Device and method for preventing restenosis

• US 6,223,085 B1
• Filed: 05/06/1997
• Issued: 04/24/2001
• Est. Priority Date: 05/06/1997
• Status: Expired due to Term

• Current Assignee: Auslo Research LLC
• Original Assignee: Urologix Inc.
• Inventors: Dann, Mitchell, Flachman, Jonathan L., Hirose, Teruo T., Rudie, Eric N., Thome, Scott P., McGrath, Jonathan R.
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US08/852,154
• Time in Patent Office: 1,449 Days
• Field of Search: 606/27-31, 606/7-13, 606/17, 607/101, 607/102, 607/113, 607/116, 607/154-156
• US Class Current: 607/101
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2017/22002 preventing restenosis
• CPC Class Codes: A61B 2017/22038 with a guide wire
• CPC Class Codes: A61B 2017/22067 Blocking; Occlusion A61B2017/22054 takes precedence
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00369 Heart valves
• CPC Class Codes: A61B 2018/00422 Angioplasty
• CPC Class Codes: A61B 2018/1435 Spiral
• CPC Class Codes: A61B 2018/183 characterised by the type of antenna
• CPC Class Codes: A61B 2018/1838 Dipole antennas
• CPC Class Codes: A61B 2018/1846 Helical antennas
• CPC Class Codes: A61B 2018/1861 with an instrument inserted into a body lumen or cavity, e.g. a catheter
• CPC Class Codes: A61N 5/045 specially adapted for treatment inside the body

Abstract

A method and apparatus for reducing restenosis of a stenotic region of a blood vessel after performing a dilatation angioplasty treatment is disclosed. The method includes radiating microwave energy from a microwave antenna to kill a medial tissue layer of the blood vessel in the stenotic region. The radiation is applied during or after inflation of dilatation balloon to permanently dilate the stenotic region. When radiation is applied during dilatation of the stenotic region, the dilatation balloon forms a seal against the inner wall surface of the blood vessel to exclude blood in the vessel from contacting the stenotic region. The method preferably further includes cooling the blood circulating in the blood vessel about a shaft of the catheter with cooling fluid circulating within cooling lumens of the catheter and cooling an inner wall surface of the blood vessel in the stenotic region during the application of radiation to the medial cell layer. Finally, the method also preferably includes perfusing blood in the vessel through the catheter across the stenotic region during dilatation of the stenotic region to maintain circulation of blood through the blood vessel during the dilatation of the stenotic region.

Claims

1. A method of preventing restenosis of a blood vessel comprising:

inserting and advancing a catheter through a cardiovascular system until a distal portion of the catheter extends across a stenotic region within the blood vessel of the system;

forcing contact between the stenotic region and a dilatation balloon located in the distal portion of the catheter;

cooling the inner wall surface of the blood vessel in the stenotic region with a first fluid circulating within the dilatation balloon; and

heating a portion of the blood vessel in the stenotic region with microwave energy from a microwave antenna within the distal portion of the catheter at a temperature above about 45°

C. for a period of time sufficient to substantially destroy a portion of the blood vessel in the stenotic region while cooling the inner wall surface of the blood vessel with the first fluid circulating within the dilatation balloon.

2. The method of claim 1 wherein the portion of the blood vessel being heated and substantially destroyed are smooth muscle cells of a medial cell layer of the blood vessel.

3. The method of claim 1 wherein the contacting step further comprises dilating the stenotic region with the dilatation balloon and further comprising:

performing the heating step and the cooling step during the dilating step, wherein the dilating step further includes;

inflating the dilatation balloon with the first fluid for a time and under a pressure sufficient to permanently dilate the stenotic region and sufficient to form a seal between the dilatation balloon and the inner wall surface of the blood vessel in the stenotic region.

4. The method of claim 1 wherein the step of cooling circulating the first fluid through a pair of cooling lumens located within the catheter in direct communication with the dilatation balloon, so the the first fluid circulates through both the cooling lumens and the dilatation balloon.

5. The method of claim 1 wherein the step of cooling further comprises circulating a second fluid within a pair of cooling lumens located within the catheter, wherein the first fluid within the dilatation balloon is cooled conductively through a wall of the cooling lumens by the second fluid circulating within the cooling lumens.

6. The method of claim 1 and further comprising:

directing blood circulating in the blood vessel to pass through a perfusion lumen within the catheter located across the stenotic region during the dilating step to maintain circulation of blood within the blood vessel.

7. A method of preventing restenosis of a blood vessel comprising:

inserting into a blood vessel of a cardiovascular system a catheter including an expansible dilatation balloon, a microwave antenna, and a pair of cooling lumens configured and arranged between the antenna and the dilatation balloon so that cooling fluid passing through the cooling lumen conductively cools an inflation fluid within the dilatation balloon;

advancing the catheter within the blood vessel to locate the microwave antenna, the dilatation balloon, and a distal portion of the cooling lumens across a stenotic region of the blood vessel;

inflating the dilatation balloon for a time and under a pressure sufficient to dilate the stenotic region and sufficient to force contact of an outer surface of the dilatation balloon against an inner wall surface of the blood vessel in the stenotic region to reduce contact between the blood in the blood vessel and the stenotic region;

cooling blood circulating within the blood vessel and cooling the inner wall surface of the blood vessel in the stenotic region with the inflation fluid in the dilatation balloon; and

heating a portion of the blood vessel with energy from the microwave antenna at a temperature above 45°

C. for a time sufficient to substantially kill a portion of the blood vessel while dilating the stenotic region with the dilatation balloon, cooling blood circulating within the blood vessel cooling the inner wall surface of the blood vessel in the stenotic region with the inflation fluid in the dilatation balloon.

8. An angioplasty catheter for preventing restenosis of a blood vessel comprising:

a catheter shaft having a distal end, a proximal end, and a plurality of lumens extending therebetween including;

an antenna lumen;

a guide wire lumen;

an inflation lumen; and

a pair of cooling lumens substantially surrounding the antenna lumen and in communication with each other adjacent the distal end of the shaft to permit circulation of cooling fluid through the cooling lumens;

a microwave antenna located within the antenna lumen, the microwave antenna having a length and being operable to emit microwave radiation in a treatment region having a treatment length along the length of the microwave antenna; and

a dilatation balloon inflatable to dilate the blood vessel, the dilatation balloon being in communication with the inflation lumen and arranged to at least partially surround the cooling lumens and the microwave antenna along the entire treatment length so that cooling fluid passing through the cooling lumens adjacent the dilatation balloon passively cools an inflation fluid within the dilatation balloon to cool an inner wall surface of the blood vessel around the microwave antenna.

9. The catheter of claim 8 and further comprising:

a tip secured onto the distal end of the catheter shaft distal to the dilatation balloon, the tip having a guide wire extension lumen in communication with the guide wire lumen and defining a chamber in communication with each of the cooling lumens to permit communication between the cooling lumens.

10. The catheter of claim 9 and further comprising:

a perfusion passageway having a distal port, a proximal port and a mid portion, the distal port and proximal ports being formed in an outer surface of the catheter shaft, the distal port being located distal to the dilatation balloon and the proximal port being located proximal to the dilatation balloon, wherein the mid portion extends between the distal and proximal ports coextensive with the dilatation balloon and is defined by an expanded diameter portion of the guide wire lumen.

11. An angioplasty catheter for preventing restenosis of a blood vessel comprising:

a catheter shaft having a distal end, a proximal end, and a plurality of lumens extending therebetween including;

an antenna lumen;

an inflation lumen; and

a pair of cooling lumens substantially surrounding the antenna lumen and in communication with each other adjacent the distal end of the shaft to permit circulation of cooling fluid through the cooling lumens;

a microwave antenna located within the antenna lumen, the microwave antenna having a length and being operable to emit microwave radiation in a treatment region having a treatment length along the length of the microwave antenna;

a dilatation balloon inflatable to dilate the blood vessel, the dilatation balloon being in communication with the inflation lumen and arranged to at least partially surround the cooling lumens and the microwave antenna along the entire treatment length so that cooling fluid passing through the cooling lumens adjacent the dilatation balloon passively cools an inflation fluid within the dilatation balloon to cool an inner wall surface of the blood vessel around the microwave antenna; and

a guide wire and perfusion lumen extending within the shaft coextensive with a length of the dilatation balloon and having a distal port and a proximal port in an outer surface of the catheter shaft, the distal port being located distal to the dilatation balloon and the proximal port being located proximal to the dilatation balloon, the guide wire and perfusion lumen having a diameter sufficient to permit passage of a guide wire and the circulation of blood therethrough.

12. An angioplasty catheter for preventing restenosis of a blood vessel comprising:

a catheter shaft having a distal end, a proximal end, and a plurality of lumens extending therebetween including;

an antenna lumen;

a guide wire lumen; and

a pair of cooling lumens substantially surrounding the antenna lumen and being in communication adjacent the distal end of the catheter to permit circulation of cooling fluid through the cooling lumens;

a microwave antenna located within the antenna lumen, the microwave antenna having a length and being operable to emit microwave radiation in a treatment region having a treatment length along the length of the microwave antenna;

a dilatation balloon inflatable to dilate the blood vessel, the dilatation balloon at least partially surrounding, and being in communication with, the cooling lumens so that the fluid passing through the cooling lumens inflates and cools the dilatation balloon, the inflatable dilatation balloon being arranged to at least partially surround the microwave antenna along the entire treatment length to cool an inner wall surface of the blood vessel around the microwave antenna.

13. An angioplasty catheter for preventing restenosis of a blood vessel comprising:

a catheter shaft having a distal end, a proximal end, and a plurality of lumens extending therebetween and including;

a guide wire lumen; and

a pair of cooling lumens including a cooling intake lumen and a cooling exhaust lumen;

a microwave antenna located within one of the cooling lumens, the microwave antenna having a length and being operable to emit microwave radiation in a treatment region having a treatment length along the length of the microwave antenna;

a dilatation balloon inflatable to dilate the blood vessel, the dilatation balloon being in communication with the cooling lumens and at least partially surrounding the cooling lumens and the microwave antenna along the entire treatment length; and

wherein the cooling lumens are in communication with each other at a distal end of the catheter within the dilatation balloon so that a fluid passing through the cooling lumens circulates within the dilatation balloon to cool an inner wall surface of the blood vessel around the microwave antenna.

14. The catheter of claim 13 wherein each of the cooling lumens has a semi-circular shaped transverse cross-section the terminates adjacent the catheter distal end within an interior of the dilatation balloon.

15. The catheter of claim 14 and further comprising a cooling and pressurization system including:

a heat exchanger;

a pump;

a reservoir;

a pressurization device;

wherein the heat exchanger, pump, reservoir and pressurization device are in communication in series and wherein the heat exchanger is in communication with the cooling intake lumen and the reservoir is in communication with the cooling exhaust lumen.

16. A method of preventing restenosis of blood vessel comprising:

inserting and advancing a catheter through a cardiovascular system until a distal portion of the catheter extends across a stenotic region within the blood vessel of the system;

forcing contact of a dilatation balloon located in the distal portion of the catheter against the stenotic region; and

heating a medial tissue layer of the blood vessel in the stenotic region with microwave energy from a microwave antenna within the distal portion of the catheter at a temperature above about 45°

C. for a period of time sufficient to substantially destroy smooth muscle cells in the medial tissue layer of the stenotic region while maintaining contact between the dilatation balloon and the stenotic region and while cooling the inner wall surface of the blood vessel in the stenotic region with a first fluid circulating within the dilatation balloon.