Liver steatosis mostly exists in a mixed form of macrosteatosis (MaS) and microsteatosis (MiS). This coexistence is responsible for previous conflicting results regarding the importance of MiS in liver transplantation. We aimed to evaluate the independent effect of MiS on posttransplant outcomes with the exclusion of the confounding effect of MaS. Seventy-one living donors who had pure MiS (defined as an MiS degree > 5% without MaS) were matched 1:1 with control donors, and 66 recipients who received pure MiS grafts were matched 1:1 with control recipients on the basis of propensity scores. Matched variables included the donor age, remnant liver volume, cold ischemia time, graft-to-recipient weight ratio and Model for End-Stage Liver Disease score. The degree of pure MiS ranged from 5% to 50%. Donors in the control and pure MiS groups were comparable with respect to peak postoperative transaminase concentrations [alanine aminotransferase (ALT): 194 versus 176 IU/L, P = 0.61] and postoperative complications. Recipients in the control and pure MiS groups were comparable with respect to recipient (P = 0.15) and graft survival rates (P = 0.56) as well as peak postoperative transaminase concentrations (ALT: 266 versus 281 IU/L, P = 0.88), and graft regeneration rates at 2 weeks (61% versus 59%, P = 0.73). The 2 groups were also comparable with respect to major complications, primary graft dysfunction/nonfunction, intensive care unit/hospital stays, and metabolic diseases. In conclusion, MiS alone does not seem to impair the posttransplant outcomes of living donors and their recipients. The interaction between MiS and MaS, and the effect of a greater degree of MiS are the next important topics to be further evaluated in the mixed steatosis population.
© 2014 American Association for the Study of Liver Diseases.