Objectives

Extensive changes were implemented to the adult heart allocation policy in 2018. The purpose of the study was to characterize changes in waitlist and post-transplant outcomes of extracorporeal membrane oxygenation (ECMO) patients being bridged to transplantation following the policy change.

Methods

Retrospective review was performed for all isolated adult heart transplants from August 2016 to December 2020 using the United Network for Organ Sharing (UNOS) database. Patients were stratified into Era 1 or Era 2 based on the policy change on October 18, 2018. Multivariable Cox-proportional hazards models were constructed to assess differences in post-transplant survival, while competing risks regressions were used for waitlist death or deterioration. 

Results

A total of 8,902 heart transplants included in analysis, with a higher proportion of heart transplants being bridged with ECMO in Era 2 compared to Era 1 (Era 2: 6.1% vs Era 1: 1.2%, P < 0.001). Among those bridged with ECMO, Era 2 recipients had shorter waitlist times (5 vs 11 days, P<0.001) along with a lower likelihood of death or clinical deterioration on the waitlist (subhazard ratio:0.45, 95% confidence interval, CI:0.30–0.68, P<0.001) compared to Era 1. Bridging with ECMO in Era 1 was associated with an increased hazard of mortality at 1-year following transplantation (hazard ratio, HR 3.78, 95%:CI:1.88–7.61, P<0.001) compared to all other heart transplants. However, bridging with ECMO in Era 2 showed a similar hazard of mortality compared to the non-ECMO cohort.

Conclusions

Use of ECMO on the heart transplant waitlist is not associated with worse outcomes under the new allocation policy. These findings give further credence to the increased use of ECMO as a safe and effective bridging modality following the policy change.