Keeping hearts alive outside the body

Cardiac specialists at The Alfred have already performed five human heart transplants after using a novel method known as ‘hypothermic ex-vivo perfusion’ to preserve the donor heart during transit.

A recent successful transplant performed on a Melbourne man saw the donor heart record an ‘ischemic’ time -  which refers to the time the heart does not have blood supply - of more than seven hours, the longest period of time recorded worldwide to date.

The trial could potentially double the amount of time donor hearts remain viable for transplantation – increasing the current four hour standard to eight hours. This would mean donor hearts could travel greater distances, ultimately saving more lives.

It is the first time the Swedish-developed hypothermic ex-vivo (outside the body) perfusion technology has been applied outside Europe.

Cardiothoracic surgeon at The Alfred, and co-principal investigator, Professor David McGiffin, said the process involves putting donor hearts on an “ex-vivo perfusion machine”, which pumps a liquid called perfusate through the heart muscle, cooling it to 8°c and keeping it supplied with oxygen.

“If the trial demonstrates that the donor heart is better protected with ex-vivo perfusion as opposed to ice slush in a cooler, it could mean all donor hearts are transported using ex-vivo perfusion, no matter what distance,” Professor McGiffin said.

The Alfred’s director of cardiology and co-principal investigator, Professor David Kaye, said the patients involved in the trial had recovered well, which could be in part attributed to the nutrition and oxygen provided to the donor heart by the perfusion system.

“The best chance that a patient has of surviving heart transplantation is if they come out of the operating room with a well-functioning heart despite a very, very long ischemic time, and that’s what we think this system will deliver.”

The advancement follows four years of pre-clinical research led by the Critical Care Research Group (CCRG) in Brisbane.

Professor John Fraser, who led the CCRG said it is wonderful that the hard work of so many people has now translated into real human successes at The Alfred.

“It’s a credit to the teams in Brisbane, Sydney and Melbourne. By working together across these great institutions, there is a very real chance that patients not just across Australia will benefit – but globally too,” Prof Fraser said.

Five sites across Australia and New Zealand are involved in the trial, with The Alfred the first to perform five transplants. Other sites include the Royal Children’s Hospital Melbourne, St Vincent’s Hospital Sydney, Fiona Stanley Hospital Perth and Auckland City Hospital Auckland NZ.

The Prince Charles Hospital Foundation and The Alfred Foundation have been integral in enabling the trial to progress to the first human heart transplant using hypothermic ex-vivo perfusion.

XVIVO Perfusion in Sweden developed the non-ischemic heart preservation method being used in the study.