Implantable device for telemetric measurement of blood pressure/temperature within the heart

• US 20070118039A1
• Filed: 09/06/2006
• Published: 05/24/2007
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Endotronix, Inc.
• Original Assignee: Vital Sensors, Inc. (Vital Sensors Holding Company, Inc)
• Inventors: Bodecker, Volker, Niemeyer, Axel, Meyer, Stefan, Ostermeier, Max
• Granted Patent: US 7,682,313 B2
• Time in Patent Office: Days
• US Class Current: 600/486
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/0008 Temperature signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/02158 provided with two or more sensor elements
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6882 Anchoring means

Abstract

A system and method for the intra corporal, telemetric measuring of blood pressure, particularly within the heart or a great vessel, includes a substantially rigid sensor chip mounted in a holder and an antenna. The holder is anchored within an appropriate location in the cardiovascular system, such as in the cardiac septum, via a catheter or other minimally-invasive procedure to position at least one capacitive pressure sensor on the chip in the blood flow to be sensed. Measured values are transmitted telemetrically from the chip to an extra corporal monitoring device.

Claims

1. An intra-cardiac pressure measuring system for measuring blood pressure inside the cardiovascular system of a patient, said system comprising:

an antenna;

an integrated chip including a first substantially rigid substrate, at least one pressure sensor disposed within said substrate to generate signals indicative of a sensed pressure, and electronic signal processing components to process the signals generated by said at least one pressure sensor, said electronic signal processing components being operatively connected to said antenna, said integrated chip being powered by a signal received at said antenna;

an anchor structure to mount said integrated chip to a wall in the cardiovascular system such that said at least one pressure sensor is exposed to blood;

a remote receiver; and

wherein said integrated chip is operative to send digital signals indicative of the pressure sensed in the heart telemetrically via the antenna to said remote receiver; and

wherein said antenna, said integrated chip and said anchor structure are sized to fit within a delivery catheter for implantation in the cardiovascular system.

2. The system according to claim 1, wherein said system measures blood pressure within at least one heart chamber or one of the great vessels.

3. The system according to claim 1, wherein said at least one pressure sensor comprises capacitive-based pressure sensitive membranes housed within said substrate.

4. The system according to claim 1, wherein said at least one pressure sensor generates an analog signal in response to a sensed pressure and said electronic signal processing components include at least one analog to digital (A/D) converter to digitize within the heart the analog signals from said at least one pressure sensor.

5. The system according to claim 1, wherein said integrated chip weighs less than about one gram, has a surface area on one side of less than or equal to about 25 mm² and has a thickness of less than about 1 mm.

6. The system according to claim 5, wherein said antenna, said chip, and said anchor structure are encapsulated in a seamless, one-piece biocompatible sheathing.

7. The system according to claim 6, further comprising a pressure transferring medium interposed between said biocompatible sheathing and said at least one pressure sensor.

8. The system according to claim 6, where said biocompatible sheathing acts as a pressure transferring medium to said at least one pressure sensor.

9. The system according to claim 6, wherein said sheathing is shaped to minimize turbulence in blood flow within the heart.

10. The system according to claim 1, wherein said integrated chip further includes a unique digital identification, and wherein said unique digital identification is sent telemetrically to said receiver.

11. The system according to claim 10, wherein said receiver obtains calibration information associated with said integrated chip based on said unique digital identification.

12. The system according to claim 1, wherein said receiver includes a stored parameter and produces an alert based on the signals indicative of the pressure sensed in the heart and of the stored parameter.

13. The system according to claim 1, wherein said integrated chip comprises a first integrated chip and a second integrated chip, wherein said first integrated chip and said second integrated chip are physically and/or operably connected.

14. The system according to claim 13, wherein said first integrated chip includes said at least one pressure sensor and at least one analog to digital (A/D) converter, and said second integrated chip is operatively connected to said antenna.

15. The system according to claim 13, wherein said first integrated chip is located in a different chamber of the heart than said second integrated chip.

16. The system according to claim 1, wherein said at least one pressure sensor comprises a plurality of pressure sensors including at least one active sensor responsive to changes in pressure within the heart and at least one passive sensor that is isolated from the changes in pressure within the heart;

and

wherein said electronic signal processing components provide a signal based at least in part on a signal from said at least one active pressure sensor and a signal from said at least one passive pressure sensor.

17. The system according to claim 16, wherein said pressure signals are the result of offsetting the signal from said at least one active pressure sensor with the signal from said at least one passive pressure sensor.

18. The system according to claim 1, wherein said substantially rigid sensor includes a surface that cooperates with said anchor structure to mount said antenna and said substantially rigid sensor chip within the heart.

19. The system according to claim 2, wherein said anchor structure mounts said antenna and said substantially rigid sensor chip to the cardiac septum.

20. The system according to claim 19, wherein said antenna is mounted to one side of the cardiac septum and said substantially rigid sensor is mounted to the other side of the septum.

21. The system according to claim 19, wherein said antenna and said substantially rigid sensor are mounted on the same side of the septum.

22. The system according to claim 2, wherein said antenna includes a first surface adjacent to the cardiac septum and a second surface adjacent to at least a portion of said anchor structure.

23. The system according to claim 1, wherein said anchor structure comprises a resilient member that enables said anchor structure to expand from a compressed position shape that fits within a lumen of a delivery catheter to an expanded position.

24. The system according to claim 23, wherein said resilient member includes wire loops.

25. The system according to claim 1, wherein said antenna is flexible and foldable to fit within the lumen of a delivery catheter.

26. The system according to claim 1, wherein said substantially rigid sensor further includes a temperature sensor.

27. The system according to claim 16, wherein the structure of said active pressure sensor is substantially the same as a structure of said passive pressure sensor.

28. The system according to claim 16, wherein said plurality of pressure sensors comprise capacitive pressure sensors each having a flexible movable membrane.

29. The system according to claim 28, wherein the passive pressure sensor signal is responsive to a change in position of said membrane of said passive pressure sensor and the change of position of said membrane of said passive pressure sensor is due to a drift effect comprising a sag of said membrane.

30. The system according to claim 28, wherein a change of position of said membrane of said active pressure sensor is due to:

a change in pressure within the heart; and

a drift effect comprising a sag of said membrane.

31. A catheter for delivering said pressure measuring system according to claim 1.

32. The catheter according to claim 31, wherein said catheter includes a catheter lumen having a hollow portion and a first opening;

and

a system guide operative to laterally move said pressure measuring system within said hollow portion and out of said first opening in said catheter lumen.

34. A method of sensing blood pressure within the cardiovascular system of a subject, said method comprising the steps of:

(a) implanting within the subject a substantially rigid, integrated chip minimally-invasively using at least one catheter, the integrated chip including a substantially rigid substrate and at least one capacitive-based pressure sensor disposed within said substrate in a position to sense blood pressure within the cardiovascular system;

(b) powering on the integrated chip telemetrically by activating a power source located outside the subject;

(c) obtaining one or more analog signals from the at least one pressure sensor indicative of the pressure at the position in the cardiovascular system; and

(d) converting the analog signals to digital signals at or directly adjacent to the position in the cardiovascular system where the sensing occurs.

33. The catheter according to claim 39, wherein said integrated chip has a conic shape operative to pierce a wall or organ of the patient.

35. The method according to claim 34, wherein said implanting step comprises implanting an ASIC having a capacitive-based pressure sensor in the heart or in one of the great vessels.

36. The method according to claim 34, wherein said implanting step comprises the steps of:

delivering the capacitive-based pressure sensor at the position in the cardiovascular system; and

mounting said capacitive-based pressure sensor at the position with an anchor structure.

37. The method according to claim 36, wherein said implanting step further comprises the steps of:

delivering the anchor structure at a position to mount the capacitive-based pressure sensor in the cardiovascular system; and

expanding at least a portion of the anchor structure.

38. The method according to claim 34, further comprising implanting within the subject using the catheter a foldable antenna operatively connected to the integrated chip.

39. The method according to claim 34, further comprising the step of calculating a waveform of a heart beat based on the sensed blood pressure.

40. An integrated chip for intra-cardiac blood pressure measurement inside a patient, said integrated chip comprising:

a first substantially rigid substrate;

at least one pressure sensor disposed within said substrate to generate signals indicative of a sensed pressure;

electronic signal processing components to process the signals generated by said at least one pressure sensor, said electronic signal processing components being operatively connected to an antenna, said integrated chip being powered by a signal received at the antenna; and

wherein said integrated chip is operative to send digital signals indicative of the pressure sensed in the patient telemetrically via an antenna to a remote receiver; and

wherein said integrated chip is sized to fit within a delivery catheter for implantation.

41. The integrated chip according to claim 40, wherein said at least one pressure sensor generates analog signals and said electronic signal processing components include at least one analog to digital (A/D) converter to digitize within the patient at location where the chip is implanted the analog signals from said at least one pressure sensor.

42. The integrated chip according to claim 40, wherein said integrated chip weighs less than about one gram, has a surface area on one side of less than or equal to about 25 mm² and has a thickness of less than about 1 mm.

43. The integrated chip according to claim 40, wherein said integrated chip is not foldable.

44. The integrated chip according to claim 43, further comprising an antenna operatively connected to said electronic signal processing components, said antenna having a compressed position for delivery via a catheter and an expanded position for use after the implantation.