Background. The safety of transplanting livers with moderate to severe
microvesicular steatosis is unknown. Livers that appear fatty are oft
en abandoned at the donor hospital. We have recently used frozen-secti
on biopsy to distinguish between microvesicular and macrovesicular ste
atosis. We present here our single-center experience with transplantat
ion of 40 allografts with moderate or severe microvesicular steatosis.
Methods. We reviewed our data on 426 transplants and identified 40 ca
ses in which the donor liver contained at least 30% microvesicular ste
atosis. Early graft function, patient and graft survival, and donor ri
sk factors for steatosis were examined, and results in this cohort wer
e compared with results in all other patients who received liver trans
plants at our center during the same time period. We also analyzed the
reliability of donor frozen-section biopsies in quantitating microste
atosis. Persistence of steatosis was assessed on the basis of 1-year f
ollow-up biopsies. Results. The incidence of primary nonfunction and p
oor early graft function was 5% and 10%, respectively. One-year patien
t and graft survival rates were 80% and 72.5%, respectively. Donor obe
sity and traumatic death were commonly identified risk factors for mic
rovesicular steatosis. Frozen-section biopsy was reliable for pretrans
plant decision-making about the use of potential grafts, and the steat
osis had disappeared from the graft at 1 year in the majority of cases
. Conclusions. Livers with even severe microvesicular steatosis can be
reliably used for transplantation without the fear of high rates of p
rimary nonfunction. There was a significant incidence of poor early gr
aft function, but this did not affect outcome. Microsteatosis is usual
ly associated with some underlying risk factor in the donor and is rev
ersible, as demonstrated by follow-up biopsies after transplant.