Microwave thermal therapy of cardiac tissue

• US 5,861,021 A
• Filed: 12/20/1996
• Issued: 01/19/1999
• Est. Priority Date: 06/17/1996
• Status: Expired due to Term

• Current Assignee: Auslo Research LLC
• Original Assignee: Urologix Inc.
• Inventors: Dann, Mitchell, Rudie, Eric N., Thome, Scott P., Hirose, Teruo T.
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): HUANG, STEPHEN D
• Application Number:
  US08/771,214
• Time in Patent Office: 760 Days
• Field of Search: 604/96-98, 604/114, 604/264, 604/280, 607/101-105, 607/113, 607/116, 607/154, 607/156
• US Class Current: 607/101
• 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

Abstract

A method of applying microwave energy to cardiac tissue uses a catheter adapted for insertion into a cardiac chamber and which includes a microwave antenna, a cooling lumen structure, and an inflatable cooling balloon. Necrosing levels of microwave energy are delivered from the microwave antenna to diseased cardiac tissue spaced from the catheter. Tissues immediately surrounding the catheter are cooled and microwave energy emitted by the antenna is selectively absorbed by the cooling lumen structure surrounding the antenna. The cooling balloon of the catheter is positioned adjacent the antenna and partially surrounds the cooling lumen structure on one side of the catheter to provide additional cooling capability and additional microwave energy absorption on the side of the catheter opposite the diseased cardiac tissue to prevent unwanted heating of blood within the cardiac chamber.

Claims

1. A method for treating a diseased portion of cardiac tissue comprising:

inserting an intravascular catheter into a cardiovascular system including a microwave antenna disposed within an antenna lumen, a plurality of fluid flow lumens substantially surrounding the antenna lumen and a balloon having an inflatable portion which partially surrounds the antenna lumen, the balloon being in communication with the fluid flow lumens;

advancing the catheter through the cardiovascular system with the balloon in a deflated state until a distal end of the catheter is within a ventricle of a heart and adjacent a diseased portion of cardiac tissue spaced from a wall of the ventricle;

positioning the distal end of the catheter so that a first side of the catheter is immediately adjacent the diseased portion to be treated and a second side of the catheter is adjacent blood within the ventricle;

cooling the ventricle by directing cooling fluid to flow through the fluid flow lumens to cool a surface of the ventricle wall adjacent the catheter first side and directing cooling fluid to flow through the balloon and the fluid flow lumens to cool blood within the ventricle adjacent the catheter second side; and

heating the diseased portion of tissue spaced from a surface of the ventricle wall with microwave energy from the microwave antenna at a power range and for a time sufficient to necrose the diseased portion of tissue.

2. A method for treating ventricular tachycardia comprising:

inserting an intravascular catheter into a vascular system including a microwave antenna disposed within an antenna lumen, a pair of fluid flow lumens surrounding the antenna lumen and a balloon having an inflatable portion which partially surrounds the antenna lumen and which is in fluid communication with the fluid flow lumens and having an inflated and deflated state;

advancing the intravascular catheter through the vascular system with the cooling balloon in its deflated state until a distal end of the catheter is within a chamber of a heart adjacent a wall of the chamber;

positioning the catheter so that a first side of the intravascular catheter is immediately adjacent the chamber wall and a second side of the intravascular catheter is exposed to blood within the chamber; and

heating a portion of tissue beyond a surface of the chamber wall with microwave energy from the microwave antenna at a power range and for a time sufficient to necrose the tissue portion while delivering cooling fluid through the fluid flow lumens to cool the chamber wall surface adjacent the intravascular catheter first side and through the balloon to cool the blood within the chamber.

3. The method of claim 2 wherein the balloon of the intravascular catheter has a generally arc-shaped transverse cross-section and is immediately adjacent the fluid flow lumens on the second side of the intravascular catheter shaft.

4. The method of claim 3 and further comprising:

inserting a guide catheter within the vascular system prior to inserting the intravascular catheter and advancing the guide catheter therethrough until a distal end of the guide catheter is within a chamber of the heart adjacent the chamber wall and a proximal end of the guide catheter extends proximally outside a patient; and

inserting the intravascular catheter within a proximal end of the guide catheter with the balloon in its deflated state and advancing the intravascular catheter therethrough until the distal end of the intravascular catheter is adjacent the wall of the chamber.

5. The method of claim 4 and further comprising:

delivering fluid through the fluid flow lumens and into the balloon at a pressure sufficient to inflate the balloon and maintain the balloon in its inflated state after the first side of the intravascular catheter is positioned adjacent the surface of the chamber wall.

6. An intravascular catheter for microwave thermal therapy comprising:

an elongate shaft having a first end, a second end, an outer surface and a plurality of lumens which extend between the first end and the second end of the shaft, the plurality of lumens including;

an antenna lumen; and

a plurality of fluid flow lumens arranged about the antenna lumen; and

a balloon connected to the outer surface of the elongate shaft along a portion of the shaft, the balloon having an inflatable portion which partially surrounds the antenna lumen and which is in fluid communication with at least one of the plurality of fluid flow lumens.

7. The intravascular catheter of claim 6 wherein the plurality of fluid flow lumens further comprises a first and second pair of fluid flow lumens and the inflatable portion of the balloon is disposed adjacent the second pair of fluid flow lumens.

8. The intravascular catheter of claim 7 wherein an inner wall of the inflatable portion of the balloon is common with a wall defining an outer wall of the second pair of fluid flow lumens so that a majority of the inflatable portion of the balloon is immediately adjacent the second pair of fluid flow lumens.

9. The intravascular catheter of claim 6 further comprising an electromagnetic radiation antenna within a portion of the antenna lumen of the shaft, the portion of the antenna lumen being adjacent to the balloon.

10. The intravascular catheter of claim 9 wherein the balloon has a length greater than a length of the portion of the antenna lumen which contains the antenna.

11. An intravascular catheter for microwave therapy comprising:

an elongate shaft having a first end, a second end, an outer surface and a plurality of lumens which extend between the first end and the second end of the shaft, the plurality of lumens including;

an antenna lumen;

a plurality of fluid flow lumens arranged about the antenna lumen; and

an inflation lumen; and

a balloon connected to the outer surface of the elongate shaft along a portion of the shaft, the balloon having an inflatable portion which partially surrounds the antenna lumen and which is in fluid communication with the inflation lumen.

12. A device for treatment of ventricular tachycardia comprising:

an intravascular catheter adapted to be inserted into a ventricle of the heart, the catheter having an outer surface, a first end, a second end, a first side for orientation toward a wall of the ventricle, and a second side for orientation toward blood within the ventricle;

radiating means within the catheter for producing an emission capable of necrosing target cardiac tissue beyond a surface of the wall of the ventricle;

means within the catheter disposed between the radiating means and the outer surface of the catheter on both the first side and the second side of the catheter for preventing necrosis of the surface of the ventricle wall; and

a balloon positioned along a portion of the catheter adjacent to the radiating means, the balloon being connected to the outer surface of the catheter and having an inflatable portion on the second side of the catheter in fluid communication with the means for preventing necrosis of the surface of the ventricle wall.

13. An intravascular catheter for microwave therapy comprising:

an elongate shaft having a first end, a second end, an outer surface, and a plurality of lumens extending between the first end and the second end, the plurality of lumens including;

an antenna lumen; and

a first fluid flow lumen and a second fluid flow lumen arranged in a side by side relationship and partially surrounding the antenna lumen; and

a balloon connected to the outer surface of the elongate shaft along a portion of the shaft, the balloon having an inflatable portion which partially surrounds the antenna lumen and which is in fluid communication with the second fluid flow lumen.

14. The catheter of claim 13 wherein an inner wall of the inflatable portion of the balloon is common with a wall defining an outer wall of the second fluid flow lumen so that a majority of the inflatable portion of the balloon is immediately adjacent the second fluid flow lumen.

15. A device for treatment of ventricular tachycardia comprising:

an intravascular catheter adapted to be inserted into a ventricle of a heart, the catheter having an outer surface, a first end, a second end, a first side for orientation toward a wall of the ventricle, and a second side for orientation toward blood within the ventricle;

radiating means within the catheter for producing an emission capable of necrosing target cardiac tissue spaced from a surface of the wall of the ventricle;

first fluid circulation means within the catheter adjacent to the radiating means on both the first side and the second side of the catheter for protecting the surface of the ventricle wall; and

second fluid circulation means on the catheter along the second side of the catheter adjacent to the radiating means for cooling the blood within the ventricle.

16. The device of claim 15 wherein the intravascular catheter further comprises:

an inflation lumen for supplying a cooling fluid to the second fluid circulation means.

17. A device for treatment of ventricular tachycardia comprising:

an intravascular catheter adapted to be inserted into a ventricle of a heart, the catheter having an outer surface, a first end, a second end, a first side for orientation toward a wall of the ventricle, and a second side for orientation toward blood within the ventricle;

radiating means within the catheter for producing a microwave emission capable of necrosing target cardiac tissue spaced from a surface of the wall of the ventricle;

first cooling means within the catheter disposed between the radiating means and the outer surface of the catheter on the first side of the catheter for cooling the ventricle wall and for absorbing a first amount of the microwave emission; and

second cooling means disposed around the radiating means on the second side of the catheter for absorbing a second amount of the microwave emission from the radiating means and for cooling blood within the ventricle, the second cooling means having an inner portion and an outer portion adjacent the inner portion.

18. The device of claim 17 wherein the intravascular catheter further comprises:

an inflation lumen for supplying a cooling fluid to the outer portion of the second cooling means.

19. A device for treatment of ventricular tachycardia comprising:

an intravascular catheter adapted to be inserted into a ventricle of a heart, the catheter having an outer surface, a first end, a second end, a first circumferential portion for orientation toward a wall of the ventricle, and a second circumferential portion for orientation toward blood within the ventricle;

radiation means within the catheter for producing an emission capable of necrosing target cardiac tissue spaced from a surface of the wall of the ventricle;

first means within the catheter adjacent to the radiation means for preventing necrosis of the surface of the ventricle wall; and

a balloon connected to the outer surface of the catheter adjacent to the radiation means, the balloon being configured to inflate on the second circumferential portion of the catheter.

20. A device for treatment of ventricular tachycardia comprising:

an intravascular catheter adapted to be inserted into a ventricle of a heart, the catheter having an outer surface, a first end, a second end, a first circumferential portion for orientation toward a wall of the ventricle, and a second circumferential portion for orientation toward blood within the ventricle;

radiation means within the catheter for producing an emission capable of necrosing target cardiac tissue spaced from a surface of the wall of the ventricle;

first means within the catheter disposed between the radiating means and the outer surface of the catheter at both the first and second circumferential portions for preventing necrosis of the surface of the ventricle wall; and

a balloon connected to the outer surface of the catheter adjacent to the radiation means, the balloon defining a chamber on the second circumferential portion of the catheter.