Abstract / Summary
Background: Thoracoabdominal normothermic regional perfusion (TA-NRP) and hypothermic machine perfusion (HMP) reduce ischemia-reperfusion injury after donation after circulatory death (DCD) kidney transplantation, but their combined effects remain unclear.
Methods: Adult DCD kidney-only recipients undergoing pretransplant dialysis in the OPTN registry (2020-2025) were stratified by TA-NRP and HMP. The primary outcome was delayed graft function (DGF). Multivariable logistic regression included a TA-NRP × HMP interaction and adjusted for recipient and donor factors. Death-censored graft survival (DCGS) was evaluated by Kaplan-Meier analysis.
Results: Among 3502 recipients, DGF differed by preservation strategy. In the non-TA-NRP cohort, HMP significantly reduced DGF compared with static cold storage (SCS) (44.2% vs 53.8%; p = 0.001) and remained independently protective (adjusted OR 0.56; 95% CI 0.44-0.71; p < 0.001). In the TA-NRP cohort, DGF rates were similar between HMP and SCS (26.7% vs 27.0%; p = 0.98), with no independent association after adjustment (adjusted OR 0.82; 95% CI 0.62-1.08; p = 0.16). A significant TA-NRP × HMP interaction was observed (p = 0.039). In the absence of HMP, TA-NRP was strongly protective against DGF (adjusted OR 0.30; 95% CI 0.22-0.42; p < 0.001). At 3 years, DCGS was 93.9% (95% CI 91.5-96.4) for TA-NRP-HMP, 94.3% (90.9-97.9) for TA-NRP-SCS, 93.5% (91.5-95.6) for non-TA-NRP-HMP, and 92.7% (89.1-96.6) for non-TA-NRP-SCS, with no difference between groups (log-rank p = 0.73).
Conclusion: TA-NRP was associated with lower DGF than conventional DCD procurement. Within the TA-NRP cohort, HMP was not associated with additional reductions in DGF. These findings should be interpreted in light of the surrogate definition used to identify TA-NRP in the OPTN registry and warrant prospective validation.