Implantable drug delivery system responsive to intra-cardiac pressure

• US 6,969,369 B2
• Filed: 04/22/2002
• Issued: 11/29/2005
• Est. Priority Date: 04/22/2002
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Struble, Chester
• Primary Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US10/126,538
• Publication Number:
  US 20030199813A1
• Time in Patent Office: 1,317 Days
• Field of Search: 604/22, 604 65- 67, 604/93.01, 604/288.01, 604/288.02, 604/288.03, 604/288.04, 128/DIG.12, 128/DIG.13
• US Class Current: 604/67
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 2210/125 Heart
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

The invention is directed to techniques for monitoring the condition of a patient, such as a patient having congestive heart failure, and appropriately modifying the patient'"'"'s drug therapy as a function of a pressure in the patient'"'"'s heart, such as the estimated pulmonary artery diastolic pressure. The drugs may be administered by an implanted drug delivery device. The drug selection, the drug dosage or both may be controlled as a function of the pressure and/or the activity level of the patient.

Claims

1. An implantable medical device comprising:

a pressure monitor that estimates a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient; and

a processor that selects one of a first dosage and a first dosage rate of a therapeutic drug that corresponds to the estimated pulmonary artery diastolic (EPAD) pressure to maintain said ePAD pressure within a range of approximately about 12 mmHg to about 18 mmHg and that selects one of a second dosage and a second dosage rate of the therapeutic drug for a ePAD within a second range, wherein the second range is different than the first range.

2. The device of claim 1, wherein the processor selects one of the first dosage, the first dosage rate, the second dosage, the second dosage rate from a look-up table.

3. The device of claim 1, wherein the processor selects at least one of the first dosage and the second dosage that corresponds to the estimated pulmonary artery diastolic pressure as a function of an equation that relates said first dosage and said second dosage to ePAD pressure.

4. The device of claim 1, wherein the device is implanted in the abdomen of a patient.

5. The device of claim 1, further comprising a pressure sensor that generates a pressure signal as a function of a pressure in the heart of the patient, and

wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the pressure signal.

6. The device of claim 5, wherein the pressure sensor includes one of a capacitive absolute pressure sensor, a piezoelectric crystal transducer and a piezoresistive pressure transducer.

7. The device of claim 5, wherein the pressure sensor is disposed in a right ventricle of the heart of the patient.

8. The device of claim 5, wherein the pressure monitor estimates the pulmonary artery diastolic pressure by identifying a pressure value at a point of maximum slope of the pressure signal.

9. The device of claim 5, wherein the pressure monitor comprises a differentiating circuit that generates a differential signal that is representative of a first derivative of the pressure signal, and

wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the differential signal.

10. The device of claim 5, wherein the pressure monitor comprises a differentiating circuit that generates a differential signal that is representative of a second derivative of the pressure signal, and

wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the differential signal.

11. The device of claim 1, further comprising a drug delivery device that delivers the selected dosage or selected dosage rate of the therapeutic drug to the patient,

wherein the processor generates a control signal as a function of one of the selected dosage and the selected dosage rate, and

wherein the drug delivery device receives the control signal and delivers the selected dosage or the selected dosage rate as a function of the control signal.

12. The device of claim 11, wherein the drug delivery device comprises:

a reservoir configured to receive and store the therapeutic drug; and

an infusion apparatus that delivers the therapeutic drug to an infusion site in the body of the patient.

13. The device of claim 12, wherein the infusion site is one of the subclavian vein, superior vena cava and fatty tissue of the body of the patient.

14. The device of claim 12, wherein the drug delivery device further comprises a pump that delivers the therapeutic drug from the reservoir to a proximal end of the infusion apparatus.

15. The device of claim 11, wherein the therapeutic drug comprises a substance that increases cardiac output.

16. The device of claim 11, wherein the therapeutic drug comprises a substance that has a positive inotropic effect on the heart of the patient.

17. The device of claim 11, wherein the therapeutic drug includes one of digitalis, digoxin, digitoxin, dopamine, dobutamine, milrinone and amrinone.

18. The device of claim 1, further comprising an input/output device coupled to the processor, the input/output device configured to exchange information between a person and the processor.

19. A device according to claim 1, further comprising a drug delivery device delivers one of the selected dosage and the dosage rate of the therapeutic drug to the patient, said drug delivery device comprising:

a multi-chamber reservoir configured to receive and store at least two different therapeutic drugs;

wherein the processor generates a control signal as a function of one of the selected dosage and the dosage rate of each of said at least two different therapeutic drugs; and

wherein the drug delivery device receives the control signal and delivers one of the selected dosage and the dosage rate of one of the at least two different therapeutic drugs as a function of the control signal.

20. A device according to claim 19, further comprising:

an infusion apparatus coupled to the multi-chamber reservoir and adapted to deliver the at least two different therapeutic drugs into at least one of;

an organ, a volume of tissue, a cavity, and a vessel of the body of the patient.

21. A device according to claim 20, wherein the vessel comprises one of:

a subclavian vein, a superior vena cava vein, and an inferior vena cava; and

wherein the volume of tissue comprises a volume of fatty tissue.

22. A device according to claim 19, wherein the drug delivery device further comprises a pump that delivers one of the at least two different therapeutic drugs from the multi-chamber reservoir to a proximal end of the infusion apparatus.

23. A device according to claim 19, wherein one of the at least two different therapeutic drugs comprise a substance that increases cardiac output.

24. A device according to claim 19, wherein one of the at least two different therapeutic drugs comprise a substance that provides a positive inotropic effect on the heart of the patient.

25. A device according to claim 19, wherein one of the at least two different therapeutic drugs includes one of:

digitalis, digoxin, digitoxin, dopamine, dobutamine, milrinone, amrinone.