Introduction: Normothermic liver preservation (NMP) has become a clinical routine at several transplant centres. Reperfusion-syndrome occurs less often in recipients of NMP-livers compared to cold stored livers. We hypothesized that perfusate interleukin (IL)-6 during liver NMP correlate with recipient hemodynamics in the post-reperfusion period.

Method: Consecutive NMP-liver transplants at a single-centre were prospectively analysed. Perfusate samples were collected at 1 and 6 hours of NMP and at the end of perfusion and analysed for IL-6 levels. Median arterial pressure (MAP) and catecholamine need during surgery were recorded. The anhepatic phase was defined as baseline for MAP and catecholamine requirements.

Results: Over a period of 36 months, IL-6 perfusate measurements were assessed in 77 livers undergoing NMP and transplantation; 15/77 (19.5%) were DCD organs. The median donor age was 61 (15-87) years, median recipient age was 60 (19-73) years. Median (IQR) cold ischemia time was 6.2 (2.1) hrs, NMP-time and overall preservation time were 17.6 (10.4) hrs and 23.6 (10.6) hrs. Median (IQR) IL-6 levels (ng/L) after 1, 6 hrs and NMP-end were 52 (175), 278 (674) and 174 (2171). Neither duration of CIT nor NMP correlated with IL-6 levels over time. NMP-livers were stratified for the median of the last IL-6 measurement. Recipients receiving NMP-livers with perfusate IL-6 levels above the median developed significantly lower post-reperfusion MAP (dropping 20% from baseline) and displayed a significant higher demand of catecholamines (increase of 25% from baseline) up to 30 minutes after reperfusion. Perfusate IL-6 did not correlate with the occurrence of early allograft dysfunction.

Conclusion: Perfusate IL-6 levels during liver NMP are clinically relevant as they help to predict the post-reperfusion hemodynamics in recipients.