Bartley P. Griffith, MD and patient, David Bennett. (Image: University of Maryland School of Medicine)
David Bennett had terminal heart disease, and
the pig heart was “the only currently available option,” according to the
statement, adding, Bennett was deemed ineligible for a conventional heart
transplant or an artificial heart pump after reviews of his medical records.
“It was either die or do this transplant. I
want to live. I know it's a shot in the dark, but it's my last choice,” Bennett
said before the surgery, according to the news release.
The US Food and Drug Administration granted
emergency authorization for the surgery on December 31.
Three genes that are responsible for rejection
of pig organs by human immune systems were removed from the donor
pig, and one gene was taken out to prevent excessive pig heart tissue growth.
Six human genes responsible for immune acceptance were inserted.
Bennett’s doctors will need to monitor him for
days to weeks to see whether the transplant works to provide lifesaving
benefits. He’ll be monitored for immune system problems or other complications.
“There are simply not enough donor human
hearts available to meet the long list of potential recipients,” surgeon Dr.
Bartley P. Griffith said in a statement. “We are proceeding cautiously, but we
are also optimistic that this first-in-the-world surgery will provide an
important new option for patients in the future.”
Revivicor, a regenerative medicine company
based in Blacksburg, Virginia, provided the heart, according to the news
release.
A total of 106,657 people are on the national
transplant waiting list, and 17 people die each day waiting for an organ, according to
organdonor.gov.
Art Caplan, a professor of bioethics at New
York University, said he was a little apprehensive when he heard the news of
Bennett's transplant. “I hope they've got the data to back up trying this now,
based on their animal studies,” he said, noting the United States has a
“terrible” shortage of organs for transplants.
He believes engineering animal
parts is a solution. “The question is, can we get there with minimal
harm to the first volunteers?” he asked.
Pig heart valves have been transplanted into
humans for many years.
In October, surgeons successfully tested the
transplant of a genetically modified pig kidney into a woman in New York who
was brain-dead.
Caplan said it is too early to call the heart
transplant a success. That label will come if Bennett has a good quality of
life for months, he said. But it's still possible that he could die. Whatever
the outcome, it's important for researchers to learn something that can be
applied to future transplants, he added.
He said there also should be an independent
review of the data that went into the decision to do this first transplant. The
other ethics issue is around the consent, he said. It should come from others
besides the patient, who is very likely to agree to the surgery if he is facing
death.
“Consent for the imminently dying is important
to get ... but it's not enough,” he said, suggesting a research ethics
committee weigh in. “You want to have somebody else say, 'Yes, we agree' this
isn't a crazy, too risky thing to try.”
More than 40,000 transplants - a record - were
done in 2021, according to the Organ Procurement and Transplantation Network. (By
Katherine Dillinger. John Bonifield and Steve Almasy
contributed to this report. CNN)
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