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Updated: Jun 29, 2026
Orthotopic Liver Transplantation in Rats
Published on: July 1, 2012
Out-of-Sequence Allocation in Liver Transplantation: A Poorly Used Tool to Improve Organ Utilization
Chase J Wehrle1, Abby Gross1, Sangeeta Satish1
1Transplant Research Center, Cleveland Clinic Foundation, Cleveland, OH.
Significance:
We evaluated the impact of out-of-sequence (OOS) on organ utilization and also what factors impact the decision to employ OOS.
Background:
Deceased donor liver allocation typically follows a ranked match-run of potential recipients. Organ procurement organizations (OPOs) may deviate from liver transplant standardized allocation using OOS matches.
Methods:
All eligible donors from the Scientific Registry of Transplant Recipients (SRTR) (January 1, 2013-August 31, 2023) were identified and merged with associated match runs in the Potential Transplant Recipient (PTR) data. OOS offers were defined as bypass codes (861-863; 760-765). Hierarchical mixed-effects models with eligible donors nested in OPOs assessed OOS practices versus organ utilization, controlling for liver graft risk with the Discard Risk Index (DSRI) by risk quintile, blood type, and year.
Results:
OOS were more common each progressive year. Neither TC's ( R2 <0.01) nor OPO's ( R2 <0.01) OOS rate correlated with increased utilization. OOS was not associated with improved utilization (OR=1.11, 95% CI=0.90-1.38). Increasing graft risk in DBD&DCD grafts was associated with reduced utilization. Introducing OOS-allocation interaction terms improved utilization for DCDs of all risk levels, but only improved utilization for DSRI 5th-quintile DBDs. Thirty-eight percent of utilization was explained by graft factors versus 5% by TC-&OPO-variability (Conditional- R2 =0.431, Marginal- R2 =0.380). High-risk DCD grafts in DSRI 3rd to 5th quintiles were not more likely to be allocated through OOS despite these grafts demonstrating improved utilization with this approach. Only 15% of variation in OOS-allocation was explained by graft factors versus 23% by TC and OPO variability (Conditional R2 =0.388, Marginal R2 =0.154).
Conclusions:
OOS improves utilization in high-risk grafts, but graft risk is not correlated with their actual use. This highlights the utility of OOS, but also that this practice is currently incorrectly used.
