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.