Abstract
A proportion of patients hospitalized for an acute complication of cirrhosis are at high risk of short-term death. The term Acute-on-Chronic Liver Failure (ACLF) is used to characterize these patients. Until recently there was no evidence-based definition of ACLF. In 2013 a definition has been proposed based on results of a large prospective observational European study, called "European Association for the Study of the Liver (EASL)-Chronic Liver Failure (CLIF) Consortium Acute-on-Chronic Liver Failure in Cirrhosis (CANONIC)" study. Results of this study led to elaborate new concepts about ACLF. First, it was found that ACLF is a syndrome that is distinct from mere decompensated cirrhosis. It was also shown that ACLF is a dynamic syndrome which can improve or conversely worsen. Patients who worsen die rapidly from multiorgan failures. The CANONIC study also found that identifiable precipitating events (e.g., bacterial infection, active alcoholism) are found in only 50% of cases of ACLF indicating that these events are dispensable for defining ACLF. In addition precipitating events may be initiators of ACLF but do not drive the outcome. An important concept derived from the CANONIC study is that ACLF is associated with systemic inflammation even in patients who do not have identifiable precipitating events. Finally it was found that ACLF may develop in patients without prior episodes of decompensation or in those with recent decompensation (<3 months). Moreover these patients with "early" ACLF were more severe than patients who developed ACLF after a long of history of decompensated cirrhosis.