AIM: To evaluate treatment safety and hemodynamic changes during a single 6-h treatment with the Prometheus? liver assist system in a randomized, controlled study. METHODS: Twenty-four patients were randomized to either the study group or to one of two control groups: Fractionated Plasma Separation Adsorption and Dialysis, Prometheus? system (Study group; n = 8); Molecular Adsorbent Recirculation System (MARS)? (Control group 1, n = 8); or hemodialysis (Control group 2; n = 8). All patients included in the study had decompensated cirrhosis at the time of the inclusion into the study. Circulatory changes were monitored with a Swan-Ganz catheter and bilirubin and creatinine were monitored as measures of protein-bound and water-soluble toxins. RESULTS: Systemic hemodynamics did not differ between treatment and control groups apart from an increase in arterial pressure in the MARS group (P = 0.008). No adverse effects were observed in any of the groups. Creatinine levels significantly decreased in the MARS group (P = 0.03) and hemodialysis group (P = 0.04). Platelet count deceased in the Prometheus group (P = 0.04).CONCLUSION: Extra-corporal liver support with Prometheus is proven to be safe in patients with end- stage liver disease but does not exert the beneficial effects on arterial pressure as seen in the MARS group. AIM: To evaluate treatment safety and hemodynamic changes during a single 6-h treatment with the Prometheus? Liver assist system in a randomized, controlled study. METHODS: Twenty-four patients were randomized to either the study group or to one of two control groups : Fractionated Plasma Separation Adsorption and Dialysis, Prometheus® system (Study group; n = 8); Molecular Adsorbent Recirculation System (MARS )® (Control group 1, n = 8); or hemodialysis (Control group 2; n = 8). All patients included in the study had decompensated cirrhosis at the time of the inclusion into the study. Circulatory changes were monitored with a Swan-Ganz catheter and bilirubin and creatinine were monitored as measures of protein-bound and water-soluble toxins. RESULTS: Systemic hemodynamics did not differ between treatment and control groups apart from an increase in arterial pressure in the MARS group (P = 0.008). No adverse effects were observed in any of the groups. Creatinine levels significantly decr Platelet count deceased in the Prometheus group (P = 0.04). CONCLUSION: Extra-corporal liver support with Prometheus is proven to be safe to patients with end - stage liver disease but does not exert the beneficial effects on arterial pressure as seen in the MARS group.