Predictive value of induced hyperammonaemia and neuropsychiatric profiling in relation to the occurrence of post-TIPS hepatic encephalopathy.

Hepatic encephalopathy (HE) occurs in 20-50% of patients after transjugular intrahepatic portosystemic shunt (TIPS) placement. Older age, HE history and severe liver failure have all been associated with post-TIPS HE but it remains difficult to identify patients at risk. The aim of the present pathophysiological, pilot study was to assess the role of induced hyperammonaemia and associated neuropsychological and neurophysiological changes as predictors of post-TIPS HE. Eighteen TIPS candidates with no overt HE history (56 ± 8 yrs., MELD 11 ± 3) underwent neurophysiological [Electroencephalography (EEG)], neuropsychological [Psychometric Hepatic Encephalopathy Score (PHES) and Scan tests], ammonia and sleepiness assessment at baseline and after the induction of hyperammonaemia by an oral amino acid challenge (AAC). Pre-AAC, 17% of patients had abnormal EEG, 5% abnormal PHES, and 33% abnormal Scan performance. Post-AAC, 17% had abnormal EEG, 0% abnormal PHES, and 17% abnormal Scan performance. Pre-AAC, ammonia concentrations were 201 ± 73 µg/dL and subjective sleepiness 2.5 ± 1.2 (1-9 scale). Post-AAC, patients exhibited the expected increase in ammonia/sleepiness. Six months post-TIPS, 3 patients developed an episode of HE requiring hospitalization; these showed significantly lower pre-AAC fasting ammonia concentrations compared to patients who did not develop HE (117 ± 63 vs. 227 ± 57 µg/dL p = 0.015). They also showed worse PHES/Scan performance pre-AAC, and worse Scan performance post-AAC. Findings at 12 months follow-up (n = 5 HE episodes) were comparable. In conclusion, baseline ammonia levels and both pre- and post-AAC neuropsychiatric indices hold promise in defining HE risk in TIPS candidates with no HE history.

The influence of HE history, HE status and neuropsychological test type on learning ability in patients with cirrhosis.

BACKGROUND & AIMS: Learning ability may be impaired in patients with a history of overt hepatic encephalopathy (OHE). The aim of this study was to compare performance on the first/second attempt at a series of tests. METHODS: Two hundred and fourteen patients with cirrhosis were enrolled. On the day of study, 41% were classed as unimpaired, 38% as having minimal HE and 21% as having mild OHE; 58% had a history of OHE. Performance was compared between two versions of the trail-making test A (TMT-A), and between the first/second half of a simple/choice reaction time (sRT and cRT), and a working memory test (ScanRT). RESULTS: Both patients with and without OHE history improved in TMT-A, sRT and ScanRT. Only patients with no OHE history improved in cRT. All patients, regardless of their HE status on the day of study, improved in TMT-A and sRT. Only patients with mild OHE on the day of study improved in cRT. Only unimpaired patients improved in ScanRT. When OHE history and HE status on the day of study were tested together, only HE status had an effect. The same held true when age, the Model for End Stage Liver Disease (MELD) and educational attainment were adjusted for. CONCLUSIONS: HE status on the day of study and the type of neuropsychological test had an effect on learning ability in a well-characterized group of patients with cirrhosis.