Are there any benefits of prolonged hypothermic oxygenated perfusion?: Results from a national retrospective study

Dual hypothermic oxygenated perfusion (DHOPE) is increasingly being used to extend liver preservation to improve transplant logistics. However, little is known about its benefits in high-risk liver grafts. This study aimed to investigate whether prolonged DHOPE provides benefits other than improved logistics in all liver types. We performed a national retrospective cohort study of 177 liver transplants from 12 Italian centers preserved with DHOPE for ≥4 hours between 2015 and 2022. A control group of 177 DHOPEs of <4 hours during the same period was created using 1:1 propensity score matching. The impact of risk profiles and preservation times on the outcomes was assessed using univariable and multivariable regression models. No significant differences in posttransplant outcomes were found between prolonged and short DHOPEs. However, the prolonged group had a significantly lower incidence of posttransplant acute kidney injury (AKI) compared to the short group (30.5% vs. 44.6%, p = 0.008). Among prolonged DHOPEs, no differences in transplant outcomes were observed according to donor risk index, Eurotransplant definition for marginal grafts, and balance of risk score. DHOPE duration was associated with a lower risk of AKI in multivariable models adjusted for donor risk index, Eutrotransplant marginal grafts, and balance of risk score. Prolonged hypothermic oxygenated perfusion confirmed its protective effect against AKI in a multivariable model adjusted for donor and recipient risk factors [OR: 0.412, 95% CI: 0.200-0.850, p = 0.016]. Prolonged DHOPE is widely used to improve transplant logistics, provides good results with high-risk grafts, and appears to be associated with a lower risk of posttransplant AKI. These results provide further insight into the important role of DHOPE in preventing posttransplant complications.