Regional heterogeneity in the use of extracorporeal membrane oxygenation for heart transplant after 2018 allocation policy change

The 2018 heart transplant allocation policy has changed the profile of patients receiving heart transplant, with an increased use of acute mechanical support and decreased use of durable left ventricular assist devices. We investigated the use of extracorporeal membrane oxygenation (ECMO) use pre- and post-allocation change.

Methods

Using the UNOS database, we identified adult patients who underwent heart transplant from January, 2006 - June, 2022. The study time period was divided into pre- and post-allocation change. We divided ECMO patients by region and analyzed change in the rate of ECMO use by region between eras. Differences between groups and survival comparison were analyzed.

Results

A total of 41,636 recipients were found, of which 891 (2.1%) were on ECMO at the time of transplant. Overall ECMO use increased from 231 (0.8%) to 660 (5.5%) between eras (p<0.001). There was significant regional variation in the rate of ECMO usage (p<0.001) and significant differences in postoperative dialysis (p=0.014) and acute rejection episodes (p<0.001). There was no significant difference in pacemaker rate (p=0.172), stroke (p=0.212), treatment for rejection within 1 year (p=0.358), or post-transplant survival in the current era between regions for patients on ECMO at the time of transplant (p=0.444).

Conclusion

There is increased utilization of ECMO following implementation of an allocation system which prioritizes ECMO recipients on the waitlist and there is a differential increase in the use of ECMO in various regions. Further granular studies are needed to see which patients may benefit more from ECMO and what can be done to reduce post-transplant mortality from ECMO to transplant as it remains high before and after allocation change.