The Safe Minimally Ischemic Liver Remnant for Small-for-Size Syndrome in Porcine Hepatectomy

Abstract

BackgroundThe minimal functional remnant liver mass or graft after an ischemic injury in hepatectomy or living donor liver transplantation (LDLT) is not clear. This study sought to determine the minimal remnant liver (MRL) size after 20 minutes hepatic inflow occlusion (HIO) and the maximal portal flow with which the liver remnant can sustain in a porcine model. MethodsTwenty pigs that underwent massive hepatectomy were randomly divided into 3 groups: 30% group, the remnant constituted about 30% of total liver volume (TLV); 35%+O group, the remnant constitute about 35% of TLV with 20 minutes HIO, and 30%+O group, the remnant constituted about 30% of TLV with 20 minutes of HIO. We evaluated survival rates, kinetic portal vein pressures (PVP), hemodynamics, hepatocyte metabolism, and injury. ResultsThe 14-day survival rate in the 30%+O group was significantly reduced compared with that of either the 30% group or the 35%+O group: l00% versus 28.6% versus 85.7% respectively (P = .009). The tissue, serum analyses, and PVP in the 30%+O group were significantly different compared with the measurements among the other groups (P < .05), revealing that the liver remnant in 30%+O group could not sustain more than 3 times baseline portal flow, whereas in 35%+O group it could sustain 2.8 times baseline portal flow. ConclusionsIntraoperative ischemia can injure the sinusoidal endothelium, decreasing its ability to regulate portal hyperperfusion, causing less than 30% to 35% of TLV to show small-for-size syndrome or postoperative liver failure.