Year: 2002
Type: editorial
Abstract: The national sharing of cadaver kidneys for transplantation to HLA-matched recipients has gained considerable support over the past 14 years since it began under the United Network for Organ Sharing (UNOS). This growing acceptance was strongly influenced by scientific analyses such as that reported by Dr Bresnahan and her colleagues on page 366 in this issue of AJT. These authors and others 1-3) have used the UNOS Scientific Registry data to examine renal transplant results among HLA-matched recipients, whose graft was most often procured at a distant hospital and shipped over a long distance for transplantation. The outcomes have been consistently superior to those of locally transplanted kidneys. In many cases, these HLA-matched kidneys provide the only hope for patients who have become broadly sensitized to allogeneic HLA following pregnancies, blood transfusions or previous failure of HLA-mismatched grafts. Thus, as the article demonstrates, recipients of HLA-matched kidneys include a higher proportion of immunologically risky patients. The Bresnahan study compares the results for HLA-matched kidneys with the outcome of the mismatched contralateral kidneys from 2385 donors. By focusing their analyses on paired kidneys, the authors were able to avoid some of the confounding influences of the many different donor variables that might otherwise cloud the analysis. The authors found that despite traveling more than 900 miles on average, the HLA-matched kidney yielded a superior transplant result compared with its mate kidney transplanted locally to an HLA-mismatched recipient. Among the more serious objections to sharing kidneys among distant transplant centers was that the increased cold ischemia time to which the kidney would be exposed would effectively cancel any benefit of HLA matching (4). So what is most surprising about the results in the Bresnahan article is that the cold ischemia time averaged less than 2 h longer when the HLA-matched kidney was sent to its recipient than when the mate kidney was transplanted to a local HLA-mismatched recipient. By comparison with local kidney allocation, the national sharing program is quite efficient. If we consider that HLA typing and final crossmatches are performed at the recipient center after the kidney has been sent, the efficiency of the program seems even more impressive. A recent AJT editorial (5) outlined a growing sentiment in favor of changing the UNOS kidney allocation system and suggested that the HLA matching and national sharing processes engender needless delays and lead to discarding organs that might otherwise be transplanted. The initiatives proposed in that editorial are significant because they have been formalized into a series of UNOS allocation ‘variances’ designed to identify circumstances when HLA matching can be ignored under the assumption that cold ischemia time can be dramatically reduced and, as a result, more organs will become available for transplantation. However, Dr Bresnahan's results should make us question the logic of this argument. It takes 24 h to transplant a kidney 900 miles from where it was procured and 22.2 h to transplant the second kidney from the same donor locally. The real delays must lie in selecting an appropriate recipient, making logistical arrangements for the surgery, and getting the recipient to the hospital. These processes currently occur at the local and distant hospitals while the kidney sits on ice in a room or on an airplane, respectively. The concerns about the effects of shipping and cold ischemia on graft survival rates may also be misplaced. Kidneys with prolonged ischemia times are perceived as less desirable because they exhibit poorer function after transplantation and have lower survival probabilities. But is the prolonged cold ischemia a cause or an effect of less-than-ideal kidneys? Mange et al. (6) reported that shipped kidneys had a significantly higher risk of graft failure than locally transplanted kidneys – unless they were HLA matched. Why were the other kidneys shipped? Some were sent as paybacks for HLA-matched kidneys and others could not be placed locally in a suitable recipient. In fact, many kidneys are shipped because of concerns about donor quality and are successfully transplanted elsewhere despite prolonged cold ischemia times. Although their overall survival rates may be poorer, if the alternative was to discard the kidneys, shipping and transplanting them was probably the better choice. Concerns about the suitability of the donor kidney, including biopsy and evaluation, may cause delays in identifying a suitable local recipient under the constraints of the current local allocation system. Although we may not speed the evaluation process, we should take a lesson from the national sharing program and streamline the way we select local patients for transplantation. The kidney allocation algorithm has changed very little in the 14 years since it was implemented. Most of the changes have been in the way we count HLA mismatches or in the points that are awarded for HLA. But the donors and the patients whom we transplant have changed quite remarkably. Nearly 1 of every 7 cadaver kidneys is from a donor over age 55. The current algorithm for local allocation lists (in order) the most broadly sensitized candidates (who have usually waited the longest) and children (who would be unlikely to accept a marginal kidney). It should be clear to everyone that every kidney is not appropriate for every recipient. UNOS offers the option of placing restrictions on which kidneys would be acceptable for a patient. It can easily be made part of the patient's profile. Whenever possible, this decision should be made in advance of a kidney offer to avoid delays in placement of local kidneys. Until the cold ischemia time can be shortened for local transplants, Dr Bresnahan's results clearly show that kidneys shared for HLA-matched recipients do not incur substantial added cold ischemia time.
Institution: University of California, Los Angeles
Language: English
Subfield: Transplantation
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,300
OpenAlex ID: W2029686107