Deceased Donor Kidney Allocation, Strategies to Expand the Living Donor Pool, and Waitlist Management



Deceased Donor Kidney Allocation, Strategies to Expand the Living Donor Pool, and Waitlist Management


Phuong-Thu T. Pham

Suzanne McGuire

Christine H. Lee

Jeffrey L. Veale

Phuong-Anh T. Pham



UNITED NETWORK FOR ORGAN SHARING LISTING CRITERIA



  • United Network for Organ Sharing (UNOS) listing criteria for deceased donor kidney



    • Chronic kidney disease with estimated glomerular filtration rate (eGFR) <20 mL/min or


    • On dialysis


DECEASED DONOR KIDNEY ALLOCATION SYSTEM IN THE UNITED STATES



  • Factors determining kidney allocation



    • Waiting time



      • Preregistration dialysis time allows transplant candidates to gain waiting time upon listing (eg, patient who has been on dialysis for 5 years prior to UNOS registration will have 5 years of waiting time upon listing).


      • Candidates not yet on dialysis at the time of registration will still begin to accrue waiting time once they are registered on the waiting list.


    • Geographic area: allocation prioritized to candidates in areas closest to donor


    • Highly sensitized candidates



      • Kidney candidates are assigned a calculated panel reactive antibody (cPRA) score that is based on the “unacceptable antigens” listed for each candidate (cPRA is discussed in chapter 1). Higher cPRA scores indicate increasing difficulty in getting a kidney with a negative or acceptable crossmatch (discussion of the socalled “acceptable” crossmatch is beyond the scope of this chapter). In the current allocation system, patients with higher cPRA scores receive additional points for prioritization.









        TABLE 6-1 Calculated Panel Reactive Antibody (CPRA)-Based Allocation Points






















































        CPRA


        Points*


        CPRA


        Points*


        CPRA


        Points*


        0-19


        0


        70-74


        1.09


        96


        12.17


        20-29


        0.08


        75-79


        1.58


        97


        17.30


        30-39


        0.21


        80-84


        2.46


        98


        24.40


        40-49


        0.34


        85-89


        4.05


        99


        50.09


        50-59


        0.48


        90-94


        6.71


        100


        202.10


        60-69


        0.81


        95


        10.82




        * In the current allocation system, 0.08 points is equivalent to about a month of waiting time, 1.58 points and 2.46 points are equivalent to about 1.5 to 2.5 years of waiting time, respectively. Candidates with cPRA of 98%, 99% or 100% receive 24.40, 50.09, and 202.10 points, respectively to improve access for sensitized candidates.



      • Prioritization points will be assigned based on a sliding scale, beginning with a cPRA score of 20% (candidates with cPRA of 20% will receive 0.08 point, candidates with cPRA 75%-79% will receive 1.58 points, etc.).1 The cPRA-based allocation points are shown in Table 6-1.


      • Candidates with cPRA of 98%, 99%, or 100% will also receive local, regional, and national priority.


    • Pediatric status


    • Prior living organ donor: Prior organ donation including kidney and liver will receive priority for organ allocation.


    • Estimated posttransplant survival (EPTS) score and Kidney Donor Profile Index (KDPI)



      • The EPTS score is designed to ensure that those kidneys expected to function the longest are transplanted into those candidates expected to live the longest. It is based on four factors: candidate’s age, length of time spent on dialysis, prior transplant of any solid organ, and current diabetes status. A lower EPTS score is associated with longer estimated posttransplant longevity.


      • The donor characteristics that are used to calculate KDPI are discussed in chapter 7. In brief, lower KDPI values are associated with longer estimated allograft function, whereas higher KDPI values are associated with shorter estimated function.


      • Candidates with EPTS scores of ≤20% will receive increased priority for offers for kidneys with KDPI scores of ≤20% before other candidates at the local, regional, and national levels of distribution.1,2


      • The EPTS score will only be used in kidney allocation when the donor has a KDPI of 20% or less.1,2


      • EPTS scores will not be calculated for pediatric candidates until the candidate turns 18 years old.


  • Currently, kidneys are allocated through four sequences, defined by the KDPI score of the donor kidney (KDPI ≤20%, KDPI >20% but <35%, KDPI ≥35% but ≤85%, and KDPI >85%)—herein referred to as sequences A, B, C, and D, respectively (Table 6-2).2



    • The projected longevity of the kidney as determined by the KDPI will determine which allocation sequence is initiated (ie, A, B, C, or D).


    • Stratification within the different sequences will be based on several factors including degree of allosensitization, human leukocyte antigen (HLA) matching, and prior living organ donor among others. The allocation sequence system is shown in Table 6-2.









TABLE 6-2 Allocation Sequence System1,2










































Sequence A KDPI ≤20%


Sequence B >20% KDPI <35%


Sequence C ≥35% KDPI <85%


Sequence D KDPI >85%


cPRA 100%/99%/98%


cPRA 100/99/98


cPRA 100/99/98


cPRA 100/99/98


Zero-ABDR mismatch top 20% EPTS


Zero-ABDR mismatch


Zero-ABDR mismatch


Zero-ABDR mismatch


Prior living organ donor


Prior living organ donor


Prior living organ donor


Local + regional


Local top 20% EPTS


Local


Local


National


Regional top 20% EPTS


Regional


Regional



National top 20% EPTS


National


National



1Factors used to determine organ allocation within each sequence are listed in order of priority (e.g. priority is given first to cPRA 100%/99%/98%, followed by zero-ABDR mismatch, … etc.). If tiebreaker is needed, the date of registration will be used


2Priority for pediatric candidates, B blood type candidates (who can safely accept A2 or A2B blood type donor), and liver “safety net” are not included. Interested readers are referred to optn.transplant.hrsa.gov/media/1200/optn_policies.pdf (date accessed: November 2018). Liver safety net is discussed in chapter 16


KDPI, Kidney Donor Profile Index; cPRA, calculated panel reactive antibody



STRATEGIES TO EXPAND THE LIVING DONOR POOL

The shortage of deceased donor kidneys has led the transplant community to develop strategies to expand the living donor pool. This section discusses nonmedical aspects involved in living kidney donation. These include laws and ethics, financial aspects, patient education, living donor options, and organ import/export exchange coordination of care. Living donor evaluation is discussed in chapter 5.


Laws, ethics, and financial aspects of living kidney donation



  • The Declaration of Istanbul on Organ Trafficking and Transplant Tourism and the World Health Organization (WHO) prohibit and condemn the exploitation of vulnerable living donors (defined as illiterate or impoverished individuals, undocumented immigrants, prisoners, and political or economic refugees)3 (see chapter 19).


  • In the United States, all organ donors are registered with the Organ Procurement and Transplantation Network (OPTN)/UNOS prior to donation. This registry records all donors for data tracking and management. Additionally, the registry enables priority listing for past donors should they ever develop end-stage kidney disease and require a transplant as renal replacement therapy.


  • The Living Donor Protection Act (first introduced in 2016)4 protects living organ donors and removes some potential barriers to donation. Under this act, insurance companies are prohibited from denying or limiting life, disability, and long-term care insurance to living donors and from charging higher premiums. Living organ donors may also use time granted through the Family and Medical Leave Act (FMLA) to recover from donation. H.R. 1270 has not yet been passed by both houses of Congress as of the printing of this book.


  • The National Organ Transplant Act (NOTA) prohibits the sale of an organ.5


  • In the United States, the cost of a living donor’s evaluation, transplant surgery, and hospitalization are covered by Medicare and/or by the recipient’s insurance. Personal expenses (travel, cost of living during donation process) are usually not covered, but some insurance may reimburse for these expenses. Multiple organizations are now available to provide financial support to those individuals not otherwise able to afford the travel and subsistence expenses associated with living donation.



Patient education



Living donor options

May 8, 2019 | Posted by in NEPHROLOGY | Comments Off on Deceased Donor Kidney Allocation, Strategies to Expand the Living Donor Pool, and Waitlist Management
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