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ET-DRI

Eurotransplant Donor Risk Index
A modification of the original Donor Risk Index (Feng 2006) validated specifically in the Eurotransplant population. Incorporates donor age, cause of death, graft type, DCD status, and cold ischaemia time.
Liver Transplantation Eurotransplant Donor Assessment Hepatology
ET-DRI Calculator
Cause of Death

ET-DRI Formula

ET-DRI = exp[0.997 × ln(donor age)
+ 0.087 × (cerebrovascular cause)
+ 0.176 × (split liver)
+ 0.126 × (DCD)
+ 0.066 × ln(CIT in hours)]

Variables donor age and CIT are continuous and entered as natural logarithms. Unlike the original DRI, ET-DRI uses logarithmic rather than categorical age tiers, giving a graded rather than stepwise effect of age. If CIT = 0, a minimum value of 1 hour is used for the ln calculation. The ET-DRI scale is relative — higher values indicate greater graft failure risk compared to a reference graft.

Comparison: DRI vs ET-DRI

FeatureDRI (Feng 2006)ET-DRI (Blok/Braat 2012)
Donor ageCategorical tiers (<40, 40–49, etc.)Continuous ln(age)
Share statusLocal / regional / nationalNot included
Validated populationUNOS database (USA)Eurotransplant (8 countries)
Cause of deathTrauma / stroke / anoxia / otherCerebrovascular vs non-cerebrovascular
Graft typeWhole / splitWhole / split
CITLinear (0.010 per hour)Logarithmic (0.066 × ln[CIT])

Interpretation

ET-DRIRiskRecommendation
<1.5LowSuitable for all recipients — accept offer
1.5–2.0ModerateCombine with recipient risk assessment (SOFT score / BAR score) before accepting
>2.0HighExtended criteria donor — restrict to low-risk recipients; consider machine perfusion

Clinical Application

  • ET-DRI was derived from 5,765 liver transplants performed within the Eurotransplant system (Germany, Austria, Netherlands, Belgium, Luxembourg, Slovenia, Croatia, Hungary) between 2006 and 2011
  • Showed superior discrimination compared to the original DRI when applied to European cohorts, validating the need for population-specific recalibration of risk indices
  • The continuous age coefficient in ET-DRI means donor age has a graded effect — a 65-year-old donor carries meaningfully more risk than a 60-year-old, unlike in DRI where both fall in the same categorical tier
  • Share status (local vs regional vs national) was not predictive in the Eurotransplant population and was excluded — reflecting the more centralised European allocation system compared to the US
  • Used alongside the balance of risk (BAR) score and recipient SOFT score for complete donor-recipient matching in Eurotransplant centres
  • Machine perfusion (hypothermic oxygenated perfusion — HOPE, or normothermic machine perfusion — NMP) has been shown to improve outcomes in high ET-DRI grafts, particularly DCD livers
  • ET-DRI does not capture warm ischaemia time in DCD donors — this must be assessed separately as a critical determinant of ischaemic cholangiopathy risk

References

  1. Blok JJ, et al. Validation of the Eurotransplant donor risk index in liver transplantation within the Eurotransplant region. Am J Transplant. 2012;12(Suppl 4):S138.
  2. Braat AE, et al. The Eurotransplant donor risk index in liver transplantation: ET-DRI. Am J Transplant. 2012;12(10):2789–2796.

Related Calculators

Donor Risk Index (DRI) BAR Score SOFT Score