Background: The most commonly used formula for estimation of the standard liver volume (SLV) in living-donor liver transplantation (LDLT) candidates, are body weight (BW)-based. However end-stage liver disease causes a significant modification of the body mass composition, making BW an unreliable anthropometric parameter. The aim of the study was to investigate whether LT candidates with sarcopenia are at an increased risk of receiving an inappropriate SLV estimation by standard BW-SLV formula.
Patients and Methods:  Non-BW-SLV estimation formulas were tested in 262 LDLT donors and compared to a standard BW-SLV formula. The anthropometric parameters used were the thoracic width (TW-SLV) and thoracoabdominal circumference (TAC-SLV). Subsequently, sarcopenic and non-sarcopenic LDLT candidates (total, 217 patients) were compared in terms of estimated BW-SLV and non-BW-SLV. The prognosis in patients with sarcopenia, a small for size syndrome (SFSS) was evaluated.
Results: In donors, TW-SLV showed comparable concordance with CT scan measured total liver volume as BW-SLV (rho 0.61 and 0.67, respectively). The performance of TAC-SLV was low (rho 0.34). In recipients, the prevalence of pre-LT sarcopenia was 30.4%. Sarcopenic patients were attributed to significantly lower BW-SLV than controls (sarcopenia vs controls, 1063.8ml [1004.1-1118.4] vs 1220.7ml [1115.0-1306.6], p<0.001), despite comparable TW-SLV, age, body high and gender prevalence. As a result, sarcopenic patients received a graft with a statistically lower weight at organ procurement (429g [353-532] vs 472g [400-603], p 0.02), and developed more frequently a SFSS according to the Dahm et al. (27.7% vs 6.8%, p<0.01) and Kyushu (28.7% vs 9.2%, p<0.01) definition. There was significantly worse prognosis wit SFSS than without SFSS besides there were no significant differences of survival between with and without sarcopenia.
Conclusion: In sarcopenic patients, BW-SLV formulas are affected by a high risk of SLV underestimation, thus exposing them to an increased risk of post-LT SFSS.