An exciting method for improving the function of lungs before using them in organ transplants has been validated in a large new study.
Doctors in Toronto have been working on a system to repair damaged donor lungs inside a special bubble outside the body before transplant. CTV News profiled the method in a story back in late 2008.
Now a new study that appears in the New England Journal of Medicine finds that the technique works as well as standard transplants in the short term.
The lung treatment is called the Toronto XVIVO System. It allows doctors to assess damaged donor lungs while they are outside the body, and then "perfuse", or pump, a solution of oxygen, proteins and nutrients into the injured lungs.
This helps to repair damage caused by swelling or inflammation in the lung that is common in donor lungs. In fact, lungs are so easily damaged in the final stages of a donor's terminal illness, that only about 15 to 20 per cent of them are ever acceptable for transplantation.
Repairing the lungs using the XVIVO System should help to expand the donor organ pool and improve outcomes after transplantation.
This study, which will also be presented at the International Society for Heart and Lung Transplant in San Diego next week, looked at 136 lung transplants performed between September 2008 and January 2010.
Twenty high-risk donor lungs with impaired function and chest x-ray abnormalities were treated and tested for four hours with the Toronto XVIVO Lung Perfusion System and then transplanted. The study also included 116 lungs that were transplanted in the conventional way.
The researchers found that the XVIVO lungs performed as well or better than the conventionally-transplanted lungs.
At 72 hours after transplant, 15 per cent of the lungs treated with the Toronto XVIVO System had something called "primary graft dysfunction", which means injury following transplant. That compares to 30 per cent that developed the condition in the larger control group.
When the researchers looked at bronchial complications, length of ICU and hospital stay, death rates 30 days after surgery, as well as mechanical ventilation, both groups had similar results.
The Toronto XVIVO System also helped doctors in another way: to identify three donor lungs that were not suitable for transplantation.
"The most important finding of this study was that even donor lungs previously thought to be unusable can now be used for transplantation with excellent outcomes, if they perform with acceptable function on the XVIVO system," Dr. Marcelo Cypel, a surgical fellow in transplant and thoracic surgery who helped to develop the Toronto XVIVO System, said in a statement.
"This will give us more lungs with more predictable, safer outcomes after transplantation, and shorter periods of mechanical ventilation and intensive care unit stays for patients."
Dr. Shaf Keshavjee, director of the Toronto Lung Transplant Program at Toronto General Hospital and senior scientist at the McEwen Centre for Regenerative Medicine estimates that the XVIVO System could potentially quadruple the number of transplants a year.
The system is already being used routinely in Toronto's University Health Network as well as elsewhere in Canada and around the world. It is not yet approved by the Food and Drug Administration for use in the U.S.
In Canada, around 250 Canadians were waiting to receive a lung transplant in 2006. About 20 per cent of those will die before they receive a transplant.
