Implementation of a National Liver Review Board for exception requests in the United States: A 2-year monitoring report

The exception point system for liver allocation in the United States allows for additional waitlist priority for candidates where the Model for End-Stage Liver Disease or Pediatric End-stage Liver Disease does not effectively represent their urgency or need for a transplant. In May 2019, the review process for liver exception cases transitioned from 11 Regional Review Boards (RRBs) to 1 National Liver Review Board (NLRB), intended to increase consistency nationwide, improve efficiency, and balance transplant access for candidates with and without exception scores. This report provides a review of liver exception request and review practices, waitlist outcomes, and transplant activity in the first 2 years after implementation of the NLRB and acuity circle-based distribution in the United States. We compared initial and extension exception request forms submitted from May 13, 2017 to May 13, 2019 (prepolicy or RRB era) to the period from February 4, 2020 to February 3, 2022 (postpolicy or NLRB era). During this time, the NLRB reviewed 10,083 initial exception requests and 12,686 extension requests. Notable postpolicy highlights include (1) an increase in the proportion of initial and extension requests that were automatically approved instead of manually reviewed; (2) a decrease in the overall approval rates of initial exception requests (87.8% for adult HCC, 64.3% for adult other diagnoses, and 71.5% for pediatric); and (3) reduction in the time from exception request submission to adjudication to a median of 3.73 days. The proportions of waitlist registration and deceased donor liver transplants for patients with exception scores decreased, and waitlist outcomes between patients with and without exception scores are now comparable. Implementation of the NLRB improved efficiency, reduced case workloads, and standardized criteria for exception cases, with similar waitlist outcomes between patients with and without exception scores and improved equity in terms of access to liver transplants.

Excess waitlist mortality among candidates for multivisceral liver-intestine transplant in acuity circle allocation

Candidates for multivisceral transplant (MVT) have experienced decreased access to transplant in recent years. Using Organ Procurement and Transplantation Network data, transplant and waiting list outcomes for MVT (ie, liver-intestine, liver-intestine-pancreas, and liver-intestine-kidney-pancreas) candidates listed between February 4, 2018, and February 3, 2022, were analyzed, including model for end-stage liver disease/pediatric end-stage liver disease and exception scores by era (before and after acuity circle [AC] implementation on February 4, 2020) and age group (pediatric and adult). Of 284 MVT waitlist registrations (45.6% pediatric), fewer had exception points at listing post-AC compared to pre-AC (10.0% vs 19.1%), and they were less likely to receive transplant (19.1% vs 35.9% at 90 days; 35.7% vs 57.2% at 1 year). Of 177 MVT recipients, exception points at transplant were more common post-AC compared to pre-AC (30.8% vs 20.2%). Postpolicy, adult MVT candidates were more likely to be removed due to death/too sick compared with liver-alone candidates (13.5% vs 5.6% at 90 days; 24.2% vs 9.8% at 1 year), whereas no excess waitlist mortality was observed among pediatric MVT candidates. Under current allocation policy, multivisceral candidates experience inferior waitlist outcomes compared with liver-alone candidates. Clarification of guidance around submission and approval of multivisceral exception requests may help improve their access to transplantation and achieve equity between multivisceral and liver-alone candidates on the liver transplant waiting list.

OPTN/SRTR 2020 Annual Data Report: Liver

This year was marked by the COVID-19 pandemic, which altered transplant program activity and affected waitlist and transplant outcomes. Still, 8906 liver transplants were performed, an all-time high, across 142 centers in the United States, and pretransplant as well as graft and patient survival metrics, continued to improve. Living donation activity decreased after several years of growth. As of June 30, 2020, 98989 liver transplant recipients were alive with a functioning graft, and in the context of increasing liver transplant volume, the size of both the adult and pediatric liver transplant waitlists have decreased. On February 4, 2020, shortly before the pandemic began, a new liver distribution policy based on acuity circles was implemented, replacing donor service area- and region-based boundaries. A policy change to direct pediatric livers to pediatric recipients led to an increase in deceased donor transplant rates and a decrease in pretransplant mortality rate among children, although the absolute number of pediatric transplants did not increase in 2020. Among adults, alcohol-associated liver disease became the predominant indication for liver transplant in 2020. After implementation of the National Liver Review Board and lower waitlist priority for most exception cases in 2019, fewer liver transplants were being performed via exception points, and the transplant rate between those with and without hepatocellular carcinoma has equalized. Women continue to experience higher pretransplant mortality and lower rates of liver transplant than men.

The Effect of Acuity Circles on Deceased Donor Transplant and Offer Rates Across Model for End-Stage Liver Disease Scores and Exception Statuses

Acuity circles (AC), the new liver allocation system, was implemented on February 4, 2020. Difference-in-differences analyses estimated the effect of AC on adjusted deceased donor transplant and offer rates across Pediatric End-Stage Liver Disease (PELD) and Model for End-Stage Liver Disease (MELD) categories and types of exception statuses. The offer rates were the number of first offers, top 5 offers, and top 10 offers on the match run per person-year. Each analysis adjusted for candidate characteristics and only used active candidate time on the waiting list. The before-AC period was February 4, 2019, to February 3, 2020, and the after-AC period was February 4, 2020, to February 3, 2021. Candidates with PELD/MELD scores 29 to 32 and PELD/MELD scores 33 to 36 had higher transplant rates than candidates with PELD/MELD scores 15 to 28 after AC compared with before AC (transplant rate ratios: PELD/MELD scores 29-32, _2.34 3.32_4.71 ; PELD/MELD scores 33-36, _1.70 2.51_3.71 ). Candidates with PELD/MELD scores 29 or higher had higher offer rates than candidates with PELD/MELD scores 15 to 28, and candidates with PELD/MELD scores 29 to 32 had the largest difference (offer rate ratios [ORR]: first offers, _2.77 3.95_5.63 ; top 5 offers, _3.90 4.39_4.95 ; top 10 offers, _4.85 5.30_5.80 ). Candidates with exceptions had lower offer rates than candidates without exceptions for offers in the top 5 (ORR: hepatocellular carcinoma [HCC], _0.68 0.77_0.88 ; non-HCC, _0.73 0.81_0.89 ) and top 10 (ORR: HCC, _0.59 0.65_0.71 ; non-HCC, _0.69 0.75_0.81 ). Recipients with PELD/MELD scores 15 to 28 and an HCC exception received a larger proportion of donation after circulatory death (DCD) donors after AC than before AC, although the differences in the liver donor risk index were comparatively small. Thus, candidates with PELD/MELD scores 29 to 34 and no exceptions had better access to transplant after AC, and donor quality did not notably change beyond the proportion of DCD donors.

OPTN/SRTR 2020 Annual Data Report: Intestine

Despite small increases in additions to the intestine transplant wait- list, total waitlist numbers, overall intestine transplant rates, and overall transplants performed from 2019 to 2020, the trend over the last decade is still toward less intestine transplant activity. Waitlist mortality continues to fall for pediatric populations and is relatively stable for adults. While 1- year graft survival continues to improve, there has been no noticeable improvement in 3- and 5-year graft survival. Immunosuppression practices continue to favor use of an induction agent followed by tacrolimus-based regimens. Patient survival at 5 years is currently identical for isolated intestines and liver-inclusive allograft recipients.

OPTN/SRTR 2019 Annual Data Report: Liver

This year was notable for changes to exception points determined by the geographic median allocation Model for End-Stage Liver Disease (MELD) and implementation of the National Liver Review Board, which took place on May 14, 2019. The national acuity circle liver distribution policy was also implemented but reverted to donor service area- and region-based boundaries after 1 week. In 2019, growth continued in the number of new waiting list registrations (12,767) and transplants performed (8,896), including living-donor transplants (524). Compared with 2018, living-donor liver transplants increased 31%. Women continued to have a lower deceased-donor transplant rate and a higher pretransplant mortality rate than men. The median waiting time for candidates with a MELD of 15-34 decreased, while the number of transplants performed for patients with exception points decreased. These changes may have been related to the policy changes that took effect in May 2019, which increased waiting list priority for candidates without exception status. Hepatitis C continued to decline as an indication for liver transplant, as the proportion of liver transplant recipients with alcohol-related liver disease and clinical profiles consistent with non-alcoholic steatohepatitis increased. Graft and patient survival have improved despite changing recipient demographics including older age, higher MELD, and higher prevalence of obesity and diabetes.

OPTN/SRTR 2019 Annual Data Report: Intestine

Intestine transplant can be life-saving and can improve quality of life for patients with intestinal failure. Medical and surgical advances in treatment of intestinal failure over the past 10 to 15 years have resulted in fewer patients being added to the waiting list for intestine transplant alone or for intestine transplant in combination with liver transplant (and sometimes other organs). Consequently, fewer transplants are being performed. The numbers of listings and transplants fell to new lows in 2019. The number of programs performing transplants in at least one patient in 2019 was the lowest in the last decade, equal to 2014, at 15. Graft failure plateaued over the past decade, but early graft loss has increased in the past 2 years, notably in recipients of a combined liver and intestine allograft. Five-year patient survival for transplants in 2012-2014 varied little by graft type.