Introduction: The significance of preoperative body composition has recently attracted much attention in various diseases. However, cut-off values for these parameters remain undetermined, and these factors are not currently included in selection criteria for recipients of living donor liver transplantation (LDLT). The present study aimed to establish sex-specific cut-offs for body composition using data from healthy general population, and to develop new selection criteria for recipients of LDLT considering pre-transplant nutritional and physical statuses.
Methods: Using computed tomography of 657 donors for LDLT between April 2005 and July 2016 in our institution, skeletal muscle mass, muscle quality, and visceral adiposity were evaluated using skeletal muscle mass index (SMI), intramuscular adipose tissue content (IMAC), and visceral-to-subcutaneous adipose tissue area ratio (VSR). On the basis of younger donor data, we determined sex-specific cut-off values for low SMI, high IMAC, and high VSR (mean ± 2 standard deviations). To evaluate the validity of cut-offs for body composition parameters, we examined data from 277 patients who underwent adult-to-adult LDLT between January 2008 and July 2016. The impact of body composition on outcomes after LDLT was investigated with the aim of establishing new selection criteria for LDLT.
Results: Among the 277 LDLT recipients, 55 (20.0%), 121 (43.7%), and 83 (30.0%) patients exhibited low SMI, high IMAC, and high VSR, respectively. The overall survival rate was significantly lower for each group of patients with low SMI (P < 0.001), high IMAC (P < 0.001), or high VSR (P < 0.001) compared to the respective normal groups. In addition, low SMI, high IMAC, and high VSR contributed to an increased risk of post-LDLT mortality in an additive manner. Patients with all three factors showed the lowest survival rate after LDLT (1-year survival rate, 41.2%; P < 0.001). On multivariate analysis, low SMI (P = 0.002), high IMAC (P = 0.002), and high VSR (P = 0.001) were identified as independent risk factors for mortality after LDLT. Based on these findings, we have excluded patients showing all 3 factors (low SMI, high IMAC and high VSR) as candidates for LDLT since October 2016.
Conclusion: Using cut-off values determined from healthy donors, we investigated risk factors for post-LDLT mortality, and extracted the group that exhibited the poorest prognosis after LT, leading to the establishment of our new selection criteria for recipients of LDLT.