The portal venous system includes your portal vein and smaller veins that branch from it. This system drains blood from other organs, such as your stomach and intestines, into your liver, which filters the blood.
Portal hypertension is when the blood pressure in the portal vein gets too high. The blood goes into the smaller veins, which stretch and weaken. This can cuase internal bleeding.
This condition is most commonly caused by advanced liver disease, which causes scar tissue that can compress the portal vein.
Portal hypertension can be life-threatening, but the symptoms can be managed in many cases.