An Ocean Apart: Liver Donation After Medical Assistance in Dying in Canada and the Netherlands

We thank Parente et al1 for their thoughtful commentary on our article and congratulate them on their excellent study of outcomes of livers donated after medical assistance in dying (DCD-V) in Canada, which was published after acceptance of our systematic review.2 Their findings demonstrate comparable graft and patient survival after donation after circulatory death (DCD)-V liver transplantation relative to controlled DCD-III, despite a markedly higher donor age, nearly 20 y older, and a recipient population with significantly poorer pretransplant clinical status, including higher rates of hospitalization, intensive care unit admission, and dialysis dependence. Notably, the incidence of early allograft dysfunction was lower in the DCD-V cohort and consistent with rates reported in the Dutch/Belgian study by van Reeven et al.3 However, biliary complications, including ischemic cholangiopathy and anastomotic strictures, were more frequent in the Canadian DCD-V cohort. As 95% of grafts in this study did not undergo (dual) hypothermic oxygenated machine perfusion ((D)HOPE), this likely contributed to the observed incidence of ischemic cholangiopathy. (D)HOPE has been shown to reduce biliary complications4 and has been standard practice in DCD liver preservation in the Netherlands since 2022. The absence of (D)HOPE, in combination with higher donor age, may therefore explain these findings. Interestingly, the Canadian cohort demonstrated a higher graft survival compared with the Dutch/Belgian experience.3 Five-year graft survival reached 83.3% in Canada,1 compared with 57% in the Netherlands and Belgium,3 despite broadly comparable donor and recipient characteristics. This difference supports our hypothesis that variation in euthanasia protocols may influence graft quality. In particular, the use of thiopental in the Netherlands, as opposed to propofol in Canada, may contribute to graft injury through mechanisms such as oxidative stress related to hydroxyl radical formation. Although this remains speculative, it could partially explain the inferior graft outcomes observed in the Dutch/Belgian DCD-V cohort. Consequently, DCD-V grafts in the Netherlands are currently classified as extended criteria organs and require pretransplant viability assessment, either during normothermic regional perfusion in the donor or ex situ normothermic machine perfusion. The favorable Canadian outcomes are therefore highly relevant for informing future recommendations on DCD-V pharmacological protocols and may help reduce the need for routine viability testing. Additional factors, such as immunosuppression strategies and center differences, may also account for the large difference in 5-y survival. Another notable difference lies in the impact of DCD-V on transplant activity. In Canada, liver transplant activity increased by 21.8%, compared with 7% in the Netherlands and Belgium.1,3 Currently, approximately 10% of deceased donors in the Netherlands are DCD-V donors.5 These differences may reflect divergent clinical approaches: in the Netherlands, physicians are not allowed to proactively discuss with eligible patients organ donation, whereas in Canada, clinicians are encouraged to discuss this option, with referral to an organ donation coordinator when interest is expressed.6 In conclusion, important differences in DCD-V practice exist between Canada and the Netherlands, which may underlie the observed variation in liver transplant outcomes. Further data from other countries and direct comparative analyses are needed to optimize DCD-V liver transplantation practices.