Sequential activation RF electrode set for renal nerve ablation

• US 9,155,589 B2
• Filed: 07/22/2011
• Issued: 10/13/2015
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Jenson, Mark L.
• Primary Examiner(s): Stoklosa, Joseph
• Assistant Examiner(s): ZINK, AMANDA L
• Application Number:
  US13/188,684
• Publication Number:
  US 20120029500A1
• Time in Patent Office: 1,544 Days
• Field of Search: 606 32- 49
• US Class Current: 1/1
• 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 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00404 Blood vessels other than those in or around the heart
• CPC Class Codes: A61B 2018/00434 Neural system
• CPC Class Codes: A61B 2018/00511 Kidney
• CPC Class Codes: A61B 2018/00654 with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00892 Voltage
• CPC Class Codes: A61B 2018/124 switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image

Abstract

A catheter includes a flexible shaft having a length sufficient to access a patient'"'"'s renal artery. A treatment element at the distal end of the shaft is dimensioned for deployment within the renal artery. The treatment element comprises a radially expandable structure configured to maintain positioning within the renal artery. A multiplicity of electrodes are spaced apart on the treatment element and configured for switchable activation and deactivation in a predetermined sequence to generate overlapping zones of heating directed at perivascular nerves of the renal artery. The overlapping heating zones comprise a distal zone associated with relatively high current densities at a distance from the treatment element sufficient to ablate the perivascular renal nerves and a proximal zone associated with current densities lower than those of the distal zone and insufficient to cause thermal injury to tissue of the renal artery adjacent the treatment element.

Claims

1. A method, comprising:

positioning a treatment element within a blood vessel lumen adjacent target tissue at a treatment site of a body, the treatment element comprising a plurality of electrodes defining an electrode set and arranged relative to one another at the treatment element;

maintaining a position of the treatment element relative to target tissue at the treatment site of the body during ablation; and

switchably activating and deactivating the electrodes in a predetermined sequence to generate overlapping zones of heating directed at the target tissue;

the zones of heating overlapping to define a distal zone associated with relatively high current densities at a distance from the treatment element sufficient to ablate the target tissue and a proximal zone associated with current densities lower than those of the distal zone that cause no or negligible thermal injury to tissue at the treatment site adjacent the treatment element.

2. The method of claim 1, wherein at least some of the heating zones have spatially separated origins at the treatment element based on activation and deactivation of the set of electrodes, each of the heating zones comprising:

a distal zone of substantially continuous ohmic heating at a distance from the treatment element and sufficient to ablate the target tissue; and

a proximal zone of intermittent ohmic heating proximate the treatment element that causes insignificant thermal injury to tissue at the treatment site adjacent the treatment element.

3. The method of claim 1, comprising providing cooling at an electrode-tissue interface defined between the treatment element and tissue at the treatment site adjacent the treatment element.

4. The method of claim 1, wherein:

maintaining treatment element positioning comprising maintaining the position of the treatment element within a renal artery during ablation;

the distal zone is associated with current densities sufficient to ablate perivascular renal nerves; and

the proximal zone is associated with current densities that cause no or negligible thermal injury to tissue of the renal artery adjacent the treatment element.