UNOS DonateLife

May 29, 2009

UNOS Researchers Present Studies at American Transplant Congress

Boston -- Researchers from United Network for Organ Sharing (UNOS) authored and will present several studies at the American Transplant Congress (ATC), a joint meeting of the American Society of Transplant Surgeons and the American Society of Transplantation held at the John B. Hynes Veteran Convention Center May 30 through June 3. UNOS staff researchers are authors in a total of 10 papers being presented at ATC.

Below is a listing of studies to be presented orally or in poster sessions in which UNOS researchers are primary authors. UNOS staff researchers are indicated with an asterisk.

NOTE: This work was supported wholly or in part by Health Resources and Services Administration contract 234-2005-370011C. The content is the responsibility of the authors alone and does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

Factors Associated with Primary Non-Function Following Liver Transplantation

Embargo until Saturday, May 30 -- 5:30 p.m. EDT
Authors: Erick Edwards, Ph.D.*, Sarah Taranto*, Timothy Pruett, M.D.

Primary non-function (PNF) is a rare, life-threatening complication following liver transplantation that usually requires a retransplant. According to Organ Procurement and Transplantation Network (OPTN) policy, liver recipients experiencing PNF within 7 days of transplant qualify for Status 1A on the waiting list, while those with later non-function (delayed graft failure, or DGF) do not qualify. The researchers examined nearly five years of data to identify characteristics associated with early-term or later-term primary graft failure among recipients.

Several factors had a statistically significant association with PNF/DGF. The significant recipient factors included age, ethnicity, diagnosis, and laboratory MELD score. Significant donor factors included age, height, weight, ethnicity, infection, cigarette use, alcohol use, donation after death (DCD), and biopsy. Of the significant donor factors, some were more likely to be associated with one, rather than both, of the outcome groups.

The U.S. Experience in DCD Transplants

Embargo until Sunday, May 31, 2009 --3:03 p.m. EDT
Authors: Wida Cherikh, Ph.D.*, Shandie Covington*, Charlotte Carroll, M.S.*, Simon Horslen, M.B., Ch.B., Stuart Sweet, M.D., Ph.D.

The authors studied more than 13 years of data to identify trends and outcomes in organ donation after cardiac death (DCD).

The number of DCD transplants has increased in the past few years. During the period studied, 118 DCD transplants were performed in pediatric recipients and 7,775 in adults. Although incidence of delayed graft function was much higher in DCD kidney transplants than other deceased donor transplants for both pediatric and adult recipients, graft and patient survival rates were not significantly different. Graft and patient survival were comparable for pediatric recipients of DCD liver transplants compared to other deceased donors, but the graft and patient survival rates were significantly lower for adult recipients of DCD livers as compared to other deceased donor livers. The researchers conclude that increased utilization of DCD donors should be considered, particularly for critically ill children waiting for liver transplantation.

Patterns of Calculated Panel Reactive Antibody (CPRA) Use for Candidates on the OPTN Kidney Waiting List

Embargo until Sunday, May 31, 2009 -- 5:30 p.m. EDT
Authors: Ann M. Harper*, Lori Gore*, Mary S. Leffell, Ph.D., J. Michael Cecka, Ph.D.

The calculated panel reactive antibody score (CPRA) was introduced to provide uniformity in reporting immune sensitization status for kidney transplant candidates to minimize the likelihood of early immune rejection of kidney transplants. CPRA estimates the percentage of donors that would be incompatible based on unacceptable human leukocyte antigens (HLA) listed for each candidate. The researchers analyzed CPRA values for nearly 25,000 candidates to compare how well the CPRA equated with the traditional panel reactive antibody (PRA) score used in the OPTN match system.

In nearly 44 percent of the cases, the CPRA was either equal to the PRA or within 10 percent of the PRA value. In about 30 percent of cases, the CPRA was more than 10 percent higher than the match PRA, and in about 20 percent of cases the CPRA was more than 10 percent lower than the match PRA. Nearly 75 percent of highly sensitized candidates (PRA>80) had CPRA values that were either identical to or within 10 percent of traditional PRA. The values were identical in about 24 percent of highly sensitized candidates, versus about 12 percent for moderately sensitized candidates. Most highly sensitized patients based upon the traditional PRA also were highly sensitized based on their CPRA, suggesting that laboratories are entering unacceptable antigens for these candidates to prevent predictably positive crossmatches.

Donor Factors That Predict Kidney Utilization

Embargo until Sunday, May 31, 2009 -- 5:30 p.m. EDT
Authors: Anna Y. Kucheryavaya, M.S.*, Leah B. Edwards, Ph.D.*, Maureen A. McBride, Ph.D.*, Timothy Pruett, M.D.

The authors performed regression analysis on organ offers from more than 7,500 adult potential deceased non-DCD kidney donors to identify donor factors that might predict whether at least one kidney is transplanted from the donor.

Acceptable donor FiO2 values (a measure of whether a patient is receiving enough oxygen) resulted in a higher likelihood that at least one kidney was transplanted. Donor factors that resulted in a lower likelihood of either kidney being transplanted included diabetes , history of cancer, noncompliance with hypertension treatment, IV drug usage , no kidney biopsy (N=3,092), elevated creatinine, older age, higher blood urea nitrogen and very low or very high body mass index. The results of these models could be used to develop additional donor screening criteria and help streamline the process of placing donor kidneys.

The New Heart Allocation System: Is It Working as Designed?

Embargo until Tuesday, June 2 -- 9:30 a.m. EDT
Authors: Leah B. Edwards, Ph.D.*, Maryl R. Johnson, M.D., J. David Vega, M.D.

The researchers analyzed adult heart transplant waiting list mortality and one-year post-transplant survival for a time period before and after a July 2006 change to allocation policy. This policy amendment afforded broader geographic sharing of hearts to the two most urgent candidate statuses (1A and 1B).

Wait list death rates declined for each of the active candidate statuses (1A, 1B and 2); death rates among Status 1A and 1B candidates declined by about 30 percent. Transplants increased among the more urgent candidates since the policy implementation. Post-transplant survival was comparable among the two eras, although there appears to be a trend in improved survival for Status 1A recipients. The amended policy appears to be working as intended, although additional follow-up is needed to assess long-term outcomes.

The Changing Landscape of Living Kidney Donors in the U.S.

Embargo until Tuesday, June 2 -- 2:15 p.m. EDT
Authors: Jennifer L. Wainright, Ph.D.*, Matthew Cooper, M.D., Lee Bolton*, Connie L. Davis, M.D.

The study group examined changing trends in the living donor population among nearly 50,000 living donor kidney transplants between 2000 and 2007.

Some living donor characteristics have remained relatively stable over time, including age and gender ratio (about 57 percent of living donors are female). Living donors with relatively high body mass index appear to be increasing. Lack of health insurance for living donors is more common in non-white donors.

Living donors' relationships to recipients showed significant change over the study period, including increases in anonymous unrelated donors but a decrease in parent to pediatric recipient donation. Anecdotal evidence has suggested that a change in pediatric kidney allocation policy may be responsible for the decrease in parental living donors, but this trend began before the mid-2005 policy change.

Do Donor Conversion Rates Vary by Age or Ethnicity/Race?

Embargo until Tuesday, June 2 -- 4:00 p.m. EDT
Authors: John Rosendale*, Jeffrey Orlowski, M.S., CPTC, Charles Alexander, RN, M.S.N., M.B.A., CPTC, Franki Chabalewski, RN, M.S.*

Conversion Rates (CRs) are measures of how often patient deaths that could be considered donation opportunities actually become donors. The group analyzed all eligible deaths reported over nine months in 2008 to identify opportunities to increase donation in different potential donor populations.

The 18-29 year old age group had a significantly higher CR than did the 1-10, 30-49, and the 50-70 year old age groups. There was no significant difference between the 18-29 and 11-17 groups. Eligible donors reported as white ethnicity had a significantly higher CR than eligible donors that were reported for all other ethnicity/races. This information may guide additional efforts to identify factors to encourage donation among groups with a lower conversion rate.

Association of Donor to Recipient CMV Serostatus Combination with Survival after Deceased Donor Kidney Transplants

Embargo until Tuesday, June 2 -- 4:24 p.m. EDT
Authors: Wida Cherikh, Ph.D.*, Timothy Pruett, M.D.

Cytomegalovirus (CMV) is a viral infection that usually occurs after solid organ transplant and has been shown to cause significant morbidity and mortality. The researchers did a regression analysis of more than 45,000 deceased donor kidney transplants to determine the effect of donor and candidate CMV serostatus on graft and patient survival.

Since CMV is prevalent in the general population, the highest proportion of kidney transplants involved donors and recipients who both had CMV positive serostatus at transplant. There were significant differences in graft and patient survival among the combinations of donor and recipient CMV status. In particular, the combination of CMV-positive donor to a previously CMV-negative recipient was associated with a significantly increased risk of death within 4 years of transplantation. The use of acyclovir or ganciclovir to treat post-transplant CMV infection was associated with improved graft survival but was not associated with better patient survival.

Prior Living Kidney Donors Who Subsequently Needed Chronic Maintenance Dialysis

Embargo until Tuesday, June 2 -- 5:00 p.m. EDT
Authors: Wida Cherikh, Ph.D.*, Pang-Yen Fan, M.D., Charlotte Carroll, M.S.*, Jude Maghirang, M.S.*, Henry Randall, M.D., Carlton Young, M.D.

The group used databases from the OPTN and the Center for Medicare and Medicaid Services (CMS) to identify and examine people who had been a living kidney donor and were later placed on chronic maintenance dialysis.

A total of 88 people were identified as previous kidney living donors who were subsequently placed on chronic maintenance dialysis. Of these, 23 were also identified on the OPTN kidney waiting list between January 1996 and July 2008. There were higher proportions of male living donors and those reported as African-American on dialysis and/or the kidney waiting list as compared to the overall living donor population. African-American living donors also seemed to be younger than Caucasian living donors at donation and at start of dialysis, but the years between donation and dialysis seemed comparable. The findings underscore the need for diligent evaluation and long-term follow-up of living donors to ensure their safety and health.

The Organ Procurement and Transplantation Network (OPTN) is operated under contract with the U.S. Department of Health and Human Services, Health Resources and Services Administration, Division of Transplantation by the United Network for Organ Sharing (UNOS). The OPTN brings together medical professionals, transplant recipients and donor families to develop organ transplantation policy.