Beyond the body surface area vauthey formula to identify the minimal donor volume for right-lobe living-donor liver transplantation

Abstract

Several studies have reported on the preoperative assessment of liver function as a predictor of postresection liver failure. Recently, the impact of volumetric data on the outcome of liver resections and, in particular, graft function in living-donor liver transplantation1 has been emphasized. The majority of Western centers involved in adult-to-adult living-related liver transplantation have adopted the Vauthey formula to calculate liver volumes, including the minimal donor volume. This formula, published by Vauthey et al.2 zref validated in a meta-analysis as a precise and unbiased approach to estimating the total liver volume, was derived from linear regression by calculation of the total liver volume based on the body surface area (BSA) in a total of 292 patients in centers in the United States and Europe. This formula is considered more reliable than the Urata formula, which has been found to have limitations in Western patients because of autopsy findings indicating that liver weight in Japanese adults is lower than that in European and American adults.4 With this BSA Vauthey formula [total liver volume (cm3) = −794.41 + 1267.28 × BSA (m2)], it is possible to identify a minimal donor volume sufficient for avoiding postresection liver failure. In our experience with 75 right hepatectomies (Couinaud segments 5–8) performed for adult-to-adult living-related liver transplantation, in 21 (28%) cases, we used the donor's right lobe, even though the minimal donor volume according to the BSA Vauthey formula was higher than the real left-lobe volume calculated with a computed tomography (CT) scan. In those 21 patients, the difference between the minimal donor volume identified by the BSA Vauthey formula and the CT scan–calculated left-lobe volume ranged from 14.57 to 134.29 cm3 (median, 64.33 cm3). This difference was below 50 cm3 in 8 patients, between 51 and 100 cm3 in 8 patients, and above 101 cm3 in 5 patients. The 75 donors, who were completely homogeneous for gender and age, were divided into 2 groups: A (minimal donor volume according to the BSA Vauthey formula) and B (minimal donor volume below the cutoff in the BSA Vauthey formula), and potential differences were analyzed. Comparing group A with group B, we found no statistically significant difference in the total length of stay (P = 0.635) or onset of surgical complications (occurring within 90 days of surgery and stratified according to the most recent version of the Clavien classification of postoperative surgical complications; P = 0.132). There was no mortality in either group The trends of the total serum bilirubin, international normalized ratio, and transaminases (alanine aminotransferase/aspartate aminotransferase) were examined in a further analysis during the first postoperative week in groups A and B. Those liver function tests showed no statistically significant differences in the 2 groups (P > 0.05), with the peak on postoperative day 3 and normalization on postoperative day 7. Right-lobe living donation can be safely accomplished when the difference between the minimal donor volume identified by the BSA Vauthey formula and the real remnant volume calculated by a CT scan is below 150 cm3. Salvatore Gruttadauria*, Fabrizio di Francesco*, James Wallis Marsh*, Amadeo Marcos*, Bruno Gridelli*, * Istituto Mediterraneo Trapianti e Terapie ad, Alta Specializzazione, Palermo, Italy.