Divided-organ approach works in U.K., but may be a tough sell in U.S.
by Michael Smith, North American Correspondent, MedPage Today October 22, 2017

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• Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

WASHINGTON — Wider use of “split livers” for transplant — in which the organ is divided and used in two recipients — could save the lives of dozens of children and teens a year, a researcher said here.
Analysis of transplant data from 2010 through 2015 suggested there were enough “split-able” livers available to treat all of the 261 children who died on the transplant waiting list during that period, according to Emily Perito, MD, of the University of California San Francisco (UCSF).
At the same time, the larger portion of the liver would be available for an adult recipient, saving two lives instead of one, Perito told reporters at the Liver Meeting, the annual conference of the American Association for the Study of Liver Diseases (AASLD).
Unlike most organs, the liver can regenerate itself and indeed the phenomenon is the basis for what are called “living donor transplants,” in which one person donates part of the liver to a patient.
For a whole liver from a deceased donor, pediatric patients very often have to wait for one the right size. But Perito noted that an adult liver from a deceased donor can be split into unequal parts, with the smaller left side going to a child and the remainder going to an adult.
While there is an increased risk of complications, they are usually manageable, Perito said. But despite that, less than 2% of all pediatric transplants in the U.S. involve a split liver and many children die on the waiting list every year.
In the U.K., she noted, the situation is very different: From 2011 through 2014, 18% of pediatric liver transplants involved a split liver and there were no deaths on the waiting list.
Analysis suggests a similar picture is possible across the U.S., she said.
Perito’s data are “compelling” and might help move the U.S. along the path to wider use of split livers, commented AASLD media briefing moderator Norah Terrault, MD, also of UCSF. She was not involved in the study.
“We don’t want to have a child dying on the list,” Terrault said, and using split livers more extensively could prevent that, as it has done in the U.K.
But she added that the logistical complexity of the issue can be daunting to physicians used to dealing with a single organ and single recipient. “That’s the complication that has led to decreased enthusiasm here in the U.S. The surgeons have to decide to do this,” she told MedPage Today.
To estimate the effect of split livers, Perito’s group first looked at the more than 35,000 deceased donor organs that were available from 2010 through 2015, and found that about 2,300 were potentially split-able — the donors were neither too old nor too young, and didn’t have other characteristics making the organs unsuitable.
Of those, just 4% were actually used for a split-liver transplant, they found.
Also, about half of the organs went to recipients who would have been at high risk had they had a split-liver transplant, leaving about 1,100 organs potentially suitable. Some 78% of the adult recipients had said they would accept a segmented organ and only 3% were listed as requiring a cold ischemia time of less than 6 hours.
The analysis showed that in each of the 11 regions defined by the United Network for Organ Sharing, which allocates organs for transplant, the number of potentially split-able organs was greater than the number of children who died on the wait lists, Perito said.
She acknowledged several barriers to increasing the number of split-liver transplants, including changes to practice, concern for patient outcomes, potential complications, technical and logistical complexity, and the fact that many transplant centers have limited experience with split-liver transplants.
But she said those could be overcome by changes in allocation policy to encourage the practice, increased training for physicians, and improved methods of splitting the organ to reduce damage.

The study was supported by the NIH, UCSF, OPTN, HRSA, and the Minneapolis Medical Research Foundation.
Perito disclosed no relevant relationships with industry.
Terrault disclosed relationships with Dynavax, Gilead, Bristol-Myers Squibb, Conatus, Intercept, Merck, Novartis, AbbVie, Biotest, Eisai, and Vertex.
• Primary Source
American Association for the Study of Liver Diseases
Source Reference: Perito S, et al “Increasing split liver transplantation in the U.S. could decrease pediatric deaths on the waiting list” AASLD 2017.