Interleukin 6 at reperfusion: A potent predictor of hepatic and extrahepatic early complications after liver transplantation

Background and aims: Ischemia-reperfusion injury impacts early liver graft function. Interleukin 6 (IL-6) as early as at reperfusion has shown to predict in-hospital complications, but its impact on vascular complications and long-term outcomes is not ascertained. Methods: A retrospective study was conducted on all consecutive patients transplanted during a 6-year period to define significant early systemic inflammatory response (ESIR). The main end-point was 3-year graft survival. Significant ESIR was defined according to IL-6 level at reperfusion on an exploratory set of 121 patients and validated on an independent cohort (n = 153). Results: Significant ESIR was defined as IL-6 at reperfusion >1000 ng/mL in the exploratory cohort. Three-year graft and overall survival were lower in patients with ESIR in the determination set (P = 0.001 and 0.045, respectively). This was confirmed in the validation set (P = 0.045 and 0.027). In patients with high cytolysis, IL-6 identified patients at risk for arterial thrombosis. The main determinants for IL-6 level were intragraft lactate level, cold ischemia time, and anhepatic phase duration (P = 0.005). IL-6 level independently predicted graft survival (P = 0.0003). Conclusions: IL-6 at reperfusion is a valid biomarker to predict long-term survival. Furthermore, it helps the interpretation of cytolysis in the prediction of early vascular complications.