Model for end‐stage liver disease (MELD) exception for hepatic encephalopathy

Hepatic encephalopathy (HE), a common complication of cirrhosis and end-stage liver disease, has been shown by univariate and multivariate analyses to be a predictor of death in patients with liver failure. The Model for End-Stage Liver Disease (MELD) scoring system does not prioritize patients with HE. The original multivariate analysis leading to the institution of the MELD did not demonstrate that HE increased the model’s ability to predict 3-month pretransplant mortality. Recently, however, data have begun to emerge that point to HE as a predictive factor for short-term mortality and that suggest that the inclusion of HE would improve the predictive ability of the MELD score. An analysis of a model by the Scientific Registry of Transplant Recipients that included HE was strikingly better than MELD at predicting short-term mortality. Said and colleagues recently identified HE as an independent predictor of mortality, and others agree that HE provides additional prognostic information. Despite this, HE remains a subjective diagnosis, and an easily quantifiable and verifiable method for scoring patients is lacking. Recurrent or poorly responsive HE often has an underlying pathophysiology that may be controlled in the setting of otherwise relatively good liver function, such as large spontaneous portosystemic shunts, a proportion of which can be closed; recurrent dehydration, which can be managed by rehydration; sepsis, which can be treated by identifying the underlying cause; and dietary noncompliance, which can be corrected. Cases that are submitted to Regional Review Boards for additional priority because of failure to respond to maximal medical therapy should include clear documentation of patient medication compliance with neomycin, lactulose, sodium benzoate or Buphenyl, rifaximin, and metronidazole. Other conditions for which Regional Review Boards might consider granting additional priority include grade IV hepatic coma requiring hospitalization in an intensive care unit and endotracheal intubation for mechanical ventilation. Cerebral edema associated with HE in the patient with cirrhosis is quickly lethal and may justify an exception if the intracranial pressure is high. Another example is profound HE associated with a large portosystemic shunt that cannot be occluded for technical reasons. Chronic intermittent sepsis in a patient with a low MELD score who has, for example, low-grade prostatitis or breakthrough severe HE requiring hospitalization and airway protection might also justify a MELD exception. To facilitate the development of an accurate method for fair prioritization of liver transplant candidates with HE, we suggest that an estimate of the time spent in (duration of) grade III/IV HE be included in the model. We propose that the West Haven criteria for grading mental status be used to assess for the presence of HE (Table 1). Other, more sophisticated measures need to be studied for their potential use as objective criteria of HE over time. Inclusion of duration of severe HE may identify difficult-to-manage and frequently recurrent HE. The Scientific Registry of Transplant Recipients analysis established that a one-time (cross-sectional) assessment of HE predicts mortality independent of the MELD score. We propose that the strength of this prediction will be greatly enhanced by factoring in duration of severe HE.