T. J. Janas1, B. T. Ho2, A. Desai2, D. P. Ladner3, V. S. Rohan3, Z. C. Dietch3 1Northwestern University, Weinberg College Of Arts And Sciences, Chicago, IL, USA 2Feinberg School Of Medicine – Northwestern University, Division Of Nephrology, Department Of Medicine, Chicago, IL, USA 3Feinberg School Of Medicine – Northwestern University, Division Of Transplantation, Department Of Surgery, Chicago, IL, USA
Introduction: Organ donation after circulatory death (DCD) occurs after withdrawal of life support (WLST). Donor warm ischemia time (WIT) is a period after WLST and before organs are flushed with preservation solution during which organs suffer ischemic injury. Although thresholds for tolerable WIT determine whether a kidney is utilized for transplant, there is wide variability in how transplant centers define WIT and little data to predict organ viability or performance as a function of WIT. We performed a scoping review to assess reported measures of WIT and graft function after DCD.
Methods: We adhered to PRISMA Extension for Scoping Reviews guidelines to conduct this review. A search strategy that included both MeSH terms and keywords was used to search PubMed July 2023. Inclusion and exclusion criteria were established by two independent reviewers. Inclusion criteria were English-language studies that defined WIT in DCD kidney donation. Animal studies, studies limited to uncontrolled DCD, and studies evaluating normothermic regional perfusion were excluded. The measures of WIT cited in eligible studies were identified. If cited, the associations of WIT and outcomes of DCD kidneys were recorded.
Results: We identified 99 studies published between 2002 and 2022, of which eight satisfied criteria for inclusion. Six of eight published studies were from the USA. Five distinct measures of tolerable WIT were identified from eight studies. The most common measure of WIT in DCD kidney utilized was the interval between WLST to organ flush with preservation solution (n=4). Other measures included: hypotension or hypoxia (SBP<50mmHg or SpO2<90%) to declaration of death (n=1), hypotension or hypoxia (SBP<60mmHg or SpO2<60%) to organ flush (n=1), hypotension (SBP<50mmHg) to organ flush (n=1), and circulatory arrest to organ flush (n=1). Three of eight studies discussed the effect of WIT transplant outcomes and reported that WIT did not influence long-term outcomes. However, more than 40% of DCD kidneys experienced delayed graft function.
Conclusion: This review identified wide variability in measures currently used to define tolerable WIT in DCD kidney donation and limited data that links measures of WIT to organ viability or kidney function after transplant. Enhanced parameters to assess tolerable ischemic injury in DCD may allow for the expanded use of kidneys for transplantation, improve prediction of kidney function after transplant, and avoid unnecessary discard of potentially transplantable organs.
