Prevalence of hepatic encephalopathy in patients with non-cirrhotic portal hypertension: A systematic review and meta-analysis

Noncirrhotic portal hypertension: current trends and future directions

PURPOSE OF REVIEW

Noncirrhotic portal hypertension (NCPH) comprises a diverse group of vascular liver disorders characterized by elevated portal pressure without cirrhosis. Due to overlapping clinical features, distinguishing NCPH from cirrhosis and porto-sinusoidal vascular disorder (PSVD) remains challenging. This review explores recent advancements in diagnosis, differentiation, and evolving treatment strategies.

RECENT FINDINGS

NCPH is characterized by preserved liver function and near-normal hepatic venous pressure gradients (HVPG). It shares risk factors with PSVD, including infections, drugs, toxins, and prothrombotic conditions. Diagnostic advancements, such as liver stiffness measurement (LSM) and splenic stiffness measurement (SSM), offer noninvasive differentiation from cirrhosis, while liver biopsy remains crucial for confirming PSVD and noncirrhotic portal fibrosis (NCPF). Imaging is reliable for diagnosing extrahepatic portal vein obstruction (EHPVO). Transjugular intrahepatic portosystemic shunts (TIPS) for refractory variceal bleeding or ascites, achieving rebleeding control in 72-80% of cases. Surgical shunts and splenectomy remain essential for uncontrolled bleeding and portal biliopathy, demonstrating excellent variceal control (93-95%).

SUMMARY

NCPH requires a high index of suspicion for diagnosis. Differentiation from cirrhosis and PSVD relies on clinical, histological, and hemodynamic assessments. Management focuses on endoscopic, interventional, and surgical strategies tailored to disease severity. Future research should standardize diagnostic criteria, explore targeted therapies, and refine prognostic tools to improve outcomes.

Prevalence of hepatic encephalopathy in non-cirrhotic portal hypertension: A systematic review and meta-analysis

INTRODUCTION AND OBJECTIVES

The prevalence of hepatic encephalopathy (HE) in non-cirrhotic portal hypertension (NCPH) is not well established, despite evidence of its occurrence in both minimal (MHE) and overt forms (OHE). Accurate diagnosis and management of HE can reduce morbidity and improve patients' and their families' quality of life. This study aimed to systematically review the prevalence of HE in NCPH.

MATERIALS AND METHODS

Systematic research in five databases (MEDLINE, LILACS, MEDRXIV, SCIELO and Scopus) was carried out from January to April 2024 to detect studies that address the prevalence of MHE and OHE in patients with NCPH, using the terms: "Hepatic Encephalopathy" or "Psychometrics" or "Cognition Disorders" or "Cognition" and "Noncirrhotic Portal Hypertension".

RESULTS

Twelve studies were included, including 575 patients. The prevalence of HE in patients with NCPH is 12 % (95 % CI: 6-24; I2 83 %, p<0.01), with high heterogeneity, with the pooled prevalence in studies evaluating MHE being 21 % (95 % CI: 11-38; I2 73 %, p<0.01) and the prevalence of OHE being 4 % (95 %CI: 1-15; I2 83 %, p<0.01). The prevalence of HE by etiology of NCPH is as follows: EHPVO is 25 % (95 %CI: 11-45; I2 0 %; p=1), PVT 2 % (95 %CI: 0-15; I2 0 %, p=1), in PSVD 8 % (95 %CI: 5-14; I2 87 %; p<0.01) and idiopathic NCPH 9 % (95 %CI: 5-14; I2 68 %, p<0.01), with the last two analyzes showing high heterogeneity.

CONCLUSIONS

HE occurs in approximately 12 % of patients with NCPH, with MHE being more common than OHE. Etiology plays a significant role in HE prevalence.

Hepatic encephalopathy in non-cirrhotic portal hypertension

Hepatic encephalopathy (HE) is traditionally associated with hepatic parenchymal diseases, such as acute liver failure and cirrhosis. Its prevalence in non-cirrhotic portal hypertension (NCPH) patients, extrahepatic portal vein obstruction (EHPVO), and non-cirrhotic portal fibrosis (NCPF) is less well described. HE in NCPH allows one to study the effect of portosystemic shunting and ammonia without significant hepatic parenchymal injury. The current review narrates the spectrum and management of hepatic encephalopathy in NCPH patients. We synthesized data from various studies on the occurrence and management of HE in NCPH, mainly EHPVO, idiopathic non-cirrhotic portal hypertension (INCPH), and porto-sinusoidal vascular disease (PSVD). The prevalence of minimal hepatic encephalopathy (MHE) in NCPH is reported from 12 to 60%, depending on the condition and diagnostic criteria. MHE was reported in nearly a third of EHPVO patients. Studies show that venous ammonia levels are significantly elevated in patients with MHE and spontaneous shunts (82.4 ± 20.3 vs. 47.1 ± 16.7 µmol/L, P = 0.001). Large portosystemic shunts substantially increase the risk of HE, with 46-71% of patients with persistent or recurrent HE having identifiable shunts. Management of HE in NCPH primarily focuses on reducing ammonia levels through lactulose, which has shown improvement in 53% of patients with MHE after three months (P = 0.001). Shunt occlusion in patients with large portosystemic shunts is helpful in selected cases. HE in NCPH, particularly in EHPVO, is associated with elevated ammonia levels and spontaneous shunts. Despite the high prevalence of HE in NCPH, this is still a neglected aspect in the care of NCPH. A high index of suspicion and the application of appropriate screening tools are crucial for timely diagnosis and management. HE screening tools that are well-studied in cirrhosis, are also valid in NCPH. Effective management strategies include lactulose, rifaximin, dietary modifications, and shunt embolisation in some cases. Future research should focus on the long-term natural history and efficacy of treatment strategies in this population.

Non-cirrhotic portal fibrosis/idiopathic portal hypertension: APASL recommendations for diagnosis and management

Since the Asian Pacific Association for the Study of the Liver (APASL) published guidelines on non-cirrhotic portal fibrosis/idiopathic portal hypertension in 2007, there has been a surge in new information, especially with the introduction of the term porto-sinusoidal vascular disorder (PSVD). Non-cirrhotic intra-hepatic causes of portal hypertension include disorders with a clearly identifiable etiology, such as schistosomiasis, as well as disorders with an unclear etiology such as non-cirrhotic portal fibrosis (NCPF), also termed idiopathic portal hypertension (IPH). This entity is being increasingly recognized as being associated with systemic disease and drug therapy, especially cancer therapy. An international working group with extensive expertise in portal hypertension was assigned with formulating consensus guidelines to clarify the definition, diagnosis, histological features, natural history, and management of NCPF/IPH, especially in the context of PSVD. The guidelines were prepared based on evidence from existing published literature. Whenever there was paucity of evidence, expert opinion was included after detailed deliberation. The goal of this manuscript, therefore, is to enhance the current understanding and help create global consensus on the issues surrounding NCPF/IPH.

Porto-sinusoidal Vascular Disease: Classification and Clinical Relevance

Non-cirrhotic portal hypertension (NCPH) is a well-recognized clinico-pathological entity, which is associated with clinical signs and symptoms, imaging, and endoscopic features of portal hypertension (PHT), in absence of cirrhosis. In patients with NCPH without known risk factors of PHT or extrahepatic portal vein thrombosis, the condition is called idiopathic non-cirrhotic portal hypertension (INCPH). There are multiple infectious, immune related causes, systemic diseases, drug and toxin exposures, haematological disorders, and metabolic risk factors that have been associated with this INCPH. However, the causal pathogenesis is still unclear. The Vascular liver disorders interest group group recently proposed porto-sinusoidal vascular disease (PSVD) as a syndromic entity, which provides definite histopathological criteria for diagnosis of NCPH (table 1). The three classical histo-morphological lesions specific for PSVD include obliterative portal venopathy, nodular regenerative hyperplasia, and incomplete septal fibrosis. The PSVD definition includes patients with portal vein thrombosis, PVT, and even those without PHT, thus broadening the scope of diagnosis to include patients who may have presented early, prior to haemodynamic changes consistent with PHT. However, this new diagnosis has pros and cons. The cons include mandating invasive liver biopsy to assess the PSVD histological triad in all patients with NCPH, an erstwhile clinical diagnosis in Asian patients. In addition, the natural history of the subclinical forms of PSVD without PHT and linear progression to develop PHT is unknown yet. In this review, we discuss the diagnosis and treatment of INCPH/PSVD, fallacies and strengths of the old and new schema, pathobiology of this disease, and clinical correlates in an Asian context. Although formulation of standardised diagnostic criteria is useful for comparison of clinical cohorts with INCPH/PSVD, prospective clinical validation in global cohorts is necessary to avoid misclassification of vascular disorders of the liver.