Mini-Focus On Heart Transplantation PolicyState-of-the-Art ReviewImpact of the 2018 UNOS Heart Transplant Policy Changes on Patient Outcomes
Central Illustration
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.
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