Liver transplant with Dr. Jonathan Merola

Up until the 1980s, the vast majority of children on the transplant wait lists passed away due to the lack of available organs.

In the 1990s, techniques that took advantage of the liver's segmental anatomy and ability to regenerate greatly increased organ availability, with segmental transplants (Baron graphs or segmental grafts) decreasing waitlist mortality from 80% to just 10%.

For children under 1 year of age, mortality remains at about 30% due to size constraints.

The most common indication for pediatric liver transplant is biliary atresia.

Native liver survival after a Kasai procedure can be as high as 80%, with keys being early diagnosis and selective use of antibiotics and steroids.

In adults, organ allocation is based on the MELD score, which estimates a patient's chances of survival in the next 3 months, ranging from 6 to 40 (higher is worse), based on creatinine, bilirubin, serum sodium, and INR.

In children, the PELD score is used for those under 12 years of age, calculated using albumin, bilirubin, INR, and degree of growth failure without creatinine, with special designations of 1A for acute liver failure and 1B for hepatoblastoma.

Only about 25% of kids with acute liver failure survive their condition without a transplant or death.

A study from a major liver center in Denmark used high volume plasmapheresis for 16 children when bilirubin exceeded 20 or if they had a toxic ingestion as a cause.

A native liver with over 90% necrosis will eventually recover, taking advantage of the liver's regenerative capacity.

In auxiliary liver transplant, the native left liver can be resected leaving the right lobe behind, then transplanted with a new left lobe maintained with immunosuppression for 6 months while the native liver recovers.

Hepatoblastoma is the most common liver tumor for kids under 5, and for tumors too extensive to be resected, transplant is the only treatment of choice.

About 60% of hepatoblastomas are unresectable at the time of diagnosis, and about 20% of patients remain unresectable after chemotherapy.

The second most common indication for pediatric liver transplant is metabolic liver disease, most caused by single gene mutations affecting enzymes principally harbored in the liver.

Dr. Merola explained that in the future, many metabolic liver diseases may be cured with cellular therapies using isolated pluripotent stem cells with corrected deficient genes, expanded as liver organoids and infused back into the patient.

Living donor liver transplant offers the advantage of hastening organ access and a faster recipient recovery, with recipients having much shorter length of stay and requiring fewer transfusions because they don't have to wait until extremely sick.

At Cincinnati Children's Hospital, they make liberal use of infrarenal aortic conduits where a piece of donor iliac artery is placed end to side on the aorta and the other end anastomosed end to end to the recipient hepatic artery, giving excellent arterial flow when the small native hepatic artery is inadequate.

Graft survival after pediatric liver transplant routinely exceeds 30 to 40 years, especially for living and partial donor grafts.

Primary nonfunction results from severe ischemic injury and possibly preformed antibodies, but fortunately happens in less than 1% of transplants.

Vascular complications are much more common in pediatric transplant and usually occur within the first 30 days.

Hepatic artery thrombosis is the most common vascular complication, and when it happens within the first week and revascularization is not possible, it receives a special designation since urgent retransplant is the only treatment.

Biliary strictures are the Achilles' heel of liver transplant, but thankfully most can be managed with endoscopic dilation.

Acute rejection in children is about 20% in the first year, but does not affect survival of the liver transplant if treated early with steroids.

Untreated rejection can lead to chronic injury, which is the most common cause for late graft loss.

There are two types of ex vivo perfusion platforms available: normothermic platform and cold perfusion pulsatile platform, both shown to help livers recover when they're high risk grafts.

Many transplant centers, particularly in the adult population, are using the pump, putting high risk livers on pump to assess if they perform adequately before transplant.

The next step in ex vivo organ perfusion technology is treatment of livers: making fatty livers less fatty, enhancing immune compatibility, and changing blood group antigens.