Overview of Intestinal and Multivisceral Transplantation
Multivisceral transplantation (MVT) is a type of surgery where several organs are transplanted at the same time. This article is specifically about the simultaneous transplantation of the intestine, stomach, liver system, and a complex area called the pancreaticoduodenal complex – which comprises the pancreas and a part of the small intestine. Based on the recipient’s condition, surgeons can choose to transplant different combinations of these organs. Another approach some surgeons take is to transplant any organ that depends on two major arteries – the superior mesenteric artery and the celiac artery.
The concept of such a comprehensive organ transplant was first introduced in 1960 by Thomas Starzl, who is often referred to as the father of modern transplantation. Initially, this type of transplant was tested on dogs to study the effects of removing the nerve supply to the new organs. The concept was revived in the 1980s and tested on humans. However, these attempts were not entirely successful as the first patient experienced severe bleeding after the operation, and the next two developed a serious condition known as posttransplant lymphoproliferative disorder (PTLD), which is a rapid increase of cells after a transplant.
Despite these early setbacks, the first successful MVT happened in December 1989. The patient was not reliant on parenteral support, which means nutrition given intravenously, for 10 months, but ultimately died from pancreatic cancer that had spread.
Since 1988, there have been 1,916 intestinal transplants performed with additional organs. The most common combination includes the liver, intestine, and pancreas (performed 1,105 times), and the second most common is the liver and intestine together (performed 464 times). Thanks to developments in medications to suppress the immune system (preventing it from rejecting the new organs) and improved care after the operations, the survival rates have greatly improved. In the 1990s, only around 40% of patients survived for a year after the operation, but now over 80% do. The five-year survival rate is currently around 60%.
Why do People Need Intestinal and Multivisceral Transplantation
Intestinal transplantation is a surgical procedure considered when intestinal failure has led to problems in multiple organs. Intestinal failure happens when the body can no longer maintain the right balance of proteins, fats, carbohydrates, salts, fluids, and other vital substances. This condition is often due to short bowel syndrome which affects up to 70% of people receiving intestinal transplants. Do note not everyone with short bowel syndrome will require transplantation. There are more factors to take into account.
An intestinal transplant might be necessary for the following situations:
- Repeated infections in the main intravenous line used for nutritional support (More than two infections per year or one infection caused by fungi).
- Organ problems that happen due to the long term use of intravenous feeding, often seen as liver problems.
- Blood clotting or narrowing of veins making it difficult to feed the patient through an intravenous line.
- Frequent dehydration despite receiving intravenous feeding and fluids.
Other common reasons for adults to need an intestinal transplant include short bowel syndrome, loss of blood supply to the small intestine (mesenteric ischemia), abdominal tumors, inflammatory bowel diseases (which might lead to short bowel syndrome), damage due to radiation therapy to the abdomen, and injuries to the abdomen.
For children, the most common reason is a condition called volvulus, where the intestine twists on itself. Other reasons include a birth defect where the baby’s intestines stick out of the body (gastroschisis), severe intestinal infection (necrotizing enterocolitis), conditions that affect the intestine’s movements (such as Hirschsprung’s disease), birth defects where a part of the intestine is not developed completely (intestinal atresias), and short bowel syndrome.
When a Person Should Avoid Intestinal and Multivisceral Transplantation
Just like the rules for other transplants involving solid organs, there are some situations where multivisceral transplant (MVT), or a transplant involving several organs, may not be recommended:
– If the patient has a disease that has spread to other parts of the body (called metastatic disease) and this cannot be treated with a transplant.
– If the patient has a full body (systemic) or specific local infections that can’t be managed or treated.
– If the patient has heart or lung disease that could make the transplant outcomes less successful.
– If the patient does not have enough family or social support to help them with recovery and managing their health after the transplant.
– If the patient is currently struggling with drug or alcohol addiction.
Who is needed to perform Intestinal and Multivisceral Transplantation?
Like many surgeries involving organ transplants, it’s important that different health professionals all work together to give the patient the best care. Depending on the exact type of organ transplant, different kinds of doctors and medical professionals are needed before and after the surgery. These include liver specialists, dieticians who will help plan the patient’s meals, managers who oversee the patient’s care, social workers, nurses who specialize in organ transplants, the surgeons who will perform the operation, and therapists who help the patient get back to their normal activities.
All of these people play a crucial role in helping the patient recover over the long term. Sometimes, if the patient has been using alcohol or drugs, a psychiatrist might also need to be involved. However, many organ transplants involve children, who might not need this kind of mental health evaluation.
Preparing for Intestinal and Multivisceral Transplantation
Before a transplant, several tests and evaluations are done to ensure the patient and the organ are a perfect match and that the patient is healthy enough for the operation.
These tests include HLA typing and blood crossmatching—both tests used to make sure the organ won’t be rejected by the body. Standard laboratory tests are also done, such as a complete blood count (CBC), a comprehensive metabolic panel (CMP), prealbumin—a protein level test, and a coagulation panel—to check how well the blood clots.
Other tests include checking for specific viruses like cytomegalovirus, Epstein-Barr virus, hepatitis A, B, and C, and HIV. These tests are run because these viruses can cause complications if they’re in the patient’s body when the transplant happens.
The doctor also will examine the length and functioning of the bowel using a computed tomography (CT) scan—a type of imaging test that uses x-rays to make detailed pictures of the inside of your body.
Another key step is checking the blood vessels (veins and arteries) in the abdomen. This helps doctors understand if there are any blockages or issues that could make the transplant less successful.
Some patients may be asked to undergo additional imaging tests like splenoportography and mesentericography—both tests that look specifically at the blood vessels supplying the liver and intestines.
Some patients may need to go through a procedure called angioplasty to open up these blood vessels. This is done before surgery.
Doctors will also take a small sample of the donor’s liver and of the recipient’s liver (if needed). This liver biopsy allows doctors to look for any liver damage.
The patient will also have their teeth and possibly their ears, nose, and throat checked to make sure they don’t have any infections that could affect the surgery. In some cases, it might be necessary to remove a tooth before the operation.
The patient’s overall health will be evaluated to understand their risk for surgery and any potential issues that could come up during the surgery. This might include a heart test (coronary angiography), a lung function test, and a nutritional status check to understand if the patient is well-nourished and ready for surgery. This tailored pre-surgery evaluation helps doctors aim for a successful transplant.
How is Intestinal and Multivisceral Transplantation performed
Isolated Intestinal Transplantation (IITx) is a surgical procedure that is often carried out more in adults compared to children. Essentially, this process can involve a living donor, and it involves transplanting a section of the small intestine from one individual to another. The procedure can also be adapted to include the pancreaticoduodenal complex – a portion of the digestive system that includes the pancreas and a part of the small intestine.
The process of transplanting the section of the donor’s small intestine involves carefully identifying and separating the blood vessels that supply and drain blood from the selected portion. After extracting the small intestine from the donor, it is attached to the recipient’s digestive tract which is the proximal duodenum/ jejunum – the beginning part of the recipient’s small intestine.
For some patients, it might also be necessary to also include a segment of the ascending colon and its associated arteries in the procedure, depending on their unique situation. Afterwards, frequent post-operation checks are done using a technique called endoscopic access, which involves a small camera being inserted into the body to inspect the transplanted organ inside the recipient’s body.
The procedure is adapted when living donors are involved by ensuring that the donor and recipient each have enough healthy bowel left for normal function. Basically, a certain length (about 150 cm) of an ileal segment – a portion of the small intestine nearest to the large intestine- is removed from the donor and transplanted into the recipient. For the recipient, vascular anastomosis – the connection of blood vessels- might also be created using the major blood vessels such as intra-renal aorta or infrarenal vena cava depending on their anatomy.
There’s a special case of IITx called the Combined Liver-Intestine, where liver transplant is also involved, typically in people whose liver functions have been compromised due to prolonged use of parenteral nutrition – nourishment given via the bloodstream – which is more common in children. Previously, the liver and small intestine were transplanted separately, but due to complications, they started to be transplanted together. During this transplantation, the patient ends up having two duodena (parts of the small intestine) and two pancreases.
There are more complex forms of this procedure such as the Multivisceral which does not have a clear standard as it adapts to the individual patient’s need. It can involve transplantation of multiple organs like the kidney, spleen, stomach, and more. For example, sometimes, in addition to the small intestine, the stomach of the donor is also added into the recipient but modified to exclude the liver.
Possible Complications of Intestinal and Multivisceral Transplantation
For people who receive a small bowel transplant, one of the most common problems faced is called rejection. This means that the person’s body doesn’t accept the new organ, and tries to fight it as if it were a foreign object. Although newer drugs developed in the 1990s helped make the surgery more successful, the small bowel is particularly tricky because it is a large organ and plays a key role in our immune system.
The standard drugs taken by patients after surgery are tacrolimus, mycophenolate mofetil, and prednisone. These help to reduce the chances of rejection. Determining whether rejection is occurring often involves carefully watching for certain symptoms, such as increased output from the stoma (the opening where waste exits the body), belly pain and bloating, and weight loss.
This is supplemented by carrying out regular checks, what doctors call ‘surveillance’, performed at intervals planned by the medical team. The gold standard for diagnosing rejection involves taking small samples of tissue from various parts of the graft (the new organ) for inspection under a microscope.
A concerning issue called Graft versus Host Disease (GVHD) may occur. Think of it like this: it’s as if the donor cells in the new organ recognize the cells of the patient’s body as foreign and start attacking them. GVHD is seen in about 6% of patients, but is serious and can be fatal. Detection involves advanced lab techniques, including amplifying and testing for specific DNA sequences. Medical professionals treat GVHD by increasing the dose of drugs that control the immune response, or sometimes through stem cell therapy.
Then there’s PTLD, a complicated condition that actually involves a range of different symptoms. It can cause abnormal and potentially harmful growth of immune system cells, more specifically B lymphocytes. This condition is often connected to a virus called Epstein-Barr. Its treatment includes reducing the drugs that suppress the immune system and giving antiviral medication, yet this puts the new organ at risk of rejection.
Infections are another big risk for people who get an organ transplant. When immunity is reduced to help the body accept the new organ, it unfortunately opens up the possibility of infections that are often harmless for people with normal immunity. One example is cytomegalovirus, which is particularly problematic in small bowel transplant patients because it tends to infect cells of the digestive system.
Surgery related complications can also occur usually during the early days following the transplant. These might include leakage from the area where the new organ is stitched to the bowel, blockages in graft blood vessels, and bleeding. Some of these can be managed without extra surgery, but a blockage in the graft’s artery is a critical situation which needs immediate surgery. In some cases, it might not be possible to save the new organ, and a second transplant might be necessary.
What Else Should I Know About Intestinal and Multivisceral Transplantation?
Intestinal and multivisceral transplants, which involve replacing diseased organs in the body with healthy ones, have come a long way since the late 1980s. Back then, they were risky procedures, but today they can truly change a patient’s life for the better.
According to a study of 500 of these transplants, patient survival rates were found to be 85% after 1 year, 61% after 5 years, and 42% after 10 years. However, it’s important to note that the survival rates for the transplanted organs (called grafts) were a bit lower – 80% after one year, 50% after five years, and 33% after ten years.
Additionally, when comparing multivisceral transplants to parenteral nutrition (a method of providing nutrients directly into the bloodstream), patients who received the transplant had a significant improvement in their ability to function in daily life, decreased anxiety, and overall higher quality of life. In fact, about 85% of the patients even reported having a normal functional status following the transplant.
