Assessment of donor fatty livers for liver transplantation

The effect of fatty liver on graft survival, especially with reference to macrovesicular and microvesicular steatosis, is still uncertain. This preliminarily study was designed to create a noninvasive method for the quantification of the hepatic fat content in vivo and to establish provisional criteria for the assessment of fatty donor livers before liver transplantation among transplant surgeons, radiologists, and pathologists.

Different degrees of rat fatty liver model were established by feeding rats a diet deficient in choline and methionine for different periods of time. Computed tomography (CT) with test tubes containing variable percentages of fat equivalent substance were used to assess the severity of fatty change of the rat liver. This was then correlated with the histological classification, level of hepatic enzymes, and graft survival.

Linear correlation between the fat volume fraction added to the test tubes and CT density were found. The process of producing a fatty liver via diet alteration peaked at week 3. At this time hepatic enzymes, radiological fat content, and posttransplantation survival were worse (P=0.013), compared with other time points. Radiological assessment of fatty liver correlated well with survival and serum glutamic oxaloacetic transaminase and glutamic pyruvate transaminase levels.

Severe microvesicular steatosis does not influence recipient survival, however, macrovesicular steatosis affects graft survival. Caliber CT is a practical and simple method that allows an accurate noninvasive quantitative assessment of hepatic fatty infiltration. It has potential to be a useful parameter for the assessment of donor livers for clinical liver transplantation.