The portal vein carries blood from your stomach, pancreas, and other digestive organs to your liver. It differs from other veins, which all carry blood to your heart. The liver plays an important role in your circulation. It filters out toxins and other waste matter that the digestive organs have deposited in your bloodstream. When the blood pressure in the portal vein is too high, you have portal hypertension. Portal hypertension can be quite serious, though it’s treatable if diagnosed in time. It’s not always easy to diagnose, however. Typically, you become alerted to the condition when you start experiencing symptoms.