Transplant Statistics: Annual Report

APPENDIX D
Policy-Related Activities of the OPTN/UNOS Committees as of September 2001

By-laws and policies have been adopted by the Board of Directors pursuant to UNOS' contract with the Health Resources and Services Administration (HRSA) within the United States Department of Health and Human Services (HHS), and after circulation and discussion among organ transplant professionals and patient representatives. These have been submitted to the Secretary of HHS for review and, as of September 2001, were considered voluntary guidance to members of the Organ Procurement and Transplantation Network (OPTN) until approved as OPTN rules and requirements by the Secretary of HHS.

The OPTN/UNOS Committees are responsible for updating these by-laws and policies and for developing new policies for the OPTN, subject to the approval of HHS. This appendix provides a summary only of recent policy-related activities of the OPTN/UNOS Committees. See "Policies & ByLaws" at www.optn.org for the complete text of any policy.

DATA ADVISORY COMMITTEE

The Data Advisory Committee (hereafter referred to as the DAC) is a new permanent standing committee under the current OPTN contract. Its first official meeting was held in May 2001. At that meeting, several policy-related issues were discussed and resolutions were passed. Among the resolutions brought to the Board of Directors at their June 2001 meeting, three are described below.

1. Release of Information to the Public (Policy 9.0)

Due to regulatory and contractual requirements, Policy 9.0 needed to be substantially revised. The committee discussed the policy and drafted several proposed modifications for consideration by the Board. Most modifications pertained to the type of center- and OPO-specific information that can be released to the public without individual member permission, provided that the DAC deems the data and analysis are appropriate. The committee drafted a resolution asking that the Board approve Policy 9.0 as amended by the DAC and that it be submitted concurrently for public comment.

Current Status.The Board approved the resolution in June 2001. A public comment document was disseminated in August 2001. It is expected that final approval will be sought at the November 2001 Board of Directors meeting.

2. Access to Data (Policy 10.0)

Due to regulatory and contractual requirements, Policy 10.0 needed to be substantially revised. The committee discussed the policy and drafted several proposed modifications for consideration by the Board. Among the modifications were:

Patient- and institution-identified data will be made available to the Scientific Registry for Transplant Recipients (SRTR) contractor.
All requests to the OPTN for data should be made through the UNOS Data Request System. Routinely available data will comprise the following: (a) data provided in regularly updated UNOS Standard Reports; (b) data requested by OPTN/UNOS members regarding their own institution and/or patients; (c) simple tabulations requested by OPTN/UNOS members regarding U.S. data; and (d) data requested by HHS.
Requests involving 20 hours or more of programming time or any statistical analyses that are considered to be extensive may be subject to additional requirements.
Unless they are releasable according to Policy 9.0 or Policy 10.2, data will be provided with the deletion of all patient- and center-specific identifying information. Comprehensive datasets with center and patient identifying information encrypted may be given out for research purposes with the approval of the DAC. Under some circumstances, center-specific data (standard analysis files) not otherwise releasable may be provided to bona fide researchers, subject to the approval of the DAC using as guidance the UNOS Agreement for Release of Data, as approved by the DAC. In order to obtain these data, the submitting individual must meet the conditions for their release and sign an Agreement for Release of Data, which sets forth confidentiality and security stipulations for the data's release and use.
The scientific and analytical content of all abstracts or manuscripts developed from customized data requests, comprehensive encrypted datasets, or standard analysis files must be approved by the DAC and any ad hoc work group appointed by that committee prior to their public presentation or publication. If the analysis has not been provided prior to release by the investigator or institution, UNOS cannot assume responsibility for the correctness of the findings or interpretations. Failure to include UNOS in pre-release preparation may be an adverse consideration in subsequent applications by the investigator or institution for additional data.
Any UNOS staff member who makes a significant intellectual contribution to a study abstract, presentation, or manuscript should be offered the opportunity to be included as an author. UNOS staff may not be listed as study authors without obtaining written permission from the appropriate staff member(s).
A copy of all published abstracts, manuscripts, or news releases should be submitted to UNOS administrative staff and/or the DAC for informational purposes as soon as practicable.
Publications that use UNOS data collected for the OPTN shall include the following notice: The data reported here have been supplied by UNOS. The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy or interpretation of the OPTN or the U.S. Government.

The committee approved a resolution asking that the Board of Directors approve Policy 10.0 as amended by the DAC and that it be submitted concurrently for public comment.

Current Status.
The Board approved the resolution in June 2001. A public comment document was disseminated in August 2001. It is expected that final approval will be sought at the November 2001 Board of Directors meeting.

3. Data Submission Requirements (Policy 7.0)

The Scientific Advisory Committee is a committee under the SRTR contract and has no responsibilities under the new OPTN contract. Therefore, the DAC determined that policy 10.5, Reporting Data to the Scientific Advisory Committee, should be moved from Policy 10.0 to Policy 7.0 as Policy 7.3. Further, the section heading was changed to Reporting Data to the OPTN. In addition, the committee made a number of "housekeeping" changes and recommended that the Board approve all changes as of June 29, 2001.

Current Status.
The Board of Directors approved the resolution at the June 2001 meeting.

HISTOCOMPATIBILITY COMMITTEE

The Histocompatibility Committee worked on several policy-related activities over the last year. The three most significant items are listed below.

1. Laboratory Membership (By-Laws, C.7000 of Appendix B, Attachment 1)

A subcommittee of the Histocompatibility Committee reviewed the requirements relating to subcontracting laboratories and suggested changes to the by-laws on Institutional Membership. The committee crafted a resolution for consideration by Board of Directors, indicating that OPTN/UNOS member laboratories may engage subcontractor laboratories provided the subcontractor is CLIA (Clinical Laboratory Improvement Amendments) certified/exempt and is either an OPTN/UNOS member or accredited by the American Society for Histocompatibility and Immunogenetics (ASHI) in the category and approved for the method(s) which cover the referred testing. Laboratory results must be returned to the referring laboratory and the identity of the subcontracting laboratory and the portion of the testing for which it is responsible must be noted in the report of the OPTN/UNOS laboratory.

Current Status.
The Board of Directors approved the resolution in November 2000.

2. Standards for Histocompatibility Testing (By-Laws, Appendix B, Attachment 1-A)

The committee made extensive revisions to the OPTN/UNOS Standards for Histocompatibility Testing. Key changes include:

Standards were added to ensure that all relevant CLIA requirements were included.
Several sections of the standards were revised in order to avoid redundancy and to provide a more logical sequence.
Standards relating to HLA typing by either serological or molecular methods were combined into one section headed "HLA Typing."
The sections on Serologic HLA Typing - Class I and Serologic HLA Typing - Class II were combined into one subsection headed "HLA Typing by Microcytotoxicity."
Certain standards were changed from "should" (recommended) to "must" (mandatory) because of changes in laboratory practice and/or in order to be consistent with existing CLIA regulations.
Standards that were more appropriate as Guidelines rather than Standards were deleted.
Changes were made in several words to clarify meaning and intent such as "validate" vs. "verify" and "immunogenetics and transplantation testing" vs. "histocompatibility testing."
A new section on Chimerism Analysis was added (Section L).
Prospective HLA typing of recipients and donors for A, B, and DR antigens were made mandatory for kidney and pancreas transplantation, and typing for C, DR51, DR52, DR53, and DQ antigens was highly recommended.

Current Status.
The final revised Standards will be submitted to the Board of Directors for approval at the November 2001 meeting.

3. HLA Table of Unacceptable Antigens and Equivalences

The organ match algorithms screen out candidates who have unacceptable antigens entered that match to antigens the donor possesses. Prior to June 1996 there was a common table of HLA unacceptable equivalences that was used for all organs. However, a resolution to revise the allocation algorithms for kidney and pancreas resulted in the creation of two Unacceptable Antigen Equivalences Tables, one for kidney, kidney-pancreas, pancreas, and pancreas islets; and one for the thoracic, liver, and intestine match algorithms. The kidney-pancreas table has been updated every year while the thoracic/liver/ intestine table has remained unchanged since October 1996. However, there was never any intention to create separate tables; immunologically, there is no basis for separate tables. Therefore, the committee offered to the Board of Directors a resolution that there be only one Unacceptable Antigen Equivalences Table, that all organs use this table, and that this table shall be the one currently used by kidney and pancreas organs.

Current Status.
The Board of Directors approved the resolution in June 2001.

KIDNEY AND PANCREAS TRANSPLANTATION COMMITTEE

The Kidney and Pancreas Transplantation Committee (hereafter referred to as the K/P Committee) is responsible for assessing and developing policies related to kidney, pancreas, and pancreas islet cell transplantation. Several recent activities are described below.

1. Allocation of Kidneys and Kidney-Pancreas Combinations (Policies 3.5 and 3.8)

National policy for allocating kidneys and kidney-pancreas combinations has attempted, both historically and currently, to balance factors of justice and medical utility by focusing upon the following factors:

Antigen Matching/Mismatching - Differences in the HLA between the kidney donor and recipient stimulate the recipient's immune system to reject the donor kidney. Kidney transplant success generally increases, therefore, with greater HLA identity.
Blood Type - Compatibility between donor and recipient ABO blood group is necessary for the success of kidney transplants. Current policy includes restrictions on the allocation of kidneys from donors with blood types that are compatible across blood groups, however, to avoid disproportionate advantage to certain patients.
Sensitization - Exposure to the HLA antigens of another individual can result in a relatively high panel reactive antibody (PRA) level and sensitization against a significant portion of potential donors. Patients with high PRAs generally need donors with a very good HLA match (low mismatch) to avoid rejection and they often wait for lengthy periods of time before a suitable transplant becomes available.
Waiting Time - Unlike certain of the other organ systems, kidney transplantation typically is not a life saving procedure. Relative waiting time has had unique relevance in the allocation of kidneys in defining system fairness.
Age for Pediatric Patients - Young children and adolescents experience unique problems associated with dialysis and disruption to expected growth and development processes due to renal failure. Early reversal of the condition through transplantation can avoid the special problems of dialysis and ameliorate many of the adverse effects of end stage renal disease that confront pediatric patients.

The allocation policies are dynamic and have been modified over time to address apparent inequities. This review continues on an ongoing basis. Recent modifications or proposals for modification to the policies include the following.

Eliminate Requirements for Sharing Kidney-Pancreas Combinations for Zero Antigen Mismatches. The K/P Committee recommended, and in June 2001, the Board approved, a proposal to eliminate existing requirements for sharing kidney-pancreas combinations for patients who are a zero antigen mismatch (i.e., the "optimal" match level in terms of expected transplant outcome) with donors unless the patient is highly sensitized (i.e., PRA greater than or equal to 80%). This was based upon current data that no longer show significant benefit in terms of short-term or 3-year kidney or pancreas graft survival from receipt of a zero antigen mismatched versus a mismatched kidney-pancreas transplant. The policy has been retained for highly sensitized patients due to difficulties for these patients in getting transplanted at all.

Current Status.
This proposal is awaiting implementation on the national computer for matching donors and patients in need of kidney-pancreas transplantation.

Maintain Zero Antigen Mismatch Policy for Kidney Alone Transplants. UNOS policy also requires that isolated kidneys be allocated for all patients (sensitized or unsensitized) who are zero antigen mismatched with the donor located anywhere in the nation (locally, then regionally, then nationally) before being allocated to patients who are mismatched with the donor, with payback to the national pool. In developing the proposal regarding the allocation of organs for combined kidney-pancreas transplants for zero mismatched patients, transplant outcomes for recipients of zero mismatched isolated kidneys also were examined. For these patients, a significant graft survival benefit continues to exist. Transplant outcomes for recipients of payback kidneys were assessed as well to determine if the system for sharing zero antigen mismatched kidneys is indirectly creating a negative impact due to relatively poor results from kidneys shared back to the national pool following receipt of the "optimally matched" organs. Recipients of payback kidneys appear to experience at least as good transplant outcomes as do recipients of other kidneys. No further changes in policy related to the sharing of zero antigen mismatched kidneys were, therefore, recommended at that time.

HLA Matching and Allocation Policy. The current allocation system also assigns priority for certain lesser levels of HLA match that do not produce the same degree of benefit as a zero antigen mismatch but still result in improved graft survival. This system, which assigns a relatively large number of points for HLA matching (equal to 7 years of waiting time in the event of a zero BDR mismatch), favors patients with antigens common to the pool of available donors. This commonality affects patients within diverse ethnic groups differently. While there continue to be some benefits from HLA matching in terms of graft survival and potentially reduced sensitization in case of a need for re-transplantation, these benefits occur at the cost of disparate waiting times for patients with uncommon antigens. Additionally, in modern times, improvements in graft survival available from HLA matching (particularly at lesser levels than a zero antigen mismatch) are being replaced by enhanced immunosuppressive therapies. Moreover, studies now demonstrate improved long-term patient survival for recipients of kidney transplantation versus individuals waiting for kidney transplantation on dialysis. Potential graft survival advantages resulting from receipt of a well matched kidney transplant must be weighed against potential patient survival disadvantages resulting from prolonged waiting times without a transplant. As with the kidney allocation system overall, a decision to retain or modify HLA match points requires a balance among factors of medical utility and justice.

The K/P Committee, in conjunction with a Joint Subcommittee of the K/P and OPTN/UNOS Minority Affairs Committees, have determined that in this case the balance favors a change in policy to remove a factor in the system that results in disparate benefits among different patient ethnic groups. They, therefore, have approved a proposal that would remove points for HLA matching from the system for kidney allocation, while retaining current priority for allocation of zero antigen mismatched isolated kidneys with payback to the national pool. See the Minority Affairs Committee section, item #3 for further details and current status.

Procurement and Use of Expanded Criteria Donor Kidneys. The K/P Committee, in conjunction with the OPTN/UNOS Organ Availability Committee, as well as representatives of participants at an American Society of Transplantation and American Society of Transplant Surgeons-sponsored conference on Maximizing Use of Organs Recovered from the Cadaver Donor held in March 2001, also have developed a proposed system for expedited placement of kidneys recovered from less than ideal donors. As with the proposal for eliminating points for HLA matching, the OPTN/UNOS Board of Directors has not yet considered this proposal. It would (1) define expanded criteria donors according to relative risk of graft failure using factors of donor age, creatinine, CVA (cerebrovascular/stroke) as cause of death, and hypertension; and (2) establish a system for allocating kidneys procured from the expanded criteria donors to patients determined to be suitable candidates for receipt of the organs and listed for the rapid placement protocol (informed consent would be expected). Priority would be assigned first for zero antigen mismatched patients, among this group of patients with time limitations, and next for all other eligible patients, locally, regionally, and nationally, based upon time waiting. The intent would be to maximize procurement and use of the expanded criteria donor kidneys, providing a mechanism for effective placement of these organs with as little cold ischemia time (i.e., time without oxygenated blood) as feasible. This has particular potential importance in light of the severe shortage of cadaveric donor kidneys available for transplantation.

Current Status.
This proposal was distributed for public comment in August 2001 and will be reconsidered by the K/P and Organ Availability Committees in light of public comment prior to presentation to the OPTN/UNOS Board of Directors in November 2001.

2. Recommendations Regarding Undirected Living Organ Donation

In 1999, the Transplant Administrators Committee made a recommendation, approved by the Board of Directors, asking UNOS to develop policies and procedures to assist transplant centers in accepting and allocating living donor organs provided as altruistic, undirected gifts, for the benefit of unspecified patients on the OPTN waiting list. The K/P Committee developed a process and recommended its approval by the Board. The process was then distributed to various OPTN/UNOS committees for review and input. In July 2000, the subcommittee assigned to develop the proposal began reviewing committee comments and a final report and recommendations were made to the full K/P Committee in October 2000. The proposal:

Stresses the importance of maintaining anonymity of living donors to the extent possible acknowledging that such anonymity cannot be guaranteed. Potential donors and recipients should be advised of these limitations and given the option to decline to proceed with the transaction based upon their individual preferences.
Addresses allocation of organs donated anonymously and without direction. The intent is to encourage adherence to standard policies for organ allocation, acknowledging that this may not always be realistic or in the best interest of the donor and/or recipient in certain situations. In such instances, final decisions regarding allocation of the organs must be left to the medical judgment of the individuals' healthcare providers.
Adds language to direct attention to several issues intended to promote public confidence in our nation's system of organ donation and allocation.
Provides a sample protocol that centers can use as guidance for establishing a voluntary living donation protocol.

After discussion, the K/P Committee voted unanimously to approve a resolution asking the Board of Directors to approve the proposal and sample protocol for transplant centers to use as guidance in accepting and allocating living donor kidneys from volunteer donors. The resolution further states that the proposal and sample protocol be widely disseminated to the transplant community and the public through UNOS Update, the OPTN web site, and other appropriate mechanisms.

Current Status.
The Board of Directors amended the resolution to reference potential effects from the donation upon living donors' ability to obtain insurance, and then approved it in November 2000. It is now in the process of dissemination.

3. Pancreas Islet Procurement, Allocation, and Transplantation Issues

There is an increasing level of research in the field of pancreas islet cell transplantation that holds great promise. The K/P Committee has been discussing various issues regarding procurement, allocation, and transplantation of pancreas islets, including:

Immune Tolerance Network (ITN). Work is being done by the Immune Tolerance Network (ITN) to address the increasing incidence of diabetes, in particular, and to regulate immune tolerance in general. The ITN, established in 1999, includes leaders in islet and kidney transplantation and over 70 basic and clinical researchers from nine countries. One of its objectives is sponsoring cutting edge trials intended to push the boundaries of immune tolerance protocols.
The burden of diabetes is increasing in this country. It currently affects 300,000-500,000 people in the U.S., and that number is expected to grow. Approximately 50% of these individuals will develop neuropathy. As a result, the demand for islet and whole pancreas transplantation also will increase. Some pancreata are suitable for both whole organ and islet recovery; among those that are not suitable for pancreas transplantation, it is estimated that 70% of them would be suitable for islet transplantation.
System for Monitoring Islet Transplantation Policy and Outcomes. Current OPTN policy addresses allocation of whole pancreata and allocation of pancreas islets. According to the standard algorithm, pancreata must be offered for whole organ transplantation locally, regionally, nationally, and through the facilitated pancreas allocation system before they can be offered locally for clinical islet transplantation. Several OPOs have asked the Board of Directors to approve variances to the standard protocols in an effort to gain additional experience with islet transplantation. They have raised concerns that, in practice under the standard system, there is little or no access to pancreas islets and no means to test the efficacy of their protocols. Results from these alternative systems will be valuable in assessing the utility of options for islet transplantation. They also may demonstrate that it is time to modify the standard algorithm to allow greater access to islet transplantation nationwide.

Current Status.
The K/P Committee is pursuing opportunities to improve current systems for recording and monitoring pancreatic islet allocation and transplantation to permit further evaluation of these procedures and a more complete assessment of the national system for islet allocation.

LIVER AND INTESTINAL TRANSPLANTATION COMMITTEE

The Liver and Intestinal Organ Transplantation Committee (hereafter referred to as the Liver Committee) has spent most of its time over the last year on the Model for End-Stage Liver Disease (MELD) and the Pediatric End-Stage Liver Disease (PELD) scoring systems, the highlights of which are described below.

1. Model for End-Stage Liver Disease (MELD) and Pediatric End-Stage Liver Disease (PELD) (Policy 3.6, Allocation of Livers)

In November 2000, the OPTN/UNOS Board of Directors approved changes to Policy 3.6 for concurrent public comment and submission to the Secretary of HHS. The primary emphasis of the proposal was the replacement of medical urgency status codes 2A, 2B and 3 with a continuous numerical scale. The intent of the proposed policy change was to better categorize patients based on the severity of their illness, using objective, verifiable medical criteria. This would fulfill the allocation policy performance goal specified in �121.8(b) of the Final Rule for operation of the OPTN, 42 CFR Part 121, which requires that the OPTN set priority rankings "through objective and measurable medical criteria, for patients or categories of patients who are medically suitable candidates for transplantation to receive transplants." The proposal also limited the role of waiting time in liver allocation, which is consistent with the recommendation of the Institute of Medicine (IOM), who found waiting time to be "a poor measure of differences in access to transplantation" and "not a good indicator of medical urgency or priority."

The Model for End-Stage Liver Disease (MELD) and Pediatric End-Stage-Liver Disease (PELD) scoring systems were developed as a collaborative effort of the Liver Committee, the Pediatric Transplantation Committee, and the Liver Disease Severity Scale (LDSS) Committee throughout 2000. An initial proposal was circulated for public comment in August 2000, and a public forum focusing on the proposed scoring systems was held in September 2000. Both MELD and PELD have been validated using several different datasets and patient cohorts, and appear to be very good predictors of pretransplant mortality.

The Liver and Pediatric Committees met in January 2001, and the LDSS Committee met via teleconference in March 2001. During their deliberations, the committees proposed refinements to the language in Policy 3.6, much of which related to the replacement of the existing medical urgency status codes 2A, 2B, and 3 with the MELD scoring system in cases where the policy proposal had been unclear or potentially inconsistent with the MELD/PELD proposal. There were also a number of policy issues that needed to be resolved, including the Patient Reassessment and Recertification Schedule, how to incorporate patients with hepatocellular carcinoma (HCC) into the new system, and formulating the MELD score. The Executive Committee of the OPTN/UNOS Board of Directors approved these modifications and the policy proposal was circulated for public comment in March 2001. The Liver Committee reviewed all public comments submitted as of the May 2001 meeting, and provided responses to each comment. In several cases, the committee proposed specific modifications to the policy proposal. These were reported in the June 2001 report to the OPTN/UNOS Board of Directors.

Major Components of the Proposed Policy Change. At the time this report went to press, the OPTN/UNOS Board of Directors had not approved the policy proposal outlined below, and the proposal was undergoing refinements by the committees involved in the policy development process. As such, the provisions outlined below should be considered preliminary.

The criteria for Status 1 (adult and pediatric) will remain as currently defined.
Adult patients will be assigned a mortality risk score corresponding to the degree of medical urgency, calculated in accordance with the MELD scoring system. This will replace the current adult medical urgency statuses 2A, 2B, and 3. A separate mortality risk score will be computed for pediatric patients, the PELD score, to replace current pediatric medical urgency statuses 2B and 3. The March 2001 proposal included a provision to convert PELD scores to MELD scores using a mathematical formula, to ensure that adult and pediatric patients are ranked by equivalent probabilities of pretransplant death for the purposes of allocation.
The sequence of allocation for adult donors (donors � 18 years of age) is as follows:

3. All other Local patients, in order of the MELD scores

4. All other Regional patients, in order of the MELD scores

5. National Status 1 patients

6. All other National patients, in order of the MELD scores

The preference for pediatric donor liver allocation to pediatric patients acknowledging issues of medical urgency for adult patients, as approved by the Board of Directors in June 2000, will be maintained within the new MELD/PELD system. The proposal developed by the Pediatric Committee and endorsed by the Liver Committee is as follows: for allocation of pediatric donor livers, the waiting list will essentially be divided into two groups: the first consisting of those with a pretransplant mortality of greater than 50%, and the second consisting of all other patients. Within each group, pediatric patients will receive priority for pediatric donor livers.
Each patient would be stratified within mortality risk score category (probability of pretransplant death) by blood type similarity, that is, identical, compatible, or incompatible. The Liver Committee also has recommended that with the exception of Status 1 patients, (i.e., for those patients stratified by the MELD scoring system) blood type O donor livers can only be allocated to blood type O and B patients.
Patients will accrue waiting time within Status 1 or any assigned mortality risk score (probability of pretransplant death). Waiting time accrued while listed at a lower status or score will not be included in the total waiting time if the patient is offered a liver while waiting at a higher status or score. Stratification of patients within a particular status or score will be based on total waiting time in that status or score plus time previously accrued at that score plus any waiting time accrued at any higher status or score.
Patients' mortality risk scores (probability of pretransplant death) will be reassessed and recertified according to a schedule based on ranges of MELD scores, such that the highest risk score categories would require more frequent updates. Thus, patients could not remain within a particular MELD/PELD score indefinitely without review.
The proposal included a provision for patients with hepatocellular carcinoma (HCC), whose MELD scores would likely not be high enough for them to receive a transplant prior to their becoming too ill for transplant due to the cancer. Guidelines for Exceptional Cases (e.g., hepatopulmonary syndrome, familial amyloidosis, primary oxaluria) will be incorporated into the UNOS Liver Review Board Guidelines. Special cases require prospective review by the Regional Review Board. The proposal also includes provisions for pediatric candidates with metabolic diseases (e.g., Ornithinine Transcarbamylase Deficiency or Crigler-Najjar Disease Type I) or hepatoblastoma.
A transition plan for patients listed at the time of implementation of the proposal was included.

The MELD and PELD Equations. The MELD score, as currently specified, will include serum creatinine, bilirubin, and INR. The PELD score, as currently specified, will include age <1 year, albumin, total bilirubin, INR, and growth failure. In the MELD formula, the maximum serum creatinine level will be set to 4.0 mg/dl. For patients on dialysis, the serum creatinine value will automatically be set to 4.0 mg/dl. MELD scores will be limited to a total of 40 points maximum. Patients with a higher calculated MELD score would still be eligible for liver offers, but would not be given additional priority. MELD and PELD scores will be rounded to whole integer values.

Advantages of the MELD. Some of the advantages of the MELD scoring system, as a replacement for adult statuses 2A, 2B and 3, and the PELD scoring system, for replacement of pediatric statuses 2B and 3, can be summarized as follows:

The MELD/PELD score is based on the risk of pretransplant mortality within 3 months. This will allow classification of patients based on their medical urgency in a more precise manner than with the current medical urgency statuses 2A, 2B, and 3. Patients most in need of organs will be more likely to receive them.
The MELD has been validated using a variety of databases. PELD has been validated using data from the University of Pittsburgh, with preliminary results demonstrating strong concordance. Both the MELD and PELD systems are undergoing a thorough validation using current OPTN waiting list data. It appears that the mortality risk probabilities underlying the MELD/PELD scores are reasonably accurate to allow classification of patients by risk of pretransplant death.
The MELD/PELD score is based on objective, easily verifiable laboratory values; subjective or potentially manipulated variables such as encephalopathy and ascites have been eliminated.
Waiting time is used as a tie-breaker for patients with similar medical need. Thus, patients do receive some credit based on their waiting time, but waiting time cannot advantage patients with lesser medical urgency above patients with greater medical urgency.

Current Status.
In June 2001, the OPTN/UNOS Board of Directors endorsed further development of the MELD and PELD scoring systems for liver allocation. The Board anticipated that a comprehensive version of Policy 3.6 (Allocation of Livers) utilizing the MELD/PELD scoring systems would be submitted for approval at the November 2001 Board of Directors meeting, and that programming of the UNet^sm computer system will take place in parallel with the remaining policy development process. The Board's decision was based on a review of data that suggest that these scoring systems accurately rank patients in the order of their probability of death on the waiting list using objective criteria and potentially may reduce the number of pretransplant deaths.

The LDSS and Liver Committees met in July 2001 during which time they discussed the sequence of pediatric donor allocation, the conversion of the PELD score, issues relating to special case patients who may fall outside of the MELD scoring system, and various questions relating to the implementation and programming of the MELD system.

2. Analysis of Alternative Liver Distribution Units

The Liver Distribution Units Subcommittee was charged with examining and analyzing the alternative distribution units for liver allocation. This subcommittee reported directly to the Liver Committee.

The subcommittee's initial deliberations focused on attempting to define a fair liver allocation system and on various measures of fairness. In general, the subcommittee agreed that a fair liver allocation system is one in which patients of equivalent medical status have a generally equal opportunity to receive a transplant. The Liver Committee reviewed the data outputs from the UNOS Liver Allocation Model (ULAMsm) for 17 alternative distribution plans using nine different configurations of distribution units. These plans were requested in an effort to meet the goal of ensuring that patients with an equal severity of illness and probability of dying will have a relatively equal probability of receiving an organ offer. The size of the distribution units ranged from 13-136 million persons in population. In each case, there was increased sharing, at least for the most medically ill patients. After review of these reconfigurations of the liver distribution units, the subcommittee ultimately determined that there was not a consensus on what benefit might be derived by redrawing the allocation distribution units. This is due to multiple factors including widely varying rates of organ availability across the country that are geographically distributed and center-specific factors (e.g., listing practices, center behavior practices). The subcommittee's conclusion was that broader sharing does not increase the total number of transplants performed, nor does it reduce the total number of deaths or increase the total life years of patients. The full committee believed that, until such time as the MELD score is implemented, it is premature to make any recommendations regarding allocation distribution because it is likely that the MELD score will have a greater impact upon directing organs to patients most in need. The OPTN/UNOS Board of Directors endorsed this concept.

MEMBERSHIP AND PROFESSIONAL STANDARDS COMMITTEE

The Membership and Professional Standards Committee (hereafter referred to as the MPSC) reviews applications for (a) membership in the OPTN, (b) key personnel changes, and (c) program status changes. Among its recent by-laws and policy-related deliberations are the following:

1. Modifications to the Transplant Physician Requirements (By-Laws, Appendix B, Section III)

The committee discussed the criteria that state that transplant physicians "should" observe the organ procurement and transplantation process, as well as the selection and management of multiple organ donors prior to the approval of their key personnel application. Currently, if a primary transplant physician has not completely satisfied the criteria, the MPSC requests that a plan for fulfilling it be presented with the program's application, and the criteria must be satisfied before the application can be approved. Because the committee believes that it is important that the primary transplant physician understand all aspects of patient and donor care, it set forth a resolution to change the word "should" (recommended) to "must" (mandatory). The MPSC approved a resolution to the Board of Directors indicating that transplant physicians must observe the organ procurement and transplantation process as well as the selection and management of multiple organ donors prior to the approval of the program's application.

Current Status.
The modification to the transplant physician requirements was sent out for public comment in August 2001, as directed by the Board of Directors. The Board will consider the change at the November 2001 meeting.

2. Potential Transplant Recipient (PTR) Data Submission (Policy 7.5)

In January 2001, UNOS staff presented data to the Data Subcommittee of the MPSC on the timely submission of PTR forms and turndown data. A compliance report for 2000 indicated that 71% of expected forms had been received and completed but only 50% of the PTR forms for January 5-21, 2001, had been submitted within 15 days of the match run. OPTN/UNOS Policy 7.5 specifies that the PTR forms must be submitted within 15 days of the match run date for each cadaver donor organ that is allocated to a recipient. The subcommittee expressed concern about the ability of the OPOs to meet this requirement and asked the OPO Committee for any comments they wished to make. In May 2001 the Data Subcommittee reviewed feedback from the OPO Committee and updated reports that showed that during March 5-21, 2001, only 35% of PTR forms were completed within 15 days of the match run. Data showed no correlation in the number of match runs entered by an OPO and the percentage of PTR forms completed on time. The MPSC determined that staff support and technical limitations of OPO computer systems and Internet service providers were in large part responsible for the lack of PTR forms compliance. The committee unanimously adopted a resolution stating that PTR forms must be submitted within 30 days of a match run and that after 45 days from the date of the offer the refusal reason will be considered accurate and validated.

Current Status.
The resolution went out for public comment in August 2001 and will be considered by the Board of Directors at the November 2001 meeting.

3. Membership Criteria for Intestinal and Islet Cell Transplantation Programs

The MPSC, both in October 2000 and May 2001, discussed the status of intestinal transplant programs and islet cell transplantation programs. Currently, programs simply notify the OPTN/UNOS of their initiation via a letter of intent and completion of a staff survey. The committee believes it is time to consider whether more formal membership criteria are needed for these types of programs. The MPSC suggested that a joint subcommittee for islet cell transplantation programs be formed with the K/P Committee and that a joint subcommittee for intestinal transplantation programs be formed with the Liver Committee. These joint subcommittees would examine the status of islet cell and intestinal transplantation and determine if it is time to develop more formal membership criteria, application processes, and reporting criteria including listing and follow-up of recipients.

Current Status.
The K/P Committee and the MPSC have already selected participants for the joint subcommittee on islet cell transplantation. The MPSC is in the process of selecting participants for the Joint Intestinal Transplantation Subcommittee and the Liver Committee will review the recommendation at its Fall 2001 meeting.

MINORITY AFFAIRS COMMITTEE

The Minority Affairs Committee (hereafter referred to as the MAC) focuses on transplantation policy as it relates to and affects minority transplant candidates and recipients. In 2000-2001, the committee addressed a number of issues, of which three are described below.

1. Eliminating Phenotypic Priority in the Kidney Allocation System (Policy 3.5.2.3, Mandatory Sharing)

Policy 3.5.2.3 stipulates that when there are multiple zero antigen matches found for a single kidney donor, the allocation sequence assigns the highest priority at that level of allocation to the candidate who is phenotypic identical to the donor, before any other zero antigen mismatched patients. Phenotypic identity occurs when both the donor and recipient have the same number of antigens identified, and the identified antigens have the same values. The MAC believes that minority candidates have been disadvantaged in an HLA-driven allocation system and that phenotypic identity has created one more obstacle to achieving equity in renal organ distribution.

The Board of Directors approved the priority for phenotypic identity in the mandatory sharing policy in June 1996, based on a resolution from the K/P Committee. The policy change sought to improve access for patients with fewer than six antigens identified, who would otherwise have less access to zero antigen mismatched organs. At the time, little was known of the impact the policy would have on organ distribution, though it was suggested that the policy be monitored to determine if it had a negative effect on allocation.

Over time, the MAC has reviewed data that strongly suggest that in an HLA-driven allocation system, minority patients experience longer waiting times because they are disadvantaged in the HLA matching distribution process. For example, of cadaveric kidney transplants performed between March 6, 1995, and August 31, 1999, White recipients received 78% of phenotypic identical organs. Black recipients received 8% of phenotypic identical organs, while Hispanic and Asian recipients received 11% and 2%, respectively. Further, data reviewed by the committee showed no significant difference in short- and long-term survival between phenotypic identical matched and other zero antigen mismatched recipients.

The MAC understands that the intent of the 1996 policy establishing phenotypic priority was to provide better opportunities for kidney transplant candidates with limited options to match with a zero antigen mismatched donor. However, the committee believes these patients are just as likely to be offered a zero antigen mismatched organ, given an appropriate donor and, that time waiting would be a more equitable means of deciding a tie when multiple recipients are found for the same donor. In September 2000, the committee drafted a resolution to that effect, forwarding it to the K/P Committee and sending it out for public comment concurrently. The MAC continued to review data and consider comments from the K/P Committee and the public. Data presented at the May 2001 meeting reinforced what the committee had already learned. Whites received 84% of the six antigen matched transplants, 80% of the phenotypic identical transplants, and 72% of the other zero antigen mismatched transplants. Non-white recipients were more likely to receive other zero antigen mismatched transplants than either six antigen or phenotypic identical matched kidneys. The risk of graft failure for recipients of either six antigen or phenotypic identical matched kidneys was not significantly different from recipients of other zero antigen mismatched kidneys.

Based on these data, the MAC presented a resolution to the Board of Directors stating that Policy 3.5.2.3 (Mandatory Sharing) shall be amended to eliminate the priority given to phenotypic identical candidates over other zero antigen mismatched candidates when multiple zero antigen mismatches are found for a single donor, and that allocation of that organ shall be based on waiting time at each level of sequence to which the priority has been applied.

Current Status.
The Board of Directors approved the resolution at the June 2001 meeting. Implementation is pending programming on the UNOS computer system.

2. Voluntary Variance to Transplant Cadaveric A2 and A2B Donor Kidneys into Blood Group B Recipients

Historically, the requirement for ABO compatibility in renal allocation policy has been found to present a significant barrier to donor organs for minority candidates, based on donor pool availability. This is especially true for blood group B candidates who made up 17% of the national kidney waiting list in 1998, but had access to and received approximately 11% to 12% of cadaveric kidney donor organs in the same year. By comparison, blood type A candidates made up close to 28% of the national waiting list yet had access to and received 38% of the cadaveric kidney transplants in 1998. The renal snapshot waiting list on August 7, 2000 showed that Black registrants made up 48% of blood type B registrants (compared with 32% for Whites), and 68% of the national blood group B waiting list was comprised of minority candidates. The median waiting time for blood type B candidates added on the kidney waiting list in 1996 was 1,426 days, as compared with 1,213 days for blood type O, 641 days for blood type A, and 379 days for blood type AB candidates. Patients with either blood type B or O are disadvantaged based on the availability of those blood groups within the donor population.

The committee reviewed numerous studies on the obstacles and effectiveness of transplanting across ABO blood types. Beginning in the 1980s, studies indicated that blood group A donor organs, sub-typed as A2, could be successfully transplanted into non-A recipients and that this could be done without modification of the recipient's immune status before transplantation. By 1995, studies showed that graft and patient survival rates among ABO-incompatible renal transplants were comparable to those of ABO-compatible transplants. Over the years, increasing numbers of transplant practitioners have reported successful transplantation of A2 renal organs into blood group B and O candidates. These transplants have been most successful in patients with low anti-A titers. Three OPTN member institutions have variances that allow them to allocate blood group A2 and A2B donor kidneys into blood group B and O patients. Based on their results, the MAC believes there is a need for a larger standardized study to fully evaluate the viability of this type of transplantation. In March 2000 it formed a subcommittee to develop a proposal for a voluntary kidney allocation variance. The variance was drafted and submitted to the Histocompatibility and K/P Committees and for public comment.

In May 2001 the MAC completed the review of all proposal comments and concerns, which were focused in three areas: (a) the impact the policy would have upon the allocation of kidneys to blood group A candidates, (b) the need for more national data, and (c) general concern for transplanting across ABO barriers.

Impact on kidney allocation to blood group A candidates. Blood group A2 kidneys comprise between 15% to 20% of blood type A kidneys. Nationally, blood group A candidates have access to approximately 38% of the donor population, though they constitute only about 28% of renal waiting list candidates. In contrast, blood group B candidates have access to approximately 11% of donors, while comprising about 17% of waiting list candidates. Based on these data, the committee believes that the impact on blood group A candidates is minimal compared to the disadvantage that currently exists for blood group B candidates.
Need for more national data. The committee acknowledges that there are a limited number of OPOs nationally with variances permitting them to utilize this means of sub-typing of renal organs. However, the availability of a voluntary variance will enhance opportunities to gather additional national data and to report on those outcomes. The proposed variance is limited to three years and posttransplant outcomes will be evaluated on an annual basis. In addition, the committee will evaluate the increasing organ availability for blood type B patients, the percentage change in the transplant rate among blood type B candidates, the effect on blood type A candidates, and any change in waiting time to transplant.
Transplanting across ABO barriers. Practitioners have reported increasing success with these types of transplants, particularly in patients with low anti-A titers. The proposal at this time is limited specifically to blood group B recipients based on clinical data that demonstrate that a greater proportion of B patients have low anti-A titer histories as compared to blood group O patients.

After a thorough review of committee and public comments, the MAC modified their proposal and submitted a resolution to the Board, calling for a standardized national voluntary variance to transplant blood group A2 and A2B cadaveric kidneys into blood group B waiting list candidates.

Current Status.
The Board of Directors approved the resolution at the June 2001 meeting. Implementation is pending programming on the UNOS computer system for individual local units that so notify UNOS and that have OPO approval to participate in the variance.

3. Effect of HLA Matching on Allocation of Renal Organs to Minority Candidates (Policy 3.5.9.2, Quality of Antigen Mismatch)

One of the ongoing issues considered by the MAC is the effect of HLA matching upon the allocation and distribution of organs to minority renal candidates, to determine whether there is a sustained benefit to HLA matching for minority renal candidates. Most recently, the committee considered the cost implications involved in HLA typing. The committee agreed to focus on answering two questions:

Does the use of HLA matching decrease access to cadaveric kidneys for Blacks or other minorities?
What is the effect of HLA matching on short- and long-term graft and patient survival?

The committee reviewed data presented by URREA and UNOS staff at their April 5-6, 2001 meeting and made the following conclusions:

HLA matching appears to have a minimal or no effect on patient and graft survival with the exception of White recipients who demonstrated some decrease in graft survival at the >3 mismatch level.
The distribution of organs to White or Hispanic patients on the kidney waiting list appears to be driven more by HLA, while recipients of Black, Asian, or other ethnic groups were more likely to receive their transplants based on waiting time rather than on HLA points.
The costs of HLA typing were minimal compared to the overall costs of transplantation as well as the costs of posttransplant dialysis after a graft failure.

The committee made no formal resolutions at the time but did agree to continue exploring the possibility of de-emphasizing HLA allocation policy in favor of broader sharing and maintenance of priority for zero antigen mismatched organs.

A joint subcommittee of members of the OPTN/UNOS MAC and K/P Committee as well as the chair of the Histocompatibility Committee was formed during the first quarter of 2001 to further examine issues of utility and justice and the impact of HLA in the kidney allocation system. Subsequent to these meetings and based on the findings of the joint subcommittee, proposed modifications to UNOS Policy 3.5.9.2 (Quality of Antigen Mismatch) were made removing points for HLA matching from the system for kidney allocation while retaining current priority for allocation of zero antigen mismatched kidneys with payback to the national pool.

Current Status.
Policy modifications were distributed for public comment in August 2001 and will be reconsidered by the K/P Committee and the MAC in light of public comment prior to presentation to the Board in November 2001.

ORGAN PROCUREMENT ORGANIZATION (OPO) COMMITTEE

The OPO Committee addresses organ procurement and donation issues, as well as topics of concern to Organ Procurement Organizations. Several of the committee's recent resolutions to the Board of Directors are described below:

1. Submission of Potential Transplant Recipient (PTR) Refusal Reasons (Policy 7.5)

In November 2000 the committee discussed the language of Policy 7.5, noting inconsistencies regarding the circumstances in which organ offers require validation. Section 7.5 states that PTR refusal reasons must be submitted� for each cadaver donor organ that is allocated to a recipient. Section 7.5.5.1 states that PTR refusal reasons for all offers shall be validated. The committee agreed that the intent was that all organ offers be validated. While it is more work for the OPO, the benefit of validating all offers is that formal documentation within the UNet^sm system can demonstrate that OPOs are making sufficient effort to place organs. Therefore, the committee unanimously agreed to forward to the Board of Directors a resolution modifying the language of Section 7.5 such that PTR refusal reasons must be submitted to UNOS for each cadaver donor organ that is offered to a potential recipient.

Current Status.
The Board passed the resolution at its November 2000 meeting.

The Committee also discussed the 15-day turnaround time from the match run for submission of PTR refusal reasons, as requested by the MPSC. Please see the MPSC section, item #2 for further details.

2. Standard Packaging of Human Organs and Tissue Typing Materials (Policy 5.5)

Several OPOs contacted UNOS regarding Policy 5.5, specifically sections 5.5.3 and 5.5.3.1, which state that in addition to sterile barriers, a rigid container must protect all organs, except livers. However, in current practice, recovered lungs are protected by a triple sterile barrier and stored within coolers during transportation, as required by policy, but they are not placed in rigid containers. The committee agreed that in this situation, policy should be consistent with current medical practice. It unanimously approved a resolution excluding lungs from the rigid container requirement.

Current Status.
The Board passed the resolution at its November 2000 meeting.

3. Additives to Flush Solution (Policy 2.6.4 and 2.6.8, Organ Procurement Quality)

OPOs surveyed in 2000 indicated that many were modifying or eliminating manufacturer recommended additives to flush solution. For example, penicillin was being excluded because of potential patient reactions and the shortage of access to penicillin. In response to a letter of inquiry, the flush solution manufacturer stated that it was not mandatory to include it.

Additives to flush solution currently are not documented on a national level, though knowledge of the additives could be of value when evaluating a patient posttransplant (e.g., evaluating the penicillin-sensitive patient who received an organ preserved with flush solution containing penicillin). The committee agreed that additives are medications given to the donor and documentation should be required as it is for other medications. Therefore, the committee unanimously set forth a resolution modifying Policy 2.6.4 and 2.6.8, requiring that the Host OPO be responsible for ensuring that donor medication administration, including flush solutions and additives, is duly recorded during the retrieval process.

Current Status.
The Board of Directors passed the resolution at its November 2000 meeting.

4. Qualifications of Organ Recovery Teams

Currently, there is no policy defining specific qualifications required for organ recovery team members. During committee discussion, it was stated that institutions with fellowship programs are more likely to have recovery teams led by fellows to ensure sufficient training experiences. However, the transplant community needs to have a reasonable expectation of the abilities of recovery team members. For example, current UNOS policy states that the Host OPO, when available, will perform a physical evaluation of the donor. Therefore, recovery team surgeons should be expected to conduct a thorough internal exam, particularly given the increase in organs recovered from expanded donors.

In addition, UNOS Policy 2.8 requires that a transplant center that has accepted an extra-renal organ be allowed to send its own recovery personnel with rare exception. Currently, there is limited recourse for OPOs if they believe that the individual performing the organ recovery does not have the appropriate qualifications. In response to the OPO Committee's concerns, the Liver Committee unanimously approved a resolution stating that:

UNOS will support the efforts of the American Society of Transplant Surgeons (ASTS) in developing qualification guidelines for organ recovery personnel;
UNOS will work with the ASTS, the Association of Organ Procurement Organizations (AOPO), and other interested parties to review and amend the guidelines;
Once the guidelines are finalized, the OPO Committee will develop a policy proposal for consideration by the OPTN/UNOS Board of Directors.

Current Status.
The Board passed the resolution at its November 2000 meeting. ASTS agreed to draft guidelines at its May 2001 Annual Meeting, through its Standards for Organ Procurement Committee.

PATIENT AFFAIRS COMMITTEE

The Patient Affairs Committee (hereafter referred to as the PAC) addresses transplantation issues of particular concern to patients and from a patient perspective. In 2000-2001, the PAC sent resolutions to the Board of Directors on two key patient issues.

1. Patient Notification of Transplant Listing or Waiting List Removal (By-Laws, Appendix B, Section III(C), Transplant Program Requirements)

In August 2000, the PAC submitted for public comment a proposal regarding the notification of patients when they are listed for a transplant, when they will not be listed for a transplant, or when they are removed from the waiting list. The PAC agreed that patients have a right to this information and should be notified in a timely fashion in order to give them the opportunity to pursue other options if necessary. The PAC reviewed public comments as well as feedback from the MAC, the Pediatric Committee, and the K/P Committee. After consideration of all comments, the PAC modified the proposal slightly such that patients should be notified within seven business days from:

The date that the patient is placed on the waiting list (including the date of listing); or
The completion of the patient's evaluation as a candidate for transplantation, stating that the evaluation has been completed and that the patient will not be listed for transplant at this time; or
The removal from the waiting list as a transplant candidate for reasons other than transplantation or death.

The committee did not intend with this proposal to create an undue burden of paperwork for transplant programs and encouraged the use of form letters and/or the UNet^sm registration form. In addition, the committee recommended that the patient notification requirements be incorporated into the UNOS patient web site and other printed patient materials.

Current Status.
The Board of Directors approved, in November 2000, the resolution requiring that patients be notified when listed or removed from the waiting list as described above, with a friendly amendment that patients be notified within 10 rather than 7 business days.

2. Insurance Coverage for Non-Immunosuppressant Prophylactic Medications

In April 2001 the PAC reviewed a report about a patient who was put "on hold" on the waiting list due to his/her inability to pay for a specific non-immunosuppressant prophylactic medication, which is not covered by Medicare. The committee was concerned about this incidence and about other incidences of patients being kept off the waiting list for financial reasons, or being required to sign contracts or put money in escrow if they cannot afford certain prophylactic medications. The PAC discussed the issue and passed a motion to work with the Transplant Administrators Committee to address this concern. The committee also prepared a resolution for the Board asking UNOS staff, subject to availability and financial resources, to discuss with CMS and other appropriate Federal agencies, the effect of non-coverage of specific non-immunosuppressant, prophylactic medications and the subsequent effect of not being listed for transplant or losing valuable waiting time if placed on hold.

Current Status.
The Board of Directors approved the resolution at the June 2001 meeting.

PEDIATRIC TRANSPLANTATION COMMITTEE

The Pediatric Transplantation Committee (hereafter referred to as the Pediatric Committee) is charged with considering issues relating to pediatric organ transplantation. These issues include: pre- and postoperative care, expeditious transplantation of children, and the specific medical, social, and psychological needs of children. The committee considers the broad implications of such issues as well as specific policy concerns. Some of the committee's recent activities are listed below.

1. Allocation of Pediatric Donor Livers to Pediatric Liver Candidates (Policy 3.6, Allocation of Livers).

The purpose of this proposal is to assign preference in the allocation of pediatric donor livers (i.e., <18 years old) to pediatric liver transplant candidates within medical urgency statuses and the standard distribution areas for liver allocation, provided that the transplant program receiving the liver offer does not transplant less than the whole organ into an intended recipient without offering the remaining portion(s) for transplantation. The proposal's intent is to improve pediatric liver transplant recipient outcomes by age-matching donors with recipients, while preserving the balance of medical justice and utility in allocating livers to both adult and pediatric patients. Modeling results indicated that approximately 59 pediatric donor livers (out of 2,868) per year would be redirected from adult to pediatric recipients. Further, modeling results showed improved transplant outcomes for pediatric recipients of age-matched liver donors, while minimal, if any, impact was found among adult transplant candidates. In an effort to ensure no unintended harm to adult patients, the proposal included incentives for transplanting split livers, allowing two patients to be transplanted with a single donor organ. The proposal was issued for public comment in March 2000 and, after review, the Pediatric Committee approved a resolution to the Board to adopt the proposed policy as described above.

Current Status.
The Board of Directors approved the proposal in June 2000. The policy became effective as of February 14, 2001.

2. New UNOS Status Criteria for Prioritizing Liver Transplant Candidates with Pre-Existing Liver Disease - Pediatric End-Stage Liver Disease (PELD) Model (Policy 3.6, Allocation of Livers)

For some time, the Liver Committee and the Pediatric Committee have worked collaboratively to develop revised liver allocation policy, in response to the OPTN Final Rule developed by HHS, effective March 2000. The committees agreed to a continuous numeric scale that determines a patient's risk of mortality on the waiting list (a more detailed discussion of the development of this proposal is provided under the summary of activities for the Liver Committee). The Liver Disease Severity Scale (LDSS) Committee was established to facilitate further development of a continuous numeric scale to determine a patient's risk of mortality on the waiting list. The Model for End-State Liver Disease (MELD), designed for adult liver patients, assigns a point score for patients based on the probability of dying on the waiting list, calculated from a formula that considers serum creatinine, bilirubin, and INR. A similar risk score for pediatric patients, the Pediatric End-Stage Liver Disease (PELD) score, was developed in parallel to the MELD.

In developing the PELD, the Pediatric and LDSS Committees discussed various factors unique to pediatric patients. These include:

Age less than 1 year old at the time of listing,
Growth failure,
Nutritional support requiring TPN or nasogastric feeding,
Hepatoblastoma, and
Metabolic diseases such as Ornithine Transcarbamylase Deficiency and Crigler-Najjar disease.

The PELD system has been validated using data from the University of Pittsburgh. Both the MELD and PELD systems are currently undergoing additional validation using current OPTN waiting list data. However, the Pediatric Committee has expressed concern about whether the validation study will include a sufficient number of pediatric cases to provide a statistically or clinically significant analysis of the PELD model.

During the June 2001 Board of Directors meeting, the Board approved the recommendation that UNOS proceed simultaneously with the development and programming of the MELD and PELD systems for liver allocation. It is expected that refinements to the systems will be determined in November 2001. The Pediatric Committee continues to consider the following issues, specific to pediatric patients, in relation to the implementation of this proposal.

Sequence of Pediatric Donor Liver Allocation. UNOS policy to assign allocation preference of pediatric donor livers to pediatric liver transplant candidates was implemented in February 2001. As the proposed MELD/PELD systems were approved under current policy, the LDSS Committee continues to consider ways to maintain pediatric priority in the proposed MELD/PELD models. The LDSS recently agreed with the recommendation of the Pediatric Committee to establish a threshold probability of pretransplant death above which pediatric patients would receive priority in the allocation of pediatric donor livers (within distribution areas), relative to adult patients listed at this threshold or higher, and below which pediatric patients would receive priority in the allocation of pediatric donor livers (within distribution areas), relative to adult patients listed at this threshold or lower. A 50% risk of 3-month pretransplant mortality is the selected threshold.
Conversion of the PELD to a pediatric MELD-equivalent score. The LDSS Committee continues to study the accuracy of the conversion equation that will be used to convert the PELD score into a pediatric MELD-equivalent score (that is, measuring the risk of pretransplant mortality). The concern of the Pediatric Committee has been that, without a similar baseline distribution of survival, the conversion would in fact "downgrade" the PELD scores when converting them to MELD equivalents.
Continuation of Pediatric Designation after a Patient's 18th Birthday without a Transplant. Current UNOS policy for liver allocation defines a pediatric patient as one who is between the ages of 0 and 17. The Pediatric Committee believes that the liver allocation policy should be amended, consistent with policies for allocating hearts and kidneys, such that children retain their priority or consideration assigned under the policy from the time of listing until they have been transplanted, regardless of their actual age at transplant. The purpose is to ensure that considerations provided in the policy for children are not eliminated upon reaching adulthood by chronological age unless the patient has by this time received his/her needed transplant.

Current Status.
Please see the Liver Committee section, item #1 for current status details.

3. Review of Organ Disposition for Pediatric Donors

For some time, the committee has been involved in the review of cases involving donors who had at least one organ transplanted, but from whom the liver or heart was not recovered. In November 1998, the UNOS Board of Directors approved the Pediatric Committee's proposed project to review 400 cases involving donors who had at least one organ transplanted in 1997 and 1998, but from whom the liver or heart was not recovered. The purpose of the project is to determine if pediatric donor organs are being procured to their full potential.

The Committee has reviewed several iterations of data over the last few years in an attempt to assess why certain organs were not recovered. The committee has been concerned, for example, with the number of reviewed cases in which there was no recipient located, or poor organ function was listed for hearts or livers, while other organs were recovered and transplanted and weight and serologies appeared appropriate. Most recently, members of the Pediatric Committee specializing in heart and liver transplantation were asked to review the cases relevant to their specialty and select those cases requiring further examination. The committee then requested and reviewed information linking the donor cases with historical computer match runs associated with heart and liver offers. Through this effort the committee has reduced the list to a total of 55 cases in which at least one organ was procured but in which the heart or liver was not recovered. Twenty-six OPOs were found to have at least one case to review.

Current Status.
The Pediatric Committee has forwarded a memorandum to the OPO Committee detailing the status of the project and requesting input on the potential for a system of rapid identification and placement for pediatric donor organs.

4. Establishment of UNOS Membership Criteria for Pediatric Transplant Programs

In November 1999, the Board of Directors approved a recommendation that the Pediatric Committee survey all transplant centers that performed at least one organ transplant on patients age 0-18 years old during an appropriate period after January 1, 1988. The purpose of the questionnaire is to obtain and evaluate program-specific information about how the pediatric programs are structured. This in turn, should help the committee better understand factors that may be used to distinguish pediatric transplant programs from other transplant programs.

Current Status.
The questionnaire has been modified several times and was "pre-tested" using committee members' own transplant centers as the sample group; committee members coordinated questionnaire completion for their individual centers. The committee expects to distribute the questionnaire to relevant transplant programs in the near future.

THORACIC TRANSPLANTATION COMMITTEE

The OPTN Final Rule requires that the OPTN measure the efficacy of allocation policies through the use of performance goals or indicators. To that end, and more importantly, to improve the allocation system for hearts and lungs, the Heart Allocation and Lung Allocation Subcommittees of the Thoracic Transplantation Committee (hereafter referred to as the Thoracic Committee) are developing models for risk stratification of transplant candidates. A summary of the actions of the Thoracic Committee and the subcommittees is described below.

1. Risk-Stratified System for Heart Allocation (Policy 3.7, Allocation of Thoracic Organs)

The Heart Allocation Subcommittee is analyzing data and deliberating ways to construct a risk-stratified system for allocating hearts. The main objective of the heart risk-stratified model is to maximize the difference between the pretransplant risk of mortality and the posttransplant risk of mortality. The model will generate a risk score that is assigned to each patient at the time a match is run for a specific donor. Patients will then be ranked on the basis of this score, with patients having the greatest potential benefit (i.e., the greatest difference between pre- and posttransplant mortality) being ranked the highest. In other words, a patient with a high probability of death without a transplant and a low probability of death with a transplant would have a higher risk score than a patient with a low probability of death without a transplant and a high risk of posttransplant mortality.

At its meetings in the fall of 2000 the subcommittee decided to:

Analyze the sufficiency of variables currently collected and identify variables that need to be updated on a periodic basis;
Develop an analysis of the actuarial pre- and posttransplant survival rates for each category of patients listed under Status 1A and Status 1B;
Analyze donor characteristics and their relation to geographic distribution areas; and
Use these analyses to develop and refine a risk-stratified model.

The Thoracic Committee suggested that a separate pediatric model might need to be developed, given the different risk factors associated with pre- and posttransplant outcomes for adult and pediatric patients. The committee has sought and will continue to seek input from pediatric specialists.

At a meeting in May 2001, the subcommittee reviewed some data and analyses but it was not enough to create a model. The subcommittee determined that hemodynamic and functional variables, along with comorbidity and therapeutic intervention data are needed before a model can be developed. The subcommittee also recommended that data should be updated every 6 months for Status 2 patients, every month for Status 1B patients, and weekly for Status 1A patients. The subcommittee agreed that it would continue its efforts toward developing a risk-stratified system by conducting additional analyses and identifying variables critical to the development of a model. In addition, the subcommittee will work on modifying and reviewing the proposed minimum inotrope level analysis.

In June 2001, the Thoracic Committee asked the Board of Directors to approve, in principle, that heart allocation be based upon a model of the projected risk of mortality on the waiting list, balanced by the projected posttransplant survival, noting that the data variables needed to make that determination will be prospectively collected but are yet to be determined.

Current Status.
The Board approved the resolution at the June 2001 meeting. The Heart Allocation Subcommittee will submit its completed list for public comment in January 2002.

2. Risk-Stratified System for Lung Allocation (Policy 3.7, Allocation of Thoracic Organs)

The Lung Allocation Subcommittee began discussing a risk-stratified system for lung allocation in the summer of 2000. Based on data examined by the subcommittee, it was apparent that waiting list mortality risk was higher for some lung diagnoses than for others. The subcommittee discussed developing policy that would prioritize one diagnosis category over another but it was agreed that such a policy must also consider the perioperative risk and posttransplant survival for each diagnosis category. The subcommittee examined numerous risk factors relating to death on the waiting list collected at the time of listing and a multivariate analysis was performed. The analysis revealed that the most significant predictor of pretransplant mortality is diagnosis at the time of listing, though several other variables were also significant predictors of pretransplant mortality. These variables were then applied to a cohort of transplanted patients to determine which factors also affected posttransplant survival. Again, diagnosis at the time of listing was found to be the most significant.

At present, lungs are allocated on the basis of patient waiting time only, but the results of the multivariate analysis indicated that the analysis could be used to construct a risk stratification system for lung patients that would direct lungs towards patients at increased risk of death on the waiting list. Patients potentially could be grouped within ranges of scores, or stratified on a continuous scale. Waiting time potentially may be used among patients with similar relative risk of death without a transplant.

In May 2001, the subcommittee reached a consensus that an ideal organ distribution algorithm would rank potential recipients by their risk of mortality on the
waiting list coupled with and balanced by their risk of mortality 1 year after a transplant. Four primary diagnosis categories have been identified and may be used as an initial basis for the creation of a risk stratification system for lung allocation:

Emphysema/Alpha-1-Antitrypsin Deficiency/Chronic Obstructive Pulmonary Disease
Cystic Fibrosis
Idiopathic Pulmonary Fibrosis
Primary Pulmonary Hypertension

These four categories account for 80% of waiting list patients. For the remaining 20% of patients, the subcommittee agreed to assign each one of the separate diagnostic categories into one of the four primary categories based on apparent similarities.

As part of the development of a risk-stratified model, the subcommittee identified a list of variables that should be part of the data reporting process at the time of listing and at 6 month intervals, with allowances for listing centers to update the data more frequently in certain cases. After discussion with the full committee, the Thoracic Committee made a formal resolution to the Board, listing specific variables required at listing on the lung transplant waiting list and every 6 months thereafter. It also stated that all data determined to be necessary for the development of the risk-stratified model be mandated.

Current Status.
The Board of Directors passed the resolution at the June 2001 meeting. The data elements are still being refined.

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