Systems and methods for ex-vivo organ care and for using lactate as an indication of donor organ status

• US 20070275364A1
• Filed: 04/25/2007
• Published: 11/29/2007
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: TransMedics, Inc. (TransMedics Group, Inc.)
• Original Assignee: TransMedics, Inc. (TransMedics Group, Inc.)
• Inventors: Hassanein, Waleed, Khayal, Tamer, Elbetanony, Ahmed, Cecere, Giovanni, Lezberg, Paul, Sousa, Dennis, Hansen, Elizabeth
• Granted Patent: US 8,304,181 B2
• Time in Patent Office: Days
• US Class Current: 435/1.200
• CPC Class Codes: A01N 1/02 Preservation of living parts
• CPC Class Codes: A01N 1/0247 for perfusion, i.e. for circulating fluid through organs, blood vessels or other living parts

Abstract

The invention provides, in various embodiments, systems, devices and methods relating to ex-vivo organ care. In certain embodiments, the invention relates to maintaining an organ ex-vivo at near-physiologic conditions. The present application describes a method for using lactate measurement in the arterial and the venous blood lines of the Organ Care System Heart perfusion device to evaluate the: 1) The overall perfusion status of an isolated heart and 2) The metabolic status of an isolated heart and 3) the overall vascular patency of an isolated donor heart. This aspect of the present invention uses the property of myocardial cell'"'"'s unique ability to produce/generate lactate when they are starved for oxygen and metabolize/utilize lactate for energy production when they are well perfused with oxygen.

Claims

1. An organ care system for perfusing a heart comprising:

a module including a chassis, an organ chamber assembly mounted to the chassis for containing the heart during perfusion and including a fluid conduit with a first interface for connecting to an aorta of the heart and a second interface for connecting to a pulmonary vein of the heart, a Lactate A sensor for sensing lactate in the fluid conduit connected to the aorta of the heart, a Lactate V sensor for sensing lactate in the fluid conduit connected to the pulmonary vein of the heart, wherein a Lactate V-A differential is calculated using lactate values sensed by the Lactate A sensor and the Lactate V sensor.

2. The system of claim 1, wherein the organ chamber assembly is disposable.

3. The system of claim 1 wherein the V-A differential is calculated at least once an hour.

4. The system of claim 1, comprising a flow select valve for selecting between flowing the perfusion fluid to the first interface and flowing the perfusion fluid to second interface.

5. The system of claim 1, wherein the disposable single use module includes a reservoir mounted to the chassis of the disposable single use module in fluid communication with the organ chamber assembly and sized and shaped for containing perfusion fluid for the heart.

6. The system of claim 1, further comprising a sensor for measuring the aortic pressure in the organ care system.

7. A method of preserving a heart ex vivo comprising:

placing a heart in a protective chamber of an organ care system,

connecting the heart to a perfusion fluid circuit to perfuse fluid to the heart, and

pumping a perfusion fluid to the heart,

and,

monitoring lactate in the heart to assess heart status.

8. The method of claim 7 wherein the step of monitoring the lactate in the heart includes monitoring the lactate value of the perfusion fluid in an arterial conduit and monitoring lactate value of the perfusion fluid in a venous conduit.

9. The method of claim 8 wherein a V-A lactate differential value is calculated using the lactate value of the perfusion fluid in the venous conduit and the lactate value of the perfusion fluid in the arterial conduit.

10. The method of claim 8 wherein the lactate values are monitored at regular intervals.

11. The method of claim 10 wherein the regular intervals are about 60 minutes or less.

12. The method of claim 10 wherein the total length of time that the lactate values are monitored is more than one hour.

13. The method of claim 7 further comprising the step of measuring the perfusion pressure in the conduit connected to the aorta.

14. The method of claim 13 further comprising the step of evaluating the coronary vascular patency of the heart using both the perfusion pressure and the lactate value.

15. The method of claim 14 wherein the step of monitoring the lactate values includes monitoring the lactate value of the perfusion fluid in an arterial conduit and monitoring lactate value of the perfusion fluid in a venous conduit and wherein a V-A lactate differential value is calculated using the lactate value of the perfusion fluid in the venous conduit and the lactate value of the perfusion fluid in the arterial conduit.

16. A method of preserving a heart ex vivo comprising:

placing a heart in a protective chamber of a portable organ care system,

providing a perfusion fluid to the heart while the heart is in the protective chamber,

flowing the perfusion fluid in a conduit circuit including the heart, and,

measuring the lactate in the fluid conduit to assess the status of the heart.

17. The method of claim 16 wherein the step of measuring the lactate value includes measuring the lactate value of the perfusion fluid in an arterial conduit and measuring lactate value of the perfusion fluid in a venous conduit.

18. The method of claim 17 wherein a V-A lactate differential value is calculated using the lactate value of the perfusion fluid in the venous conduit and the lactate value of the perfusion fluid in the arterial conduit.

19. The method of claim 17 wherein the lactate value is measured at regular intervals.

20. The method of claim 19 wherein the regular intervals are less than about 60 minutes.

21. The method of claim 19 wherein the total length of time that the lactate value are measured is more than one hour.

22. The method of claim 16 wherein the conduit circuit includes a portion connected to an artery and further comprising the step of measuring the perfusion pressure in the conduit connected to the artery.

23. The method of claim 22 further comprising the step of evaluating the coronary vascular patency of the heart using both the perfusion pressure and the lactate value.

24. The method for evaluating heart perfusion status comprising:

placing a heart in a protective chamber of an organ care system,

pumping a perfusion fluid into the heart via a retrograde perfusion of an aorta of the heart,

providing a flow of the perfusion fluid away from the heart via a right ventricle of the heart, and

measuring the lactate value of the fluid leading to the aorta of the heart,

measuring the lactate value of the fluid leading away from the right ventricle of the heart, and

evaluating the status of the heart using the measured lactate values.

25. The method of claim 24 further comprising the step of subtracting the lactate value of the perfusion fluid leading to the aorta of the heart from the lactate value of the perfusion fluid leading away from the heart to determine a V-A lactate differential.

26. The method of claim 25 wherein the V-A lactate differential is determined multiple times during the course of a heart perfusion.

27. The method of claim 26 further comprising measuring the pressure of the fluid leading to the aorta of the heart.

28. The method for evaluating heart perfusion status comprising:

placing a heart in a protective chamber of an organ care system,

pumping a perfusion fluid into the heart,

providing a flow of the perfusion fluid away from the heart, and

measuring the lactate value of the fluid leading to the heart,

measuring the lactate value of the fluid leading away from the heart, and

evaluating the status of the heart using the measured lactate values.

29. The method of claim 28 further comprising the step of subtracting the lactate value of the fluid leading to the heart from the lactate value of the fluid leading away from the heart to determine a V-A lactate differential.

30. The method of claim 29 wherein the V-A lactate differential is determined multiple times during the course of a heart perfusion.

31. The method of claim 28 further comprising measuring the pressure of the fluid leading to the heart and the step of using the pressure of the fluid leading to the heart with the measured lactate values to evaluate the status of the heart.