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Hepatology. 2019 Jan 31. doi: 10.1002/hep.30534. [Epub ahead of print]

Prognostic Role of Ammonia in Cirrhotic Patients.

Author information

1
Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India.
2
Liver Failure Group, UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, NW3 2PF, UK.
3
Intensive Care Unit, Royal Free Hospital, London, NW3 2QG, UK.

Abstract

Ammonia is thought to be central to the pathogenesis of hepatic encephalopathy (HE), but its prognostic role in cirrhotic patients with acute decompensation (AD) is unknown. The aims of this study were to determine the relationship between ammonia levels and severity of HE, association with organ dysfunction and short-term mortality. We identified 498 patients from two institutions as part of prospective observational studies in cirrhotic patients. Plasma ammonia levels were measured on admission and Chronic Liver Failure-Sequential Organ Failure Assessment criteria was used to determine the presence of organ failures. 28-day patient survival was determined. Receiver operator characteristic analysis was used to identify the cut-off points for ammonia value and multivariable analysis was performed using Cox proportional hazard regression model. 28-day mortality was 43.4%. Plasma ammonia correlated with severity of HE (p<0.001), was significantly higher in non-survivors (93 [73-121] vs. 67 [55-89] μmol/L, p<0.001) and was an independent predictor of 28-day mortality (HR 1.009, p<0.001). An ammonia level of 79.5μmol/L had sensitivity of 68.1% and specificity of 67.4% for prediciting 28-day mortality. An ammonia level of ≥79.5μmol/L was associated with a higher frequency of organ failures (liver [p=0.004], coagulation [p<0.001], kidney [p=0.004] and respiratory [p<0.001]). Lack of improvement in baseline ammonia at day 5 was associated with high mortality (70.6%). Ammonia levels correlate not only with the severity of HE but also the failure of other organs and is an independent risk factor for mortality. Lack of improvement in ammonia levels is associated with high risk of death making it an important biomarker and a therapeutic target. This article is protected by copyright. All rights reserved.

KEYWORDS:

Ammonia; acute decompensation; acute on chronic liver failure; hepatic encephalopathy; hyperammonaemia

PMID:
30703853
DOI:
10.1002/hep.30534

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