Minimal hepatic encephalopathy: follow-up 10 years after successful liver transplantation.

Background: The long-term effect of liver transplantation (LT) on cognitive functions and the complete reversibility of minimal hepatic encephalopathy are poorly documented. Much evidence indicates that spatial attention improves starting from the immediate period after LT. However, at least in the first 2 years, some cognitive defects seem to persist to some degree, especially for supramodal nonverbal cognitive functions. The aim of this study is to investigate (i) whether the improvements observed in the perioperative period fluctuate or remain stable 10 years after LT and (ii) whether the functions that have been found defective also improve.

Methods: We called patients previously included in a prospective study (Mattarozzi et al., Arch Neurol 2004; 61: 242) for a further neuropsychological evaluation. We compared the cognitive evaluation after 7 to 10 years with previous data gathered 6 and 18 months after LT.

Results: The improvements obtained in the first 2 years after transplantation remain stable during the 7 to 10 years thereafter, especially for visuospatial attention, F(12,96) 1.70; P=0.04 and selective attention, F(6,66) 3.51; P=0.005. Furthermore, these findings also seem to suggest an improvement in supramodal cognitive functions, such as spatial planning intelligence, measured by the Elithorn Maze Test, F(3,33) 7.42; P=0.002. Verbal short-term memory, F(3,33) 3.69; P=0.038, and visuospatial short-term memory, F(6,64) 2.97; P=0.013, show a more fluctuating trend over time.

Conclusions: Despite the risk of surgery, the neurotoxicity of immunosuppression therapy, and the effects of aging and related comorbidities, our data indicate that LT is able to significantly improve patients' cognitive functions in the long term.