Method For Reducing Hypertension Using An Implantable Electroacupuncture Device

• US 20150012055A1
• Filed: 07/30/2014
• Published: 01/08/2015
• Est. Priority Date: 08/30/2011
• Status: Active Grant

• Current Assignee: Valencia Bioscience, Inc.
• Original Assignee: Valencia Technologies Corporation
• Inventors: Greiner, Jeffrey H., Peterson, David K. L., Thenuwara, Chuladatta
• Granted Patent: US 9,358,382 B2
• Time in Patent Office: Days
• US Class Current: 607/44
• CPC Class Codes: A61H 2201/5005 for controlling frequency distribution, modulation or interference of a driving signal
• CPC Class Codes: A61H 2201/5035 Several programs selectable
• CPC Class Codes: A61H 2201/5038 freely programmable by the user
• CPC Class Codes: A61H 2201/5097 wireless
• CPC Class Codes: A61H 39/002 Using electric currents electrotherapy A61N1/32
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36117 for treating hypertension
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36175 Pulse width or duty cycle
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3758 Packaging of the components within the casing
• CPC Class Codes: A61N 1/3782 producing a voltage above the power source level
• CPC Class Codes: Y10S 128/907 Acupuncture

Abstract

Disclosed is an implantable, coin-sized, self-contained, leadless electroacupuncture (EA) device having at least two electrode contacts attached to the surface of its housing. The electrodes include a central cathode electrode on a bottom side of the housing, and a circumferential anode electrode that surrounds the cathode electrode. In one embodiment, the anode annular electrode is a ring electrode placed around the perimeter edge of the coin-shaped housing. The EA device is adapted to be implanted through a very small incision, e.g., less than about 2-3 cm in length, directly adjacent to a selected acupuncture site known to moderate or affect a hypertension condition of a patient. Appropriate power management circuitry within the device allows a primary battery having a relatively high internal impedance to be used without causing unacceptable dips in battery voltage when the instantaneous battery current surges. Stimulation pulses are generated during a stimulation session that has a duration of T3 minutes and which is applied every T4 minutes. The duty cycle, or ratio of T3 to T4, is very low, not greater than 0.05. This low duty cycle, along with careful power management, allows the EA device to perform its intended function for several years.

Claims

1. A method of treating hypertension in a patient using a leadless electrode configuration integrated into a self-contained, implantable coin-sized electroacupuncture (EA) device, the EA device having a longest linear dimension D2 no greater than 25 mm, and a thickness W2 no greater than 2.5 mm, wherein the thickness W2 is measured in a plane orthogonal to the longest dimension D2, and wherein the ratio of W2 to D2 is no greater than about 0.13, the method comprising:

(a) making a short incision no longer than about 25 mm in a limb of the patient near at least one of acupoints PC5, PC6, ST36 or ST37;

(b) forming a tissue pocket under the skin adjacent the incision;

(c) implanting the thin EA device in the patient by sliding the thin edge of the EA device through the incision into the formed pocket;

(d) closing the incision;

(e) allowing the closed incision to heal;

(f) enabling the EA device to generate stimulation sessions at a duty cycle that is less than 0.05, each stimulation session comprising a series of stimulation pulses, wherein the duty cycle is the ratio of T3/T4, where T3 is the duration in minutes of each stimulation session, and T4 is the time in minutes between stimulation sessions; and

(g) delivering the stimulation pulses of each stimulation session through the electrode configuration integrated into the leadless EA device to body tissue of the patient in the vicinity of at least one the acupoints PC5, PC6, ST36 or ST37.

2. The method of claim 1 further including assembling the leadless EA device using an assembly process that includes placing a power source and electronic circuits inside of an hermetically-sealed coin-sized case, integrating at least two electrodes on an outside surface of the coin-sized case, and providing an electrical connection from the power source and circuits on the inside of the case with the electrodes on the outside surface of the case through at least one radial feed-through pin that passes through a recess in a perimeter wall of the case.

3. The method of claim 2 wherein integrating the at least two electrodes on an outside surface of the coin-sized case comprises placing a ring electrode around the perimeter edge of the coin-sized case, and placing a central electrode on at least one side of the coin-sized case and configuring the electrodes so that the spacing between the center of the central electrode and an edge of the ring electrode closest to the central electrode comprises at least 5 mm.

4. The method of claim 3 wherein placing a power source inside of the coin-sized EA case comprises placing a coin-cell battery in the case having a nominal output voltage of no more than 3 volts.

5. The method of claim 4 wherein placing electronic circuits inside of the coin-sized case comprises:

inserting a boost converter circuit into the case that boosts the nominal output voltage of the coin-cell battery to an output voltage V_OUT that is at least three times the nominal output voltage of the coin-cell battery;

inserting a control circuit into the case that selectively monitors the boost converter circuit and limits the amount of current that may be drawn from the coin-cell battery; and

inserting an output circuit powered by V_OUT and controlled by the control circuit that generates the stimulation pulses of each stimulation session.

6. The method of claim 5 wherein enabling the EA device to generate stimulation sessions includes generating the series of stimulation pulses within each stimulation session so that each stimulation pulse has a duration of between 0.1 and 1.0 millisecond and occurs at a rate of between 1 and 5 Hz.

7. The method of claim 6 further including setting T3, the duration of the stimulation session, to a value between 10 minutes and a maximum T3 value, T3(max), when T4 is set to a value between 720 minutes and 1,200 minutes, wherein T3(max)=0.05(T4), so that when T4 is 720 minutes, T3(max) is 36 minutes;

and when T4 is 1,200 minutes, T3(max) is 60 minutes; and

when T4 is greater than 720 minutes but less than 1,200 minutes, T3(max) has a value between 36 minutes and 60 minutes as defined by the equation T3(max)=0.05(T4).

8. A method of treating hypertension in a patient using a small, leadless, implantable electroacupuncture device (IEAD) powered by a small disc primary battery having a specified nominal output voltage of 3 volts, and having an internal impedance of at least 5 ohms, the IEAD being configured, using electronic circuitry within the IEAD, to generate EA stimulation pulses in accordance with a specified stimulation regimen and apply the EA stimulation pulses through at least two electrodes/arrays located on the housing of the IEAD to the patient'"'"'s body tissue at a selected tissue location, said at least two electrodes/arrays comprising at least one central electrode/array of a first polarity, having a maximum width of no more 7 mm, centrally located on a first surface of the small IEAD housing, and at least one annular electrode/array of a second polarity spaced apart from the central electrode/array by at least 5 mm measured from the edge of the annular electrode/array closest to the central electrode/array to the center of the central electrode/array, said method comprising:

(a) implanting the IEAD below the skin surface of the patient at one or more acupoints selected from the group of acupoints comprising PC5, PC6, ST36 and ST37, with the first surface of the IEAD facing inwardly into the patient'"'"'s body tissue at the selected acupoint;

(b) enabling the IEAD to provide stimulation pulses in accordance with a stimulation regimen that provides a stimulation session at a rate of once every T4 minutes, with each stimulation session having a duration of T3 minutes, where the ratio of T3/T4 is no greater than 0.05.

9. The method of claim 8 further including setting the time T4 to be at least 720 minutes [½

day], but no more than about 20,160 minutes [14 days].

10. The method of claim 9 further including setting T3, the duration of the stimulation session, to a value between 10 minutes and 60 minutes if T4, the rate of occurrence of the stimulation session, is set to a value between 1,200 minutes and 20,160 minutes [14 days];

and setting T3 to a value between 10 minutes and a maximum T3 value, T3(max), if T4 is set to a value between 720 minutes and 1,200 minutes, wherein T3(max) varies as a function of T4 as defined by the equation;

T3(max)=0.05*T4.

11. The method of claim 8 further including setting the stimulation pulses during a stimulation session to have a duration of T1 seconds, that occur at a rate of once every T2 seconds, where the ratio of T1/T2 is no greater than 0.01.

12. The method of claim 11 further including setting the time T1 to be 0.1 to 1.0 millisecond and the time T2 to be 250 to 1000 milliseconds.

13. The method of claim 8 further including controlling the electronic circuits within the IEAD to limit instantaneous current drawn from the small disc primary battery so that the output voltage of the primary battery does not drop more than about 11% below the output voltage of the primary battery when current is being drawn from the primary battery, where the output voltage of the primary battery is equal to the specified nominal output voltage of the primary battery less the voltage drop caused by the instantaneous current flowing through the internal impedance of the primary battery.

14. The method of claim 13 wherein the electronic circuitry within the IEAD includes a boost converter circuit, and wherein the method of controlling the electronic circuits within the IEAD to limit the instantaneous current drawn from the battery comprises modulating the operation of the boost converter circuit between an ON state and an OFF state.