High-grade microsteatosis and delay in hepatic function after orthotopic liver transplantation

Macrovesicular steatosis may be used to exclude potential donor livers from use in transplantation. Livers with more than 50% macrovesicular steatosis are believed to be at risk for delayed graft function and primary graft nonfunction. However, the significance of even extensive microsteatosis is uncertain. The hematoxylin and eosin-stained slides of postperfusion donor liver biopsies from 161 transplants were examined. The type of steatosis (macrovesicular, low-grade microvesicular, and high-grade microvesicular ) was determined, and the extent of each type was semiquantitated into 3 groups (none, ≤50%, and >50%). These were analyzed in conjunction with the donor and recipient age and the recipient's sex and MELD score against postoperative outcome parameters, including serial measures of serum lactate, days in the intensive care unit and overall in hospital, and death less than 3 months posttransplant. High-grade microsteatosis usually coexisted with macrosteatosis and infrequently with low-grade microsteatosis. There was no significant association between the extent of either macrosteatosis or low-grade microsteatosis (even when >50%) and any of the outcome parameters. In contrast, the presence of high-grade microsteatosis was significantly associated with delayed hepatic function, but not with the other outcome parameters. Donor age greater than 60 years was associated with late postoperative rise in serum lactate, and higher recipient MELD score was associated with extended stay in the intensive care unit and in the hospital. In this patient population, the association of steatosis with adverse outcomes was largely restricted to delay in postoperative hepatic function, and was due to the subgroup that displayed high-grade microsteatosis.