U of T researchers have devised a way to refurbish donor lungs before they’re transplanted
Just like old cars, used and slightly damaged human organs can now be refurbished before they are passed on to new owners.
Every year in Toronto, some 300 sets of lungs become available for transplant, but only about 100 of them are used. The rest are deemed too injured – they have water inside them or carry hospital infections – so they are discarded.
But what if you could take a damaged lung from a donor and fix it outside the body before transplanting it? Dr. Marcelo Cypel and Dr. Shaf Keshavjee, both thoracic surgeons with the Toronto Lung Transplant Program, have done exactly that.
Typically, when a lung becomes available, it is chilled and then transplanted as quickly as possible, usually within a few hours. Cypel and Keshavjee, however, using their “Toronto technique,” keep the lung at body temperature. They place it under a protective dome and perfuse it with a bloodless solution of oxygen, nutrients and antibiotics, among other things. A lung can last at least 12 hours under these conditions.
The technique offers two clear advantages over chilling. First, as they watch the lung breathe and measure its function, the surgeons can carefully assess its quality – something that can’t be done while it’s preserved on ice and dormant. Some lungs that look good on visual inspection end up performing poorly; others that look bad perform well. The other advantage is that at least some damaged lungs can be rehabilitated: fluid-filled lungs can be dried out and infected ones can be treated with antibiotics. Without the rest of the body to worry about, the treatments can be more intense.
Last year, 23 lungs that otherwise would have been discarded were treated and transplanted into patients (with their knowledge and consent). These patients fared no worse than the ones who got the usual donor lungs. Cypel thinks that soon, 100 extra pairs of lungs a year could be salvaged for transplant in Toronto, doubling the number of transplants possible here.
There are currently around 80 people waiting for lung transplants in Ontario. About a third of the people waiting for lungs will die before they get them, says Cypel. This technique could significantly shrink that waiting list.
The ex-vivo lung perfusion costs $8,000 per set of lungs – about what it costs a hospital to keep a patient in intensive care for just one day. This raises the question of whether just damaged lungs or all lungs should be evaluated before transplant, given that proper assessment could dramatically improve recovery times and outcomes. “It’s probably the way to go,” says Cypel, who is conducting a cost-benefit analysis on the topic. The researchers published their overview earlier this year.
The concept is set to be used with other organs, too. Last October, a group in the U.K. published a report of the first kidney that, like the lungs, had been preserved at near body temperature and perfused with a special solution. That kidney was successfully transplanted into a recipient – and it compared favourably to its twin kidney, which had been kept in cold storage and transplanted into someone else. Livers will almost certainly be next, and there’s reason to believe that thyroids, ovaries and even hearts could one day benefit as well.