The recipients, both of whom had end-stage heart failure, were reported to be recovering extremely well.
Until now, transplant units have relied solely on donor hearts from brain-dead patients whose hearts are still beating. The use of "donated after circulatory death" (DCD) hearts, where the heart is no longer beating, represents a paradigm shift in organ donation and will make far more hearts available for transplant.
The two DCD transplants, performed by UNSW Conjoint Associate Professor Kumud Dhital at St Vincent's Hospital Heart Lung Transplant Unit, were possible thanks to pioneering research undertaken by the Victor Change Cardiac Research Institute and St Vincent's Hospital.
The two organisations have jointly developed a special preservation solution and portable console in which donor hearts can be housed, resuscitated and transported.
"Heart in a box"
The ex vivo Organ Care System (OCS – Transmedics TM) involves connecting the donor heart to a sterile circuit where it is kept beating and warm. This limits the detrimental effects of cold ischaemia (a period where the heart is without oxygen or nutrients) that occurs with the standard organ preservation mode of packing the heart on ice in an esky. Once inside the portable device, the heart is reanimated and preserved, and can be functionally assessed until it is ready to be placed inside the recipient.
The OCS technology – affectionately referred to as the "heart in a box" – also means organs can be transported over longer distances.
It has this year allowed the St Vincent's Transplant Unit to conduct several standard heart transplants (i.e. using non-DCD organs), using organs that had travelled substantial distances and, most importantly, using "marginal hearts" – non-DCD hearts that would previously have been regarded as unsuitable for transplantation.
"Major inroad" to reducing donor organ shortage
There are far more people in need of transplants than there are donor organs. DCD transplants have already made an enormous positive impact on liver, kidney and lung transplantation rates, but until now, it was not possible to do the same with hearts. The "heart in a box" technology is a game changer.
"This breakthrough represents a major inroad to reducing the shortage of donor organs," said UNSW Professor Peter MacDonald, Medical Director of the St Vincent's Heart Transplant Unit and Head of the Transplantation Research Laboratory at Victor Chang.
"In all our years, our biggest hindrance has been the limited availability of donor organs."
Associate Professor Dhital said: "It is interesting to note that DCD hearts were utilised for the first wave of human heart transplants in the 1960s, with the donor and recipient in adjacent operating theatres.
"This co-location of donor and recipient is extremely rare in the current era, leading us to rely solely on brain dead donors – until now."
The milestone coincides with the 30th anniversary of the St Vincent's Heart Lung Transplant Unit and the 20th anniversary of the Victor Chang Institute.