There are two important complications of the TIPS procedure. The first is hepatic encephalopathy, a condition in which it is believed that toxic products from the intestines (for example, ammonia) that are normally removed from the blood by the liver remain in the blood and are delivered to the brain. (The TIPS allows the toxin-containing blood to bypass the liver.) The effects on the brain can vary from minor alterations in thinking to full coma. A second complication is heart failure due to the sudden increase in the amount of blood returning to the heart through the shunt. The heart is unable to pump the returning blood fast enough, resulting in heart failure. Finally, one complication may be caused by the shunt itself; problems such as infection and shunt occlusion, requiring placement of another shunt.