martes, 3 de septiembre de 2019

What is a liver transplant?

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By Dr. Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Editor)

Liver transplantation is a major operation that involves removal of a damaged or diseased liver from the body and replacing it with a healthy one from a donor. 1-7

Why is the liver important in the body?

The liver is one of the largest organs of the body and is considered akin to a factory in the body as it performs many complex metabolic functions. It is located in the upper right portion of the abdomen beneath the rib cage. It has two main lobes that are made up of tiny lobules.

Blood supply to the liver comes from two main sources. The hepatic artery supplies oxygen rich blood that originates in the heart and the portal vein supplies blood that carries absorbed nutrients from the intestine and the spleen. The portal vein thus brings in chemicals from the digestive tract to enter the liver for detoxification and filtering before it can reach rest of the circulation.

The portal vein brings in chemicals and proteins that are raw materials that the liver cells need to manufacture proteins, cholesterol, and glycogen required for normal body activities.

The liver forms glycogen from excess glucose to be stored in the body as reserve. It also helps in formation of normal blood clotting factors and proteins that are vital for life. The liver plays a vital role in storage of iron and other chemicals as well.

In addition, the liver makes bile. This is a yellowish green fluid that contains among other substances, water, chemicals, and bile acids and is made from the breakdown of dead red blood cells.

Bile is stored in the gallbladder. When there is food in the stomach and duodenum (upper part of the small intestine), bile is secreted into the duodenum, to aid in digestion of food.

Being such an important organ the liver is also the only organ in the body that can easily replace damaged cells. However, if large parts of the liver are damaged, it fails to meet the needs of the body.

What is liver damage and who needs a transplant?

Liver may be damaged due to disease, infection or alcohol. Long disease like cirrhosis, infections like hepatitis C and alcoholic cirrhosis are common causes for liver transplant. In children primary biliary cirrhosis is a common cause for requirement of liver transplant.

Liver transplant is needed when the cirrhosis or liver disease reaches a certain level at which the liver gradually loses all its functions. This is called end-stage liver disease or liver failure.

Each year around 600 to 700 liver transplants are carried out in the UK. This is far lower that the number of people who need a new liver and are put on waiting lists.

Over the last two decades the number of people who require a liver transplant has increased by 90%, but the number of available donations has remained the same. This has resulted in high number of deaths due to end stage liver disease. In 2008, there were 16,087 deaths from liver disease in the UK.

What are the types of liver transplant?

There are basically three types of liver transplant. The donor may be a recently dead person from whom the liver may be obtained after consent of the family or consideration of the wishes of the donor when he or she was living. This is called a deceased organ donation.

Another type is a living donor organ transplant that involves a section of liver that is removed from a living donor and transplanted into the patient. Since liver has an inherent capacity to regenerate both the transplanted section and the remaining section of the donor’s liver grow back to a normal liver.

Another type of donation is split donation. In this a liver is removed from a person who recently died and split into two – a larger and smaller portion. Each piece is then used for transplantation in two different persons. Both pieces grow to a normal sized liver with time.

What happens after liver transplant?

Liver transplants first began in the 1960’s and since then long term survival after a transplant has improved to a great degree. It is estimated that there are currently 6,000 liver transplant survivors in the UK. After the surgery around 85 out of 100 people live for at least one year and 65 out of 100 live for five years or more.

Once the liver is transplanted, the body often treats it as a foreign tissue and mounts an immune reaction towards it. This, in extreme, is termed a graft rejection and may cause the newly transplanted organ to be completely damaged and destroyed. To prevent this, there are several drugs called immunosuppressants. A liver transplant patient needs to take these drugs lifelong to prevent rejection of their new liver.

In addition there is also a heightened risk of cardiovascular disease and coronary heart disease after transplant. A healthy diet and regular exercise may help normalize life after a liver transplant.