Recent Changes in Durable Left Ventricular Assist Device Bridging to Heart Transplantation

Impact of 2018 allocation system change on outcomes in patients with durable left ventricular assist device as bridge to transplantation: A UNOS registry analysis

BACKGROUND

This study compared outcomes of patients waitlisted for orthotopic heart transplantation with durable left ventricular assist devices (LVAD) before and after the October 18, 2018 heart allocation policy change.

METHODS

The United Network of Organ Sharing database was queried to identify 2 cohorts of adult candidates with durable LVAD listed within seasonally-matched, equal-length periods before (old policy era [OPE]) and after the policy change (new policy era [NPE]). The primary outcomes were 2-year survival from the time of initial waitlisting, as well as 2-year post-transplant survival. Secondary outcomes included incidence of transplantation from the waitlist and de-listing due to either death or clinical deterioration.

RESULTS

A total of 2,512 candidates were waitlisted, 1,253 within the OPE and 1,259 within the NPE. Candidates under both policies had similar 2-year survival after waitlisting, as well as a similar cumulative incidence of transplantation and de-listing due to death and/or clinical deterioration. A total of 2,560 patients were transplanted within the study period, 1,418 OPE and 1,142 within the NPE. Two-year post-transplant survival was similar between policy eras, however, the NPE was associated with a higher incidence of post-transplant stroke, renal failure requiring dialysis, and a longer hospital length of stay.

CONCLUSIONS

The 2018 heart allocation policy has conferred no significant impact on overall survival from the time of initial waitlisting among durable LVAD-supported candidates. Similarly, the cumulative incidence of transplantation and waitlist mortality have also been largely unchanged. For those undergoing transplantation, a higher degree of post-transplant morbidity was observed, though survival was not impacted.

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.