The Assessment of Portal Hypertension

Portal hypertension (PH) and the relative clinical manifestations represent major complications of advanced chronic liver disease (ACLD). PH is caused by a progressive increase in the resistance to portal blood flow into the liver due to substantial angio-architectural changes associated with liver tissue fibrosis, neo-angiogenesis and increased vascular tone within the hepatic microcirculation. The gold standard method for evaluating the severity of portal hypertension is the hepatic venous pressure gradient (HVPG). Liver stiffness measurement (LSM), mainly assessed by vibration-controlled transient elastography (VCTE), has been proposed as a non-invasive test able to provide important diagnostic and prognostic information in the setting of PH. However, the good correlation between LSM and PH is lost in clinically severe PH, i.e. HVPG >12 mmHg, mainly due to the inability of LSM to detect the extra-hepatic components of PH. Accordingly, the measurement of spleen stiffness (SSM), being a more accurate surrogate of HVPG, has been proposed as a non-invasive test able to predict the presence of PH and oesophageal varices (EV).