Variable stiffness angioplasty catheter

Claims

What is claimed is:

1. A coronary angioplasty dilation catheter, comprising:

(a) an elongated flexible shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilation procedure;

(b) means for defining a guide wire receiving lumen, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

(c) an inflatable balloon member disposed at the distal end of the shaft;

(d) means for fluid communication between the proximal end of said shaft and said balloon so as to provide an inflation pressure; and

(e) means for defining a waist portion disposed between said balloon member and said shaft, said waist portion being disposed at the distal end of said shaft and being of reduced outer diameter and reduced wall thickness as compared to said shaft, the length of said waist portion between said balloon member and said shaft being equal to at least one-half of the length of said balloon member.

2. A vascular dilatation catheter according to claim 1, wherein said waist portion is made of a different material than that of said shaft.

3. A vascular dilatation catheter according to claim 2, wherein said means defining a guide wire lumen and said elongate flexible shaft comprise an elongate double lumen tubular member.

4. A coronary angioplasty dilatation catheter comprising:

(a) an elongated tubular shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

(b) an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient, the distal end of said tubular member extending beyond the distal end of said shaft said tubular member having a first section and a second section, said second section disposed distally of said first section;

(c) an inflatable balloon member disposed at the distal end of the shaft, positioned substantially coaxially over said tubular member, sealably connected at the distal end to said tubular member, and sealably connected at the proximal end to said shaft;

(d) means for fluid communication between the proximal end of said shaft and said balloon member so as to provide an inflation pressure; and

(e) means for defining a waist portion disposed between said balloon member and said first section of said tubular member wherein said second section of said tubular member is of reduced outer diameter and reduced wall thickness as compared to said first section of said tubular member, the length of said waist portion between said balloon member and said first section being equal to at least one-half of the length of said balloon member.

5. A vascular dilatation catheter according to claim 4, wherein said waist portion is made of a different material than that of said shaft.

6. A vascular dilatation catheter according to claim 5, wherein said tubular member and said shaft comprise an elongate double lumen tubular member.

7. A vascular dilatation catheter according to claim 1, wherein said balloon member is formed integrally with said waist portion.

8. A vascular dilatation catheter according to claim 1, wherein said waist portion is formed integrally with said shaft.

9. A vascular dilatation catheter according to claim 4, wherein said balloon member is formed integrally with said waist portion.

10. A vascular dilatation catheter according to claim 4, wherein said waist portion is formed integrally with said shaft.

11. An angioplasty dilatation catheter, comprising:

an elongated flexible shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

an inflatable balloon member disposed at the distal end of the shaft, positioned substantially coaxially over said tubular member, sealably connected at the distal end to said tubular member;

means for fluid communication between the proximal end of the shaft and said balloon member; and

means for defining a waist portion formed integrally with said balloon member and disposed at the distal end of said shaft between said shaft and said balloon member, said waist portion being of reduced outer diameter and reduced wall thickness as compared to said shaft, the length of said waist portion between said balloon member and said shaft being equal to at least one-half of the length of said balloon member.

12. The angioplasty dilatation catheter of claim 11 wherein the waist portion and said balloon member are made of a material comprising a polyolefin.

13. The angioplasty dilatation catheter of claim 12 wherein said polyolefin comprises a polyethylene.

14. The angioplasty dilatation catheter of claim 11 further including at least one radiopaque marker disposed within said balloon member.

15. The angioplasty dilatation catheter of claim 11 further including a tip member extending distally from said balloon member, said tip member being more flexible than said balloon member.

16. The angioplasty dilatation catheter of claim 15 wherein said tip member comprises a length of said annular tubular member extending distally of said balloon member.

17. The angioplasty dilatation catheter of claim 11 wherein said shaft is formed integrally with said waist portion.

18. An angioplasty dilatation catheter, comprising:

an elongated flexible main shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

an inflatable balloon member;

means for fluid communication between the proximal end of the main shaft and said balloon member so as to provide an inflation pressure; and

a waist portion shaft disposed between said balloon member and said main shaft, the distal end of said waist portion shaft being formed integrally with said balloon member and the proximal end of said waist portion shaft being bonded to the distal end of said main shaft, said waist portion shaft being of reduced outer diameter and reduced wall thickness as compared to said main shaft, the length of said waist portion shaft between said balloon member and said main shaft being equal to at least one-half the length of said balloon member.

19. The angioplasty dilatation catheter of claim 18 wherein said waist portion shaft and said balloon member are made of a material comprising a polyolefin.

20. The angioplasty dilatation catheter of claim 19 wherein said polyolefin comprises a polyethylene.

21. The angioplasty dilatation catheter of claim 18 further including at least one radiopaque marker disposed within said balloon member.

22. The angioplasty dilatation catheter of claim 18 further including a tip member extending distally from said balloon member, said tip member being more flexible than said balloon member.

23. The angioplasty dilatation catheter of claim 22 wherein said tip member comprises a length of said annular tubular member extending distally of said balloon member.

24. An angioplasty dilatation catheter, comprising:

an elongated flexible main shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

an inflatable balloon member, positioned substantially coaxially over said tubular member, sealably connected at the distal end to said tubular member;

a tip member extending distally from said balloon member, said tip member being more flexible than said balloon member;

a waist portion shaft disposed substantially coaxially over said tubular shaft member between said balloon member and said main shaft, the distal end of said waist portion shaft being formed integrally with said balloon member and the proximal end of said waist portion shaft being bonded to the distal end of said main shaft, said waist portion shaft being made of a different material than said main shaft and being of reduced outer diameter and reduced wall thickness as compared to said main shaft, the length of said waist portion shaft between said balloon member and said main shaft being equal to at least one-half of the length of said balloon member; and

an annular lumen being defined through said tubular shaft, said main shaft and said waist portion shaft, said annular lumen providing fluid communication between the proximal end of said main shaft and said balloon member so as to provide an inflation pressure.

25. The angioplasty dilatation catheter of claim 24 wherein said waist portion shaft and said balloon member are made of a material comprising a polyolefin.

26. The angioplasty dilatation catheter of claim 25 wherein said polyolefin comprises a polyethylene.

27. The angioplasty dilatation catheter of claim 24 further including at least one radiopaque marker disposed within said balloon member.

28. The angioplasty dilatation catheter of claim 25 further including at least one radiopaque marker disposed within said balloon member.

29. A coronary angioplasty dilatation catheter, comprising:

(a) an elongated flexible shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

(b) means for defining a guide wire receiving lumen, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

(c) an inflatable balloon member disposed at the distal end of the shaft;

(d) means for fluid communication between the proximal end of said shaft and said balloon so as to provide an inflation pressure; and

(e) means for defining a waist portion disposed between said balloon member and said shaft, said waist portion being disposed at the distal end of said shaft and being of reduced outer diameter and reduced wall thickness as compared to said shaft, the length of said waist portion between said balloon member and said shaft being equal to at least one length of said balloon member.

30. A coronary angioplasty dilatation catheter, comprising:

(a) an elongated tubular shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

(b) an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient, the distal end of said tubular member extending beyond the distal end of said shaft said tubular member having a first section and a second section, said second section disposed distally of said first section;

(c) an inflatable balloon member disposed at the distal end of the shaft, positioned substantially coaxially over said tubular member, sealably connected at the distal end to said tubular member, and sealably connected at the proximal end to said shaft;

(d) means for fluid communication between the proximal end of said shaft and said balloon member so as to provide an inflation pressure; and

(e) means for defining a waist portion disposed between said balloon member and said first section of said tubular member wherein said second section of said tubular member is of reduced outer diameter and reduced wall thickness as compared to said first section of said tubular member, the length of said waist portion between said balloon member and said first section being equal to at least one length of said balloon member.

31. An angioplasty dilatation catheter, comprising:

an elongated flexible main shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

an inflatable balloon member;

means for fluid communication between the proximal end of the main shaft and said balloon member so as to provide an inflation pressure; and

a waist portion shaft disposed between said balloon member and said main shaft, the distal end of said waist portion shaft being formed integrally with said balloon member and the proximal end of said waist portion shaft being bonded to the distal end of said main shaft, said waist portion shaft being of reduced outer diameter and reduced wall thickness as compared to said main shaft, the length of said waist portion shaft between said balloon member and said main shaft being equal to at least one length of said balloon member.

32. An angioplasty dilatation catheter, comprising:

an elongated flexible main shaft having a distal end for entry into the vascular system and a proximal end for manipulation externally of the body and for attachment to instruments for use in a dilatation procedure;

an elongated tubular member defining a guide wire receiving lumen, disposed axially within said shaft, so that the catheter can be advanced along a guide wire in the vascular system of the patient;

an inflatable balloon member, positioned substantially coaxially over said tubular member, sealably connected at the distal end to said tubular member;

a tip member extending distally from said balloon member, said tip member being more flexible than said balloon member;

a waist portion shaft disposed substantially coaxially over said tubular shaft member between said balloon member and said main shaft, the distal end of said waist portion shaft being formed integrally with said balloon member and the proximal end of said waist portion shaft being bonded to the distal end of said main shaft, said waist portion shaft being made of a different material than said main shaft and being of reduced outer diameter and reduced wall thickness as compared to said main shaft, the length of said waist portion shaft between said balloon member and said main shaft being equal to at least one length of said balloon member; and

an annular lumen being defined through said tubular shaft, said main shaft and said waist portion shaft, said annular lumen providing fluid communication between the proximal end of said main shaft and said balloon member so as to provide an inflation pressure.

FIELD OF THE INVENTION

This invention relates to vascular catheters for use in percutaneous transluminal angioplasty procedures. In particular, the invention is especially adapted to treatment of coronary arteries with catheters introduced percutaneously remote from the heart and advanced along a guide wire to a coronary artery for dilating a stenosis therein.

BACKGROUND OF THE INVENTION

Angioplasty has become an accepted and rapidly expanding method for the treatment of certain types of vascular disease. In percutaneous transluminal angioplasty, a guide wire is introduced percutaneously into the patient's vascular system and advanced and steered to the site of the stenosis. A dilation catheter is then advanced over the guide wire until it is positioned at the stenosis site so that it can be inflated to dilatate the artery and reestablish a more adequate blood flow path therethrough.

Such techniques are especially important in the treatment of coronary artery diseases by percutaneous transluminal coronary angioplasty. In coronary applications, guide catheters, guide wires and angioplasty catheters have been specially developed for maneuvering through numerous arterial branches and into the particular coronary artery branch where treatment is desired. Because of the many branches which must be successfully negotiated and the convoluted, tortuous path which must be followed by the catheter, numerous specialized instruments have been developed for this purpose, with the result that an increasingly large number of cases can be successfully treated. However, certain problems still can be encountered in the positioning of the angioplasty catheter, especially in the final few tight branches an turns leading to a stenosis site in a coronary artery. The problem can occur after a guide wire has successfully been advanced into position and while the dilatation catheter is being advanced over the guide wire. When encountering a sharp turn to a smaller artery, it is possible that the distal end of the dilatation catheter may be too stiff to make the small radius turn. This can cause great difficulty in trying to manipulate and maneuver the catheter around the turn, and in extreme cases can result in the catheter actually advancing down the wrong branch and pulling the guide wire out of the intended branch.

Prior art catheters tend to have a relatively stiff shaft which transitions at the beginning of the balloon to a lower stiffness. This means that the flexible distal portion of a prior art catheter consists only of the relatively small tip and the balloon, with the stiffer shaft starting immediately adjacent the balloon. This may not provide sufficient flexibility to permit the catheter to follow sharp bends, and may result in the stiff shaft pushing the balloon past the branch and even pulling the guide wire out of the branch.

An alternate construction in the prior art uses a central lumen defining tube, and an outer, relatively flexible tube which forms the shaft and which has the balloon formed integrally therewith at the end. While this type of construction provides great flexibility for following sharp bends, after a number of such bends have been encountered, the shaft is too soft to transmit sufficient axial force without buckling, and it becomes impossible to advance the catheter any farther.

SUMMARY OF THE INVENTION

To overcome these and other problems, the present invention provides a variable stiffness, or variable softness catheter, which has a tip area that is soft enough to follow sharp tortuous bends of a guide wire without dislodging it, and which has a shaft portion which is stiff enough to provide the necessary axial force transmission so that the catheter can be advanced even after following a great number of bends. This is accomplished in the present invention by providing a catheter construction which has a shaft portion which is stiff enough to transmit axial forces needed to advance the catheter, a relatively flexible tip and balloon portion, and an intermediate portion, referred to herein as a "waist" portion between the shaft and the balloon, which has less stiffness than the shaft and permits a greater degree of flexibility of the whole tip area for following sharp turns as the catheter is being advanced.

According to another aspect of the invention, a set of matched catheters is provided for use in an angioplasty procedure, with individual catheters of the set having different lengths of the less-stiff waist portion. This allows the physician to match the catheter to the particular procedure at hand, and if a sharp bend is encountered which the tip cannot follow without tending to "pull" the wire from the intended branch, as referred to above, then it is a simple matter to withdraw the catheter, leaving the guide wire in place, and reintroduce another catheter from the set with a longer waist, so that the sharp bend can be accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, FIG. 1 is a sectional view of a catheter and hub assembly in accordance with one embodiment of the invention;

FIG. 2A is an enlarged sectional view of the tip portion of a catheter according to the present invention;

FIG. 2B is a view similar to FIG. 2A but showing a catheter having a different length of the waist portion;

FIG. 3A is a diagrammatic view illustrating the problem encountered in the prior art of attempting to maneuver a stiff catheter into a sharp turn to a branch of an artery;

FIG. 3B is a diagrammatic view similar to FIG. 2A illustrating the operation of a catheter of the present invention in accomplishing the sharp turn;

FIGS. 4A and 4B are enlarged sectional views of the tip portions of short and long waist catheters according to an alternative embodiment of the invention;

FIGS. 5A and 5B are enlarged sectional views of short and long waist catheters according to another embodiment of the invention; and

FIGS. 6A and 6B are enlarged sectional views showing short and long waist catheters according to a further embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is shown generally in FIG. 1, and the tip portion thereof is shown in greater detail in enlarged sectional views 2A and 2B which are substantially identical except for a difference in the length of the intermediate or waist portion.

The catheter generally has a tip area 10, an inflatable balloon area 12, intermediate or waist portion 14, and a shaft portion 16 which extends all the way up to the proximal end of the catheter and includes an appropriate fitting or hub assembly 18 for connection to the apparatus for applying dilatation pressure, and for administering medication and sensing arterial pressure as is generally known in the art.

In construction of the catheter, a hollow inner tube 21 is provided which runs the entire length of the catheter, and which defines the central lumen 22. Inner tube 21 may be made of any number of materials, and in the preferred embodiment is ma