Angioplasty catheter

• US 4,921,483 A
• Filed: 09/23/1987
• Issued: 05/01/1990
• Est. Priority Date: 12/19/1985
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Leocor, Inc.
• Inventors: Wijay, Bandula, Angelini, Paolo
• Primary Examiner(s): Truluck, Dalton L.
• Assistant Examiner(s): DeFranco, Denise W.
• Application Number:
  US07/100,363
• Time in Patent Office: 951 Days
• Field of Search: 604/95-103, 604/280, 604/4, 604/266, 128/344, 128/348.1, 128/656-658, 128/672-675
• US Class Current: 604/103.1
• CPC Class Codes: A61M 2025/0006 which can be secured against axial movement, e.g. by using a locking cuff
• CPC Class Codes: A61M 2025/0081 Soft tip
• CPC Class Codes: A61M 2025/1059 having different inflatable sections mainly depending on the response to the inflation pressure, e.g. due to different material properties
• CPC Class Codes: A61M 2025/1079 having radio-opaque markers in the region of the balloon
• CPC Class Codes: A61M 2025/1093 having particular tip characteristics
• CPC Class Codes: A61M 25/0068 Static characteristics of the catheter tip, e.g. shape, atraumatic tip, curved tip or tip structure
• CPC Class Codes: A61M 25/0069 Tip not integral with tube
• CPC Class Codes: A61M 25/0071 Multiple separate lumens multiple separate lumens throughout the catheter A61M25/0026
• CPC Class Codes: A61M 25/1002 characterised by balloon shape A61M25/1006, A61M25/1009 take precedence
• CPC Class Codes: A61M 25/104 used for angioplasty

Abstract

An angioplasty catheter has an elongated body with at least one lumen extending therethrough. A tip, constructed of materials softer than the elongated body is attached to the distal end of the body. The tip segment has at least one lumen passing therethrough which is in alignment withthe lumen in the elongated body. A guide is adapted to pass through the aligned lumens. A balloon is connected to the distal segment of the elongated body over its outer periphery, thereby creating a balloon cavity therebetween. At least one additional lumen is provided in the elongated body in flow communication with the balloon cavity, for selective inflation and deflation thereof, with a contrast fluid.

Claims

1. A low profile catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

an elongated body having a proximal and distal segment, said body defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said distal segment of said body, said tip defining at least one substantially smooth bore lumen therethrough, said lumen in said body in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said body in said tip;

said body being made of a harder material than the material of said tip;

a balloon mounted in close proximity to the outer surface of said distal segment of said body defining a balloon cavity therebetween, said balloon having a proximal and distal neck, said balloon disposed substantially proximally to said tip, juncture means for providing a transition between said tip and said distal segment of said body, said distal neck of said balloon mounted adjacent to the juncture between said elongated tip segment and said distal end of said distal segment of said body;

said proximal neck of said balloon mounted to said elongated body;

said distal segment of said body being substantially nondistensible as the balloon is inflated to substantially its full normal operating inflation pressure; and

means within said body for selectively inflating and deflating said balloon through said cavity.

2. The catheter of claim 1 wherein:

the proximal end of said tip has an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said distal segment of said body; and

the distal neck of said balloon is connected directly onto the outer surface of said distal segment of said body adjacent to the proximal end of said tip whereupon the outer surface of the distal neck of said balloon is substantially longitudinally aligned with the outer surface of said tip.

3. The catheter of claim 1 wherein:

the proximal end of said tip has an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said distal segment of said body; and

said tip further comprising;

an external mounting shoulder adjacent its proximal end; and

said distal neck of said balloon is connected to said external shoulder whereupon the outer surface of the distal neck of said balloon is substantially aligned with the outer surface of said tip adjacent the proximal end of said tip.

4. The catheter of claim 3 wherein said inner shoulder further comprises:

an annular surface; and

a radial surface adjacent one end of said annular surface;

said annular and radial surfaces of said shoulder connected to said distal end of said distal segment.

5. The catheter of claim 1 wherein:

said tip is mounted to the distal extremity of said body thereby defining a joint therebetween;

said tip having an outer surface substantially in longitudinal alignment with the outer surface of said distal segment of said body;

said distal neck of said balloon is mounted over said aligned outer surface.

6. The catheter of claim 5 further comprising:

a tapered transitional segment extending from the distal end of the outer surface of said distal neck of said balloon to the outer surface of said tip.

7. The catheter of claim 1 wherein:

said tip further comprises at least one taper between its proximal and distal ends;

said tip has an overall length in the range of about 1-30 mm;

said tip is formed of a soft elastomeric polymeric material.

8. The catheter of claim 1 wherein:

said tip is formed with a radiopaque filler.

9. The catheter of claim 1 wherein:

said tip further includes a coil spring embedded into said tip adjacent its distal end, said spring having a longitudinal axis aligned with the longitudinal axis of said tip, said spring circumscribing said lumen in said tip receiving the guide.

10. The catheter of claim 1 further comprising:

a tubular hold down sleeve, mounted to said balloon said sleeve adapted to be fitted substantially circumscribing said balloon to retain said balloon in a wing-folded position after said balloon has been substantially liquid filled, whereupon when said sleeve is removed, said balloon retains a low profile by retaining said wing-folds as the catheter is inserted into the vascular system or other body cavity.

11. The catheter of claim 1 wherein;

said balloon is formed having a plurality of stages of differing outside diameters when said balloon is inflated;

whereupon the same catheter can be used to dilate a stenosis in progressively increasing dimensional increments.

12. The catheter of claim 1, further comprising:

a first pressure sensing element mounted to the body of the catheter, adjacent to proximal end of said catheter, distally to said balloon, said first element adapted to sense pressure in the vascular system or the patient'"'"'s body cavity distally of said balloon during inflation and transmit a first electrical signal in relation thereto;

a second pressure sensing element mounted to the catheter, adjacent to proximal end of said catheter, said second element adapted to sense pressure in the vascular system or the patient'"'"'s body cavity proximally of said balloon during inflation and transmit a second electrical signal in relation thereto;

signal conduction means mounted to the body of the catheter connected to said first and second pressure sensing elements for conducting said first and second electrical signals to the proximal end of the catheter located outside the patient'"'"'s body.

13. The catheter of claim 1, further comprising:

connection means mounted in flow communication with said lumen in said body of the catheter on a first end and adapted to be connected to a blood supply source in the patient'"'"'s vascular system on a second end, for selectively allowing perfusion of the patient'"'"'s own blood during inflation of said balloon.

14. The catheter of claim 13, further comprising:

pump means mounted to said connection means for overcoming resistance to flow within said connection means and said lumen.

15. The catheter of claim 13, wherein:

said second end of said connection means is adapted to be connected to a blood supply source coming from the renal vein of the vascular system.

16. The catheter of claim 15, wherein:

lumen cross-sectional area in said inner body member proximate to said tapered segment thereon;

a balloon, said balloon having a proximal neck connected to said outer body member adjacent the distal end of said outer body member;

said balloon having a distal neck connected in close proximity to the outer surface of said distal end of said inner body member; and

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating adjacent said distal end of said inner body member.

17. The catheter of claim 1, comprising:

a coating of at least a portion of the exterior of the catheter coming in contact with the patient comprising of a combination of a lubricating material and an anti-clotting material.

18. The catheter of claim 17, wherein:

said lubricating material is silicone and said anti clotting material is heparin.

19. The catheter of claim 18, wherein:

the catheter is plasma treated to improve the bonding of the silicone and heparin coating.

20. A low profile catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

a tubular outer body member;

a tubular inner body member disposed substantially within said outer body member thereby defining an annulus therebetween;

said inner body member having a distal end extending beyond the distal end of said outer body member;

said inner body member defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said inner body member, said tip defining at least one substantially smooth bore lumen therethrough, said lumen in said inner body member in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said inner body member and said tip;

said inner body member being made of a harder material than the material of said tip;

a balloon, said balloon having a proximal neck extending from and connected to said outer body member adjacent to distal end of said outer body member;

said balloon having a distal neck extending to and connected in close proximity to the outer surface of said distal end of said inner body member and substantially proximally of said elongated tip segment;

said distal end of said inner body member being substantially nondistensible as the balloon is inflated to substantially its fully operating inflation pressure; and

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating proximally of said tip.

21. The catheter of claim 20 wherein;

said balloon is formed having a plurality of stages of differing outside diameters when said balloon is inflated;

whereupon the same catheter can be used to dilate a stenosis in progressively increasing dimensional increments.

22. The catheter of claim 20, further comprising:

a first pressure sensing element mounted to the catheter, adjacent to proximal end of said catheter, said first element adapted to sense pressure in the vascular system or the patient'"'"'s body cavity distally of said balloon during inflation and transmit a first electrical signal in relation thereto;

a second pressure sensing element mounted to the catheter, adjacent to proximal end of said catheter, said second element adapted to sense pressure in the vascular system or the patient'"'"'s body cavity proximally of said balloon during inflation and transmit a second electrical signal in relation thereto;

signal conduction means mounted to the inner and outer body members of the catheter connected to said first and second pressure sensing elements for conducting said first and second electrical signals to the proximal end of the catheter located outside the patient'"'"'s body.

23. The catheter of claim 20, further comprising:

connection means mounted in flow communication with said lumen in said inner body member of the catheter on a first end and adapted to be connected to a blood supply source in the patient'"'"'s vascular system on a second end for selectively allowing perfusion of the patient'"'"'s own blood during inflation of said balloon.

24. The catheter claim 23, further comprising:

pump means mounted to said connection means for overcoming resistance to flow within said connection means and said lumen.

25. The catheter of claim 20, comprising:

a coating of at least a portion of the exterior of the catheter coming in contact with the patient comprising of a combination of a lubricating material and an anti-clotting material.

26. The catheter of claim 25, wherein:

said lubricating material is silicone and said anti clotting material is heparin.

27. The catheter of claim 26, wherein:

the catheter is plasma treated to improve the bonding of the silicone and heparin coating.

28. A catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

a tubular outer body member;

a tubular inner body member disposed substantially within said outer body member thereby defining an annulus therebetween;

said inner body member having a distal end extending beyond the distal end of said outer body member;

said inner body member defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said inner body member, said tip defining at least one lumen therethrough, said lumen in said inner body member in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said inner body member and said tip;

said inner body member being harder than said tip;

a balloon, said balloon having a proximal neck connected to said outer body member adjacent the distal end of said outer body member;

said balloon having a distal neck connected in close proximity to the outer surface of said distal end of said inner body member;

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating adjacent said tip;

the proximal end of said tip having an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said inner body member;

the distal neck of said balloon is connected directly onto the outer surface of said distal end of said inner body member adjacent to the proximal end of said tip, whereupon the outer surface of the distal neck of said balloon is substantially longitudinally aligned with the outer surface of said tip adjacent its proximal end;

said proximal neck of said balloon is connected to the inner surface of said outer body member;

said outer body member is tapered adjacent its distal end;

said inner body member further comprises a tapered segment thereon, positioned adjacent to said tapered segment of said outer body member, thereby reducing the catheter profile at the distal end of said inner body member while permitting a larger lumen cross sectional area in said inner body member proximate to said tapered segment thereon.

29. The catheter of claim 28 wherein said inner body member and said tip are further formed having an infusion lumen extending therethrough said infusion lumen extending substantially parallel to said lumen receiving the guide.

30. the catheter of claim 28, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

37. The catheter of claim 28, 31 or 34 wherein:

said annulus has a substantially constant cross sectional area, proximately and distally adjacent said tapered segment on said inner body member.

38. The catheter of claim 37 wherein:

the distal extremity of said outer body member is tapered down to meet the outer surface of said proximal neck of said balloon.

31. A catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

a tubular outer body member;

a tubular inner body member disposed substantially within said outer body member thereby defining an annulus therebetween;

said inner body member having a distal end extending beyond the distal end of said outer body member;

said inner body member defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said inner body member, said tip defining at least one lumen therethrough, said lumen in said inner body member in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said inner body member and said tip;

said inner body member being harder than said tip;

a balloon, said balloon having a proximal neck connected to said outer body member adjacent the distal end of said outer body member;

said balloon having a distal neck connected in close proximity to the outer surface of said distal end of said inner body member;

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating adjacent said tip;

the proximal end of said tip having adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said inner body member; and

said tip further comprises;

an external mounting shoulder adjacent its proximal end;

said distal neck of said balloon is connected to said external shoulder, whereupon the outer surface of the distal neck of said balloon is substantially aligned with the outer surface of said tip adjacent the proximal end of said tip;

said proximal neck of said balloon is connected to the inner surface of said outer body member;

said outer body member is tapered adjacent its distal end;

said inner body member further comprises a tapered segment thereon, positioned adjacent to said tapered segment of said outer body member, thereby reducing the catheter profile at the distal end of said inner body member while permitting a larger lumen cross sectional area in said inner body member proximate to said tapered segment thereon.

32. The catheter of claim 31 wherein said inner body member and said tip are further formed having an infusion lumen extending therethrough said infusion lumen extending substantially parallel to said lumen receiving the guide.

33. The catheter of claim 31, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

34. A catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

a tubular outer body member;

a tubular inner body member disposed substantially within said outer body member thereby defining an annulus therebetween;

said inner body member having a distal end extending beyond the distal end of said outer body member;

said inner body member defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said inner body member, said tip defining at least one lumen therethrough, said lumen in said inner body member in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said inner body member and said tip;

said inner body member being harder than said tip;

a balloon, said balloon having a proximal neck connected to said outer body member adjacent the distal end of said outer body member;

said balloon having a distal neck connected in close proximity to the outer surface of said distal end of said inner body member;

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating adjacent said tip;

said tip is mounted to the distal extremity of said inner body member thereby defining a joint therebetween;

said tip having an outer surface substantially in longitudinal alignment with the outer surface of said distal end of said inner body member;

said distal neck of said balloon is mounted over said aligned outer surfaces;

said proximal neck of said balloon is connected to the inner surface of said outer body member;

said outer body member is tapered adjacent its distal end; and

said inner body member further comprises a tapered segment thereon, positioned adjacent to said tapered segment of said outer body member, thereby reducing the catheter profile at the distal end of said inner body member while permitting a larger lumen cross sectional area in said inner body member proximate to said tapered segment thereon.

35. The catheter of claim 34 wherein said inner body member and said tip are further formed having an infusion lumen extending therethrough said infusion lumen extending substantially parallel to said lumen receiving the guide.

36. The catheter of claim 34, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

39. A catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

a tubular outer body member;

a tubular inner body member disposed substantially within said outer body member thereby defining an annulus therebetween;

said inner body member having a distal end extending beyond the distal end of said outer body member;

said inner body member defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said inner body member, said tip defining at least one lumen therethrough, said lumen in said inner body member in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said inner body member and said tip;

said inner body member being harder than said tip;

said outer body member is tapered adjacent its distal end;

said inner body member further comprises a tapered segment thereon, positioned adjacent to said tapered segment of said outer body member, thereby reducing the catheter profile at the distal end of said inner body member while permitting a larger lumen cross sectional area in said inner body member proximate to said tapered segment thereon;

a balloon, said balloon having a proximal neck connected to said outer body member adjacent the distal end of said outer body member;

said balloon having a distal neck connected in close proximity to the outer surface of said distal end of said inner body member; and

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating adjacent said tip.

40. The catheter of claim 39 wherein;

said balloon is formed having a plurality of stages of differing outside diameters when said balloon is inflated;

whereupon the same catheter can be used to dilate a stenosis in progressively increasing dimensional increments.

41. The catheter of claim 39, further comprising:

a first pressure sensing element mounted to the catheter, said first element adapted to sense pressure in the vascular system or the patient'"'"'s body cavity distally of said balloon during inflation and transmit a first electrical signal in relation thereto;

a second pressure sensing element mounted to the catheter, said second element adapted to sense pressure in the vascular system or the patient'"'"'s body cavity proximally of said balloon during inflation and transmit a second electrical signal in relation thereto;

signal conduction means mounted to the inner and outer body members of the catheter connected to said first and second pressure sensing elements for conducting said first and second electrical signals to the proximal end of the catheter located outside the patient'"'"'s body.

42. The catheter of claim 39, further comprising:

connection means mounted in flow communication with said lumen in said inner body member of the catheter on a first end and adapted to be connected to a blood supply source in the patient'"'"'s vascular system on a second end, for selectively allowing perfusion of the patient'"'"'s own blood during inflation of said balloon.

43. The catheter claim 42, further comprising:

pump means mounted to said connection means for overcoming resistance to flow within said connection means and said lumen.

44. The catheter of claim 42, wherein:

said second end of said connection means is adapted to be connected to a blood supply source coming from the renal vein of the vascular system.

45. The catheter of claim 39, comprising:

a coating of at least a portion of the exterior of the catheter coming in contact with the patient comprising of a combination of a lubricating material and an anti-clotting material.

46. The catheter of claim 45, wherein:

said lubricating material is silicone and said anti clotting material is heparin.

47. The catheter of claim 46, wherein:

the catheter is plasma treated to improve the bonding of the silicone and heparin coating.

48. The catheter of claim 39, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

66. The catheter of claim 39 wherein:

said tip further includes a coil spring embedded into said tip adjacent its distal end, said spring having a longitudinal axis aligned with the longitudinal axis of said tip, said spring circumscribing said lumen receiving the guide.

67. The catheter of claim 39 wherein:

said tip is formed with a radiopaque filler.

68. The catheter of claim 39 wherein:

said tip further comprises at least one taper between its proximal and distal ends;

said tip has an overall length in the range of about 1-30 mm;

said tip is formed of a soft elastomeric polymeric material.

69. The catheter of claim 39 wherein said inner body member and said tip are further formed having an infusion lumen extending therethrough said infusion lumen extending substantially parallel to said lumen receiving the guide.

70. The catheter of claim 69 wherein:

said infusion lumen terminates at an acute to a right included angle measured between the longitudinal axis of said tip and said infusion lumen, said infusion lumen terminating proximally to the distal end of said tip.

71. The catheter of claim 72 wherein:

said proximal neck of said balloon is connected to the outer surface of said outer body member;

said outer body member further comprising at least one bleed lumen disposed within the wall of said outer body member and extending longitudinally through it substantially through its length, said bleed lumen in flow communication with said annular cavity.

72. The catheter of claim 39 further comprising:

the proximal end of said tip has an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said inner body member;

the distal neck of said balloon is connected directly onto the outer surface of said distal end of said inner body member adjacent to the proximal end of said tip, whereupon the outer surface of the distal neck of said balloon is substantially longitudinally aligned with the outer surface of said tip adjacent its proximal end.

73. The catheter of claim 72 wherein:

said proximal neck of said balloon is connected to the inner surface of said outer body member.

74. The catheter of claim 73 wherein said inner body member and said tip are further formed having an infusion lumen extending therethrough said infusion lumen extending substantially parallel to said lumen receiving the guide.

75. The catheter of claim 74 wherein:

said infusion lumen terminates at an acute to a right included angle measured between the longitudinal axis of said tip and said infusion lumen, said infusion lumen terminating proximally to the distal end of said tip.

76. The catheter of claim 75 wherein:

said tip further comprises at least one taper between its proximal and distal ends;

said tip has an overall length in the range of about 1-30 mm;

said tip is formed of a soft elastomeric polymeric material.

77. The catheter of claim 76 wherein:

said tip is formed with a radiopaque filler.

78. The catheter of claim 77 wherein:

said tip further includes a coil spring embedded into said tip adjacent its distal end, said spring having a longitudinal axis aligned with the longitudinal axis of said tip, said spring circumscribing said lumen receiving the guide.

79. The catheter of claim 39 wherein;

the proximal end of said tip has an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said inner body member; and

said tip further comprises;

an external mounting shoulder adjacent its proximal end; and

said distal neck of said balloon is connected to said external shoulder, whereupon the outer surface of the distal neck of said balloon is substantially aligned with the outer surface of said tip adjacent the proximal end of said tip.

80. The catheter of claim 79 wherein:

said proximal neck of balloon is connected to the outer surface of said outer body member;

said outer body member further comprising at least one bleed lumen disposed within the wall of said outer body member and extending longitudinally through it substantially through its length, said bleed lumen in flow communication with said annular cavity.

81. The catheter of claim 79 wherein said inner shoulder further comprises:

an annular surface; and

a radial surface adjacent one end of said annular surface;

said annular and radial surfaces of said shoulder connected to said distal end of said inner body member.

82. The catheter of claim 39 wherein:

said tip is mounted to the distal extremity of said inner body member thereby defining a joint therebetween;

said tip having an outer surface substantially in longitudinal alignment with the outer surface of said distal end of said inner body member; and

said distal neck of said balloon is mounted over said aligned outer surfaces.

83. The catheter of claim 82 further comprising:

a tapered transitional segment extending from the distal end of the outer surface of said distal neck of said balloon to the outer surface of said tip.

84. The catheter of claim 82 wherein:

said proximal neck of said balloon is connected to the outer surface of said outer body member;

said outer body member further comprising at least one bleed lumen disposed within the wall of said outer body member and extending longitudinally through it substantially through its length, said bleed lumen in flow communication with said annular cavity.

49. A low profile catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

an elongated body having a proximal and distal segment, said body defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said distal segment of said body, said tip defining at least one substantially smooth bore lumen therethrough, said lumen in said body in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over guide extending through said lumen in said body and said tip;

said body being harder than said tip;

a balloon mounted in close proximity to the outer surface of said distal segment of said body defining a balloon cavity therebetween, said balloon having a proximal and distal neck said balloon cavity disposed between said distal segment of said body and said portion of said balloon between said proximal and distal necks of said balloon, said distal neck of said balloon mounted adjacent to the juncture between said elongated tip segment and said distal end of said distal segment of said body;

means within said body for selectively inflating and deflating said balloon through said cavity;

the proximal end of said tip having an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said distal segment of said body;

the distal neck of said balloon is connected directly onto the outer surface of said distal segment of said body adjacent to the proximal end of said tip whereupon the outer surface of the distal neck of said balloon is substantially longitudinally aligned with the outer surface of said tip;

said distal segment of said body further comprises a tapered transition section for reducing the cross sectional area of said distal segment of said body to a smaller size than said proximal segment of said body, as measured in a plane perpendicular to the longitudinal axis of said body; and

said balloon connected distally to said tapered transition such that the profile of the catheter does not exceed the cross-section of said proximal segment when said balloon is deflated.

50. The catheter of claim 49, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

55. The catheter of claim 49, 51 or 53 wherein:

said tube and said tip are further formed having an infusion lumen extending therethrough, said infusion lumen extending substantially parallel to said lumen receiving the guide.

56. The catheter of claim 55 wherein:

said infusion lumen terminates at an acute to a right included angle as measured between the longitudinal axis of said tip and said infusion lumen, said infusion lumen terminating proximally to the distal end of said tip.

57. The catheter of claim 56 wherein said inflation and deflation means further comprises:

at least one balloon lumen extending through said proximal and distal segments of said body and terminating adjacent said balloon cavity thereby permitting fluid flow through said body into said balloon cavity.

58. The catheter of claim 57 wherein:

said balloon lumen terminates adjacent the distal end of said balloon cavity.

59. The catheter of claim 57 comprising:

a first and second balloon lumens, said first balloon lumen adapted for filling said balloon cavity with an inflating liquid and said second balloon lumen adapted to carry entrained gas from the balloon cavity.

60. The catheter of claim 59 wherein:

said first lumen terminates adjacent the proximal end of said balloon cavity; and

said second lumen terminates adjacent the distal end of said balloon cavity.

61. The catheter of claim 60 wherein:

said tip further comprises at least one taper between its proximal and distal ends;

said tip has an overall length in the range of about 1-30 mm;

said tip is formed of a soft elastomeric polymeric material.

62. The catheter of claim 61 wherein:

said tip is formed with a radiopaque filler.

63. The catheter of claim 62 wherein:

said tip further includes a coil spring embedded into said tip adjacent its distal end, said spring having a longitudinal axis aligned with the longitudinal axis of said tip, said spring circumscribing said lumen in said tip receiving the guide.

64. The catheter of claim 63 further comprising:

a tubular hold down sleeve, mounted to said balloon said sleeve adapted to be fitted substantially circumscribing said balloon to retain said balloon in a wing-folded position after said balloon has been substantially liquid filled, whereupon when said sleeve is removed, said balloon retains a low profile by retaining said wing-folds as the catheter is inserted into the vascular system or other body cavity.

65. The catheter of claim 57 further comprising:

a tubular hold down sleeve, mounted to said balloon said sleeve adapted to be fitted substantially circumscribing said balloon to retain said balloon in a wing-folded position after said balloon has been substantially liquid filled, whereupon when said sleeve is removed, said balloon retains a low profile by retaining said wing-folds as the catheter is inserted into the vascular system or other body cavity.

51. A low profile catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

an elongated body having a proximal and distal segment, said body defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said distal segment of said body, said tip defining at least one substantially smooth bore lumen therethrough, said lumen in said body in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said body and said tip;

said body being harder than said tip;

a balloon mounted in close proximity to the outer surface of said distal segment of said body defining a balloon cavity therebetween, said balloon having a proximal and distal neck, said balloon cavity disposed between said distal segment of said body and said portion of said balloon between said proximal and distal necks of said balloon, said distal neck of said balloon mounted adjacent to the juncture between said elongated tip segment and said distal end of said distal segment of said body;

means within said body for selectively inflating and deflating said balloon through said cavity;

the proximal end of said tip having an adjacent internal mounting shoulder circumscribing said lumen extending therethrough;

said shoulder is mounted to the distal end of said distal segment of said body;

said tip further comprising;

an external mounting shoulder adjacent its proximal end;

said distal neck of said balloon is connected to said external shoulder whereupon the outer surface of the distal neck of said balloon is substantially aligned with the outer surface of said tip adjacent the proximal end of said tip;

said distal segment of said body further comprises a tapered transition section for reducing the cross sectional area of said distal segment of said body to a smaller size than said proximal segment of said body, as measured in a plane perpendicular to the longitudinal axis of said body; and

said balloon connected distally to said tapered transition such that the profile of the catheter does not exceed the cross-section of said proximal segment when said balloon is deflated.

52. The catheter of claim 51, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

53. A low profile catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

an elongated body having a proximal and distal segment, said body defining at least one lumen extending therethrough;

an elongated tip segment connected adjacent to the distal end of said distal segment of said body, said tip defining at least one substantially smooth bore lumen therethrough, said lumen in said body in flow communication with said lumen in said tip thereby allowing the catheter to be advanced over a guide extending through said lumen in said body and said tip;

said body being harder than said tip;

a balloon mounted in close proximity to the outer surface of said distal segment of said body defining a balloon cavity therebetween said balloon having a proximal and distal neck, said balloon cavity disposed between said distal segment of said body and said portion of said balloon between said proximal and distal necks of said balloon, said distal neck of said balloon mounted adjacent to the juncture between said elongated tip segment and said distal end of said distal segment of said body; and

means within said body for selectively inflating and deflating said balloon through said cavity;

said tip is mounted to the distal extremity of said body thereby defining a joint therebetween;

said tip having an outer surface substantially in longitudinal alignment with the outer surface of said distal segment of said body;

said distal neck of said balloon is mounted over said aligned outer surfaces;

said distal segment of said body further comprises a tapered transition section for reducing the cross sectional area of said distal segment of said body to a smaller size than said proximal segment of said body, as measured in a plane perpendicular to the longitudinal axis of said body; and

said balloon connected distally to said tapered transition such that the profile of the catheter does not exceed the cross-section of said proximal segment when said balloon is deflated.

54. The catheter of claim 53, wherein:

the length (L₁) of the catheter proximally to said taper divided by the inside diameter (D₁) of said lumen proximally to said taper taken to the fourth power is less than or equal to about 2-4 times the quotient of the length (L₂) of the catheter distally to said taper divided by the inside diameter (D₂) of said lumen distally of said taper taken to the fourth power.

85. A catheter for dilating stenotic lesions in the vascular system and other body cavities, insertable over a guide comprising:

a tubular outer body member;

a tubular inner body member disposed substantially within said outer body member thereby defining an annulus therebetween;

said inner body member having a distal end extending beyond the distal end of said outer body member;

said inner body member defining at least one lumen extending therethrough;

said outer body member is tapered and adjacent its distal end;

said inner body member further comprises a tapered segment thereon, positioned adjacent to said tapered segment of said outer body member, thereby reducing the catheter profile at the distal end of said inner body member while permitting a larger lumen cross-sectional area in said inner body member proximate to said tapered segment thereon;

a balloon, said balloon having a proximal neck connected to said outer body member adjacent the distal end of said outer body member;

said balloon having a distal neck connected in close proximity to the outer surface of said distal end of said inner body member; and

said balloon defining an annular cavity extending from and in flow communication with said annulus and terminating adjacent said distal end of said inner body member.