How I do it: assessment of hepatic functional reserve for indication of hepatic resection

Liver resection of up to 75% of the total liver volume (TLV) has been regarded as safe in normal livers, but this concept was challenged by the results of living donor hepatectomies. In normal livers or livers with resolved jaundice, hepatectomy of 65% of TLV may be safe, except for patients with an indocyanine green retention rate at 15 min (ICG R15) of over 15%, excessive hepatic steatosis, and age of over 70 years. However, the permissible extent of hepatectomy has been much restricted in cirrhotic livers because most post‐hepatectomy liver failure (PHLF) has occurred in cirrhotic livers. Our routine protocols for the assessment of functional hepatic reserve (FHR) include biochemical liver function tests, ICG R15, Doppler ultrasonography, and triphasic liver computed tomogram (CT) with volumetry. Blood cell count and gastroesophageal endoscopic findings are taken into consideration for cirrhotic livers, as well as age, diabetes, cardiopulmonary function, and general performance. Preoperative portal vein embolization has been used for safe hepatectomy even in cirrhotic livers. We think that any cirrhotic liver showing optimal FHR should have a remnant liver of 40% of TLV to prevent PHLF. ICG R15 and triphasic CT with volumetry have been the most useful methods for assessment of FHR and determination of hepatecomy extent in our institution.