Apparatus and method for ablating tissue

• US 8,308,719 B2
• Filed: 12/10/2007
• Issued: 11/13/2012
• Est. Priority Date: 09/21/1998
• Status: Expired due to Fees

• Current Assignee: St. Jude Medical, Atrial Fibrillation Division, Inc. (Abbott Laboratories)
• Original Assignee: St. Jude Medical, Atrial Fibrillation Division, Inc. (Abbott Laboratories)
• Inventors: Sliwa, John W., Ciciarelli, Timothy E.
• Primary Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US11/953,601
• Publication Number:
  US 20080091195A1
• Time in Patent Office: 1,800 Days
• Field of Search: 606/27, 606/28, 606/41, 600/437, 600/439, 600/459, 600/462, 600/466, 601/2, 601/3
• US Class Current: 606/28
• CPC Class Codes: A61B 17/22012 in direct contact with, or very close to, the obstruction or concrement for removing obstructions in blood vessels by laser A61B18/245
• CPC Class Codes: A61B 17/2202 the ultrasound transducer being inside patient's body at the distal end of the catheter
• CPC Class Codes: A61B 18/00 Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• CPC Class Codes: A61B 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• 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 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/00252 for by-pass connections, i.e. connections from heart chamber to blood vessel or from blood vessel to blood vessel
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/22077 with a part piercing the tissue A61B2017/22044 takes precedence
• CPC Class Codes: A61B 2017/3419 Sealing means between cannula and body
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00232 having an irregular shape
• CPC Class Codes: A61B 2018/00261 arranged in a line
• CPC Class Codes: A61B 2018/00285 Balloons
• CPC Class Codes: A61B 2018/00291 : using suction
• CPC Class Codes: A61B 2018/00351 : Heart
• CPC Class Codes: A61B 2018/00363 : Epicardium
• CPC Class Codes: A61B 2018/00392 : Transmyocardial revascularisation
• CPC Class Codes: A61B 2018/00577 : Ablation
• CPC Class Codes: A61B 2018/00654 : with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00797 : measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00839 : Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2018/142 : at least partly surrounding the target, e.g. concave, curved or in the form of a cave
• CPC Class Codes: A61B 2018/1467 : using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2090/3614 : using optical fibre
• CPC Class Codes: A61B 2090/3782 : transmitter or receiver in catheter or minimal invasive instrument
• CPC Class Codes: A61B 2090/395 : with marking agent for marking skin or other tissue
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration
• CPC Class Codes: A61B 34/20 : Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/287 : Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61N 1/06 : for high-frequency therapy
• CPC Class Codes: A61N 1/3629 : in combination with non-electric therapy
• CPC Class Codes: A61N 2007/0065 : Concave transducers
• CPC Class Codes: A61N 2007/0078 : with multiple treatment transducers
• CPC Class Codes: A61N 2007/027 : with multiple foci created simultaneously
• CPC Class Codes: A61N 7/02 : Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

A control system alters one or more characteristics of an ablating element to ablate tissue. In one aspect, the control system delivers energy nearer to the surface of the tissue by changing the frequency or power. In another aspect, the ablating element delivers focused ultrasound which is focused in at least one dimension. The ablating device may also have a number of ablating elements with different characteristics such as focal length.

Claims

1. A method of ablating cardiac tissue, the method comprising:

providing a tissue ablation device including a plurality of ablating elements and at least one adjustment structure coupled to at least one of the plurality of ablating elements;

placing the tissue ablation device in a first position on an epicardial surface;

activating the at least one of the plurality of ablating elements at least once to emit ultrasonic energy focused in at least one dimension towards tissue to be ablated; and

adjusting the at least one adjustment structure, wherein movement of the adjustment structure physically moves at least one of the plurality of ablating elements relative to the tissue, and wherein movement of the at least one of the plurality of ablating elements moves a focus of the ultrasonic energy emitted by the at least one of the plurality of ablating elements into at least one preset position relative to the tissue to be ablated without relocating the device from the first position on the epicardial surface.

2. The method according to claim 1, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure such that the focus of the ultrasonic energy is proximate an endocardial surface of the cardiac tissue.

3. The method according to claim 2, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure such that the focus of the ultrasonic energy is closer than about 1 mm to about 3 mm to the endocardial surface of the cardiac tissue.

4. The method according to claim 2, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure such that the focus of the ultrasonic energy is proximate the endocardial surface of the cardiac tissue and within a thickness of the cardiac tissue.

5. The method according to claim 2, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure such that the focus of the ultrasonic energy is proximate the endcoardial surface of the cardiac tissue and at least partially outside a thickness of the cardiac tissue within a blood pool.

6. The method according to claim 1, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure such that the focus of the ultrasonic energy is proximate an epicardial surface of the cardiac tissue.

7. The method according to claim 6, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure such that the focus is located within the innermost about 3 mm of endocardial tissue adjacent a blood pool.

8. The method according to claim 1, wherein the step of adjusting the at least one adjustment structure comprises adjusting the at least one adjustment structure to move a focus of the ultrasonic energy emitted by the at least one of the plurality of ablating elements into a plurality of positions relative to the tissue to be ablated, whereby a substantially continuous lesion is created in the cardiac tissue.

9. The method according to claim 8, wherein the substantially continuous lesion is a transmural lesion.

10. The method according to claim 8, wherein the adjusting step is carried out while the at least one of the plurality of ablating elements is actively ablating.

11. The method according to claim 8, wherein the adjusting step is carried out between activations of the at least one of the plurality of ablating elements.

12. The method according to claim 1, wherein the step of activating the at least one of the plurality of ablating elements to emit ultrasonic energy focused in at least one dimension comprises pulse-activating the at least one of the plurality of ablating elements to emit ultrasonic energy.

13. The method according to claim 12, wherein the step of pulse-activating the at least one of the plurality of ablating elements to emit ultrasonic energy comprises activating the at least one of the plurality of ablating elements for a pulse duration between about 0.1 seconds and about 1.5 seconds.

14. The method according to claim 13, wherein the pulse duration is between about 0.2 seconds and about 1.2 seconds.

15. The method according to claim 12, wherein the pulse duration is between about 0.25 seconds and about 1.0 seconds.

16. The method according to claim 12, wherein the step of pulse-activating the at least one of the plurality of ablating elements to emit ultrasonic energy comprises activating the at least one of the plurality of ablating elements to emit ultrasonic energy in short bursts.

17. The method according to claim 1, further comprising:

monitoring a temperature of the cardiac tissue; and

adjusting one or more properties of the at least one of the plurality of ablating elements to maintain the monitored temperature of the cardiac tissue below a preset threshold temperature.

18. The method according to claim 17, wherein the preset threshold temperature is about 100 degrees C.

19. A method of epicardially ablating cardiac tissue, the method comprising:

providing a tissue ablation device including at least one ablating element;

acoustically coupling the tissue ablation device to an epicardial surface of a heart; and

activating the at least one ablating element a first time at a first frequency for a first duration and a second time at a second frequency for a second duration to emit ultrasonic energy focused in at least one dimension towards cardiac tissue to be ablated, wherein the second duration is longer than the first duration,

wherein a focus of the ultrasonic energy emitted by the at least one ablating element is located proximate the endocardium, such that a lesioning temperature can be attained proximate an interface between an endocardial surface and a cardiac blood pool.

20. The method according to claim 19, wherein the step of acoustically coupling the tissue ablation device to an epicardial surface of a heart comprises acoustically coupling the tissue ablation device to the epicardial surface of the heart across an intermediate acoustic standoff.

21. The method according to claim 19, wherein the focus of the ultrasonic energy emitted by the at least one ablating element is movable relative to the at least one ablating element by varying one or more ablating element driving parameters.

22. The method according to claim 19, wherein the focus of the ultrasonic energy emitted by the at least one ablating element is movable relative to the tissue to be ablated by varying a spatial state of the at least one ablating element without acoustically decoupling the tissue ablation device from the epicardial surface of the heart.

23. The method according to claim 19, wherein the second frequency is greater than the first frequency.

24. A method of ablating cardiac tissue, the method comprising:

providing a tissue ablation device including a plurality of ablating elements, at least one of the ablating elements having an ablation energy deposition behavior versus tissue depth that can be depth-adjusted via a change in an operating parameter of the at least one ablating element;

acoustically coupling the tissue ablation device to cardiac tissue to be ablated; and

activating the at least one ablating element at two or more states of the operating parameter, wherein the at least one ablating element is activated a first time at a first frequency for a first duration and a second time at a second frequency for a second duration, wherein the second duration is longer than the first duration, thereby delivering the ablation energy at two or more depths in the cardiac tissue to be ablated.

25. The method according to claim 24, wherein the plurality of ablating elements comprises a plurality of ultrasonic transducers.

26. The method according to claim 25, wherein the operating parameter is ultrasonic frequency.

27. The method according to claim 24, wherein the plurality of ablating elements comprises a plurality of laser ablating elements.

28. The method according to claim 27, wherein the operating parameter is laser wavelength.