Lungs in a Dome and Heart in a Box: The Future of Organ Transplant Research in 2012 and Beyond
“I wanted to thank you and the team. Even though I didn’t get the transplant that night, the experience renewed my strength. When you came in the room to give me the news I could see it was difficult for you, and when Dr. D’Ovidio spoke to me afterward, he was visibly disappointed but you both reminded me to keep hope alive. That level of compassion and drive has truly inspired and re-energized me and my family. We thank you for that gift of inspiration.”
These were the words my patient had for me when I made the dreaded walk to his hospital room to inform him and his family that unfortunately the potential donor offer (in this case, lungs) that we had matched for him was not good enough quality to proceed with transplant. In the organ transplant world, this is sometimes referred to as a “dry run”: when upon clinical evaluation, the donor organ is deemed unsuitable for transplant, and the patient called in is discharged home.
Unfortunately, dry runs occur more frequently than we would like: this combined with the fact that there are significantly more people on a transplant waiting list (122,400 in the US as of December 30, 2011)1 than there are available donors, contributes significantly to waiting list mortality. In 2011, the total number of transplants performed in the US for the year was 21,3542.
In an effort to address the ongoing disproportionate numbers of waiting list candidates to actual transplant recipients, much research is now focused on expanding the donor pool via different methods. A new technique, known as “Ex-Vivo Lung Perfusion (EVLP)” is now being tested in the context of an FDA clinical trial in 5 centers in the United States; donor lungs can be reperfused and reassessed in a controlled environment prior to making a decision to proceed with transplant. Many of the dry runs that are encountered are simply scenarios where the procurement team does not have enough information or tools to assess lungs that they may have concerns about; this technique gives the team the ability to further test the lungs for up to 4 hours and make a truly informed clinical decision. The lungs are ventilated and reperfused at a normothermic temperature, i.e., at normal body temperature and the lungs are flushed with a protein-enriched fluid for up to 4 hours. Previous research results with EVLP in high-risk donor lungs in Toronto were released in April 2011 showing that lungs that were physiologically stable after EVLP had similar outcomes as to conventional transplants. The lungs that were eventually used for transplant post-EVLP were seen to have improved gas exchanges as well as a decreased incidence of primary graft dysfunction 72 hours after transplantation as compared to the control arm. Here are two stories from the first two patients to undergo an EVLP lung transplant at Columbia University Medical Center in New York, the first you can read here and the second you can watch below :
Along a similar vein, a technique known as “Heart in a Box” where a donor heart can be preserved outside of the body for a much longer time than a standard cooler is being tested at UCLA among other centers in the United States. This procedure means that the heart could be kept viable across longer distances for example, and has the potential to significantly expand the donor pool. A mother of two at UCLA has already benefited from this revolutionary technique which you can read about here.
Similarly, ex-vivo preservation is being investigated in both liver and kidney transplant fields in an effort to preserve the donor organs for longer periods of time, and perhaps even improve them. While these advances are crucial to saving lives and improving the efficiency of transplant medicine to meet the needs of patients on a waiting list, raising awareness of organ donation is also key. Often, when discussing the newest research in this field with friends or family who are not involved in medicine, I can see they are uncomfortable with a seemingly macabre subject matter, and occasionally it makes me wonder if we’re making a difference. That feeling is always fleeting however, because even in the disappointing moments like a dry run mentioned above, patients inspire and remind me of how each advance and step we make toward improving the field offers them additional time to spend with loved ones, learn and experience new things, and just enjoy each beautiful day without being sick. If it can give my patient a chance to dance with his wife again, a young girl the ability to attend her graduation, or a loving parent the health and strength to take care of her young children, then that’s all the encouragement we should ever need.
Organ Procurement and Transplantation Network (OPTN): http://optn.transplant.hrsa.gov
1) OPTN – report run on December 30, 2011 – total waiting list registrants in USA
2) OPTN – report run on December 30, 2011 – total organ transplants in 2011 in USA