Definition of ACLF and inclusion criteria for extra-hepatic organ failure.

A prominent characteristic of ACLF is rapid hepatic disease progression with subsequent extra-hepatic organ failure, manifesting as either hepatic coma or hepatorenal syndrome, which is associated with a high mortality rate in a short time. The APASL definition mainly emphasizes recognizing patients with hepatic failure. These patients may subsequently develop extra-hepatic multisystem organ failure leading to high mortality. It is therefore worthwhile to identify the short interim period between the development of liver failure and the onset of extra-hepatic organ failure, the potential therapeutic 'golden window.' Interventions during this period may prevent the development of complications and eventually change the course of the illness. Organ failure is suggested to be a central component of ACLF and may behave differently from chronic decompensated liver disease. Clear and practical criteria for the inclusion of organ failure are urgently needed so that patients with these life-threatening complications can be treated in a timely and appropriate manner. Recent studies suggested that the scoring systems evaluating organ failure [acute physiology, age and chronic health evaluation (APACHE) and sequential organ failure assessment (SOFA) scores] work better than those addressing the severity of liver disease [Child-Pugh and model of end-stage liver disease (MELD) scores] in ACLF. However, a key problem remains that the former scoring systems are reflective of organ failure and not predictive, thus limiting their value as an early indication for intervention.