Apparatus and method for occluding a vessel by RF embolization

Patent metadata

Field	Value
Publication number	US-10052151-B2
Application number	US-201514681644-A
Country	US
Kind code	B2
Filing date	Apr 8, 2015
Priority date	Apr 10, 2014
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

An RF ablation system includes an electrode element of elongate form and a cathode pad. A control unit includes a processing unit, a power unit and, optionally, a temperature sensor and/or an impedance sensor. The control unit in one embodiment carries out RF ablation in at least two phases, the first phase at a higher energy level and a second phase, after at least partial retraction of the anode element, at a second lower phase in order to close any remaining lumen within a blood clot formed within the vessel during the first phase. Other embodiments provide for sensing retraction of the anode terminal and effecting RF ablation during and/or after the retraction process in order to create a more effective occlusion barrier.

First claim

The invention claimed is:

1. Apparatus for closing a blood vessel have a vessel wall, the apparatus comprising:
an elongate electrode element for being passed endoluminally to a treatment site and having at least one electrical terminal at a distal end thereof;
a power supply for supplying energy to the electrode element;
a detection unit for detecting at least one operational change at the at least one electrical terminal; and
a control unit connected to the power supply and to the detection unit; wherein the control unit is operable to control the power supply to supply energy to the electrode element at a first step at a first power level to heat blood within the blood vessel without ablating the vessel wall to cause a primary blood coagulation, the first power level being substantially constant during the first step,
to detect at least one operational change at the at least one electrical terminal, and

in a second step, to control the power supply after detecting the at least one operational change to supply energy to the electrode element at a second power level lower than the first power level to cause a secondary blood coagulation once the operational change has been detected, the second power level being substantially constant during the second step.

2. Apparatus according to claim 1 , including a user notification unit coupled to the control unit, the control unit being operable to generate a notification on detection of the operational change in the at least one electrical terminal.

3. Apparatus according to claim 1 , wherein the control unit is operable to command a partial retraction of the electrode element in a proximal direction on detection of the operational change.

4. Apparatus according to claim 3 , including a positioning unit coupled to the control unit, the positioning unit being operable to effect said partial retraction of the electrode element in a proximal direction on detection of said operational change.

5. Apparatus according to claim 3 , wherein the control unit is operable to generate a notification to effect said partial retraction of the electrode element.

6. Apparatus according to claim 1 , including an electrode position sensor coupled to the control unit, wherein the control unit is operable to control the power supply to supply energy to the electrode element at the or a second power level lower than the first power level when partial retraction of the electrode element has been detected.

7. Apparatus according to claim 6 , wherein the control unit is operable to command the power supply to supply power to the electrode element until the electrode element has been retracted by a predetermined distance.

8. Apparatus according to claim 7 , wherein the predetermined distance is equivalent to a desired length of closure of the vessel.

9. Apparatus according to claim 1 , wherein the operational change includes at least one of: change in measured impedance and change in temperature.

10. Apparatus according to claim 9 , including a temperature sensor at the distal end of the electrode element.

11. Apparatus according to claim 1 , wherein the electrode element includes an anode terminal, the apparatus including a cathode pad; or the electrode element includes anode and cathode terminals.

12. Apparatus for closing a blood vessel have a vessel wall, the apparatus comprising:
an elongate electrode element having at least one electrical terminal at a distal end thereof;
a power supply for supplying energy to the electrode element;
a detection unit for detecting at least one operational change at the at least one electrical terminal;
a position sensor arranged to detect the position of the distal end of the electrode in a patient;
a control unit connected to the power supply, to the detection unit and to the position sensor; wherein the control unit is operable to control the power supply to supply energy to the electrode element at a first step at a first power level to heat blood within the blood vessel without ablating the vessel wall, the first power level being substantially constant during the first step,
to determine movement of the electrode and to apply power to the electrode when the electrode has been deemed to have been moved by a first predetermined distance, and
in a second step, to supply energy to the electrode element after detecting the at least one operational change at a second power level lower than the first power level once the electrode has been deemed to have been moved by the first predetermined distance and the operational change has been detected, the second power level being substantially constant during the second step.

13. Apparatus according to claim 12 , wherein the control unit is operable to apply power to the electrical terminal continuously when in an initial position and while the electrode element is moved by the predetermined distance; or wherein the control unit is operable to apply power to the electrical terminal discontinuously, when in an initial position and after the electrode element has been moved by the predetermined distance.

14. Apparatus according to claim 12 , wherein the control unit is operable to apply power to the electrical terminal up to a second distance greater than the first predetermined distance.

15. Apparatus according to claim 14 , wherein the second distance is equivalent to a desired length of closure of the vessel.

16. Apparatus according to claim 12 , wherein the electrical terminal has a conductive length and the first predetermined distance is less than said conductive length.

17. Apparatus according to claim 12 , including a positioning unit coupled to the control unit, the positioning unit being operable to move the electrode element in at least a proximal direction.

18. A method of closing a blood vessel having a vessel wall by means of apparatus including an elongate electrode element for being passed endoluminally to a treatment site and having at least one electrical terminal at a distal end thereof and a power supply for supplying energy to the electrode element; the method including the steps of:
supplying energy to the electrode element at a first step at a first power level to heat blood within the blood vessel without ablating the vessel wall to cause a primary blood coagulation, the first power level being substantially constant during the first step;
detecting at least one operational change at the at least one electrical terminal; and
when said operational change has been detected, in a second step, supplying energy to the electrode element at a second power level lower than the first power level to cause a secondary blood coagulation, the second power level being substantially constant during the second step.

19. A method according to claim 18 , including the step of generating a user notification on detection of the operational change in the at least one electrical terminal.

20. A method according to claim 18 , including the step of partially retracting the electrode element in a proximal direction on detection of the operational change.

21. A method according to claim 20 , including the step of detecting partial retraction of the electrode element.

22. A method according to claim 20 , wherein the electrode element is retracted by a predetermined distance while supplying power thereto.

23. A method according to claim 22 , wherein the predetermined distance is equivalent to a desired length of closure of the vessel.

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Assignees

• Cook Medical Technologies Llc

Inventors

• Elgaard Per
• Torp Allan

Classifications

• A61B2018/1467

  using more than two electrodes on a single probe · CPC title

• A61B2018/00898

  Alarms or notifications created in response to an abnormal condition · CPC title

• A61B2018/00875

  Resistance or impedance · CPC title

• A61B2018/00791

  Temperature · CPC title

• A61B2018/00702

  Power or energy · CPC title