Renal transplantation from living donors

Should be seriously considered to help overcome the shortfall in organs

Renal transplantation has become a victim of its own success. Increasing numbers of patients are referred for transplantation, but there has been no concomitant increase in the supply of kidneys from the traditional cadaveric donor pool. On the contrary, death rates from road accidents and strokes have declined over the past 20years.1 Over 4500patients in the United Kingdom and Ireland are awaiting a kidney transplant but only a third are likely to receive one within the next year. Clearly, therefore, the full potential of renal transplantation will be realised only if other donor sources can be developed.

Greater use of kidneys from living donors offers scope for increasing the number of kidney transplants. In the UK and Ireland kidneys from living donors account for only 5-10% of transplants compared with 30% in the United States2 and 45% in Norway.3 The geography and demographics of Norway have been important factors in the development of their living donor programme. Norway's terrain and climate mean that patients may take several hours to travel to their nearest dialysis unit. Consequently, the Norwegians have developed a utilitarian approach to living donor transplantation: a live donor transplant is the surest way to break free of the demands of travelling for dialysis. Over 1400living donor kidney transplants have now been performed in Norway, and living donation is widely accepted by the public—almost everyone has heard of or knows someone who has either donated or received a living donor kidney.

The results of living donor kidney transplantation are better than those of cadaveric transplantation, and this provides further justification for considering its use. The half life of a cadaveric kidney is about eight years, which compares poorly with averages of 12and 26years for living donor kidneys matched for one and two haplotypes respectively.4 Living donor kidney transplants between genetically unrelated donors also fare better than cadaveric transplants with closer HLA matching, and the results for unrelated living donor transplantation are similar to those for living donor transplants matched for one haplotype.5 As a result of these findings, interest in living unrelated donor transplantation has increased recently, and several British transplant units will now undertake such transplants, mainly between spouse donor-recipient pairs, although the number performed is still small.

Why might living donor kidney transplants have a better outcome than cadaveric kidneys? Firstly, because of stricter selection criteria, living donors have a normal glomerular filtration rate and are free from conditions that may damage renal function. Secondly, living donor kidneys are not subject to the detrimental cardiovascular, metabolic, and hormonal disturbances present in brain stem dead donors. Thirdly, living donor transplantation is undertaken electively, and the cold ischaemic time can be reduced to one hour or less, whereas ischaemic times of 24hours and longer are not unusual for cadaveric transplantation.

The main objection to living kidney donation is that it exposes the healthy donor to the risks of major surgery and life with a solitary kidney entirely for the benefit of the recipient. Careful, prospective follow up of large numbers of living donors has, surprisingly, been uncommon, so our knowledge of the precise risks of the procedure is incomplete. The available evidence, mainly from retrospective surveys, suggests that donor nephrectomy is generally very safe, with a perioperative mortality of about 0.03%.6 With careful donor selection and rigorous prophylactic measures it should be possible to reduce mortality further. A series of 1200donor nephrectomies performed in Oslo, with no deaths, was recently reported.7 Much of the morbidity after nephrectomy is related to the wound. The donor kidney is usually removed through a large loin incision, often with the removal of the 12th rib. This approach may cause considerable postoperative pain and may necessitate referral to a pain clinic because of chronic problems. Fortunately, modern methods of postoperative pain relief have dramatically improved operative recovery, and donors managed with epidural analgesia suffer little postoperative pain.

Donor nephrectomy has recently been performed safely using minimally invasive surgery.8 The laparoscopic procedure has been performed in over 130patients at Johns Hopkins Hospital, Baltimore. Blood loss, length of stay, and postoperative analgesia are all reduced after laparoscopic nephrectomy. 8 9 Moreover, return to normal activities was quicker in patients undergoing a laparoscopic operation. Perhaps even more important, the early data suggest that introducing a laparoscopic technique is associated with up to an 85% increase in rate of donations from living donors.9 Clearly these findings require confirmation in other centres but this approach is likely to prove popular with patients. Because the procedure requires surgical expertise in both renal transplantation and advanced laparoscopic techniques its availability may be limited. The long term consequences of donor nephrectomy, which may include an increased risk of hypertension and microscopic proteinuria,10 are not, of course, influenced by the type of surgery.

The traditional attitude to living donors in the United Kingdom has been understandably cautious. However, the severe shortage of cadaveric kidneys and the success of living donor programmes in other countries has led many British transplant surgeons and nephrologists to reconsider their views. We now need quantitative data on the potential for living donation to increase the transplantation rate in the United Kingdom and to determine the resource implications of such an expansion. Any increase in living donor transplantation must accord with the highest possible standards of clinical care. Establishing long term prospective follow up of all British donors would help to answer the criticisms of those who believe that unilateral nephrectomy is harmful even in healthy individuals.