Expanding the Renal Transplant Donor Pool: How Far is too Far?

Saturday, February 11, 2012
Expanding the Renal Transplant Donor Pool: How Far is too Far?
By Peter Laird, MD

The renal transplant waiting list in the United States continues to increase exponentially while the available living and deceased donors stagnates behind this growing demand as seen in this graph from the US Department of Health and Human Services HRSA. News accounts of fathers and mothers giving kidneys to their children make headlines on a routine basis. The news of the so called "gift of life" from renal transplant supersedes any like acknowledgement of nocturnal home hemodialysis which has outcomes equal to cadaveric transplant. Yet, the march to procure even more kidneys is leading America down the path of ethical quagmires as the demand continues to expand the donor pools by ever loosening criteria. A little over a decade ago, the solution for many was the new expanded donor criteria (ECD) where donors previously excluded as "marginal" for HTN, age, diabetes, risk of infectious disease transmission and or malignancy as well as other criteria are now grouped into the ECD category. Most transplant centers now offer shorter waiting times for patients who will agree to the ECD criteria by an informed consent agreement.

Patients waiting for renal transplants faced with nearly ten years on the list now opt more frequently for expanded criteria donors making this the fastest growing segment of available renal donors. Another method of expanding the donor pool is a new criteria of death aside from the standard brain death criteria ushered in during the 1960's. In the 1990's, transplant centers began using donation by cardiac death (DCD) either by controlled DCD by withdrawing life sustaining care, or from uncontrolled emergency room cardiac deaths. Many ethicist have spoken out against this type of donation since the controlled donation by cardiac death occurs before brain death in some instances. Both ECD and DCD cadaveric transplants are increasing dramatically.

Expanded donor criteria may in the end prove more costly for several reasons. First, ECD grafts must undergo extensive testing to assure that they are free of infectious agents easily transmitted by transplant and other tests that add to the direct costs of each transplant. In addition, because ECD and DCD grafts fail to last as long as standard criteria donors (SCD), transplant patients can expect more complications and difficulties with a new organ adding not only to the burden of care, but also the burden of further pain and suffering that these failures bring about.

In my opinion, the most troublesome aspect of the expanded donor criteria is the inclusion of donors at high risk of transmissible agents including HIV and Hepatitis. Today, our testing cannot exclude all new cases of these viruses prior to the donor mounting an immune response to these agents which can take weeks in some cases. The feared transmission of HIV with this new criteria happened in 2007 leading many transplant surgeons to restrict the use of high infectious risk donors in their programs:

High Infectious risk donors: what are the risks and when are they too high?

RECENT FINDINGS: HRD organs are discarded at a higher rate than non-HRDs, and many surgeons have decreased the use of HRDs in response to a recent widely publicized case of HIV and hepatitis C virus (HCV) transmission. Special informed consent use can mitigate legal risk and might increase provider comfort with HRD utilization. Nucleic acid testing (NAT) mitigates infectious risk by decreasing the window period, particularly for HCV in which the risk of undetected window period infection decreases by an order of magnitude. Estimated risk of undetected window period HIV infection varies by HRD behavior category (range 0.035-4.9 per 10,000 donors when NAT is used), HCV risk is higher (range 0.027-32.4 per 10.000).

SUMMARY: Given long waiting times and high wait list mortality, organs from HRDs can be used to expand the organ supply. Estimates of HRD infectious risk can be used to guide patient and provider decision making.

Patients need to know and understand well all of the terms used in transplant programs today what the meaning of ECD and high risk donors (HRD) who include IV drug users, hemophiliacs, prostitution history, high risk sexual activity, exposure to HIV and jail sentencing. The CDC considers all of these donors high risk and following testing in transplant recipients for HIV and Hepatitis is now standard transplant follow up. The tragedy of four patients hoping for the gift of life in 2007 to only find out a new fatal disease is part of their medical fight should make us stop and consider how far is too far to expand donor criteria. The even more tragic sense of this epic story is that few patients are counseled that nocturnal home hemodialysis has the same survival benefit as cadaveric transplant.

When seeking renal replacement treatment (RRT) options, the patient must realize that all treatment options are not equal especially when evaluating the use of extended donor criteria. The hope of "the gift of life" should not end tragically with a new disease added to their burden. For those that are willing to take these risks, then they must fully realize all of the criteria and all of the terms used. The "gift of life" may not be what it seems as time passes.

I believe that America needs to return to a more sensible realization that the supply of available kidneys will not keep up with the exponential increase in demand for kidneys. I believe that the real hope for the majority of ESRD patients in America will be an expansion of home dialysis options. So far, the dialysis industry has done little to expand the pool of available home dialysis patients or reduce costs. It is time for a paradigm shift and return to optimal standards for all RRT options including renal transplant lest history record that we have expanded the criteria too far.

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