherein the balloon is expandable to a predefined size and shape.

67. The method of claim 66, wherein the balloon expands the tube to the predefined size and shape.

68. The method of claim 67, further comprising providing a mold having an internal cavity, positioning the tube within the internal cavity, and radially expanding the balloon within the tube while the tube remains positioned in the internal cavity.

69. The method of claim 68, wherein the internal cavity has a size and shape analogous to the predefined size and shape of the balloon.

70. The method of claim 63, wherein the balloon and the tube are heated to approximately 35°

C.-60°

C. during the step of radial expanding.

71. The method of claim 53, wherein the step of applying a radial expansion force plastically deforms the tube beyond its elastic limit.

72. The method of claim 53, wherein the step of applying a radial expansion force includes inserting a tube of extruded material into the tube and expanding the tube to apply the radial expansion force to the tube.

73. The method of claim 72, wherein the tube and the tube are heated to the glass transition temperature of the extruded material during the step of radial expanding.

74. The method of claim 72, further comprising providing a mold having an internal cavity, positioning the tube within the internal cavity, and radially expanding the tube within the internal cavity.

75. The method of claim 74, further comprising heating the tube to the glass transition temperature of the extruded material during the step of radially expanding the tube within the internal cavity of the mold.

76. The method of claim 53, further comprising heat setting the shaped form after the step of applying a radial expansion force to the tube.

77. A method of manufacturing a radially expandable device, having a shaped form the method comprising the steps of:

forming a monolithic tube of expanded fluoropolymer material having a microporous structure having spaces between microfibrils that define microporous through-pores extending from an inner wall to an outer wall of the tube, such that the microstructure of nodes interconnected by fibrils has one or more predetermined porosities suitable for regulating a flow of fluid therethrough at one or more substantially constant flow rates for a range of fluid pressures,

applying a radial expansion force to the tube to expand the tube from a collapsed diameter to an inflated diameter and to alter the geometry of the microporous through-pores, to thereby form the shaped form, the shaped form having a fine nodal structure conducive to radial expansion by a radially applied fluid force; and

removing the expansion force,

wherein the shaped form is radially and inelestically expandable from the collapsed diameter to the inflated diameter upon application of the radially applied fluid force from a deployment mechanism within the shaped form as fluid permeates through the microporous through-pores and the fluid permeates at a substantially constant rate over a range of fluid pressures.

78. A method of manufacturing a fluid permeatable device, having a shaped form, the method comprising the steps of:

forming a monolithic expanded tube of extruded fluoropolymer material having a microstructure of nodes interconnected by fibrils with one or more predetermined porosities suitable for regulating a flow of fluid therethrough at one or more substantially constant flow rates for a range of fluid pressures, and

further expanding the tube by radially expanding the tube from an initial diameter to a maximum diameter to thereby form the shaped form, the shaped form having uniform through-pores between the microfilbril lengths within a wall of the fluoropolymer material and a fine nodal structure conducive to radial expansion by a fluid force,

wherein the fluid force can maximize the shaped form to the maximum diameter simultaneous with fluid permeating through the through-pores of the wall between the microfilbril lengths and out of the wall,

wherein the maximum diameter and the shape of the shaped form is independent of the fluid force used to maximize the shaped form to the maximum diameter as fluid permeates through-pores of the wall of the fluoropolymer material, and

wherein a rate at which the fluid permeates through-pores of the wall is substantially constant over a range of fluid pressures.

79. A radially expandable device having a shaped form, comprising:

a body constructed of fluoropolymer material, the fluoropolymer material having a microstructure of nodes interconnected by fibrils;

wherein the body can receive a contrast agent or dye through a fluid conduit to expand the body from a reduced diameter collapsed configuration to an increased diameter expanded configuration;

wherein the microstructure of nodes interconnected by fibrils has a predetermined porosity suitable for regulating a flow of the contrast agent or dye therethrough at a substantially constant rate independent of fluid pressures as the contrast agent or dye is introduced for expansion of the body; and

wherein the contrast agent or dye is applied in a manner commensurate with visualizing a target location within a patient.