Critical Care and Transplant Decision-Making in Acute and Acute-on-Chronic Liver Failure: A Scoping Review

Background Acute liver failure (ALF) and acute-on-chronic liver failure (ACLF) are distinct, rapidly progressive conditions associated with high short-term mortality. For selected patients, liver transplantation (LT) is the only definitive therapy that requires timely referral and expert multidisciplinary assessment. Objectives This scoping review synthesizes contemporary evidence guiding the decision between LT and conservative management in ALF and ACLF, focusing on prognostic models, clinical thresholds, futility criteria, ethical considerations, and emerging decision-support tools. Methods PRISMA-ScR guidelines were used to conduct this review. PubMed, Scopus, Web of Science, and Google Scholar were searched for English-language clinical trials, observational studies, guidelines, and reviews published through September 1, 2025 addressing LT decision-making, prognostication, or critical care in ALF and ACLF. Data were charted and thematically synthesized. Results In ALF, early referral to a transplant center is recommended. Prognostic tools such as King's College Criteria and the ALFSG Index assist risk stratification but must be interpreted alongside dynamic clinical assessments. In ACLF, early transplant evaluation is advised, particularly for grade 3 disease. Scores including CLIF-C ACLF, NACSELD-ACLF, and TAM inform mortality risk, while persistent hyperlactatemia (>9 mmol/L), vasopressor dependence (norepinephrine >1 μg/kg/min), and severe hypoxemia (PaO 2 /FiO 2 < 150 mm Hg) signal limited transplant benefit. Conservative management may suit patients with reversible precipitants or contraindications to LT. Post-transplant outcomes are generally favorable but depend on pre-transplant severity and frailty. Pregnant patients, children, and older adults require individualized decision-making, and marked racial, socioeconomic, and regional disparities in transplant access persist. Conclusion Prognostic scores in ALF reliably identify patients who will die without LT but not those who will recover, so referral to transplant centers should precede certainty. In ACLF-3, days 3–7 after stabilization are decisive. The same physiological thresholds should delay transplantation when reversible and deny it only when refractory; serial trajectory predicts outcome better than any single measurement.