Impact of Graft Steatosis on Post-operative Complications After Liver Transplantation
Condition: Post-operative Complications
MeSH terms: Fatty Liver; Postoperative Complications
Study type: Observational

Summary: 
      1. Clinical impact of graft steatosis on postoperative complications after OLT.

        2. Recommendations to improve outcomes after transplantation of steatotic livers and
           increase donor pool.
    

Detailed description: 
      Introduction Solid organ transplantation has become the standard of care for selected
      patients with end-stage organ dysfunction. With improved surgical techniques, more effective
      immunosuppressive therapies, and better anti-infective medications, outcomes after solid
      organ transplantation have improved over the last several years.

      The excellent survival rates reported after orthotopic liver transplantation (OLT) have
      increased the demand for liver transplants and have enhanced the disparity between the number
      of available donor organs and the need for such organs.

      The lack of available organs for liver transplantation (LT) associated with the increased
      death rates among patients on most waiting lists for LT has triggered the use of so-called
      extended criteria donor (ECD) grafts, previously called ''suboptimal grafts''. Among the wide
      range of these ECD livers, hepatic steatosis is one of the most frequent disorders, which is
      mostly related to an increasing prevalence of non-alcoholic fatty liver disease (NAFLD).

      Non-alcoholic fatty liver disease (NAFLD) is increasingly significant in healthy individuals
      for its high worldwide prevalence, an association with the metabolic syndrome such as insulin
      resistance, diabetes, dyslipidemia and obesity, and an association with liver-related
      morbidity and mortality.

      Clinical evaluation and current imaging modalities, and serological and laboratory tests can
      be strongly suggestive of the presence of hepatic steatosis, but none of these is capable of
      distinguishing steatohepatitis (SH) from uncomplicated steatosis; likewise, these evaluations
      can generally detect advanced liver disease (e.g. portal hypertension), but none can truly
      assess the degree of liver necroinflammatory injury, lesser stages of fibrosis and
      architectural remodeling. Liver biopsy evaluation, therefore, remains the 'gold standard' to
      unequivocally diagnose SH and to document the severity of hepatic injury and fibrosis.

      Steatosis is assessed according to the pattern and the amount of fatty infiltration in
      hepatic tissue sections. Traditionally, fatty accumulation has been classified
      morphologically as macrovesicular or microvesicular. Macrovesicular steatosis is
      characterized by a single, bulky fat vacuole in the hepatocyte that displaces the nucleus to
      the edge of the cell. The less conspicuous microvesicular steatosis, usually related to
      toxins or metabolic disorders, is characterized by accumulation of tiny lipid vesicles in the
      cytoplasm of hepatocytes without nuclear dislocation. Current quantification and grading of
      liver steatosis originates from studies performed in the early 1990s, when steatosis was
      classified as mild, moderate, or severe if, less than 30%, 30-60%, or more than 60% of
      hepatocytes, respectively, display fatty infiltrations.

      Although usually benign, fatty liver may associate with serious injury, with inflammation and
      hepatocyte necro-apoptosis, non-alcoholic steatohepatitis (NASH), in 20-30% of subjects.
      Those patients are at risk of developing fibrosis, one fifth progressing to liver cirrhosis.
      It is apparently more slowly progressive than other chronic liver diseases, such as alcohol
      or viral-induced disease. Moreover, the problem of hepatocytes being fatty, overcomes the
      liver itself, as it increases the risk for cardiovascular disease and death and duplicates
      the risk for type 2 diabetes mellitus (T2DM), independently of the severity of liver injury.

      Severe fatty livers are more susceptible to warm and cold ischemia reperfusion injury than
      normal ones. The type of damage is not through the pathway of cellular apoptosis, but
      necrosis.

      The use of steatotic grafts for orthotopic liver transplantation (OLT) is associated with a
      high rate of primary graft dysfunction and decreased graft and patient survival particularly
      with macro-steatosis.
    

Intervention name(s): steatosis
Intervention type(s): Procedure
Intervention description(s): Liver Transplantation with graft steatosis
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        All adult patients candidate for liver transplantation are included in this study
      
Keywords: Liver Transplantation - Steatosis - Fatty Liver