Prolonged Heart Preservation: The Road From Organ Transport Toward Organ Banks

From the origins of organ transplantation, organ storage has been based on Cold Storage (CS); many different solutions have been designed to warrant optimal organ preservation. Until now, in thoracic transplantation no solution has shown superior results in the setting of a clinical trial and the preservation of the graft remains a sort of grandmother receipt different from center to center.
During the last 10 years many solutions for organ storage for transplantation have been investigated and two philosophies emerged as possible game-changers of a field dominated by a dramatic mismatch between the number of organs and the number of possible recipients: warm ex-situ perfusion and cold oxygenated perfusion. Recently the denominator of the number of potential donors has steeply increased thanks to the opening of donation toward the DCD (donation after cardiac death). Such a possible evolution carries the opportunity to spread the feasibility of organ donation to a large number of clinical settings that are now precluded to transplantation, so counteracting the burden of organ shortage in transplantation.
This policy has impacted dramatically the number of donations especially for abdominal organs and lung.
In 2017, after a great number of preclinical data and animal experiments, the first DCD heart donation in the world was performed in Australia adopting the ex-situ perfusion of the heart to re-perfuse the graft, judge its performance and then transplant.

Ex-situ organ perfusion (ESOP- better than ex-vivo since it is used predominantly after a brain or circulatory death) has been advocated as the more physiologic way to perfuse the organs during the transport time. Many groups and industries are approaching the field and many different strategies have been discussed and experimented until now with different grades of clinical application and of evidences in different organs accounting for their ischemic vulnerability.

Recently the group of Robert Bartlett published seminal work dealing with a significant lengthening of ex-situ perfusion by modifying the milieu of the perfusion (through cross-circulation with an animal, plasma exchange and administration). This group addressed this challenge as a moving target by attempting to reach a reproducible way to sustain the organs during the ex-situ heart perfusion (ESHP). Extended graft perfusion more than 24 hours for up to three days is expected to redraw the landscape of heart transplantation.

Together, with the potential of an enlarged pool of donors, this technology has the tremendous potential to recondition or even heal or modify organs during perfusion and this goal over the long term could lead to the creation of real organ banks keeping transiently the organs living or even modifying their immunologic and functional profile.