Preoperative estimation of operative risk in liver surgery, with special reference to functional reserve of the remnant liver following major hepatic resection.

Hepatic functional reserve was evaluated in 76 patients with known liver, biliary tract or pancreas diseases using kinetic analysis of removal of indocyanine green (ICG) with special reference to maximal removal rate (Rmax). In surgery other than hepatectomy, if ICG Rmax is below 0.4 mg/kg/min the operative risk should be considered high. In hepatic surgery, even if ICG Rmax is above 0.4 mg/kg/min the operative risk was high and it should be required to be above 1.0 mg/kg/min for extended lobectomy or hepatectomy. Furthermore, prior to hepatectomy the functional reserve of the remnant liver was estimated from an effective liver volume rate, calculated from the rate of uptake of radioisotope as measured by on-line computer system, and ICG Rmax. The functional reserve of the remnant liver was compared with the operative results, such as morbidity or mortality for each patient. When ICG Rmax of the remnant liver was below 0.4 mg/kg/min the prognosis was poor in hepatic surgery, because of there were three postoperative death and seven complications such as ascites or liver failure in the ten cases. On the other hand, when above 0.4 mg/kg/min, the prognosis was good without any postoperative death or complications in the twelve cases of hepatic surgery, as the completely same results for general surgery, in which it is as well when ICG Rmax of whole liver is above 0.4 mg/kg/min.