Hypertension system and method

• US 20100262021A1
• Filed: 01/27/2009
• Published: 10/14/2010
• Est. Priority Date: 01/28/2008
• Status: Active Grant

• Current Assignee: St. Jude Medical Luxembourg Holdings Ii S.A.R.L.
• Original Assignee: CardioMEMS Incorporated
• Inventors: Yadav, Jay, Ellis, Michael G.
• Granted Patent: US 8,360,984 B2
• Time in Patent Office: Days
• US Class Current: 600/486
• CPC Class Codes: A61B 2560/045 with a separable interface unit, e.g. for communication
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: G01L 19/083 electrical

Abstract

Disclosed are hypertension systems and related methods that include a blood pressure sensor located or implanted under the skin of a patient, and electronics, which may have the size and shape of a wrist watch, for example, that monitors the blood pressure of the patient by communicating with the implanted sensor.

Claims

1. Hypertension apparatus comprising:

an implantable blood pressure sensor for implantation beneath skin of a wrist of a patient; and

wireless monitoring electronics for wirelessly monitoring and recording blood pressure of the patient.

2. The apparatus recited in claim 1 wherein the wireless monitoring electronics has the size and shape of a wrist watch.

3. The apparatus recited in claim 1 wherein the wireless monitoring electronics is disposed on a wrist of the patient.

4. The apparatus recited in claim 1 wherein the implantable blood pressure sensor comprises an implantable inductive-capacitive (LC) sensor.

5. The apparatus recited in claim 4 wherein the inductive-capacitive (LC) sensor is configured to resonate at a frequency corresponding to the blood pressure.

6. The apparatus recited in claim 4 wherein the resonant frequency output by the inductive-capacitive (LC) sensor corresponds to the blood pressure of the patient.

7. The apparatus recited in claim 1 wherein the wireless monitoring electronics comprises a miniaturized one port network analyzer.

8. The apparatus recited in claim 4 wherein the inductive-capacitive (LC) sensor comprises an inductor and a pressure-sensitive variable capacitor.

9. The apparatus recited in claim 1 wherein the wireless monitoring electronics comprises:

a transmit coil coupled to a frequency source and a bounce back circuit, and wherein the transmit coil is energized by the frequency source; and

wherein, when the frequency source is varied, and when the frequency corresponds to the resonant frequency of the sensor, energy bounces back from the transmit coil to the bounce back circuit and is detected and processed to output the blood pressure of the patient.

10. The apparatus recited in claim 9 wherein the frequency source comprises a direct digital synthesizer.

11. The apparatus recited in claim 9 wherein the wireless monitoring electronics comprises:

a transmit coil coupled to a frequency source and a bounce back circuit, and wherein the transmit coil is energized by the frequency source;

wherein the frequency source comprises a voltage controlled oscillator coupled to and controlled by a microcontroller that also comprises a frequency counter; and

wherein an analog sweep voltage from a digital-to-analog (D/A) output of the microcontroller drives an analog frequency control input of the voltage controlled oscillator to energize the transmit coil with pulses of differing frequency.

12. The apparatus recited in claim 1 wherein:

the implantable blood pressure sensor comprises an inductor and a variable capacitor;

the wireless monitoring electronics comprises a transmit coil coupled to a frequency source and a bounce back circuit, wherein the transmit coil is energized by the frequency source, and wherein the transmit coil is coupled to a directional coupler having first and second outputs;

a first output of the directional coupler is coupled to the voltage controlled oscillator and to a prescaler having an output coupled to an input of a microcontroller;

a digital-to-analog (D/A) output of the microcontroller is coupled to an analog input of the voltage controlled oscillator; and

a second output of the directional coupler is coupled to the bounce back circuit.

13. The apparatus recited in claim 12 wherein the bounce back circuit comprises an amplifier coupled to a detector, and wherein an output of the detector is coupled to an analog input of the microcontroller.

14. The apparatus recited in claim 12 wherein the wireless monitoring electronics comprises:

a timekeeping chip coupled to the microcontroller; and

a barometric pressure integrated circuit coupled to the timekeeping chip and the microcontroller that compensates blood pressure readings based upon atmospheric pressure.

15. The apparatus recited in claim 12 wherein the microcontroller is coupled to a liquid crystal display used to display the blood pressure of the patient.

16. A hypertension monitoring method comprising:

implanting a blood pressure sensor beneath skin of a wrist of a patient; and

wirelessly monitoring and recording blood pressure of the patient.

17. The method recited in claim 16 wherein:

implanting the blood pressure sensor comprises configuring an inductive-capacitive (LC) sensor to resonate at a frequency corresponding to the blood pressure of the patient, and wherein the resonant frequency output by the inductive-capacitive (LC) sensor corresponds to the blood pressure of the patient; and

wherein wirelessly monitoring the blood pressure of the patient comprises;

transmitting a variable frequency signal by way of a transmit coil;

detecting a resonant frequency signal corresponding to the resonant frequency of the blood pressure sensor in the patient using a bounce back circuit coupled to the transmit coil; and

processing the resonant frequency signal bounced back from the bounce back circuit to determine the blood pressure of the patient.