Validating graft and standard liver size predictions in right liver living donor liver transplantation

Abstract

A formula was derived from 159 living liver donors to estimate the liver size of a normal subject in our previous study. Standard liver weight (g) = 218 + body weight (kg) x 12.3 + 51 (if male). The standard liver volume (SLV) is attained by a conversion factor of 1.19 mL/g. In order to assess the accuracy of this formula, the total liver volume (TLV) of each of the subsequent consecutive 126 living liver donors was determined using the right liver graft weight (RGW) on the back-table, right/left liver volume ratio on computed tomography, and the conversion factor. The estimated right liver graft weight (ERGW) of each donor was determined by the right liver volume on computed tomography and the conversion factor. The SLV and ERGW were compared with the TLV and RGW respectively for each donor by paired sample t-test. The donor characteristics of both series were similar. The SLV and TLV were 1,099.6 ± 139.6 mL and 1,108.5 ± 175.2 mL, respectively (p = 0.435) (R2 = 0.476). The difference between the SLV and TLV was only -8.9 ± 128.2 mL (-1.0 ± 11.7%). The ERGW and RGW were 601.5 ± 104.1 g and 597.1 ± 102.2 g, respectively (p = 0.332) (R2 = 0.781). The conversion factor from liver weight to volume for this series was 1.20 mL/g. The difference between the ERGW and RGW was 4.3 ± 49.8 g (0.3 ± 8.8%). The ERGW was smaller than the RGW for over 10% (range 0.21 to 40.66 g) in only 18 of these 126 right liver donors. None had underestimation of the RGW by over 20%. Standard liver size and graft weight estimations were accurate using the formula and conversion factor.