Endoscopic Ultrasound-Guided Interventions for the Measurement and Treatment of Portal Hypertension

Endoscopic ultrasound guided liver biopsy and portal pressure gradient: when, why and how? Can it become the standard of care in endo-hepatology?

INTRODUCTION

The armamentarium of 'Endo-hepatology' is proliferating with the advancements in techniques and availability of new devices in the field of endoscopic ultrasound (EUS). This has resulted in the merger of multitude of diagnostic and therapeutic interventions, such as EUS-liver biopsy (LB), EUS-angioembolization of gastric varices, EUS-portal pressure gradient (PPG) measurement, and others into a 'one-stop-shop' for efficient patient management. Lack of standardization of these techniques forms a major hinderance in their widespread adoption.

AREAS COVERED

A comprehensive literature search was undertaken across various databases on EUS-LB and EUS-PPG till November 2024 for reviews, observational studies, and randomized trials on EUS-LB and EUS-PPG, describing its indications, technique, and data of safety and efficacy, detailing its role in day-to-day clinical practice.

EXPERT OPINION

EUS-LB and EUS-PPG have shown promise in the ever-growing field of endo-hepatology. EUS-LB has exhibited excellent safety profile and comparable tissue yield compared to its percutaneous counterpart. On the other hand, EUS-PPG seems to be a viable alternative although it needs to be standardized further. From a patient and hospital perspective, they might prove to be convenient and cost-effective. Nevertheless, more evidence is warranted before they can be labeled as the new standard of care.

Methods for assessing portal hypertension

Many researchers and clinicians have taken the value of hepatic venous pressure gradient (HVPG) as an essential prognostic factor in subjects with chronic liver diseases. HVPG ≥ 10 mmHg indicates the presence of clinically significant portal hypertension, the main predictor of the risk of variceal bleeding, hepatic decompensation, and mortality. However, HVPG measurement is invasive and requires high expertise, so its routine use outside tertiary care centers or clinical trials is limited. Clinically significant portal hypertension also might be detected using non-invasive options such as ultrasonography, elastography, magnetic resonance imaging, and indices derived from laboratory parameters. Our review aims to present the feasibility and applicability of HVPG in modern clinical practice in patients with liver cirrhosis, including invasive and non-invasive methods, based on literary sources from the MEDLINE database.

Interventional Endoscopic Ultrasound: Current Status and Future Frontiers

Interventional endoscopic ultrasound has fueled remarkable advancements in the field of therapeutic procedures, revolutionizing minimally invasive interventions for a diverse range of conditions. This review highlights the latest breakthroughs and advancements in therapeutic endoscopic ultrasound, showcasing its potential to transform patient care.

Endoscopic ultrasound-guided vascular interventions: An expanding paradigm

Endoscopic ultrasound (EUS) has expanded its arena from a mere diagnostic modality to an essential therapeutic tool in managing gastrointestinal (GI) diseases. The proximity of the GI tract to the vascular structures in the mediastinum and the abdomen has facilitated the growth of EUS in the field of vascular interventions. EUS provides important clinical and anatomical information related to the vessels' size, appearance and location. Its excellent spatial resolution, use of colour doppler with or without contrast enhancement and ability to provide images "real-time" helps in precision while intervening vascular structures. Additionally, structures such as venous collaterals or varices can be dealt with optimally using EUS. EUS-guided vascular therapy with coil and glue combination has revolutionized the management of portal hypertension. It also helps to avoid radiation exposure in addition to being minimally invasive. These advantages have led EUS to become an upcoming modality to complement traditional interventional radiology in the field of vascular interventions. EUS-guided portal vein (PV) access and therapy is a new kid on the block. EUS-guided portal pressure gradient measurement, injecting chemotherapy in PV and intrahepatic portosystemic shunt has expanded the horizons of endo-hepatology. Lastly, EUS has also forayed into cardiac interventions allowing pericardial fluid aspiration and tumour biopsy with experimental data on access to valvular apparatus. Herein, we provide a comprehensive review of the expanding paradigm of EUS-guided vascular interventions in GI bleeding, portal vein access and its related therapeutic interventions, cardiac access, and therapy. A synopsis of all the technical details involving each procedure and the available data has been tabulated, and the future trends in this area have been highlighted.

Update on endoscopic ultrasound-guided liver biopsy

Endoscopic ultrasound guided liver biopsy (EUS-LB) has emerged as a minimally-invasive alternative to the traditional (percutaneous or transjugular) liver biopsy techniques for the diagnosis of liver parenchymal diseases. Po-tentially, EUS-LB combines the advantages of percutaneous and transjugular liver biopsy in addressing focused sampling in addition to measuring portal pressure. Additionally, EUS-LB facilitates access to both the lobes of the liver which is not considered with the traditional percutaneous liver biopsy. Multiple studies have compared EUS-LB with conventional liver biopsy and reported comparable diagnostic yield, increased acquisition of complete portal tracts, and longer specimen length as compared to the traditional approaches. EUS-LB is associated with lesser post-procedural pain and shorter recovery time, while providing lower risk of complications when compared to traditional liver biopsy. Innovations in needle types, needle sizes and suction techniques have aimed at further optimizing the EUS-LB technique. This review article updates current literature with focus on the variations in the technique and equipment used for EUS-LB, and compares EUS-LB with traditional methods of liver biopsy.

Endoscopic Treatment of Esophageal Varices

Acute variceal bleeding is a complication of portal hypertension, usually due to cirrhosis, with high morbidity and mortality. There are 3 scenarios for endoscopic treatment of esophageal varices: prevention of first variceal bleed, treatment of active variceal bleed, and prevention of rebleeding. Patients with cirrhosis should be screened for esophageal varices. Recommended endoscopic therapy for acute variceal bleeding is endoscopic variceal banding. Although banding is the first-choice treatment, sclerotherapy may have a role. Treatment with Sengstaken-Blakemore tube or self-expanding covered metallic esophageal stent can be used for acute variceal bleeding refractory to standard pharmacologic and endoscopic therapy.

A state-of-the-art comprehensive review summarizing the emerging data on endoscopic ultrasound-guided liver diseases management

Liver diseases are among the most common diseases worldwide accounting for substantial morbidity and mortality. Most liver diseases necessitate radiological evaluation or accurate diagnosis and recently for management as well. In the last decade, the application of therapeutic endoscopic ultrasound (EUS) procedure has been increasingly utilized for the management of various liver diseases. In this comprehensive narrative review article, we provide systematic overview on EUS-guided therapeutic interventions in various liver diseases summarizing most updated data regarding technical success, outcomes and safety profiles. Overall, 35 articles have reported on the use of EUS in the treatment of liver diseases with excellent technical success, favorable radiological response and high safety profiles for EUS-guided treatment of solid and cystic liver lesion and for EUS-guided angiotherapy for gastric varices, except for EUS-guided cyanoacrylate glue injection which was associated with life-threatening fatal systemic embolization adverse events. This suggests that EUS-guided intervention is a new promising therapeutic intervention for the treatment of various liver diseases with durable effect and a limited potential for adverse events.

Role of endoscopic ultrasound in the field of hepatology: Recent advances and future trends

The role of endoscopic ultrasound (EUS) as a diagnostic and therapeutic modality for the management of various gastrointestinal diseases has been expanding. The imaging or intervention for various liver diseases has primarily been the domain of radiologists. With the advances in EUS, the domain of endosonologists is rapidly expanding in the field of hepatology. The ability to combine endoscopy and sonography in one hybrid device is a unique property of EUS, together with the ability to bring its probe/transducer near the liver, the area of interest. Its excellent spatial resolution and ability to provide real-time images coupled with several enhancement techniques, such as contrast-enhanced (CE) EUS, have facilitated the growth of EUS. The concept of “Endo-hepatology” encompasses the wide range of diagnostic and therapeutic procedures that are now gradually becoming feasible for managing various liver diseases. Diagnostic advancements can enable a wide array of techniques from elastography and liver biopsy for liver parenchymal diseases, to CE-EUS for focal liver lesions to portal pressure measurements for managing various liver conditions. Similarly, therapeutic advancements range from EUS-guided eradication of varices, drainage of bilomas and abscesses to various EUS-guided modalities of liver tumor management. We provide a comprehensive review of all the different diagnostic and therapeutic EUS modalities available for the management of various liver diseases. A synopsis of all the technical details involving each procedure and the available data has been tabulated, and the future trends in this area have been highlighted.

EUS-Guided versus Percutaneous Image-Guided Liver Biopsy: A Battle for Supremacy!

Liver biopsy has been the gold standard investigation for diagnosing and staging liver diseases. Image-guided percutaneous liver biopsy is a time-tested technique for obtaining the liver tissue in diffuse liver diseases. However, it is contraindicated in patients with ascites, altered mental status, skin infections, coagulopathy, and thrombocytopenia. It is associated with adverse events including postprocedure pain, bleeding, and pneumothorax. Transvenous liver biopsy can be performed in most cases with these contraindications, but it is an expensive technique and has its own inherent risks. Endoscopic ultrasound (EUS)-guided liver biopsy (EUS-LB) is a relatively new technique that has shown promising results and seems to have a potential of replacing percutaneous liver biopsy. In this news and views, we discuss the results of a randomized controlled trial (RCT) comparing EUS-guided and percutaneous techniques of liver biopsy. This RCT reported that percutaneous technique is superior in terms of diagnostic adequacy and total expenditure without any significant adverse effects compared with EUS-LB. EUS-LB is a promising technique that needs to be further explored in terms of appropriate situations in which it can be preferred over percutaneous or transvenous routes.

A State-of-the-Art Review on the Evolving Utility of Endoscopic Ultrasound in Liver Diseases Diagnosis

Liver diseases are amongst the most common diseases worldwide and manifest as a parenchymatic and/or biliary injury due to several causes as well as focal liver lesions, ranging from benign to malignant ones. The diagnosis of liver diseases is based mainly on biochemical and advanced imaging studies and, when required, on liver biopsy. Endoscopic ultrasound (EUS), which combines endoscopy and ultrasonography, is one of the main examination techniques used in gastroenterology as it is applied to evaluate abnormalities in the lumen of the upper and lower gastrointestinal tract and to define pancreatic and hepato-biliary features, often in chronic patients. Given its high spatial resolution and its proximity to the liver, EUS is gaining popularity in the diagnostic work up of liver diseases. This is a comprehensive overview of the current literature on the diagnostic indications for EUS use in patients with liver diseases. We performed a MEDLINE\PubMed and Embase search, and all articles that were relevant, after reviewing abstracts, were assessed and the full text was analyzed to extract data regarding technical success, diagnostic yield, bioptic characteristics, and complications rate. EUS-guided imaging and biopsy techniques in liver diseases have shown consistent favorable promising results among the reports through the literature, with an excellent diagnostic yield and safety profile, especially in the context of focal lesions and portal hypertension. The application of EUS in the diagnosis of liver diseases is a promising technique and should be considered as a first-line therapeutic option in selected cases.