METHODS AND SYSTEMS FOR THERMALLY-INDUCED RENAL NEUROMODULATION

• US 20080255642A1
• Filed: 06/26/2008
• Published: 10/16/2008
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Ardian Luxembourg SARL (Medtronic Plc)
• Original Assignee: Ardian, Inc. (Medtronic Plc)
• Inventors: Thai, Erik, Levin, Howard R., Gelfand, Mark, Zadno, Nicolas, Clark, Benjamin J., Gifford, Hanson, Zarins, Denise, Wu, Andrew, Deem, Mark
• Granted Patent: US 9,345,900 B2
• Time in Patent Office: Days
• US Class Current: 607/99
• 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

1-117. -117. (canceled)

118. A method for thermally inducing neuromodulation, the method comprising:

positioning an electrode within a patient;

determining a tissue site suitable for treatment;

delivering energy via the electrode to a neural structure of the patient proximate to or within the tissue site;

increasing the energy delivered to the electrode to a predetermined first power level over a first period of time;

maintaining the energy delivered to the electrode at the first power level for a second period of time after reaching the first power level;

measuring a temperature value related to the patient or the electrode; and

if the temperature value is less than a preset threshold temperature, then increasing the energy delivered to the electrode until a maximum power threshold is reached or an interlock condition is satisfied.

119. The method of claim 118 wherein the determining a tissue site suitable for treatment comprises delivering electrical pulses to the patient and measuring impedance.

120. The method of claim 118 wherein positioning an electrode includes positioning an electrode at least proximate to a body lumen, and wherein delivering energy via the electrode includes delivering energy to a neural structure related to renal function.

121. The method of claim 118, further comprising:

deriving an average temperature based on the temperature value; and

if the average temperature is less than the preset temperature threshold, then increasing the energy delivered to the electrode to a second power level.

122. The method of claim 121 wherein increasing the energy delivered to the electrode to a second power level includes increasing the energy delivered to the electrode to a second power level by a predetermined amount.

123. The method of claim 118 wherein increasing the energy delivered to the electrode includes increasing the energy delivered to the electrode in predetermined power increments.

124. The method of claim 123 wherein increasing the energy delivered to the electrode in predetermined power increments comprises increasing the energy delivered to the electrode in increments of about 1 watt.

125. The method of claim 118 wherein the preset threshold temperature is from about 60 degrees Celsius to about 75 degrees Celsius.

126. The method of claim 118 wherein the preset threshold temperature is about 65 degrees Celsius.

127. The method of claim 118 wherein the threshold temperature is a first threshold temperature, and wherein the method further includes ceasing the energy delivered to the electrode if the temperature value exceeds a second threshold temperature greater than the first threshold temperature.

128. The method of claim 127 wherein the second threshold temperature is about 85 degrees Celsius.

129. The method of claim 118 wherein the preset threshold temperature is a first threshold temperature, and wherein the method further includes decreasing the energy delivered to the electrode if the temperature value exceeds a second threshold temperature greater than the first threshold temperature.

130. The method of claim 129 wherein the second threshold temperature is about 70 degrees Celsius.

131. The method of claim 129 wherein decreasing the energy delivered to the electrode further comprises decreasing the energy delivered to the electrode in predetermined power increments.

132. The method of claim 118 wherein measuring a temperature value related to the patient or the electrode further comprises:

measuring a voltage associated with the energy delivered using the electrode; and

determining a temperature value based on the measured voltage.

133. The method of claim 118 wherein measuring a temperature value related to the patient or the electrode further comprises measuring at least one of real time temperature, average temperature, temperature offset, and rate of temperature change.

134. The method of claim 118, further comprising adjusting the first and second period of time based on the temperature value.

135. The method of claim 118, further comprising issuing an alarm when the maximum power threshold is reached or an interlock condition has been satisfied.

136. The method of claim 118 wherein the maximum power threshold is from about 8 watts to about 10 watts.

137. The method of claim 118, further comprising terminating energy delivered to the electrode when the interlock condition has been satisfied.

138. The method of claim 137 wherein terminating energy delivered to the electrode when the interlock condition has been satisfied further comprises terminating energy delivered to the electrode when the temperature value reaches a maximum threshold temperature.

139. The method of claim 138 wherein terminating energy delivered to the electrode when the temperature value reaches a maximum threshold temperature further comprises terminating energy delivered to the electrode when the temperature value reaches a rate of change threshold.

140. The method of claim 137, further comprising measuring impedance, and wherein terminating energy delivered to the electrode when the interlock condition has been satisfied further comprises terminating energy delivered to the electrode when the measured impedance reaches an impedance threshold.

141. The method of claim 140 wherein terminating energy delivered to the electrode when the measured impedance reaches an impedance threshold further comprises terminating energy delivered to the electrode when the measured impedance is below about 20 Ohms or above about 500 Ohms.

142. The method of claim 140 wherein terminating energy delivered to the electrode when the measured impedance reaches an impedance threshold further comprises terminating energy delivered to the electrode when the measured impedance reaches a relative threshold.

143. The method of claim 142, further comprising storing a baseline impedance value as the relative threshold.

144. The method of claim 143, wherein storing a baseline impedance value as the relative threshold further comprises storing an impedance value measured prior to the delivery of energy.

145. The method of claim 137, further comprising measuring a treatment time from when energy delivery commences, and wherein terminating energy delivered to the electrode when the interlock condition has been satisfied further comprises terminating energy delivered to the electrode when the treatment time reaches a maximum time threshold.

146. The method of claim 145 wherein terminating energy delivered to the electrode when the treatment time reaches a maximum time threshold comprises terminating energy delivered to the electrode when the treatment time reaches about 2 minutes.

147. A method for controlling energy delivery via an electrode positioned proximate to a wall of a patient'"'"'s body lumen, the method comprising:

increasing energy delivery to a predetermined first power level over a first period of time;

maintaining energy delivery at a desired power level for a second period of time after reaching the first power level;

measuring a temperature related to the wall of the body lumen;

deriving an average temperature based on the measured temperature during the second period of time; and

if the average temperature is less than a preset threshold temperature, then increasing energy delivery from the first power level to a second power level.

148. The method of claim 147, further comprising repeating cycles of (a) maintaining the energy delivery at a desired power level for a period of time after reaching a current power level and (b) increasing energy delivery to another power level from the current power level if the average temperature is less than the preset threshold until a maximum power level of the delivered energy is reached.

149. The method of claim 148 wherein the maximum power level is from about 8 watts to about 10 watts.

150. The method of claim 148, further comprising:

measuring an impedance;

deriving an average impedance based on the measured impedance at multiple instances during the treatment period;

determining a baseline impedance value; and

if the average impedance during the treatment period is greater than the baseline impedance value, reducing or terminating energy delivery.

151. The method of claim 150 wherein determining a baseline impedance value comprises storing an impedance value measured prior to the delivery of energy.

152. The method of claim 148, further comprising maintaining the energy delivery at approximately the maximum power level for a desired treatment period.

153. The method of claim 152, further comprising decreasing the energy delivery by a preselected value from the maximum power level during the treatment period if the average temperature during the treatment period is greater than a preset average temperature threshold.

154. The method of claim 153 wherein the preset average temperature threshold is about 70 degrees Celsius.

155. The method of claim 148 wherein increasing energy delivery to another power level from the current power level further comprises increasing energy delivery to another power level in predetermined power increments.

156. The method of claim 147, further comprising maintaining the energy delivery generally at the first power level if the average temperature is greater than or equal to the preset temperature threshold.

157. The method of claim 156 wherein the preset temperature threshold is about 65 degrees Celsius.

158. The method of claim 147 wherein the preset threshold temperature is a first threshold temperature, and wherein the method further includes ceasing the energy delivery if the measured temperature equals or exceeds a second threshold temperature greater than the first threshold temperature.

159. The method of claim 158 wherein the second threshold temperature is about 85 degrees Celsius.

160. The method of claim 147, further comprising deriving a rate of change for the temperature from the measured temperature.

161. The method of claim 147, further comprising issuing an alarm based on a comparison of the derived rate of change and a rate of change threshold.

162. The method of claim 147, further comprising controlling the energy delivered to the electrode based on the derived rate of change.

163. A method for creating a lesion in a target tissue layer, wherein a first tissue layer is between a blood vessel wall and the target tissue layer, the method comprising:

irradiating the target tissue layer and the first tissue layer through the blood vessel wall with energy; and

creating a first thermal effect in the first tissue layer and a second thermal effect in the target tissue layer, wherein the second thermal effect is greater than the first thermal effect.

164. The method of claim 163 wherein creating a thermal effect in the target tissue layer comprises disabling neural structures within or proximate to the target tissue layer.

165. The method of claim 164 wherein disabling neural structures within or proximate to the target tissue layer further comprises disabling neural structures that innervate renal tissue.

166. A method for creating a lesion in a target tissue adjacent to a peripheral blood vessel, the method comprising:

delivering an electrode to a location within the blood vessel;

placing the electrode in contact with a wall of the blood vessel;

irradiating the target tissue through the blood vessel wall with energy, wherein the energy is irradiated at a power level and for a time sufficient to create a lesion in the target tissue.