Clinical implication of hepatic volumetry for living donor liver transplantation

Liver transplantation is indicated for primary and salvage treatment of hepatic malignancies including hepatocellular carcinoma (HCC) and hepatic epithelioid hemangioendothelioma, end-stage liver diseases, acute liver failure, and congenital anatomical and metabolic liver diseases such as biliary atresia, Wilson’s disease and hemochromatosis. Living donor liver transplantation (LDLT) is more widely practiced in many Asian countries, rather than in Europe and the US, due to shortage of donors who have suffered brain death. In Korea, 75.4% of LT by 2016 was LDLT. Pre-operative hepatic volumetry by using multi-detector row computed tomography (CT) or magnetic resonance imaging (MRI) is one of the most important step during the planning of LDLT because hepatic reservoir after surgery could be estimated by the hepatic volumetry, which is an important factor for donor’s and recipient’s recovery after surgery. If the graft size is too small, and mismatched compared with the recipient’s size, it is called as “small-for-size-graft (SFSG)”. In that situation, even the small graft could be well adapted, but some recipient could have symptoms related to the graft size. SFSG dysfunction was defined as ‘dysfunction of a small partial liver graft during the first postoperative week after the exclusion of other causes’. It means that the transplanted partial liver cannot satisfy metabolic demand of the recipient or can be prone to congest by excessive portal inflow before regeneration of the graft, and results in irreversible graft failure and death of the patient if there is no available organ for re-transplantation. In the general setting of LDLT, the graft volume of less than 40–50% of standardized liver volume (SLV), corresponding to a graft to recipient weight ratio (GRWR) of 0.8–1.0% could be associated with worse outcome. The mechanism of SFSG syndrome is not clear. It could be related to the shortage of parenchymal cell mass required to metabolize, and persistent elevation of portal venous pressure which causes hyperperfusion graft injury. SFSG get the entire volume of portal flow, and lead to higher portal pressure due to increased portal resistance. Moreover, as the cirrhotic recipients demonstrate higher portal flow than normal subjects, this recipients’ hemodynamics See Article on Page 54 Clinical implication of hepatic volumetry for living donor liver transplantation