Liver Function Assessment Before and After Hepatic Resection

• The main goals of liver function assessment before and after hepatic resection are ultimately prevention and early detection of postoperative liver failure (PLF).

• The minimal required volume of remnant liver parenchyma after resection is proportional to severity of parenchyma injury. Thus, both liver volumes and function tests should be assessed preoperatively.

• The estimate of remaining liver volume is usually enough to predict the risk of PLF in patients without underlying chronic liver disease. However, adequate evaluation of hepatic function in the presence of chronic underlying liver disease (i.e. cirrhosis,chronic hepatitis, chemotherapy associated liver injury, etc.) is complex. Most available tests evaluate only one or few of the multiple liver functions and rarely take into account regional variations of underlying disease severity.

• Clinical scores, such as the Child-Turcotte system and Model for End-Stage Liver Disease (MELD), combine several biochemical and clinical parameters and have variable ability to predict PLF. Indocyanine green retention test (a dynamic quantitative test) is among the most commonly used tests in the Orient, and it is incorporated in a commonly used algorithm in Japan. Molecular nuclear imaging techniques, such as 99mTC-labeled galactosyl human serum albumin (GSA) scintigraphy, have been used pre- and postoperatively to estimate functional hepatocyte volume. Associated CT images can provide functional evaluation of each hepatic region.

• Transient liver dysfunction is expected after partial hepatectomy, but severe liver function tests deterioration and/or delayed recovery should raise concern for PLF.