Shunt-preserving disconnection of the portal to systemic circulation in patients with hepatic encephalopathy

Splenic vein embolization as a feasible treatment for patients with hepatic encephalopathy related to large spontaneous splenorenal shunts

INTRODUCTION AND OBJECTIVES

Although splenic vein embolization (SVE) has been performed for the management of patients with hepatic encephalopathy (HE) related to large spontaneous splenorenal shunts (SSRS) in recent years, its role remains poorly defined. In this study, we aimed to explore the safety and efficacy of SVE for HE patients with large SSRS.

MATERIALS AND METHODS

Data from cirrhotic patients who were confirmed to have recurrent or persistent HE related to large SSRS and underwent SVE from January 2017 to April 2021 were retrospectively collected and analyzed at our center. The primary endpoints were the change of HE severity at 1 week after embolization and the recurrence of HE during the follow-up period. The secondary endpoints were procedure-related complications and changes in laboratory indicators and hepatic function (Child-Pugh score/grade and model for end-stage liver disease score).

RESULTS

Of the eight cirrhotic patients included in the study, six were diagnosed with recurrent HE, and the others were diagnosed with persistent HE. Embolization success was achieved for all patients (100%), and no immediate procedure-related complications, de novo occurrence, or aggravation of symptoms related to portal hypertension were observed during the long-term follow-up. HE status was assessed at 1 week after embolization. The results demonstrated that the symptoms were mitigated in three patients and resolved completely in five patients. During the follow-up period, all patients were free of HE within 1 month after embolization, but one patient experienced the recurrence of HE within 6 months and another one experienced the recurrence of HE within 1 year. Compared with the preoperative parameters, the Child-Pugh score and grade were significantly improved at 1 week and 1 month after embolization (all P<0.05), and the serum ammonia level was significantly lower at 1 month after embolization (P<0.05).

CONCLUSIONS

SVE could be considered as a feasible treatment for patients with HE related to large SSRS, but further validation is required.

Hyperammonemia in Hepatic Encephalopathy

The precise mechanism underlying the neurotoxicity of Hepatic Encephalopathy (HE) is remains unclear. The dominant view has been that gut-derived nitrogenous toxins are not extracted by the diseased liver and thereby enter the brain. Among the various toxins proposed, the case for ammonia is most compelling. Events that lead to increased levels of blood or brain ammonia have been shown to worsen HE, whereas reducing blood ammonia levels alleviates HE. Clinical, pathological, and biochemical changes observed in HE can be reproduced by increasing blood or brain ammonia levels in experimental animals, while exposure of cultured astrocytes to ammonium salts reproduces the morphological and biochemical findings observed in HE. However, factors other than ammonia have recently been proposed to be involved in the development of HE, including cytokines and other blood and brain immune factors. Moreover, recent studies have questioned the critical role of ammonia in the pathogenesis of HE since blood ammonia levels do not always correlate with the level/severity of encephalopathy. This review summarizes the vital role of ammonia in the pathogenesis of HE in humans, as well as in experimental models of acute and chronic liver failure. It further emphasizes recent advances in the molecular mechanisms involved in the progression of neurological complications that occur in acute and chronic liver failure.