Significant Decrease in Dialysate Albumin Concentration during Molecular Adsorbent Recirculating System (M.A.R.S.) Therapy

Abstract

The molecular adsorbent recirculating system (M.A.R.S.) is widely used as liver support therapy in patients with hepatic dysfunction. The goal of this study was to measure changes in dialysate albumin and bilirubin concentrations during clinical MARS treatments. Eight patients with acute liver dysfunction and hyperbilirubinemia were enrolled in this study. Five of them received a total of 10 treatments with MARS, in which 600 mL of 20% human albumin was used as dialysate, continuously regenerated by two adsorbent columns in the circuit. Three patients received 4 treatments of a modified MARS, in which the two adsorbent columns were bypassed in the first course for 4 h, and then connected to the circuit in the second course for another 4 h. The total, conjugated and unconjugated bilirubin (TB, CB, UCB) and albumin concentrations in serum and albumin dialysate were dynamically measured, and the adsorbent column inlet pressures were recorded during each session. In one session, dialysate albumin levels were measured during the priming process, at the time points prior to the priming process, immediately after priming, and at the end of the treatment. During MARS therapies, the reduction ratio of serum TB, CB and UCB was 26.6+/-9.0%, 29.5+/-9.6% and 14.8+/-12.3%, respectively. The molar ratio of TB/albumin in serum was approximately 20-fold higher than dialysate at all time points. A significant albumin concentration decrease from baseline in the dialysate was found (mean+/-SD, 34.6+/-16.6%). For the first four hours of modified treatments, in which only albumin dialysis without albumin regeneration by adsorbent columns was performed, the dialysate albumin decrease was substantially smaller (mean, 8.3+/-1.5%). After switching to standard MARS, there was a further decrease in the dialysate albumin concentration of 35.1+/-14.5%. In one session, dialysate albumin concentrations were measured during the priming process, and levels decreased from 196.9 g/L to 144.4 g/L. Adsorber inlet pressure increased from 40+/-10 mmHg at the start of priming to 150+/-50 mmHg at the end of priming, and further increased to 340+/-100 mmHg at the end of treatment. There is a significant reduction in dialysate albumin concentration during MARS therapy. Binding of albumin to the adsorbent columns used for albumin regeneration is largely responsible for this decrease.