Overview of Liver Transplantation
Cirrhosis and severe liver diseases were responsible for making it the ninth highest cause of death among men in the U.S in 2016. A lifesaver for these conditions is liver transplantation, which is usually done for patients suffering from intense and persistent, last-stage liver disease. This transplantation can bring a patient back to normal health and can extend their lifespan by up to 15 years.
Liver transplants provide a backup plan to treat several liver diseases when other treatments have stopped working. Data from the Scientific Registry of Transplant Recipients shows that patients who have undergone a liver transplant fare very well, with 90% of them surviving the first year after getting a liver from a deceased donor and 77% making it through five years.
Liver transplantation has been performed since 1963 and has seen constant progress, including the refinement of surgical methods, the types of organ donations available, and the expansion of the organ donor pool. There’s also been a significant emphasis on improving the quality of life for both recipients and donors.
Despite the advancements, there can be some serious hurdles. These include a shortage of donor organs, the process of selecting who gets a liver transplant, and the allocation of organs.
Anatomy and Physiology of Liver Transplantation
The liver is the largest organ inside your body and is situated under the right side of your ribcage. It’s made up of four sections: the right and left lobes, the quadrate lobe, and the caudate lobe. These lobes are separated by soft, fibrous tissue called the falciform ligament. However, for its actual functioning, the liver is essentially split into two main parts, also known as the right and left lobes. This split is identified by an imaginary line called the Cantlie line, which runs in between the spot of the gallbladder and a large vein called the inferior vena cava.
These two functional lobes are then further split into smaller sections or segments. These segments are classified from 1 to 8 based on where they get their blood supply and how they drain it. This system of assignation is known as the Couinaud system.
The liver has a unique feature of having two sources of blood supply, one from the portal vein and another from the hepatic artery. The liver’s main functional cells are known as hepatocytes. These hepatocytes are arranged into three zones:
- Zone I is the zone closest to the blood supply and is primarily involved in chemical reactions that require oxygen.
- Zone II is in the middle.
- Zone III is farthest from the blood supply and is mainly involved in getting rid of harmful substances from the body.
Interestingly, the blood and bile in the liver flow in opposite directions. Bile, a fluid that helps digest fat, move out of the liver, while blood flows into it to supply the liver with nutrients and oxygen. Usually, the right lobe of the liver contains 60% of the liver’s total volume, while the left lobe contains 40%, with the left lateral segment alone making up 20% of the total liver volume.
Why do People Need Liver Transplantation
A liver transplant might be necessary in cases of severe liver diseases, both sudden and long-term, when the available treatments aren’t working. Patients who experience severe symptoms like cognitive disturbances, severe bleeding, or fluid accumulation in the abdomen, might need a liver transplant. About 80% of all the liver transplants carried out are for those suffering from liver failure and diseases like cirrhosis.
Predicting the outcomes of these patients involves using something called the Child-Turcotte-Pugh (CTP) score. This system evaluates the patient’s condition using a series of blood tests and health information. Another tool called the Model of End-Stage Liver Disease (MELD score) uses medical data to estimate survival chances in these patients.
However, for children, a modified version of the MELD score is used. It includes the child’s age, a protein called albumin, health growth rates, and kidney health. Since 2016, doctors also look at salt levels in the blood which speaks to the severity of cirrhosis, a scarring of the liver.
When is a liver transplant necessary?
Liver transplant is beneficial for different conditions. One of them includes graft failure, when the transplanted liver isn’t functioning properly. This rejection can cause a blockage in the hepatic artery, cutting supply to the new liver. Though a second transplant is possible, it often has less successful outcomes.
Diseases like chronic hepatitis C, leading to cirrhosis used to be the top reason before 2015. However, as of 2016, it is overtaken by alcohol-related liver disease and non-alcoholic steatohepatitis.
Hepatitis B was once a leading cause of chronic liver disease and transplants, but the numbers have declined due to improved treatments. Autoimmune hepatitis (AIH), wherein your body attacks its own liver cells, requires liver transplantation if medicines and steroids aren’t working.
Then we have something called primary biliary cirrhosis (PBC) where the small bile ducts in the liver get damaged. If this disease isn’t responding to treatments, getting a liver transplant can be a way out. Similarly, for primary sclerosing cholangitis (PSC), a disease damaging the bile ducts, a transplant is recommended.
Alcohol-related liver disease is currently the most common reason for needing a liver transplant. Such patients need mental and emotional support to ensure they don’t go back to drinking post-transplant. Untreatable acute alcoholic hepatitis may also require a liver transplant sooner.
In acute liver failure (ALF) where patients’ health rapidly declines, liver transplantation may be necessary. Something like half the cases of ALF in the United States are caused by Acetaminophen, a common painkiller. Such patients get priority on the list for organ sharing.
Lastly, patients with liver cancer must meet certain criteria to be eligible for a liver transplant.
When a Person Should Avoid Liver Transplantation
The criteria for who can receive a liver transplant is expanding, but there are still some situations where it’s not possible. This is due to recent progress in liver transplant methods. There are some definitive reasons why a person can’t receive a liver transplant, while others depend on the individual’s circumstances.
Here are some definite reasons why a liver transplant can’t happen:
– If someone’s MELD score (a measure of how sick their liver is) is less than 15.
– If they have severe heart or lung problems.
– If they have AIDS (a disease that weakens the immune system).
– If they are using alcohol or drugs illegally.
– If they have certain types of liver cancer that have spread.
– If they have a serious infection that hasn’t been treated.
– If they have a physical problem that rules out liver transplantation.
– If they have a type of liver cancer called intrahepatic cholangiocarcinoma.
– If they have cancer outside the liver and haven’t been cancer-free for more than two years or are likely to see it return.
– If they have a rare form of blood vessel cancer called hemangiosarcoma.
– If they have severe liver failure that results in very high pressure in the brain or a very low amount of blood flow to the brain.
– If they don’t have emotional support or have serious mental health problems.
– If they have severe high blood pressure in the lungs.
Even though having AIDS usually rules out a liver transplant, some transplant centers are considering people who only have HIV for liver transplants.
Here are some other reasons that might make it less likely for a person to receive a liver transplant:
– If they are very weak.
– If they consistently don’t follow medical advice.
– If they are very old.
– If they have had a lot of previous surgery in the belly.
– If they have a lot of blood clots in veins around the liver or gut.
Who is needed to perform Liver Transplantation?
When it comes to delivering the best possible healthcare, a team of various medical professionals is important. This is especially true when you are preparing for a liver transplant.
Before the liver transplant, you’ll meet with various experts including a liver specialist (hepatologist), a surgeon who specializes in transplants, and a specialized nurse who coordinates your care. These healthcare professionals will sit down with you to go over vaccinations you may need, medications you will take, and lifestyle changes you may have to make. They will also discuss the surgery and what to expect before and after the operation. This includes information about how to control your immune system to avoid transplant rejection, as well as possible risks and results.
You will also meet with a psychiatrist who specializes in transplants. They will help with any alcohol or drug issues you may have and make sure you understand your upcoming surgery and what could happen afterwards.
Social workers play a part too, providing you with emotional support, particularly after the liver transplant. They can also help with arranging care when you go home and managing other parts of your life that might be affected by the surgery. There’s also a team that checks your health insurance coverage for the liver transplant operation and any medications you’ll need to control your immune system after surgery.
Nutritionists are included in this team as well, they provide advice about nutrition before and after the transplant. This includes making dietary changes if you have chronic conditions like diabetes (DM), high blood pressure (HTN) or high cholesterol (hyperlipidemia).
Preparing for Liver Transplantation
Before having a liver transplant, a number of factors need to be looked into. This includes a thorough check-up, lab tests and imaging tests for a full review of the patient’s health. This comprehensive check-up is done to ensure the patient is in the best condition for a successful surgery.
Being overweight can make the transplant surgery more risky, and can affect long-term survival. If a patient is overweight, with a body mass index (BMI) of 30 kg/m^2 or more, they should see a dietician. If a patient has a BMI of 40 kg/m^2 or more, this might make them less suitable for a liver transplant.
Heart disease risks should also be looked at during this review. All patients should undertake tests to check their heart health. If a patient has narrowed arteries, these should be treated before the transplant.
Age is not a barrier for transplants, even for patients over 70. Older patients with other health conditions under control can still benefit from a liver transplant, which can extend their expected lifespan.
Pulmonary hypertension (high blood pressure in the lungs) can lead to a higher death rate after a liver transplant. This condition is diagnosed by an ultrasound of the heart, and if severe, other tests are needed. Treatments to relax blood vessels can help, and a liver transplant can be considered if they lower the lung blood pressure.
Patients with chronic liver disease may experience breathlessness and low oxygen levels due to issues with their vessels. These patients should be tested and may need more recovery time and extra oxygen after the transplant, depending on the severity of their condition.
If a patient has kidney disease, this should also be diagnosed prior to a liver transplant because it can increase the risk of death. If a patient has serious kidney disease they may need a liver and kidney transplant at the same time.
Smoking increases a patient’s risk of death after a liver transplant, mainly due to heart disease. It also increased the risk of issues in the liver blood vessels. Many hospitals require patients to quit smoking before they can be considered for a liver transplant.
Patients should also be screened for cancers before getting a liver transplant, and any previous cancers should be dealt with before the procedure.
Infectious diseases should be treated and include viral, bacterial and fungal infections like hepatitis A and B, cytomegalovirus (CMV), Epstein-Barr virus (EBV), tuberculosis, syphilis, and certain fungal infections. It’s important to make sure all vaccines are given before the transplant, as some can’t be given afterwards due to the immunosuppressant medicines.
Nutrition is crucial to prepare for a transplant. A nutritionist should address any deficiencies. It’s also important for the patient to manage their diet if they have any other conditions like diabetes, hypertension (high blood pressure), and high cholesterol levels.
Bone health should also be looked at due to the risk of bone disease. Levels of vitamin D and calcium should be checked, as liver disease can make it harder for the body to absorb these nutrients.
Patients with HIV can still have a liver transplant if their CD4 counts (a type of immune cell) are above 100 µL and the virus is undetectable at the time of the transplant.
Lastly, a patient’s mental health should also be assessed. Any mental health conditions that could affect a patient’s recovery or their ability to take medication as directed should be evaluated. It’s also important to look at the patient’s support system and caregivers, especially for those with brain-related complications from liver disease. Substance abuse should also be noted.
How is Liver Transplantation performed
Liver transplants consist of two operations: one for the person donating the liver, and one for the person receiving the liver.
In the operation for the person receiving the liver (the recipient), the person’s current liver is completely removed. The veins attached to it are securely tied off to manage blood flow.
There are two types of liver transplant procedures based on the source of the donated liver: Deceased Donor Liver Transplantation (DDLT) and Living Donor Liver Transplantation (LDLT).
In Deceased Donor Liver Transplantation, the liver is procured from a person who has recently passed away. This is the most common type of liver transplant. Here’s what happens: after the recipient’s body is prepped for surgery, the deceased donor’s liver is connected into the recipient’s body. This is done by attaching various blood vessels in a specific order, which allows the new liver to get a good blood supply. After that, a key digestive tube is repaired. There have also been instances where one donor’s liver is split into two (a “split graft”) and transplanted into two recipients.
On the other hand, Living Donor Liver Transplantation is transplantation using part of the liver from a living person. Here’s how it works: a piece of liver is carefully removed from the donor. This section has blood vessels that must be precisely attached in the recipient’s body. Because creating a space for the liver section and its vessels is crucial, medical professionals have to very carefully operate to attach everything properly. The amount of liver from the living donor might vary; it could be either 20%, 40%, or even 60% of the total liver volume, depending on the individual situations. Sometimes, two pieces from two donors are implanted into one patient. Just like in deceased donor transplantation, the digestive tract is also repaired.
Throughout the surgery, both in removing and inserting the liver, the patient’s safety is the utmost priority. Care is taken to minimize damage to the body and to ensure that the liver is functioning well post-surgery.
Possible Complications of Liver Transplantation
After a liver transplant, there can be complications that could occur early on or later.
Early Complications
1. Lack of proper liver function in the donated liver
2. Clotting of the liver’s main artery
3. Rapid cell rejection
4. Problems with the bile duct
5. Infectious diseases
In the first week post-surgery, liver health indicators usually improve, and the new liver starts regenerating.
The biggest risk after a liver transplant is if the new liver doesn’t work. This can be identified by no or clear bile production along with worsening liver health markers. In such cases, the patient would need another liver transplant to survive.
In the first two to three days after the surgery, liver health indicators could worsen. This is usually due to damage to the new liver because of changes in environment and temperature at the time of removal and implantation. It’s important, though, to rule out the presence of a clot in the liver’s main artery. Such a clot usually happens shortly after surgery but can occur later too, causing fever and other complications leading to severe liver damage. In severe cases, a second liver transplant may be necessary.
Acute cell rejection can occur in up to 50% of patients after the liver transplant, especially in the first two months. Most patients respond well to treatments with steroids. Rejection resistant to these treatments may require a different course of treatment. A liver biopsy is required to diagnose this condition accurately. Generally, long-term outcomes are positive.
The connection between the bile ducts of the liver and the intestines is the most prone to narrowing or clotting. This can be managed with a range of procedures from non-invasive to surgical.
Patients’ immune systems are deliberately suppressed after liver transplants to prevent the body from rejecting the new organ. This makes patients vulnerable to certain infections like viral and fungal infections. Drugs used post-transplant can also lead to complications like nerve and kidney damage, and high blood sugar.
Late Complications
1. Complications arising from drugs that suppress the immune system
2. The return of the original disease that necessitated the liver transplant
3. New cases of cancer
Long-term complications are often due to side effects of the immunosuppressive drugs. Common issues include chronic kidney disease, high blood pressure, diabetes, and high levels of fat in the blood. These drugs, along with existing kidney disease and high blood pressure before the transplant, can lead to kidney failure after the transplant. This is managed by controlling blood pressure and adjusting the dosage of these drugs.
The drugs suppressing the immune system can increase the risk of heart disease due to an increase in factors like diabetes, high blood pressure, obesity, and high blood cholesterol levels. Along with a high-risk lifestyle, this can lead to a significant increase in heart disease.
The risk of weak and brittle bones is also increased due to the long-term use of steroids, in addition to poor nutrition and lack of vitamin D linked to liver disease. However, this risk has been reduced due to successful treatment with bone-strengthening drugs like bisphosphonates and reducing steroid doses.
Nerve impairments like tremors, insomnia, and numbness may also occur as a side effect of the immunosuppressive drugs.
The original liver disease that led to the transplant can return, including hepatitis B and C, which nowadays can be well-managed after liver transplantation.
New occurrences of cancer are a significant risk in the long term, causing a high number of deaths among liver transplant recipients. Multiple factors increase this risk, including the use of immunosuppressant drugs, viral infections, alcohol consumption, smoking, and older age. More common types of cancer in these patients include skin, lymphatic, cervical, vulvar, and anal cancers.
What Else Should I Know About Liver Transplantation?
When liver transplants with a living donor first started, the treatment outcomes weren’t as good as transplants from deceased donors. Over time, though, getting a transplant from a living donor was found to reduce the risk of dying by cutting down the waiting time for both children and adults to receive a transplant.
In particular, East Asian countries have played a key role in improving this type of transplant because they have fewer deceased donors available. By creating new techniques, surgeries, and ways to ensure transplanted livers work well, they’ve made a significant impact on liver transplants across the globe. As a result, survival rates for transplants using a living donor are now roughly comparable to transplants using a deceased donor. This has greatly improved the lives of patients with a constant liver disease, or sudden severe liver failure carrying a high MELD score – a score above 30 indicating a severe state of health.
