This new system effectively doubles the time available to transplant the heart from four hours to eight hours. This is not perfect but it is still a huge improvement. It is noteworthy that it may affect 30% of those on waiting lists.
Traditionally, donor hearts can only be harvested after brain death occurs, but the heart is still beating. If the heart stops beating, it is lacking a sufficient supply of oxygen. This lack of oxygen leads to damage and death of cardiac cells, which does not make for an ideal transplant organ. Thus, they need to harvest a functional heart, pack it in ice, and implant it in the recipient within four hours to ensure tissue quality. While kidneys and livers can be obtained after cardiac death, hearts have never been used.
For a heart to be successfully transplanted, many different factors need to come together all at once and this precludes many from obtaining life-saving organs, one of which is simple geography. An organ might be a perfect match for someone, but if they are slightly too far away to meet that deadline, they cannot use it.
This new technique makes use of heart death, not just brain death, which widens the pool of who can donate a heart. For instance, a person on life support may have a very small amount of brain activity left with no chance of getting better, but is not technically brain dead and therefore not a donor candidate. The patient’s family can choose to end life support, which will eventually cause the heart to stop beating. Five minutes after all cardiac activity has ended, the patient can be declared dead.
Graham’s team has spent the last 12 years developing a specialized fluid and pump that provide the heart with oxygen, reducing damage and preserving the tissue. The heart, which appears blue from lack of oxygen, begins to turn back to a normal pink color, which will also help resuscitate the organ, getting it to beat again. This feature is incredibly important, because getting it to beat on the machine is a good indicator that it will function after being transplanted into the recipient.
By keeping the donor heart functional and fresh, it just about doubles the four-hour transplant window. This allows time for a perfect match to be found, which is one of the surest signs that the surgery will be successful.
Two hearts that had been dead and then revived with Graham’s machine have been implanted into two patients who both suffered heart failure. The first was implanted two months ago into Michelle Gribilar, a 57-year-old woman from Sydney. Jan Damen received his heart about two weeks ago, and reports that he is feeling great.
“Both of the patients, I'm pleased to say, are doing extremely well. You can imagine that Peter Macdonald and Kumud Dhital, the surgeons, were on tenterhooks afterwards but the patients have done extremely well,” Graham told ABC’s Elizabeth Jackson. “The first patient now is several months out after transplantation. The second one is a shorter period but the second one went like butter.”
Graham also noted that this technique could also be used to save lives in countries including Japan, where “brain death” is not a legal definition of death, therefore disallowing hearts from those patients to be used.