Hypertension system and method

• US 8,360,984 B2
• Filed: 01/27/2009
• Issued: 01/29/2013
• 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.
• Primary Examiner(s): Haq, Shafiqul
• Application Number:
  US12/321,904
• Publication Number:
  US 20100262021A1
• Time in Patent Office: 1,463 Days
• Field of Search: None
• US Class Current: 600/488
• 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. A system comprising:

an implantable sensor assembly configured to resonate at a frequency corresponding to a physiological blood pressure of a patient, the sensor assembly comprising a unitary hermetic housing that encloses a variable capacitor and an inductor within an interior chamber of the housing, wherein the variable capacitor and inductor is configured to emit a return signal when subjected to a burst of RF energy;

an external electronics assembly further comprising;

a frequency source configured to transmit a transmission signal;

a transmit coil coupled to the frequency source;

a bounce back circuit coupled to the frequency source and the transmit coil, and

a directional coupler coupled to the transmit coil and having first and second outputs, wherein the directional coupler is configured to isolate the transmission signal from the return signal.

2. The system of claim 1, further comprising:

a voltage controlled oscillator;

a prescaler;

wherein the first output of the directional coupler is coupled to the voltage controlled oscillator and to a prescaler.

3. The system recited in claim 1, wherein the external electronics assembly has the size and shape of a wrist watch.

4. The system recited in claim 1, wherein the external electronics assembly is disposed on a wrist of the patient.

5. The system of claim 2, further comprising a microcontroller, and wherein the prescaler has an output coupled to an input of the microcontroller.

6. The system recited in claim 5, wherein the microcontroller is coupled to a liquid crystal display used to display the blood pressure of the patient.

7. The system recited in claim 5, wherein the external electronics assembly further 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.

8. The system of claim 5, wherein a digital-to-analog (D/A) output of the microcontroller is coupled to an analog input of the voltage controlled oscillator.

9. The system of claim 1;

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

10. The system of claim 1, 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.

11. The system of claim 1, wherein the frequency source comprises a direct digital synthesizer.

12. The system of claim 1, wherein the transmit coil is energized by the frequency source.

13. The system of claim 12, further comprising a microcontroller having a frequency counter, wherein the frequency source comprises a voltage controlled oscillator coupled to and controlled by the microcontroller.

14. The system of claim 13, 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.

15. The system of claim 1, wherein the frequency source is configured to vary a frequency across a predetermined range.

16. The system of claim 1, wherein the frequency source continuously sweeps across the predetermined range of frequencies.

17. The system of claim 1, wherein the external electronics assembly further comprises a voltage controlled oscillator and a frequency counter.

18. The system of claim 17, wherein the external electronics assembly further comprises a microcontroller, 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.

19. The system of claim 1, wherein the wireless monitoring electronics comprises a miniaturized one port network analyzer.

20. The system of claim 1, wherein the implantable sensor assembly is mounted within a lumen of the patient.