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

• US 20070118038A1
• Filed: 06/15/2006
• 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, Meyer, Stefan, Neimeyer, Axel, Ostermeier, Max
• Granted Patent: US 7,686,768 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 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• 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 5/6882 Anchoring means

Abstract

A system and method for the intra corporal, measuring of blood pressure includes a substantially rigid sensor structure and an antenna structure, which are separate components. The anchor structure is used to mount the within an appropriate location in the cardiovascular system, such as in the cardiac septum. The substantially rigid sensor structure includes at least one capacitive pressure sensor. Measured values are transmitted telemetrically from the sensor structure to an extra corporal monitoring device.

Claims

1. An intra-cardiac pressure measuring system for measuring blood pressure inside the heart 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 implantable holder supporting said integrated chip, said holder including an anchor structure to mount said integrated chip within a wall of the heart during surgery such that said at least one pressure sensor is exposed to blood flow in the heart;

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.

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

3. 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.

4. The system according to claim 1, further comprising a flexible wire connecting said antenna and said integrated circuit, said antenna being configured to be implanted within the patient underneath the skin to facilitate telemetric data transmission to said receiver.

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 10 mm² and has a thickness of less than about 1 mm.

6. The system according to claim 4, wherein said antenna, said chip, said wire, and said holder 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, further comprising a second substantially rigid substrate located opposite said at least one pressure sensor in said first substrate and in a spaced apart configuration, said second substrate protecting said integrated chip from mechanical damage.

14. The system according to claim 13, wherein said second substrate includes an aperture permitting blood flow within the heart to act on said at least one pressure one pressure sensor.

15. The system according to claim 14, further comprising a pressure transferring medium interposed between said at least one pressure sensor and said second substantially rigid substrate to transfer blood pressure to said at least one pressure sensor.

16. The system according to claim 13, further comprising at least one bond pad disposed between said first and second substantially rigid substrates and electrically connected to said integrated chip.

17. The system according to claim 16, further comprising at least one bond tack on said second substantially rigid substrate, wherein said at least one bond tack is connected to said at least one bond pad, and wherein said antenna is operatively connected to said integrated chip via said at least one bond pad and said at least one bond tack to provide a strain relief connection.

18. The system according to claim 13, further comprising an antenna connector to connect said antenna to said second substantially rigid substrate, wherein said antenna connector comprises a signal portion electrically connecting said antenna to said integrated chip and a support portion connected to said second substantially rigid substrate.

19. The system according to claim 18, wherein said antenna connector is attached to said second substantially rigid substrate such that there is slack in said signal portion when said support portion is taut.

20. The system according to claim 19, wherein said signal portion is connected to said integrated chip via said at least one bond tack and said support portion is connected to said second substantially rigid substrate via an opening in said second substantially rigid substrate.

21. The system according to claim 18, wherein said at least one bond tack comprises at least two bond tacks disposed on opposite sides of said aperture.

22. The system according to claim 13, wherein said second substantially rigid substrate includes a protective barrier connected thereto, and further comprising a biocompatible sheathing encapsulating at least said integrated chip and said second substantially rigid substrate, wherein said protective barrier is disposed to prevent said first substantially rigid substrate from puncturing said biocompatible sheathing.

23. The system according to claim 13, further comprising a flexible support material between said integrated chip and said second substantially rigid substrate.

24. The system according to claim 1, wherein said holder and said first substantially rigid substrate are integrally formed into a single piece.

25. The system according to claim 1, wherein said antenna is supported by said holder.

26. The system according to claim 1, wherein said holder includes a stop that limits the movement of said integrated chip into the heart chamber.

27. The system according to claim 1, wherein said integrated chip and said holder are removable from the heart after implantation.

28. 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.

29. The system according to claim 28, wherein the structure of said active pressure sensor is substantially the same as a structure of said passive pressure sensor.

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

31. The system according to claim 30, 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.

32. The system according to claim 31, 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.

33. The system according to claim 28, 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.

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 an 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.

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

36. The method according to claim 35, further comprising the step of limiting the ASIC from entering the heart chamber with a stop device.

37. The method according to claim 34, wherein the integrated chip includes a unique digital identification, and further comprising the step of telemetrically communicating the unique digital identification to an external reader.

38. The method according to claim 37, further comprising the step of obtaining calibration information associated with the integrated chip at the external reader based on the unique digital identification.

39. The method according to claim 34, wherein the integrated chip is supported in a holder and said implanting step comprises the steps of:

delivering the holder to the position in the cardiovascular system; and

mounting the holder at the position such that the at least one pressure sensor is exposed to the pressure in the cardiovascular system to be sensed.

40. The method according to claim 34, wherein the at least one capacitive-based pressure sensor comprises a plurality of capacitive-based pressure sensors including an active pressure sensor and a passive pressure sensor located within the subject in a position to directly sense blood-pressure within a position in the cardiovascular system;

and

wherein said step of obtaining one or more analog signals further comprises;

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

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

(c) generating one or more combined analog signals based on the one or more analog signals from the active pressure sensor and the one or more analog signals from the passive pressure sensor indicative of the pressure at the position in the cardiovascular system.

41. The method according to claim 40, wherein said step of converting the analog signals further comprises converting the combined analog signals to digital signals.

42. The method according to claim 40, wherein said step of generating said one or more combined analog signals includes offsetting the signal from said active pressure sensor with the signal from said passive pressure sensor.

43. An integrated chip for intra-cardiac blood pressure measurement inside the heart of 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 heart telemetrically via an antenna to a remote receiver.

44. The integrated chip according to claim 43, 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 heart the analog signals from said at least one pressure sensor.

45. The integrated chip according to claim 43, wherein said integrated chip weighs less than about one gram, has a surface area on one side of less than or equal to about 10 mm² and has a thickness of less than about 1 mm.

46. The integrated chip according to claim 43, further comprising a second substantially rigid substrate located opposite said at least one pressure sensor in said first substrate and in a spaced apart configuration.

47. The integrated chip according to claim 46, wherein said second substrate includes an aperture permitting blood pressure within the heart to act on said at least one pressure one pressure sensor.

48. The integrated chip according to claim 47, further comprising a pressure transferring medium interposed between said at least one pressure sensor and said second substantially rigid substrate to transfer blood pressure to said at least one pressure sensor.