Donor kidneys from individuals who have recently died from cardiac arrest perform just as well in recipients as kidneys from traditional 'brain-dead' donors, scientists have found.

Cardiac-death donors represent an extremely important and overlooked source of high-quality donor kidneys and have the potential to increase markedly the number of kidney transplants performed in the UK.

Professor Andrew Bradley

The University of Cambridge researchers hope their findings, published today in the journal The Lancet, will increase the use of kidneys from cardiac-death donors (kidneys which were previously viewed by some as inferior) and possibly reform how these kidneys are allocated - thereby increasing the fairness of kidney distribution as well as the likelihood of a successful transplant.

There are currently over 7000 patients waiting for a kidney transplant. Unfortunately, because of the dire lack of donation organs, almost 10 per cent of these patients die every year while waiting for a healthy kidney.

Since the 1970s, the majority of recovered organs for transplantations were from 'brain-dead' donors, patients who had suffered massive, irreversible brain injuries and needed artificial life support to stay alive. However, over the last decade there has been a reduction of these types of donors as a result of better care of patients with acute head injuries and fewer deaths from traffic accidents.

Because of the shortfall of organs, doctors have begun to use kidneys from cardiac-death donors - individuals who have suffered devastating and irreversible injuries and who have then suffered from a 'controlled' cardiac arrest (when medical support is gradually removed and the heart stops beating as a result of the injuries sustained). As these types of deaths are much more prevalent, donor organs from these patients are much more readily available.

Unfortunately, although the number of these types of transplants has increased dramatically - since 2000 they have risen from 3 to 32 per cent - there is still reluctance to adopt the use of these kidneys by some transplant specialists because of concerns about the quality of the organs. This new research, however, addresses these concerns, finding that kidneys from cardiac-death donors are of similar quality to those from brain-dead donors.

The scientists examined data from 9134 kidneys transplants which were conducted in 23 centres; 8289 of the kidneys were donated after brain death and 845 after controlled cardiac death. They found no difference in survival rates or kidney function of recipients for up to five years after transplantation. (The researchers did not have the data to explore the success rates beyond five years but indicate that there is no reason to suspect longer-term transplant outcomes would be different.) The scientists did find that some factors decreased the success rate of cardiac-death transplantations: increasing age of donor and recipient, repeat transplantation, and organs kept cold but without blood supply for longer than 12 hours.

Lead author of the paper, Professor Andrew Bradley of the Department of Surgery at the University of Cambridge, said: "Cardiac-death donors represent an extremely important and overlooked source of high-quality donor kidneys and have the potential to increase markedly the number of kidney transplants performed in the UK."

Currently, kidneys donated by 'brain-dead' donors are allocated according to a national points-based system, ensuring equal access to donor kidneys irrespective of geographical location of those on the waiting list. Because of the absence of adequate information regarding kidneys from cardiac-death donors, however, they are instead allocated locally according to the policy of individual transplant centres, an arguably less effective way of distribution as it unlikely to secure the best candidate for receiving the kidney.

Dr Dominic Summers, one of the authors of the paper, added: "What we have shown, for the first time, is that cardiac-death donor kidneys last as long and work as well as brain-death donor kidneys, and should be regarded as comparable. In view of our findings, we recommend that cardiac-death kidneys be allocated in a similar way as brain-death kidneys, ensuring better tissue matches and favouring those who have waited longest.

"Cardiac-death donor kidneys currently make up only a third of deceased donor kidney transplants, but hopefully this paper will provide the evidence and impetus to greatly expand the national programme, and improve the national organ donation rates."

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