Breathing new life into lungs
December 20, 2008
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Megan Ogilvie
Joseph Hall
Toronto researchers have pioneered a technique to repair donor lungs outside the human body, an advance that could increase the number of usable lungs available for transplant in Canada by up to sixfold.
Andy Dykstra is the first patient in the world to receive a pair of lungs repaired with the new technique that was developed by transplant surgeons at Toronto General Hospital. The 56-year-old London, Ont., man was put on the donor list in July after he nearly died the previous year from an acute attack of chronic obstructive pulmonary disease.
Dykstra's two-year wait for new lungs was cut down to less than five months because surgeons were able to offer him a donor pair that would normally not have been healthy enough to transplant.
Twelve days after his Dec. 5 surgery at Toronto General, Dykstra was healthy enough to go home and ready to get back to his active life.
"I can breathe," he told the Star from his London home. "When I walk, I can breathe. Before I couldn't do anything. I couldn't even walk around the block."
The technique, dubbed the Toronto XVIVO Perfusion System, allows surgeons to assess and treat donor lungs outside the body, which could increase the number of available lungs by four to sixfold, said Dr. Shaf Keshavjee, the director of Toronto General's lung transplant program, who helped pioneer the technique.
Currently, only about 10 to 15 per cent of harvestable lungs are suitable for transplantation due to injuries that are most often caused by swelling in the organs, Keshavjee said.
The severe brain injuries that predominantly make a set of donor lungs available also trigger damage to those organs through the release of inflammatory enzymes.
"Not only are we taking organs and transplanting them, but now we are on the threshold of improving them," he said.
The new procedure may also be applicable to other organs, including hearts, kidneys and livers, said Dr. Gary Levy, director of the hospital's Multi Organ Transplant Program.
Lungs are currently preserved by putting them on ice, said Keshavjee, a strategy that simply slows down the organ-death process. This cooling keeps the lungs viable for about six hours, he said.
The Toronto System preserves the lungs under a Star Trek-like domed apparatus at body temperature – 37 degrees Celsius – by pumping a bloodless, oxygen-carrying solution through the organs, while they expand and contract on a respirator.
This more than doubles the time the lungs can be preserved to up to at least 12 – and potentially 18 – hours, said Keshavjee. During that time, the organ can utilize its own regenerative powers to fix itself, something that does not happen when lungs are stored in the current cooling technique. Or, doctors can use anti-inflammatory drugs, or even future gene and stem cell therapies, to repair the organ at a molecular level.
"Rather than taking an organ that is slowly dying and slowly deteriorating, we can actually either keep it static, or more importantly make it better," Keshavjee said. It may also be possible to prepare the lungs with gene therapies that would ensure the recipient's body did not reject them, a major problem with almost all donated organs.
Dr. Leo Ginns, medical director of the lung transplant program at Massachusetts General Hospital, called the Toronto effort "groundbreaking" and "encouraging," and said he believed the technique could be adopted by other transplant teams around the world.
He noted that the technique must be proven on many more patients before it could become standard of care.
Right now, about 80 people are waiting for either a lung or heart-lung transplant in Ontario. Roughly 20 per cent of those patients will die on the wait list.
Keshavjee said the Toronto System could allow Toronto General to double the number of lung transplants it performs, from 100 to 200 surgeries a year, in the near future.
Dykstra's new lungs were the fourth the hospital has transplanted using the Toronto System. But his were the first to be repaired prior to transplantation. Patient confidentiality would not allow Keshavjee to reveal what those injuries were.
Dykstra can hardly believe that he's home with a healthy new pair of lungs just two weeks after Keshavjee suggested he take part in the hospital's clinical trial.
"The more he explained it to me, I knew I had to have this," he said. "It felt so right. The hairs were literally standing up on my arms as he was explaining it to me."
Toronto Star