Non-invasive assessment of portal hypertension: Liver stiffness and beyond

Portal hypertension (PH) leads to life-threatening clinical manifestations such as bleeding from gastro-oesophageal varices, ascites and its complications, and portosystemic encephalopathy. It can develop because of advanced chronic liver disease (ACLD) or due to rarer causes such as vascular liver disease. Reference standard methods to assess PH in ACLD include the measurement of hepatic venous pressure gradient and endoscopy, which have limitations due to their high resource utilisation and invasiveness. Non-invasive tests (NITs) have entered clinical practice and allow invasive procedures to be reserved for patients with indeterminate findings on NITs or for specific clinical questions. In this review, we present an update on the role of NITs, and in particular ultrasound elastography, to diagnose PH in ACLD and vascular liver disease, and to stratify the risk of liver-related events. We also provide insights into the open research questions and design of studies in this field.