Gastric varicose vein. Gastroscope (endoscope) view of a bleeding varicose vein in the stomach caused by portal hypertension (high blood pressure in the portal vein). A jet of blood (red) is seen coming from the vein at upper centre. Portal hype- rtension occurs when liver damage obstructs the portal vein, which takes blood from the spleen, stomach and intestines to the liver. This causes the veins in the stomach to widen. If a vein ruptures due to the pressure (as seen here), it can cause bouts of vomiting blood and black faeces. Surgery to reduce the pressure in the por- tal vein may effect a cure, or a tight band can be applied to the bleeding vein the seal it.