The long-struggling field of cardiac xenotransplantation has had a very good year.
In January, the University of Maryland made history by keeping a 57-year-old man deemed too sick for a human heart transplant alive for 2 months with a genetically engineered pig heart. On July 12, New York University surgeons reported that heart function was “completely normal with excellent contractility” in two brain-dead patients with pig hearts beating in their chests for 72 hours.
NYU Langone Health
Dr. Robert A. Montgomery
The NYU team approached the project with a decedent model in mind and, after discussions with their IRB equivalent, settled on a 72-hour window because that’s the time they typically keep people ventilated when trying to place their organs, explained Robert A. Montgomery, MD, DPhil, director of the NYU Langone Transplant Institute.
“There’s no real ethical argument for that,” he said in an interview. The consideration is what the family is willing to do when trying to balance doing “something very altruistic and good versus having closure.”
Some families have religious beliefs that burial or interment has to occur very rapidly, whereas others, including one of the family donors, were willing to have the research go on much longer, Dr. Montgomery said. Indeed, the next protocol is being written to consider maintaining the bodies for 2-4 weeks.
“People do vary and you have to kind of accommodate that variation,” he said. “For some people, this isn’t going to be what they’re going to want and that’s why you have to go through the consent process.”
Informed authorization
Arthur L. Caplan, PhD, director of medical ethics at the NYU Langone Medical Center, said the Uniform Anatomical Gift Act recognizes an individual’s right to be an organ donor for transplant and research, but it “mentions nothing about maintaining you in a dead state artificially for research purposes.”
“It’s a major shift in what people are thinking about doing when they die or their relatives die,” he said.
Because organ donation is controlled at the state, not federal, level, the possibility of donating organs for xenotransplantation, like medical aid in dying, will vary between states, observed Dr. Caplan. The best way to ensure that patients whose organs are found to be unsuitable for transplantation have the option is to change state laws.
He noted that cases are already springing up where people are requesting postmortem sperm or egg donations without direct consents from the person who died. “So we have this new area opening up of handling the use of the dead body and we need to bring the law into sync with the possibilities that are out there.”
In terms of informed authorization (informed consent is reserved for the living), Dr. Caplan said there should be written evidence the person wanted to be a donor and, while not required by law, all survivors should give their permission and understand what’s going to be done in terms of the experiment, such as the use of animal parts, when the body will be returned, and the possibility of zoonotic viral infection.
“They have to fully accept that the person is dead and we’re just maintaining them artificially,” he said. “There’s no maintaining anyone who’s alive. That’s a source of a lot of confusion.”
Special committees also need to be appointed with voices from people in organ procurement, law, theology, and patient groups to monitor practice to ensure people who have given permission understood the process, that families have their questions answered independent of the research team, and that clear limits are set on how long experiments will last.
As to what those limits should be: “I think in terms of a week or 2,” Dr. Caplan said. “Obviously we could maintain bodies longer and people have. But I think, culturally in our society, going much past that starts to perhaps stress emotionally, psychologically, family and friends about getting closure.”
“I’m not as comfortable when people say things like, ‘How about 2 months?’ ” he said. “That’s a long time to sort of accept the fact that somebody has died but you can’t complete all the things that go along with the death.”
Dr. Caplan is also uncomfortable with the use of one-off emergency authorizations, as used for Maryland resident David Bennett Sr., who was rejected for standard heart transplantation and required mechanical circulatory support to stay alive.
“It’s too premature, I believe, even to try and rescue someone,” he said. “We need to learn more from the deceased models.”