Accuracy of an age-adjusted formula in assessing the graft volume in living donor liver transplantation.

In living donor liver transplantation, the estimated graft volume (GV) from young donors tends to be overestimated. One reason for this error may be a decrease in GV due to dehydration by University of Wisconsin (UW) solution. The aim of this study was to clarify (1) the usefulness of an age-adjusted formula and (2) the correlation between the decrease in GV and donor age. First, we created the age-adjusted formula using regression analysis retrospectively in 167 donors, and we evaluated the difference in the error ratio of GV from the age-adjusted formula and 3-dimensional computed tomography (3D-CT) prospectively in 49 donors. Second, we measured intraoperative GV both before and after flushing with UW solution and calculated the decrease ratio, and we then evaluated the difference in the decrease ratio between young donors and older donors prospectively in 41 donors. The age-adjusted formula was created as follows: age-adjusted GV = 70.767 + (0.703 x GV estimated with 3D-CT volumetry) + (1.298 x donor age). The mean error ratio for the age-adjusted formula (9.6%) was significantly lower than that from 3D-CT (14.0%). The mean decrease ratio in all 41 donors was 5.4%, and that in young donors (6.9%) was significantly higher than that in older donors (4.4%). In conclusion, although younger donor age is a major factor for estimation errors in hepatic volumetry, our age-adjusted formula is very useful in reducing the error in estimating GV.