EUS-Guided Portal Pressure Gradient Measurement

Abstract

Portal hypertension (PH) is a known complication of liver cirrhosis and is caused by increased resistance to blood flow in the hepatic sinusoids. Once PH develops, the clinical manifestations may include esophageal and gastric varices, portal hypertensive gastropathy, ascites, splenomegaly, and thrombocytopenia. Assessing the intravascular pressure of the portal vein (relative to the hepatic vein) has been useful in determining the stage, progression, prognosis of cirrhosis, as well as the risk for developing hepatocellular carcinoma in individual patients with liver disease. While the hepatic vein can be directly measured using a trans-jugular approach (called the free hepatic venous pressure, or FHVP), the portal vein pressure is assessed indirectly from the wedged hepatic venous pressure (WHVP). In cirrhosis, the WHVP closely reflects portal (sinusoidal) pressure, as the catheter with balloon occlusion creates a continuous fluid column between the catheter, the blood in the hepatic vein, the sinusoidal tract and the portal vein. The difference or gradient between the FHVP and the WHVP is known as the hepatic venous pressure gradient (HVPG). The HVPG accurately reflects the degree of PH in all forms of sinusoidal and post-sinusoidal causes of PH, but not in pre-sinusoidal PH. A portal pressure gradient (PPG) measurement of 0–5 mmHg is considered within the normal range, while 6–9 mmHg is considered portal hypertension, ≥10 mmHg is considered “clinically significant” portal hypertension and associated with the development of esophageal varices [1], and finally, a PPG of ≥12 mmHg is associated with variceal hemorrhage [2]. Reduction of PPG by 20% or to below 12 mmHg with pharmacotherapy has been shown to decrease risk of future bleeding or rebleeding episodes [3, 4].