Discussion
Waitlisted candidates often face certain disparities when seeking a
donor heart for transplantation, both in organ availability and
posttransplant outcomes. The etiology of these disparities is
multifactorial, including blood type9, race and
socioeconomic factors10, and even geographic
features11. These disparities are likely driven and
compounded by the relative scarcity of available organs for
transplantation, as 3,500 OHTs were performed in the United States in
201912 but an additional 3,500 remain
waitlisted13. Furthermore, it is reasonable to suspect
that a candidate’s access to donor organs is also affected by their
transplanting center’s aggressiveness and likelihood to accept both
traditional donors and ECDs. The transplanting provider team may face an
interesting compromise during this selection process, balancing the
pressure of selecting the “best” possible donor for each recipient,
but also ensuring as many candidates are given the opportunity to
receive a transplant.
The shortage of available donor organs has led to an increase in
transplantation of donor organs outside of the standard criteria for
organ donation (i.e. ECDs) with acceptable outcomes noted in the lung,
kidney and liver transplant populations14–16.
However, despite progress in other areas of organ transplantation, the
outcomes following the utilization of ECDs in OHT have not been well
described17. There is wide variability in organ
acceptance practices at OHT centers across the United States and this
has been shown to impact waitlist survival with candidates listed at
centers with lower acceptance rates having higher waitlist
mortality18. This variability demonstrates that the
acceptability of certain organs is not well established, and while one
center may accept the organ for OHT, another may reject, further
reducing the potential donor pool. In fact, over 50% of donor hearts
offered in the United States are rejected for OHT19.
Donor hearts with unclear acceptability patterns tend to be outside of
the traditionally accepted donor criteria but may still be potentially
suitable for transplantation3. Furthermore,
considering that centers with more aggressive donor acceptance rates
have been shown to have superior post-OHT outcomes when compared to
centers with lower volumes20, uncertainty exists as to
if there is a volume-relationship between the use of ECDs in OHT and if
an association exists between ECD recipient’s outcomes. This study aims
to address these remaining questions.
This analysis highlights several interesting findings. First and less
surprising, aggressive transplanting centers are more frequently
utilizing donors with extended-criteria features. However, long-term
results for these centers does not seem to be negatively impacted in
comparison to centers with less frequent ECD usage. Second, in
candidates who receive donation from a donor with extended-criteria
features, long-term outcomes do not appear to be influenced by the
aggressiveness and relative volume of the transplanting center. Lastly,
in comparison to recipients of traditional criteria organs, recipients
of ECD organs did not demonstrate any differences in overall survival in
four of the five extended-criteria factors. Only donor age
>40 years was found to have increased hazards for
posttransplant mortality.