Balloon catheter

• US 20030149468A1
• Filed: 02/06/2003
• Published: 08/07/2003
• Est. Priority Date: 05/26/2000
• Status: Active Grant

• Current Assignee: Wallsten Medical SA
• Original Assignee: Wallsten Medical SA
• Inventors: Wallsten, Hans I
• Granted Patent: US 7,156,860 B2
• Time in Patent Office: Days
• US Class Current: 623/1.11
• CPC Class Codes: A61B 2018/1861 with an instrument inserted into a body lumen or cavity, e.g. a catheter
• CPC Class Codes: A61M 2025/0008 having visible markings on its surface, i.e. visible to the naked eye, for any purpose, e.g. insertion depth markers, rotational markers or identification of type
• CPC Class Codes: A61M 2025/0175 having telescopic features, interengaging nestable members movable in relations to one another
• CPC Class Codes: A61M 2025/1061 having separate inflations tubes, e.g. coaxial tubes or tubes otherwise arranged apart from the catheter tube
• CPC Class Codes: A61M 2025/1068 having means for varying the length or diameter of the deployed balloon, this variations could be caused by excess pressure
• CPC Class Codes: A61M 2025/1075 having a balloon composed of several layers, e.g. by coating or embedding
• CPC Class Codes: A61M 2205/36 related to heating or cooling
• CPC Class Codes: A61M 25/104 used for angioplasty
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media

Abstract

The invention relates to balloon catheters (1) and methods of treatment for exerting internal pressure on surrounding tissue of a mammalian duct or cavity in a section thereof having a substantially circular cylindrical configuration. The elongate rigid distal section and the intermediate section of the catheter contain a central tube (3), whose distal part is provided with at least one outlet (23) for medium within the balloon, and whose intermediate part is surrounded by an axially displaceable tube (4), onto whose distal end the proximal end of the balloon is attached. The balloon has an envelope which is constituted by at least one substantially gas- and liquid-impermeable and elastic internal layer and an external layer of limited radial expansion, said expansion being substantially independent of the axial length of said balloon. The balloon may he encompassed by a radially expandible stent (40), or can be equipped with means for supplementing treatment using pressure with heat treatment.

Claims

1. Balloon catheter for exerting internal pressure on surrounding tissue of a mammalian duct or cavity in a section thereof having a substantially circular cylindrical configuration, comprising an elongate, rigid distal section and a flexible and elastic balloon accommodating said distal section which, together with said balloon is intended for insertion into said duct or cavity section, further comprising means for the supply of a pressure medium for the expansion of said balloon, the catheter further comprising an intermediate section and a proximal section for operating the device, characterized in that said distal and intermediate sections contain a central tube, whose distal part is provided with at least one outlet for said medium within said balloon, and whose intermediate part is surrounded by an axially displacable tube, onto whose distal end the proximal end of said balloon is attached, further characterized in that said balloon has an envelope which is constituted by at least one substantially gas- and liquid-impermeable and elastic internal layer and a restricting layer of limited radial expansion, said expansion being substantially independent of the axial length of said balloon, the catheter including means for axially interlocking said tubes to each other in a position corresponding to a desired length of said balloon.

2. Balloon catheter according to claim 1, wherein said restricting layer is constituted by a braid or spiral structure with filaments of limited elasticity, or a knitted structure, optionally containing an extra interwoven filament in spiral configuration and of limited elasticity.

3. Balloon catheter according to claim 1, wherein said envelope is constituted by a triple-layered structure, where two substantially gas- and liquid-impermeable elastic layers are flanking or embracing a restricting layer of limited radial expansion.

4. Balloon catheter according to claim 1, wherein, as an alternative, said layers are integrated so as to constitute one single layer.

5. Balloon catheter according to any one of claims 1 to 3, wherein the layer of limited radial expansion is attached to at least one flanking layer.

6. Balloon catheter according to claim 3, wherein said layer of limited radial expansion is constituted by a braid structure, the filaments of which have a limited stretchability of about 150 to about 400%.

7. Balloon catheter according to claim 6, wherein the number of filaments is at least about 20 in each direction of winding.

8. Balloon catheter according to claim 6 or 7, wherein crossing filaments define an axially directed angle α

lying within the range about 100°

to about 140°

.

9. Balloon catheter according to any one of the preceding claims, wherein said central tube is composed of at least two telescopic and concentric partially overlapping tubes, one of which protrudes distally and carries the distal end of the balloon, and the other one of which carries the proximal end of the balloon whereby axial relative displacement of said tubes enables balloon length adjustment.

10. Balloon catheter according to any preceding claim for treatment of the prostate comprising a positioning balloon attached at the front end of said distal section and being expansible within the urinary bladder by introduction therein of said pressure medium or a separate pressure medium.

11. Balloon catheter according to any one of the preceding claims, comprising means generating circulation of said pressure medium within or through said balloon.

12. Balloon catheter according to any one of the preceding claims, characterized by a heating means for heating said pressure medium.

13. Balloon catheter according to claim 12, wherein said heating means is positioned within said balloon.

14. Balloon catheter according to claim 12, wherein said heating means is positioned within said intermediate section.

15. Balloon catheter according to claim 11, comprising a microwave antenna or radio-frequency emitter placed within said distal section, said antenna or emitter creating heat in the interior of surrounding tissue, whereas the circulation pressure medium cools a surface layer of said tissue around the balloon.

16. Balloon catheter according to any preceding claim, characterized by a radially expansible stent encompassing said balloon, said stent being deformable to expand synchronously with the radial expansion of the balloon when inserted in said duct or cavity, thereby being retained expanded therein upon withdrawal of the catheter from said duct or cavity.

17. Balloon catheter according to claim 16, wherein said stent is made of a thermoplastic material.

18. Balloon catheter according to claim 17, wherein said material is biodegradable, such as selected from PCA, PLLA and PLGA.

19. Balloon catheter according to claim 16, 17 or 18, wherein said stent has been made subject to heat forming at a temperature near melting temperature to give a desired stent configuration as implanted, and then cold formed to a desired configuration for insertion.

20. Balloon catheter according to any one of claims 16 to 19, characterized by means for partially deflating the balloon after expansion thereof for maintaining a desired diameter of the stent as implanted.

21. A method of treatment of a mammalian duct or cavity in a section thereof having a substantially circular cylindrical configuration by exerting an internal pressure on surrounding tissue thereof, comprising the steps:

a) estimating the axial extension of said section;

b) adjusting and securing the distance between the axial ends of an elastic balloon to match said axial extension;

c) inserting the balloon thus prepared into said duct or cavity section,;

d) initiating treatment by expanding said balloon by introducing a pressurized fluid therein to exert pressure on said walls to widen to a predetermined degree said duct or cavity within said section by using a balloon of predetermined limited radial expansion;

e) deflating said balloon and withdrawing same from said duct or cavity section.

22. A method according to claim 21, characterized by the further steps:

f) applying onto said balloon before renewed insertion thereof a radially expansible stent capable of radial deformation;

g) inserting said balloon carrying said stent into said section;

h) expanding said balloon by introducing a pressurized fluid to expand the stent; and

i) releasing the pressure to deflate the balloon and withdrawing same leaving the stent behind in an expanded state.

23. A method according to claim 21 or 22, wherein step b) is performed after step c), alternatively after step d).

24. A method according to claim 21, 22 or 23, wherein the pressure treatment is combined with heating to maintain pressure and temperature for a period of time to achieve a therapeutic effect in the tissue to be treated.

25. A method according to claim 24, wherein said fluid is circulated within or through said balloon.

26. A method according to claim 25, wherein said fluid also acts as a heating medium.

27. A method according to claim 24, wherein heating is provided by the generation of microwaves, the circulating pressure medium acting as coolant of the surface of surrounding tissue adjacent to the balloon.

28. A method according to any one of claims 24 to 27 directed to treatment of a prostate, comprising heating to maintain a temperature for a period of time resulting in partial necrosis of prostatic tissue.

29. A method according to any one of claims 21 and 23 to 28, characterized by the further step of applying onto the balloon before insertion thereof a radially expansible stent which is expanded by deformation synchronously with the expansion of the balloon said stent being left expanded behind upon removal of said catheter.

30. A method according to claim 29, wherein said stent is made of a thermoplastic material, the method comprising the steps:

a) inserting said balloon carrying said stent into said duct or cavity such as a prostatic urethra;

b) expanding said balloon by introducing a pressurized fluid and supplying heat sufficient to soften the stent to expand same and to widen said;

c) maintaining pressure and heating for a period of time and at a temperature resulting in partial necrosis of surrounding tissue;

d) interrupting heating for lowering temperature to fortify the stent; and

e) deflating the balloon and withdrawing same while leaving the stent behind in an expanded state.

31. A method according to claim 30, wherein said stent is constituted by a thermoplastic polymer and is made subject to heat forming at a temperature near melting temperature to give a desired stent configuration as implanted, and then cold formed to a desired configuration for insertion, the deflation of the balloon in step e) taking place before or simultaneously with interrupting heating.

32. A method according to claim 30 or 31, wherein after step c) the balloon is partially deflated for maintaining a desired diameter of the stent.