Machine perfusion expands the possibilities of remote habit transplantation

Machine perfusion expands the possibilities of remote habit transplantation

In places like Australia, where metropolitan areas are separated from an entire continent, donor hearts have gone unused simply because transplant teams couldn't get the organ to a recipient in time.

If there is no recipient for an available heart in Perth but there is a match in Sydney, that's almost 2,000 miles of travel or a five-hour flight. Add that to a few hours of retrieval and preparation, and that's a seven hour trip. “

Emily Granger, MBBS, cardiothoracic and heart and lung transplant surgeon at St. Vincent’s Hospital, Sydney, Australia

Dr. Granger addressed organ transport time at today's annual meeting and scientific sessions of the International Society of Heart and Lung Transplantation (ISHLT) in Boston.

“We have focused much of our research at St. Vincent on ensuring that we can protect and preserve the donor heart not just for a long time, but for a long time,” she said.

Until recently, donor hearts had to be transported in a portable cooler that took transplant teams six hours to implant a donor heart. The advent of machine perfusion, in which a device pumps a blood-like solution through the donor heart during transport, has significantly extended this window.

St. Vincent’s, a pioneer in machine perfusion, began using the technology for Circulatory Death (DCD) heart donations in 2014. Today, machine perfusion is used in more than half of the center's heart transplants.

“We realized we needed a system that would allow us to span the country,” she said. “We knew we had to remove time from the equation.”

Saint Vincent has pushed the limits of normothermic machine perfusion (NMP), in which the heart is perfused and maintained at 35 degrees Celsius for up to 8 hours. Other Australian units have even used the system for 10 hours.

“Ten years ago we had to reject donor organs because of time constraints,” she said. “Now we can accept organs from regions we never thought possible and be sure they will work.”

She said in the near future it might be possible to push the boundaries even further.

“We were actually able to look at an international exchange of donor hearts to allow for transportation between countries,” she said.

Australia is already collecting donor organs from New Zealand. However, machine perfusion could allow transplant teams to travel to the Pacific Islands and Asia.

“There are a significant number of patients on our transplant list who are very difficult to access a donor,” she said. "The answer for them could be a donor from a slightly different genetic population than our region. Their ideal donor could actually live in a different country."

Research conducted at St. Vincent’s has shown that outcomes for heart transplants with machine perfusion are comparable to transplants performed without it.

“We looked specifically at primary graft function in the transplanted heart and found no difference across modalities,” she said. “We like to think that we are eliminating the influence of time by using machine perfusion.”

Dr. Granger said the technology is a real sea change for heart transplant teams.

“When I started my career as a transplant surgeon, all we had was a portable cooler,” she said. “Space has completely changed, and the only thing that limits us right now is our imagination.”

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