Q: In the past, non heart beating transplantation proved less successful than normal ICU cadaver retrieval donor transplantation. What has improved in the retrieval and operation stage to see an upturn in the numbers and success rate of this type of transplantation?
submitted to Kidney Life Magazine by Patient Bob Price
A: Kidney transplants are now categorised as being from either deceased or living donors. The patient receiving the transplant kidney may be eligible for a pre-emptive transplant, which means before the need for dialysis.
A whole range of factors, including immunological and surgical, can affect the outcome of transplantation but increasingly the clinical state of the recipient and the quality of the transplanted organ are the key determinants of successful long term patient and graft survival. As a general rule a pre-emptive kidney transplant from a live donor provides the best outcomes against which to benchmark, or compare other kidney transplants.
Kidneys from potential donors, be they deceased or living, have to be working well and of high quality before they are accepted. The process of donor evaluation provides information about the structure and function of the kidneys before they are judged suitable for transplantation. Matching to the recipient blood group and tissue type is also necessary to avoid acute rejection and to reduce the number and dose of drugs the recipient will need to take long term to dampen down his or her immune system.
When kidneys are donated by living donors or heart-beating deceased donors who have been pronounced brain dead, the kidneys are still being perfused (receiving oxygenated blood and nutrients from the circulation) when the operation to remove the kidney is commenced. In this situation it is possible to cool the kidneys immediately they are removed from the donor’s body. Cooling slows down the metabolism of the kidney greatly which reduces the damage that would otherwise occur between the operation to remove the kidney and re-implantation of the organ into the recipient kidney patient.
In contrast when kidneys are donated by non heart beating deceased donors, the circulation (the heart) is allowed to stop before the operation to remove the organs begins. The kidneys are therefore exposed to ‘warm ischaemia’ (a period of time at body temperature without a working blood supply - which if prolonged can damage the organs). Prior to around the year 2000, most non heart beating donors were uncontrolled; by that I mean they were identified and retrieval of the organs was performed in the accident and emergency department in a great rush. The retrieval team had to get to the casualty department as soon as possible after a cardiac arrest to obtain consent, do the necessary preparation and proceed as quickly as possible, to do the surgery. As a result the amount of time the kidneys were left at 37°C (body temperature), without perfusion and oxygenation was as long as 45mins or 60minutes after the cardiac arrest of the donor.
Nowadays most non heart beating donations occur in a controlled setting from an intensive care unit. Usually the donor is ventilated until treatment is withdrawn. Treatment withdrawal is co-ordinated with the retrieval team such that the operation to remove the kidneys and other organs can occur immediately the heart stops. As a result warm ischaemic times have now been reduced to between 5 and 15 minutes and that makes a great difference to the long term viability of the kidney and consequently the long term outcome for the person receiving the donor organ. In addition we all know more about preservation solutions, the new perfusion machines look very promising and we have better immunosuppression. Nowadays the graft survival of non heart beating donor kidneys, heart beating donor kidneys and live donor kidneys are very similar and all very good.
The latest UK Transplant report provides information on the source (living or deceased donor - and if deceased, non heart beating or heart beating) of donor kidneys. The report is written in clear user-friendly fashion and is available on http://www.uktransplant.org.uk./ It shows that in 2007 there were 1440 deceased donor kidney transplants. Of the 765 deceased kidney donors, 609 were heart beating donors and 156 were non heart beating kidney donors. Most deceased donors provide two kidneys for transplantation. The number of heart beating donors has remained steady over the past ten years despite big efforts to increase donations. In contrast, the establishment of non heart beating donor programmes has increased the number of these donors by 28% in last year alone. In 2007 there were 690 living donor kidney transplants. Again we have seen a steady increase in live donor transplants following the introduction of specific live donor co-ordinators and the wider availability of laparoscopic surgery for the donors. The outcome of all three forms of kidney donation is now excellent. It is now clear that 5 year survival figures for non heart beating donor kidneys are as good as cadaveric transplantation from heart beating donors.
For the individual with kidney disease the major factor determining outcome is getting onto the Transplant Waiting List in a timely fashion. Standard 2 of the renal NSF - the one that emphasises the need for time to prepare and make choices for kidney replacement therapy - states that people with advanced kidney disease should be put on the National Transplant list within 6 months of their anticipated dialysis start date, if clinically appropriate - That’s typically when the estimated GFR or % kidney function, falls below 15mls per minute. Unfortunately delays still occur in transplant listing - many people spend months or even years on dialysis before transplant Listing.
IF YOU THINK YOU MIGHT BE SUITABLE FOR A KIDNEY TRANSPLANT YOU SHOULD DISCUSS THAT WITH YOUR CONSULTANT AND NAMED NURSE- You cannot be transplanted if you are not on the Transplant List! Following the publication of “Organs for Transplants” by the Department Of Health earlier this year, we do aim to increase the number of donor organs available by over 50% in the next 5 years We may need to go even further to achieve the goal of every person with advanced kidney disease having an optimal outcome - which for many would be to receive a pre-emptive transplant.
All these factors need to be borne in mind when tailoring treatment to the specific needs of the individual patient and in assessing the overall performance and outcomes of kidney transplant programmes.