Feedback control of ventricular assist devices

• US 20050107658A1
• Filed: 11/19/2004
• Published: 05/19/2005
• Est. Priority Date: 11/19/2003
• Status: Active Grant

• Current Assignee: Data Sciences U K Limited (International Business Machines Corporation)
• Original Assignee: Transoma Medical, Inc.
• Inventors: Brockway, Brian P.
• Granted Patent: US 7,520,850 B2
• Time in Patent Office: Days
• US Class Current: 600/16
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/8243 by induction
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/523 using blood flow data, e.g. from blood flow transducers
• CPC Class Codes: A61M 60/531 using blood pressure data, e.g. from blood pressure sensors

Abstract

Various devices, systems and methods for providing effective, long term and reliable use of pressure feedback in VADs. Exemplary embodiments are described which provide for direct LV pressure measurement, non-invasive calibration techniques to detect ventricular collapse and recalibrate the feedback mechanism, improved pressure sensor designs with reduced drift, and barometric pressure correction schemes. These devices and methods may be used alone or in combination with each other, and may also be combined with other feedback mechanisms.

Claims

1. An implantable cardiac circulatory support device, comprising:

a blood pump having an inlet and an outlet, wherein the inlet is configured to be connected to a heart and to be in fluid communication with a heart chamber;

a control circuit electrically connected to the blood pump; and

a pressure sensor electrically connected to the control circuit for providing pressure feedback thereto, wherein the pressure sensor is configured to be attached to the heart and to be in fluid communication with the heart chamber.

2. An implantable cardiac circulatory support device as in claim 1, wherein the pressure sensor includes a housing, a pressure transducer contained in the housing, and a pressure transmission catheter in communication with the pressure transducer and extending from the housing, the pressure transmission catheter having a lumen extending therethrough for referring pressure at a distal end of the catheter to the pressure transducer.

3. An implantable cardiac circulatory support device as in claim 2, wherein the pressure transmission catheter is configured to extend into the heart chamber.

4. An implantable cardiac circulatory support device as in claim 3, wherein the pressure transmission catheter is configured to extend through a heart wall defining the chamber.

5. An implantable cardiac circulatory support device as in claim 5, wherein the housing of the pressure sensor is configured to be attached to the heart wall.

6. An implantable cardiac circulatory support device as in claim 5, wherein the housing of the pressure sensor is configured to be attached to the outside of the heart.

7. An implantable cardiac circulatory support device, comprising:

a blood pump having an inlet and an outlet, wherein the inlet is configured to be connected to a heart and to be in fluid communication with a heart chamber;

a control circuit electrically connected to the blood pump; and

a pressure sensor electrically connected to the control circuit for providing pressure feedback thereto, the pressure sensor having an average drift rate of less than 0.75 mmHg per month.

8. An implantable cardiac circulatory support device as in claim 7, wherein the pressure sensor has a drift rate of less than 0.50 mmHg per month.

9. An implantable cardiac circulatory support device as in claim 8, wherein the pressure sensor has a drift rate of less than 0.10 mmHg per month.

10. An implantable cardiac circulatory support device as in claim 7, wherein the pressure sensor includes a sensor die mounted to a header to form a die mount, and wherein the die mount provides a strain relief between the header and the sensor.

11. An implantable cardiac circulatory support device as in claim 10, wherein the sensor die is encapsulated.

12. An implantable cardiac circulatory support device, comprising:

a blood pump having an inlet and an outlet, wherein the inlet is configured to be connected to a heart and to be in fluid communication with a heart chamber;

a control circuit electrically connected to the blood pump;

a pressure sensor electrically connected to the control circuit for providing pressure feedback thereto; and

a barometric pressure sensor in communication with the control circuit.

13. A method of calibrating a ventricular assist device (VAD) implanted in a patient, comprising:

observing ventricular function for an indication of ventricular collapse;

gradually increasing flow rate of the VAD until an initial indication of ventricular collapse is observed;

calibrating the VAD based upon the indication of ventricular collapse.

14. A method of calibrating a ventricular assist device (VAD) as in claim 13, wherein the step of calibrating the VAD comprises calibrating a feedback parameter.

15. A method of calibrating a ventricular assist device (VAD) as in claim 14, wherein the step of calibrating the feedback parameter comprises calibrating pressure.

16. A method of calibrating a ventricular assist device (VAD) as in claim 14, wherein the step of calibrating the feedback parameter comprises calibrating motor current.

17. A method of calibrating a ventricular assist device (VAD) as in claim 14, wherein the step of observing ventricular function comprises observing ventricular wall function.

18. A method of calibrating a ventricular assist device (VAD) as in claim 14, wherein the step of observing ventricular function comprises a non-surgical diagnostic technique.

19. A method of calibrating a ventricular assist device (VAD) as in claim 18, wherein the non-surgical diagnostic technique comprises ultrasonic imaging.

20. A method of operating a ventricular assist device (VAD), comprising:

providing a VAD having a blood pump and a control circuit;

providing primary feedback to the control circuit, wherein the primary feedback comprises pressure feedback; and

providing back-up feedback to the control circuit when the primary feedback is compromised.