Implantable biosensor and methods for monitoring cardiac health

• US 7,223,237 B2
• Filed: 04/22/2004
• Issued: 05/29/2007
• Est. Priority Date: 04/22/2004
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Shelchuk, Anne M.
• Primary Examiner(s): Winakur; Eric
• Assistant Examiner(s): BERHANU, ETSUB D
• Application Number:
  US10/830,850
• Publication Number:
  US 20050240088A1
• Time in Patent Office: 1,132 Days
• Field of Search: 600/309, 600/325, 600/333, 607/22
• US Class Current: 600/309
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36528 the parameter being measured by means of ultrasound

Abstract

The ability to continuously monitor concentrations of any of a plurality of blood-borne substances, such as proteins, improves patient monitoring and overall care through early detection of cardiac threats. Ultrasound-based technology used in analytical chemistry to determine amounts of particles suspended in a colloidal composition can be employed in an implantable sensor to monitor levels of many different substances in the blood. A sensor system is implanted in or near a blood vessel in the body and generates an electric or acoustic field directed at that blood vessel. A receiver near the generator detects energy emitted once the assaulting field is turned off. Changes in the relative amounts of the substance(s) being monitored appear as changes in the amount of energy emitted once the assaulting field is removed. The sensor may be implemented in an implantable cardiac therapy device. A non-implantable or transcutaneous sensor may also be used to monitor cardiac health.

Claims

1. A method of monitoring a concentration of suspended particles in a biomedical colloid comprising:

a. producing an assaulting acoustic field;

b. measuring a resultant electric field produced in vivo by particle interaction with the assaulting field; and

c. determining the concentration of the suspended particles based on the measured resultant field.

2. The method of claim 1, wherein said biomedical colloid is blood.

3. The method of claim 1, wherein said biomedical colloid is interstitial fluid.

4. The method of claim 1, wherein said suspended particles are proteins.

5. The method of claim 4, further comprising:

d. assessing a cardiac threat based on the concentration of the suspended proteins.

6. The method of claim 5, wherein said suspended proteins include at least one of the group consisting of BNP and ANP.

7. The method of claim 6, wherein said cardiac threat is heart failure exacerbation.

8. The method of claim 5, wherein said suspended proteins comprise at least one protein selected from the group consisting of C-reactive protein, CK-MB, ischemia-modified albumin, Troponin I, Troponin T, Troponin C, and myoglobin.

9. The method of claim 8, wherein said cardiac threat is at least one of myocardial ischemia and myocardial damage.

10. The method of claim 5, further comprising:

e. performing cardiac therapy based on the cardiac threat determined in step (d).

11. The method of claim 1, wherein a frequency of said assaulting acoustic field is determined based on properties of the suspended particles.

12. The method of claim 1, further including the step of monitoring changes in the concentration of the suspended particles over time.

13. A method of monitoring a concentration of suspended proteins in a biomedical colloid, comprising:

a. producing an assaulting field;

b. measuring a resultant field produced by particle interaction with the assaulting field, wherein one of said assaulting field and said resultant field is an electric field; and

c. determining the concentration of suspended proteins based on the measured resultant field.

14. The method of claim 13, wherein said biomedical colloid is blood.

15. The method of claim 13, wherein said biomedical colloid is interstitial fluid.

16. The method of claim 13, further comprising:

d. detecting a cardiac threat based on the concentration of the suspended proteins.

17. The method of claim 16, further comprising:

e. performing cardiac therapy based on the cardiac threat determined in step (d).

18. The method of claim 13 wherein the other of said assaulting field and said resultant field is an acoustic field.

19. An implantable cardiac therapy device including an implantable biosensor for monitoring a concentration of suspended particles in a biomedical colloid, said implantable biosensor comprising:

a generator configured to produce an assaulting acoustic field in vivo;

a transmitter configured to transmit the assaulting acoustic field; and

a receiver configured to detect a resultant electric field produced in vivo by particle interaction with the assaulting acoustic field, said resultant field being indicative of the concentration of suspended particles.

20. The implantable cardiac therapy device of claim 19, wherein said suspended particles are proteins, and wherein said biomedical colloid is blood.

21. The implantable cardiac therapy device of claim 19, wherein said biomedical colloid is interstitial fluid.

22. The implantable cardiac therapy device of claim 19, wherein said implantable biosensor is configured for implantation in close proximity to a blood vessel.

23. The implantable cardiac therapy device of claim 19, further comprising;

a processor configured to calculate a concentration of proteins in the biomedical colloid.

24. The implantable cardiac therapy device of claim 23, further comprising:

an interpreter configured to detect a cardiac threat based on the concentration of proteins.

25. An implantable cardiac therapy device comprising:

means for producing a first signal, said first signal causing an implantable biosensor to transmit an assaulting field into a biomedical colloid, said assaulting field causing said biomedical colloid to produce a resultant field;

means for receiving a second signal representative of said resultant field, wherein one of said assaulting field and said resultant field is an electric field; and

means for processing said second signal to produce a value indicative of a concentration of suspended particles in said biomedical colloid.

26. The implantable cardiac therapy device of claim 25, further comprising:

means for adjusting a pacing parameter based on said value.

27. The implantable cardiac therapy device of claim 25, wherein said biomedical colloid is blood, wherein said second signal is representative of a concentration of suspended proteins in blood, and wherein said processing means is configured to produce a value indicative of a concentration of suspended proteins in said blood.

28. The implantable cardiac therapy device of claim 27, further comprising:

means for adjusting a pacing parameter based on said value.

29. The device of claim 25 wherein the other of said assaulting field and said resultant field is an acoustic field.

30. A method of monitoring a concentration of suspended particles in a biomedical colloid comprising:

a. producing an assaulting electric field;

b. measuring a resultant field produced in vivo by particle interaction with the assaulting field; and

c. determining the concentration of the suspended particles based on the measured resultant field.

31. The method of claim 30 wherein the resultant field is an acoustic field.

32. The method of claim 30 and further including the step of storing the determined concentration in a memory.

33. An implantable cardiac therapy device including an implantable biosensor for monitoring a concentration of suspended particles in a biomedical colloid, said implantable biosensor comprising:

a generator configured to produce an assaulting field in vivo;

a transmitter configured to transmit the assaulting field; and

a receiver configured to detect a resultant field produced in vivo by particle interaction with the assaulting field, said resultant field being indicative of the concentration of suspended particles, wherein one of said assaulting field and said resultant field is an electric field.

34. The device of claim 33 wherein the other of said assaulting field and said resultant field is an acoustic field.