Implantable pressure transducer system optimized for reduced thrombosis effect

• US 20050288596A1
• Filed: 04/21/2005
• Published: 12/29/2005
• Est. Priority Date: 09/26/2002
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Eigler, Neal L., Whiting, James S., Hafelfinger, Werner, Mann, Brian M.
• Granted Patent: US 8,303,511 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/6882 Anchoring means
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61M 2025/0233 specifically adapted for attaching to a body wall by means which are on both sides of the wall, e.g. for attaching to an abdominal wall
• CPC Class Codes: A61M 25/0108 using radio-opaque or ultrasound markers
• CPC Class Codes: A61M 25/04 in the body, e.g. expansible A61M25/10, A61M16/0488 take precedence
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• CPC Class Codes: A61N 1/3629 in combination with non-electric therapy
• CPC Class Codes: A61N 2001/0578 having means for removal or extraction

Abstract

This invention relates generally to systems and methods for optimizing the performance and minimizing complications related to implanted sensors, such as pressure sensors, for the purposes of detecting, diagnosing and treating cardiovascular disease in a medical patient. Systems and methods for anchoring implanted sensors to various body structures are also provided.

Claims

1. An implantable pressure sensing system, comprising:

a pressure sensor assembly, said pressure sensor assembly comprising;

a sensing interface having a first face and a second face; and

at least one pressure sensing unit comprising a sensing surface and non-sensing surface, wherein said pressure sensing unit contacts said second face of said sensing interface; and

a sensor housing, wherein said sensor housing is hermetically sealed to said pressure sensor assembly;

wherein at least portion of said sensing interface is adapted to reduce thrombosis.

2. The implantable pressure sensing system of claim 1, wherein said sensing interface of the pressure sensor assembly comprises a diaphragm.

3. The implantable pressure sensing system of claim 1, wherein at least one said pressure sensing unit comprises a strain gauge.

4. The implantable pressure sensing system of claim 1, wherein said sensing interface and said pressure sensing unit are integrally formed in a micro electromechanical systems device.

5. The implantable pressure sensing system of claim 2, wherein at least a portion of said diaphragm comprises a plurality of grooves to facilitate tissue ingrowth.

6. The implantable pressure sensing system of claim 2, wherein at least a portion of said diaphragm has a biocompatible coating.

7. The implantable pressure sensing system of claim 6, wherein said biocompatible coating is bio-stable.

8. The implantable pressure sensing system of claim 6, wherein said biocompatible coating is bio-erodable.

9. The implantable pressure sensing system of claim 6, wherein said biocompatible coating is resistant to thrombus formation.

10. The implantable pressure sensing system of claim 6, wherein said biocompatible coating is capable of controlling tissue ingrowth.

11. The system of claim 6, wherein said biocompatible coating is configured to reduce formation of fibrous tissue.

12. The implantable pressure sensing system of claim 11, wherein said biocompatible coating does not reduce growth of endothelial tissue.

13. The implantable pressure sensing system of claim 1, wherein at least a portion of said sensor housing is configured to resist transmission of side-load forces to said sensing interface under physiologic conditions.

14. The implantable pressure sensing system of claim 13, wherein said sensor housing comprises a side-loading force absorbing structure about the sensing interface.

15. The implantable pressure sensing system of claim 1, wherein at least a portion of said sensor housing has a polished surface.

16. The implantable pressure sensing system of claim 1, wherein at least a portion of said sensor housing has a thrombosis-resistant coating.

17. The implantable pressure sensing system of claim 1, wherein said sensor housing comprises one or more materials selected from the group consisting of nitinol, stainless steel alloys, titanium alloys, cobalt chromium, tantalum, a ceramic, a glass or combination thereof.

18. The implantable pressure sensing system of claim 1, further comprising a drug-eluting component.

19. The implantable pressure sensing system of claim 18, wherein said drug-eluting component comprises a plurality of reservoirs on the surface of said sensor housing with depots of one or more releasable treatment agents.

21. The implantable pressure sensing system of claim 2, wherein said diaphragm is configured to resist the inhibition of diaphragm motion by overlying tissue overgrowth.

22. The implantable pressure sensing system of claim 21, wherein said diaphragm has a compliance substantially lower than the compliance of physiological levels of overlying tissue overgrowth.

23. The implantable pressure sensing system of claim 22, wherein said diaphragm has an average thickness sufficient to provide a compliance substantially lower than the compliance of physiological levels of overlying tissue overgrowth while capable of a displacement sufficient for said strain gauges to generate a usable sensor signal over a physiological range of blood pressures.

24. The system of claim 23, wherein said diaphragm has a diameter of about 2.5 mm and an average thickness of about 25 microns to about 76 microns.

25. The implantable pressure sensing system of claim 23, wherein said diaphragm has a diameter of about 2.5 mm and an average thickness of about 76 microns to about 127 microns.

26. The implantable pressure sensing system of claim 24, wherein said diaphragm has a diameter of about 2.5 mm, an average thickness of about 50 microns, and a displacement of about 4 nm at about the center of said diaphragm.

27. The implantable pressure sensing system of claim 22, wherein said diaphragm has a compliance of about 10,000 times less or lower than the compliance of physiological levels of overlying tissue overgrowth.

28. The implantable pressure sensing system of claim 27, wherein said diaphragm has a compliance of about 100,000 times less or lower than the compliance of physiological levels of overlying tissue overgrowth.

29. The implantable pressure sensing system of claim 23, wherein said first face and said second face of said diaphragm are generally flat to enhance diaphragm displacement capability.

30. The implantable pressure sensing system of claim 21, wherein said diaphragm comprises a material selected from a group consisting of titanium or Ti 4-6.

31. The implantable pressure sensing system of claim 1, wherein the sensor housing further comprising a filling material within the sensor housing.

32. The implantable pressure sensing system of claim 31, wherein the filling material is selected from one or more of the group comprising helium, argon or other noble gas, an electrical insulating liquid, or a moisture absorbent material.

20. The implantable pressure sensing system of claim 20, wherein said drug-eluting component further comprises a drug for controlling neointimal thickness.

33. An implantable pressure sensing system, comprising:

a pressure transducer assembly comprising a micro electromechanical systems pressure transducer;

said pressure transducer having a first face with a sensing surface and a non-sensing surface, and a second face having a connection area and a non-connection area;

a sensor housing, wherein said sensor housing is hermetically sealed to said pressure transducer assembly;

wherein said sensing surface of the pressure transducer is configured to reduce thrombosis.

34. The implantable pressure sensing system of claim 33, wherein said sensor housing is hermetically sealed to said pressure transducer assembly at the non-sensing surface of said first face.

35. The implantable pressure sensing system of claim 33, wherein said sensor housing is hermetically sealed to said pressure transducer assembly at the non-connection area of said second face.

36. The implantable pressure sensing system of claim 33, wherein said sensor housing is hermetically sealed to said pressure transducer assembly with a gold-silicon bonding layer.

37. A device for monitoring a patient, comprising:

a means for sensing a physiological parameter;

an implantable means for housing the sensing means;

a means for interfacing the sensing means with the patient environment; and

a means for reducing thrombosis on the interfacing means.