Elsevier

JACC: Heart Failure

Volume 11, Issue 5, May 2023, Pages 491-503
JACC: Heart Failure

Mini-Focus On Heart Transplantation Policy
State-of-the-Art Review
Impact of the 2018 UNOS Heart Transplant Policy Changes on Patient Outcomes

https://doi.org/10.1016/j.jchf.2023.01.009Get rights and content

Highlights

  • The 2018 United Network for Organ Sharing policy introduced a 6-tier allocation system to address shortcomings of the prior policy.

  • Since implementation, significant changes in waitlist outcomes and advanced heart failure practice patterns have emerged.

  • Further study is necessary to understand the long-term impacts of the observed changes in practice.

Abstract

In 2018, the United Network for Organ Sharing implemented a 6-tier allocation policy to replace the prior 3-tier system. Given increasing listings of critically ill candidates for heart transplantation and lengthening waitlist times, the new policy aimed to better stratify candidates by waitlist mortality, shorten waiting times for high priority candidates, add objective criteria for common cardiac conditions, and further broaden sharing of donor hearts. There have been significant shifts in cardiac transplantation practices and patient outcomes following the implementation of the new policy, including changes in listing practices, waitlist time and mortality, transplant donor characteristics, post-transplantation outcomes, and mechanical circulatory support use. This review aims to highlight emerging trends in United States heart transplantation practice and outcomes following the implementation of the 2018 United Network for Organ Sharing heart allocation policy and to address areas for future modification.

Section snippets

Urgency status

Before 2018, the majority of patients were listed as the highest priority statuses, statuses 1A and 1B.3 With the introduction of the 6-tier system targeting enhanced risk stratification, only the most critically ill patients who meet specific criteria are listed in the highest priority statuses (Table 1, Figure 1). Patients with prior status 1A indications are now stratified into statuses 1-3. In early analyses, up to 35% were listed as status 1-3 compared to 25% of the 1A cohort from the

Waitlist mortality

During the prior era, the HT waitlist continued to grow and supplanted the number of donors. The result was longer waiting times, with almost half of the patients remaining on the waitlist for more than 1 year, and larger proportions of high-urgency candidates with higher waitlist mortality rate.14 A primary goal of the policy change was to ensure that candidates with the highest urgency were stratified accordingly to increase access to donor hearts and, in turn, reduce waitlist time and

Waitlist time

Time spent on the transplant waitlist is a product of many factors. Poor clinical status with high urgency naturally warrants shorter time to transplantation, whereas clinically stable patients with less urgency may safely remain waitlisted for longer periods. Organ availability also plays a role, with regional variations in organ supply and number of candidates. In the new system, overall waitlist time has decreased from 112 days to 39 days (P < 0.001) per SRTR/UNOS data and similar findings

Post-transplantation outcomes

Although the policy change was primarily intended to reduce waitlist mortality, it is vital to ensure that the change did not have unintended negative impact on post-transplantation outcomes. Compared to the prior system, transplant recipients are of similar age, body mass index, and ethnicity have similar serum creatinine and bilirubin concentrations and have similar prevalence of diabetes, prior malignancy, and cerebrovascular disease. However, a higher number of recipients have congenital

Temporary MCS use

Following the policy change, the most marked practice change was use of temporary MCS as a BTT. At the time of listing, the number of patients supported with VA-ECMO (1.8% vs 2.7%; P = 0.02), IABP (5.3% vs 10.3%; P < 0.01), and biventricular support (1.3% vs 2.1%; P = 0.02) all increased. Other estimates have demonstrated up to tripling of temporary MCS use.6,18,30,31 However, clinical deterioration or death on the waitlist was significantly reduced in the new system for those listed with

Durable LVAD Use

Although temporary MCS is increasingly used to bridge directly to transplantation, durable LVAD has decreased significantly.5,37 In one analysis, LVAD-supported transplant candidates had a lower frequency of transplantation within 1 year of listing compared to the old system (52% vs 61%; P < 0.001),40 although other estimates show similar transplantation rates.41 Despite similar waitlist mortality in BTT LVAD patients, 1-year post-transplantation survival was lower following the policy change

Donor characteristics

As expected with changes in zone restrictions for heart allocation to the highest urgency candidates (Table 1), distance between donor and recipient centers has significantly increased in the new era.4,5,7,19 In turn, average ischemic times have increased as well, from 3.0 to 3.4 hours.4,19 Although ischemic times typically remain <4 hours, outcomes may potentially be affected with the marginally longer times in the new era. In one single-center analysis, incidence of primary graft dysfunction

Financial impact

There are limited data evaluating the financial impact of the policy change. Initial predictions suggested decreased cost-effectiveness related to increased MCS use, increased procurement radius, and longer ischemic times.47 Procurement-related transportation costs have increased since the policy change, and Nationwide Inpatient Sample database analysis shows increased cost for index HT hospitalization related to MCS use despite similar lengths of stay.48,49 Nonetheless, shorter waiting

Specific cardiomyopathies and adult congenital heart disease

The majority of patients with HCM, RCM, and congenital heart disease qualify as status 4 at the time of listing (Table 1).50 However, these patients were frequently transplanted under exception at a higher status in both eras.12 Patients tended to be status 2 at time of transplantation—typically via use of IABP—although the OPTN/UNOS guidance statement for exception use in HCM/RCM patients provides criteria for status 2 listing without IABP as well.13,50 Waitlist time is shorter and rates of

Multiorgan transplantation

Before the 2018 policy, there were no specific allocation rules related to multiorgan transplantation that included the heart. Considering the severity of illness in this vulnerable cohort, all multiorgan candidates were allowed to be listed as status 5 with the expectation that they would require status upgrades as their cardiac condition worsened. Changes in listing patterns for multiorgan transplantation have been similar to heart alone with increased use of VA-ECMO (5.2% vs 0.9%; P <

Future directions

Although the 2018 heart policy revision has accomplished a majority of its intended goals, opportunities remain to improve candidate prioritization and donor heart allocation. The high rate of exception requests suggests that either the policy does not adequately account for illness severity or that criteria developed for comorbidities are excessively stringent and/or misaligned with clinical practice. A deeper understanding and categorization of exception requests will be required to

Conclusions

Since the implementation of the 2018 OPTN/UNOS heart allocation policy focused on improving risk stratification of critically ill patients to the highest priority and improving waitlist outcomes, several trends have emerged in heart transplantation practice patterns (Figure 2). Although patient demographics and clinical characteristics remain similar, more high-priority listings have been observed. There has been a marked shift in the use of MCS devices away from durable LVADs to direct bridge

Funding Support and Author Disclosures

Dr Khazanie has received research grant support from National Institutes of Health (K23 HL145122) and the University of Colorado Ludeman Center for Women’s Health Research outside of this work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

References (57)

  • R. Cogswell et al.

    An early investigation of outcomes with the new 2018 donor heart allocation system in the United States

    J Heart Lung Transplant

    (2020)
  • W.F. Parker et al.

    Is it too early to investigate survival outcomes of the new US heart allocation system?

    J Heart Lung Transplant

    (2020)
  • T.C. Hanff et al.

    Update to an early investigation of outcomes with the new 2018 donor heart allocation system in the United States

    J Heart Lung Transplant

    (2020)
  • A.S. Varshney et al.

    Outcomes in the 2018 UNOS donor heart allocation system: a perspective on disparate analyses

    J Heart Lung Transplant

    (2020)
  • M. Shin et al.

    Higher rates of dialysis and subsequent mortality in the new allocation era for heart transplants

    Ann Thorac Surg

    (2023)
  • P.A. Alvarez et al.

    Trends, risk factors, and mortality of unplanned 30-day readmission after heart transplantation

    Am J Cardiol

    (2021)
  • T.M. Cascino et al.

    A challenge to equity in transplantation: increased center-level variation in short-term mechanical circulatory support use in the context of the updated U.S. heart transplant allocation policy

    J Heart Lung Transplant

    (2022)
  • E.M. Defilippis et al.

    Exploring physician perceptions of the 2018 United States Heart Transplant Allocation System

    J Card Fail

    (2022)
  • P. Moonsamy et al.

    Survival after heart transplantation in patients bridged with mechanical circulatory support

    J Am Coll Cardiol

    (2020)
  • M.Y. Yin et al.

    Post-transplant outcome in patients bridged to transplant with temporary mechanical circulatory support devices

    J Heart Lung Transplant

    (2019)
  • K.J. Clerkin et al.

    Impact of temporary percutaneous mechanical circulatory support before transplantation in the 2018 heart allocation system

    J Am Coll Cardiol HF

    (2022)
  • C.W. Mullan et al.

    Changes in use of left ventricular assist devices as bridge to transplantation with new heart allocation policy

    J Am Coll Cardiol HF

    (2021)
  • K.K. Khush et al.

    The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Thirty-fifth Adult Heart Transplantation Report–2018; focus theme: multiorgan transplantation

    J Heart Lung Transplant

    (2018)
  • J.H. Kwon et al.

    Prolonged ischemic times for heart transplantation: impact of the 2018 allocation change

    Ann Thorac Surg

    (2022)
  • M. Saltzberg

    Consequences of a revised heart allocation system on the cost effectiveness of cardiac transplantation in the United States: game theory based insights

    J Heart Lung Transplant

    (2019)
  • B.C. Lampert et al.

    More money and more miles: the hidden costs of donor procurement with the new heart allocation system

    J Heart Lung Transplant

    (2020)
  • M.R. Mehra et al.

    Prediction of survival after implantation of a fully magnetically levitated left ventricular assist device

    J Am Coll Cardiol HF

    (2022)
  • S. Shore et al.

    Changes in the United States Adult Heart Allocation Policy

    Circ Cardiovasc Qual Outcomes

    (2020)
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