When a liver from a deceased adult or adolescent donor is split into two separate portions for transplantation, with the smaller portion going to a young child and the larger to an adult, the child will benefit as much if they had received a whole organ from a donor close to their size, according to a paper in Liver Transplantation.      

The process of splitting a liver for transplant and allocating the halves to two different recipients began in the mid 1990s and has become more widespread over time. However, adoption of this technique has met some resistance due to early data suggesting that split liver transplants have a higher risk of graft failure and death than whole liver transplants. This new research reveals that this is no longer true among pediatric recipients.

Examining pediatric data provided by the United Network of Organ Sharing (UNOS), the authors researched the mortality and graft survival of 2,679 patients under the age of two who received liver transplants between 1995-2010. Of these cases 1,114 involved partial livers and 1,565 involved whole organs.

Their research indicates that from 1995- 2000 partial grafts had a higher risk of failure, but from 2000-2006 that risk was lower, indicating partial liver transplants became safer as experience with this practice increased. By 2006 both split and whole organs had similarly low rates of both graft failure and mortality, suggesting that their use could be increased to meet the demand for smaller grafts.

"Infants and young children have the highest risk of death on the liver transplant waiting list, mainly due to the shortage of appropriately sized organs," says Boston Children's Hospital researcher Heung Bae Kim, MD, senior author on the study. "But based on this new data, split liver transplantation may prove to be the answer to this difficult problem. If more liver donors were made available for consideration as split liver donors it could significantly reduce the number of young children on the waitlist for a liver, potentially reducing the waitlist mortality rate for this highly vulnerable population to near-zero." 

Due to their small body size, infants and young children in need of a liver transplant cannot accommodate a whole graft (donated liver) from a larger sized donor. As a result these patients have three treatment options:

• wait for a whole liver from a similarly sized deceased donor to become available
• receive a portion of liver from a living donor (usually a family member)
• receive a split liver transplant from an adolescent or adult deceased donor 

"Our study confirms that there is no longer any increased risk of graft failure and mortality in the very young, regardless of whether or not the patient receives a partial or whole graft," says Boston Children's Hospital researcher Ryan Cauley, MD, MPH, first author on the paper. "We are hopeful that this new data will support ongoing efforts to make modifications in the national liver allocation policy that makes more livers available for splitting, thereby saving lives and improving quality of life for many children and their families." 

Data on graft survival and mortality for adult recipients of split livers is currently being compiled for a separate study to be released soon.