Ratio of branched chain amino acid to tyrosine after hepatectomy.

The roles of branched chain amino acids (BCAAs) and the tyrosine (Tyr) profile after liver resection were investigated using an inexpensive enzymatic method that was recently developed to quantify their concentrations. The preoperative BCAAs-to-Tyr ratio (BTR) was significantly correlated with the preoperative indocyanin green clearance ratio. The BTR decreased immediately after surgery in all patients, but it was significantly lower in those who had undergone major hepatectomies. After the infusion of BCAA-enriched amino acid solution, the BTR increased substantially, being significantly higher in patients who had not suffered an elevation in total bilirubin after liver resection. These findings indicate that this new enzymatic method to quantify the concentration of BCAAs and Tyr is useful to control the infusion of amino acids and to study the role of amino acid metabolization during the perioperative period.