**1. Introduction**

#### **1.1. Definition**

Portal hypertensive gastropathy (PHG) is a painless condition of gastric mucosal ectasia and impaired mucosal defense, typically seen in patients with portal hypertension [1].

Portal hypertension (PH) exists when the hydrostatic pressure in the portal vein or its branches has increased. Two important factors are implicated; vascular resistance and

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

blood flow, thus if the pressure gradient anywhere along the portal venous system (between the portal vein, and hepatic veins or the inferior vena cava (IVC)) is increased, portal hypertension develops.

The normal portal venous pressure ranges from 5 to 10 mm Hg, therefore, if the hepatic venous pressure gradient (HVPG) is ≥10 mm Hg, significant portal hypertension is consid‐ ered, but if the HVPG is ≥12 mm Hg, severe portal hypertension is diagnosed [2].

The causes of portal hypertension are classified into three categories related to anatomical consideration. First, are causes originating in the portal venous system before it reaches the liver (pre‐hepatic), e.g. portal vein thrombosis, schistosomiasis, primary biliary cholangi‐ tis/primary sclerosing cholangitis, or congenital hepatic fibrosis. Second, are causes within the liver (intrahepatic) e.g. cirrhosis as a result of viral, non alcoholic fatty liver disease (NAFLD), or autoimmune. Finally, are causes between the liver and the heart (post‐hepatic) e.g. Budd‐Chiari syndrome, inferior vena cava obstruction, or hepatic veno‐occlusive dis‐ ease (**Table 1**). The most common cause of PH is cirrhosis [3].

#### **1.2. Essentials to diagnose PHG**



**Table 1.** Condition associated with portal hypertension.
