In order to better assess the quality of the liver, in this review we focus on some liver-specific donor risk indices. LIVER STEATOSIS IS strongly associated with poor graft function after LT. The impact of severe steatosis on allograft survival appears greater than other donor factors, including MG-132 mw the calculated DRI.[1] Moreover, clinicopathological studies have demonstrated an inverse correlation between steatosis and graft survival.[9] Steatosis is typically characterized qualitatively and quantitatively. Fatty infiltration is separated into two categories, macrosteatosis and microsteatosis. Macrosteatosis is characterized by a single, bulky fat vacuole

in hepatocytes, displacing the

nucleus to the edge of the cell. In microsteatosis, the cytoplasm of the hepatocytes contains tiny lipid vesicles without nuclear dislocation. Microsteatosis seems SB203580 molecular weight to have a low impact on the postoperative liver function. Macrosteatosis and microsteatosis most often present simultaneously at different degrees in the liver.[10] The quantitative evaluation is traditionally based on percentages of visualized hepatocytes containing fat vacuoles within the cytoplasm, classified as mild (<30%), moderate (30–60%) or severe (>60%).[11-13] Livers with more than 40–50% macrosteatosis should not be used.[14] In all such Rolziracetam cases, the procurement surgeon has to make the definitive decision. A percutaneous liver biopsy performed at the bedside, before organ procurement, may help prevent unnecessary donor laparotomy. In addition, livers with severe steatosis from donation after

cardiac death donors, combined with a prolonged cold ischemic time have a high risk for developing early allograft dysfunction which is correlated with shorter graft survival. Therefore, severe steatosis livers should only be considered for LT in selected recipients without the presence of additional risk factors.[15] Although hepatic steatosis is a widely accepted risk factor for postoperative complications after LT, studies have been inconsistent regarding the relevant amount of fat or type of fat. All those observations lead to controversies in the field. Some studies showed that liver grafts containing moderate degrees of microsteatosis significantly increase the rate of organ failure after LT,[16] while other groups recommended the use of microsteatotic grafts, regardless of the total amount, to safely expand the donor pool.[17] The main reason for the inconsistent outcome is the estimation of steatosis using frozen section liver biopsy which is both difficult and subjective.[18, 19] Quantification of hepatic steatosis in histological sections is strongly observer-dependent, not reproducible. El-Badry et al.