Donor Lungs Kept Alive Outside Body04/13/11
WEDNESDAY, April 13 (HealthDay News) -- Using a technique that
looks like it could have been pulled from a science fiction
thriller, transplant surgeons can now keep lungs alive outside of
the body, giving them time to heal and allowing surgeons to better
assess the health of the lungs before transplant.
In the new procedure, lungs are placed in a protective glass
dome after being removed from the donor. They're then hooked up to
a ventilator, so the lungs can continue to breathe, and the lungs
are given what's known as a perfusion solution to mimic blood
circulating through them.
"We've developed a technique that allows us to assess and treat lungs outside of the body," said the study's senior author, Dr. Shaf Keshavjee, director of the Toronto Lung Transplant Program at Toronto General Hospital.
"The pleasant surprise from our study was that we set out to prove these lungs would be equivalent, but we now have data showing that these patients can even do better," he said.
Results of the study are published in the April 14 issue of the
New England Journal of Medicine.
Currently, more than 80 percent of donor lungs are unsuitable
for transplant, with fewer than 15 percent of lungs from multiorgan
donors able to be used, according to the study. Because of the
relatively small number of organs that are deemed to be acceptable,
mortality is high among patients awaiting transplantation, the
authors pointed out.
Keshavjee said that the reason so few lungs are suitable for
transplant is that brain death and complications from treatments
received often damage the lungs. Then, when the lungs are removed
from the body, they don't have a chance to begin healing.
"What we've tried to do is make the lungs think they're still in the body. This allows them the chance to recover," said Keshavjee.
Lungs are only placed on the machine for two to four hours, but
that's enough time for them to start to heal, he said. The other
big benefit is that because the lungs are essentially alive in the
glass dome, surgeons can assess the health and function of the
lungs before transplant.
Keshavjee said he thinks this procedure could triple, or even
quadruple the number of available donor lungs.
In the current study, 136 lungs were transplanted. Twenty-three
of those lungs were selected to undergo the new technique, which is
known technically as normothermic ex vivo lung perfusion. These
lungs were chosen because they would normally have been considered
high risk for normal transplant. In addition to ventilation and
circulation, the lungs also received antibiotic and
After four hours, 20 of the lungs undergoing the new procedure
were deemed suitable for transplant. The other three sets weren't
functioning well enough to be transplanted.
Compared to 30 percent of the lungs selected in the conventional
way, only 15 percent of the ex vivo-treated lungs had what's known
as primary graft dysfunction. This is a serious complication of
transplant, and means that the lungs aren't getting circulation as
they should. Primary graft dysfunction, in fact, can lead to
rejection of the transplanted organ.
The study was sponsored by Vitrolife, a biotechnology company
that supplied materials and equipment for the research but
otherwise had no control over the study.
There was no increased risk of adverse events in the treatment
group, according to the study. Two of 20 patients died within 30
days of transplantation in the ex vivo perfusion group -- although
the cause of the deaths was not directly related to the transplant
-- as compared with six of 116 in the control group, the
After a year, the survival rate was 80 percent for the patients
with ex vivo-treated lungs and 83.6 percent for the control group,
according to the report.
In addition to increasing the available number of lungs for
transplant, Keshavjee said that this new technique will also
eventually allow doctors to treat disease in potential donor lungs
before transplanting them. "We're entering an era of personalized
medicine and with molecular and gene-based therapies, we may be
able to fix organs before using them," he said.
In addition to lungs, Keshavjee said that this technique could
likely be used for other organs to increase the number of available
organs for transplant. He said liver surgeons at Toronto General
Hospital have started working on adapting this technique for
"This study is extremely exciting. It's really on the frontier of what we're able to do in terms of organ preservation and transplantation," said Dr. Michael Goldstein, director of kidney and pancreas transplantation at Mount Sinai Medical Center and medical director of the New York Organ Donor Network in New York City.
Goldstein also pointed out that this technique could allow
donated lungs to become more widely available geographically. He
said that, currently, donated lungs typically can't travel very
far, which means that the person who might be most in need might
not get the donated lungs simply because of distance. But, if the
lungs remain viable for longer periods of time, that geographical
limitation might be eliminated.
Dr. Joseph Pilewski, medical director of the lung
transplantation program at the University of Pittsburgh Medical
Center, said that having the extra time this technique provides
might also allow surgeons to better match donated lungs to
potential recipients, possibly reducing the risk of rejection.
Neither Goldstein nor Pilewski expressed any concerns about the
medical aspects of the new lung-preserving procedure. Both pointed
out that the device and technique are labor intensive, and
currently require a significant infrastructure investment, but both
expect that the technique will be refined to become more
"This group in Toronto has really made significant progress in a short period of time. Right now, this may end up being limited to a few centers, but other companies will probably jump in. In the long run, about three to five years, I think this technique has great potential to change the way we practice. This technique is promising and has a large number of potential uses," said Pilewski.
Learn more about lung transplants from the
U.S. National Heart, Lung and Blood
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