Methods and systems for thermally-induced renal neuromodulation

• US 9,314,644 B2
• Filed: 06/26/2008
• Issued: 04/19/2016
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Ireland Manufacturing Unlimited Company (Medtronic Plc)
• Original Assignee: Medtronic Ardian Luxembourg SARL (Medtronic Plc)
• Inventors: Wu, Andrew, Clark, Benjamin J., Thai, Erik, Zadno, Nicolas, Zarins, Denise
• Primary Examiner(s): HENSON, DEVIN B
• Application Number:
  US12/147,154
• Publication Number:
  US 20090062873A1
• Time in Patent Office: 2,854 Days
• Field of Search: 600/549, 606 48- 51, 606/34, 606/41, 606/42, 606/45, 606/46, 604/114, 128/898
• US Class Current: 1/1
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• 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 18/1815 using microwaves
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/22054 with two balloons
• CPC Class Codes: A61B 2017/22068 Centering
• 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 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00279 deployable
• 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 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00511 Kidney
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00636 Sensing and controlling the application of energy
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61B 2018/00702 : Power or energy
• CPC Class Codes: A61B 2018/00714 : Temperature
• CPC Class Codes: A61B 2018/00755 : Resistance or impedance
• CPC Class Codes: A61B 2018/00779 : Power or energy
• CPC Class Codes: A61B 2018/00791 : Temperature
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00994 : combining two or more different kinds of non-mechanical energy or combining one or more non-mechanical energies with ultrasound
• CPC Class Codes: A61B 2018/143 : multiple needles
• CPC Class Codes: A61B 2018/1432 : curved
• CPC Class Codes: A61B 2018/144 : Wire
• CPC Class Codes: A61B 2018/1475 : Electrodes retractable in or deployable from a housing
• CPC Class Codes: A61B 90/39 : Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: A61F 2007/0056 : for cooling
• CPC Class Codes: A61F 2007/0075 : using a Peltier element, e.g. near the spot to be heated or cooled
• CPC Class Codes: A61F 2007/126 : for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61F 7/007 : characterised by electric heating
• CPC Class Codes: A61F 7/10 : Cooling bags, e.g. ice-bags
• CPC Class Codes: A61F 7/12 : Devices for heating or cooling internal body cavities
• CPC Class Codes: A61M 2025/0087 : Multiple injection needles protruding laterally from the distal tip
• CPC Class Codes: A61M 2025/0092 : Single injection needle protruding laterally from the distal tip
• CPC Class Codes: A61M 2025/1047 : having centering means, e.g. balloons having an appropriate shape
• CPC Class Codes: A61M 25/0084 : being one or more injection needles
• CPC Class Codes: A61M 25/04 : in the body, e.g. expansible A61M25/10, A61M16/0488 take precedence
• CPC Class Codes: A61M 25/10 : Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: A61N 1/0558 : Anchoring or fixation means therefor
• CPC Class Codes: A61N 1/057 : Anchoring means; Means for fixing the head inside the heart
• CPC Class Codes: A61N 1/06 : for high-frequency therapy
• CPC Class Codes: A61N 1/36007 : of urogenital or gastrointestinal organs, e.g. for incontinence control
• CPC Class Codes: A61N 1/36017 : with leads or electrodes penetrating the skin
• CPC Class Codes: A61N 1/403 : for thermotherapy, e.g. hyperthermia
• CPC Class Codes: A61N 2007/0026 : Stimulation of nerve tissue
• CPC Class Codes: A61N 2007/003 : Destruction of nerve tissue
• CPC Class Codes: A61N 5/0601 : Apparatus for use inside the body
• CPC Class Codes: A61N 5/0622 : Optical stimulation for exciting neural tissue
• CPC Class Codes: A61N 7/02 : Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: A61N 7/022 : intracavitary

Abstract

Methods and system are provided for thermally-induced renal neuromodulation. Thermally-induced renal neuromodulation may be achieved via direct and/or via indirect application of thermal energy to heat or cool neural fibers that contribute to renal function, or of vascular structures that feed or perfuse the neural fibers. In some embodiments, parameters of the neural fibers, of non-target tissue, or of the thermal energy delivery element, may be monitored via one or more sensors for controlling the thermally-induced neuromodulation. In some embodiments, protective elements may be provided to reduce a degree of thermal damage induced in the non-target tissues. In some embodiments, thermally-induced renal neuromodulation is achieved via delivery of a pulsed thermal therapy.

Claims

1. A system for controlling therapeutic energy delivery, the system comprising:

an electrode configured for placement within a renal blood vessel;

a power output module for delivering energy via the electrode to a treatment site proximate to the wall of the renal blood vessel;

a temperature sensor for sensing a voltage corresponding to a temperature of the treatment site or of the electrode;

an impedance sensor for measuring an impedance value at the treatment site; and

a module for determining a temperature value based on the sensed voltage,

wherein the system is programmed with an algorithm comprising instructions that cause the power output module to

increase energy delivery to the electrode at a generally constant rate to a predetermined first power level over a first period of time,

maintain energy delivery to the electrode at the first power level for a second period of time after reaching the power level, and

if the measured temperature value of the treatment site or the electrode is less than a preset temperature threshold and the measured impedance value is less than a predetermined impedance threshold, then increase energy delivery to the electrode until a target maximum power level is reached.

2. The system of claim 1 wherein the temperature value is chosen from the group of real time temperature, average temperature, temperature offset, rate of temperature change, and combinations thereof.

3. The system of claim 1 wherein the temperature sensor is connected to the electrode.

4. The system of claim 1 wherein the temperature sensor is embedded within the electrode.

5. The system of claim 1 wherein the electrode comprises the impedance sensor.

6. The system of claim 1 wherein the temperature sensor and the impedance sensor are the same sensor.

7. The system of claim 1 wherein the system further includes instructions that cause the energy delivery to be maintained at the predetermined first power level if the temperature value is greater than or equal to the preset threshold temperature.

8. The system of claim 7 wherein the preset threshold temperature is about 65 degrees Celsius.

9. The system of claim 8 wherein the predetermined first power level is about 5 watts.

10. The system of claim 9 wherein the first period of time is about 15 seconds.

11. The system of claim 10 wherein the second period of time is at least 3 seconds.

12. The system of claim 1 wherein the preset threshold temperature is from about 45 degrees Celsius to about 90 degrees Celsius.

13. The system of claim 1 wherein the preset threshold temperature is from about 60 degrees Celsius to about 75 degrees Celsius.

14. The system of claim 1 wherein the algorithm futher comprises instructions that cause (a) the power output module to increase energy delivery to the electrode to a second power level if the measured temperature value is less than the preset threshold temperature following the second period of time, and (b) the energy delivery to the electrode to be reduced to a third power level less than the second power level if the temperature value reaches a second threshold temperature.

15. The system of claim 14 wherein the second power level is about 6 watts.

16. The system of claim 14 wherein the second power level is about 8 watts.

17. The system of claim 14 wherein the second threshold temperature is about 70 degrees Celsius.

18. The system of claim 14 wherein the reduction in power occurs in increments.

19. The system of claim 14 wherein the increase in power from the predetermined first power level to the second power level occurs in increments.

20. The system of claim 1, further comprising an external ground pad.

21. The system of claim 1 wherein the electrode has a cross-sectional dimension of from about 0.02 inches to about 0.085 inches.

22. The system of claim 1 wherein the electrode has a cross-sectional dimension of about 0.049 inches.

23. The system of claim 1 wherein the system further includes instructions that cause energy delivery to be terminated if an interlock condition is satisfied.

24. The system of claim 23 wherein the interlock condition is satisfied when the temperature value reaches a maximum threshold temperature.

25. The system of claim 24 wherein the maximum threshold temperature is an average temperature or real time temperature from about 70 degrees Celsius to about 85 degrees Celsius.

26. The system of claim 25 wherein the maximum threshold temperature is an average temperature or real time temperature of about 85 degrees Celsius.

27. The system of claim 24 wherein the maximum threshold temperature is a rate of change threshold.

28. The system of claim 23 wherein the interlock condition is satisfied when the measured impedance reaches the predetermined impedance threshold.

29. The system of claim 28 wherein the impedance threshold is a measured impedance below about 20 Ohms or above about 500 Ohms.

30. The system of claim 28 wherein the impedance threshold is a relative threshold.

31. The system of claim 30 wherein the system further includes instructions to store a baseline impedance value as the relative threshold.

32. The system of claim 31 wherein the baseline impedance value is the impedance measured prior to the delivery of energy.

33. The system of claim 28 wherein the impedance threshold is a rate of impedance change and/or the sum of a minimum impedance plus a preselected threshold.

34. The system of claim 23, further comprising a module for measuring a treatment time beginning when energy delivery commences, and wherein the interlock condition is satisfied when the treatment time reaches a maximum procedure time.

35. The system of claim 34 wherein the maximum procedure time is about 2 minutes.

36. The system of claim 1 wherein the algorithm further includes instructions that prevent power from exceeding the target maximum power level.

37. The system of claim 36 wherein the target maximum power level is from about 8 watts to about 10 watts.

38. The system of claim 36 wherein the target maximum power level is greater than about 10 watts.

39. A system for controlling therapeutic energy delivery, the system comprising:

an electrode configured for placement within a renal blood vessel and for delivering energy to a treatment site at or proximate to a wall of the renal blood vessel;

a temperature sensor for sensing a voltage corresponding to a temperature of the treatment site or of the electrode; and

a module for determining a temperature value based on the sensed voltage,

wherein the system is programmed with an algorithm comprising instructions that (a) increase energy delivery, from an energy generator external to patient to the electrode, at a generally constant rate to a predetermined first power level over a predetermined first period of time, (b) maintain energy delivery to the electrode at the first power level for a second period of time, and (c) increase energy delivery to the electrode in predetermined increments if a measured temperature value is less than a preset temperature threshold and a measured impedance value is less than a predetermined impedance threshold until the power level has reached a target maximum power threshold.