Changes in Wait List Mortality, Transplantation Rates and Early Post-Transplant Outcomes in LVAD BTT with New Heart Transplant Allocation Score. A UNOS Database Analysis

Impact of the 2018 UNOS Heart Transplant Policy Changes on Patient Outcomes

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.

A national assessment of one-year heart outcomes after the 2018 adult heart allocation change

PURPOSE

On 10/18/2018 the Organ Procurement and Transplantation Network (OPTN) implemented modifications to adult heart allocation to better stratify the most medically urgent candidates by WL mortality. This paper reviews two years of post-policy monitoring with focus on post-transplant outcomes, especially for recipients with MCSDs.

METHODS

Cohorts of WL additions and recipients pre (10/18/16-10/17/18) and post (10/18/18-10/17/20) policy implementation were compared using the OPTN database. Competing risks analyses of waitlist mortality and Kaplan-Meier one-year post-transplant survival were performed by medical urgency statuses and policy era. Similar analyses were performed for subsets of candidates and recipients on devices.

RESULTS

Pre-implementation status 1A candidates had the highest cumulative incidence of removal from the waitlist due to death or too sick to transplant and the highest cumulative incidence of transplant, followed by statuses 1B and 2. Median time to transplant decreased from 226 to 85 days for those transplanted. There was no difference in one-year patient survival (pre=91.3% [90.2, 92.4]; post=91.8% [90.8, 92.9]; p=0.44) overall, or for recipients transplanted with an LVAD (pre=91.7% [90.1, 93.2]; post=91.4% [89.7, 93.2]; p=0.85) or IABP (pre=91.7% [88.1, 95.4]; post=92.1% [90.1, 94.0]; p=0.92).

CONCLUSION

The policy improved stratification of the most medically urgent candidates according to risk of death on the WL with decreased median wait times, higher transplant rates and no observed adverse effect on 1-year patient survival. No adverse effects for candidates listed or transplanted on IABP, ECMO, or LVAD were observed.

Critically appraising the 2018 United Network for Organ Sharing donor allocation policy: adding life boats or rearranging the deck chairs?

PURPOSE OF REVIEW

Due to the growing mismatch between donor supply and demand as well as unacceptably high transplant waitlist mortality, the heart organ allocation system was revised in October 2018. This review gives an overview of the changes in the new heart organ allocation system and its impact on heart transplant practice and outcomes in the United States.

RECENT FINDINGS

The 2018 heart allocation system offers a 6-tiered policy and therefore prioritizes the sickest patients on the transplant waitlist. Patients supported with temporary mechanical circulatory support devices are prioritized as Status 1 or Status 2, resulting in increased utilization of this strategy. Patients supported with durable left ventricular assist devices have been prioritized as Status 3 or 4, which has resulted in decreased utilization of this strategy. Broader geographic sharing in the new heart allocation system has resulted in prolonged donor ischemic times. Overall, the new heart allocation system has resulted in significantly lower candidate waitlist mortality, shorter waitlist times, and higher incidence of transplantation.

SUMMARY

The new United Network for Organ Sharing allocation policy confers significant advantages over the prior algorithm, allowing for decreased waitlist times and improved waitlist mortality without major impact on posttransplant survival.