Every year, dozens of infants and small children in need of a liver transplant die waiting for a donor organ to become available. But it’s not usually a lack of donor organs (grafts) that prevents doctors from saving these children—it’s a lack of organs small enough to fit in their bodies.
“Infants and young children waiting for a new liver are at the greatest risk of dying on the organ waiting list, mainly due to a shortage of appropriately sized organs for them,” says Heung Bae Kim, MD, director of Boston Children’s Hospital’s Pediatric Transplant Center. “It’s a troubling statistic, but there are things that can be done to change that.”
The change Kim is referring to would alter current donor organ allocation policies to make more livers available for a special surgical technique called split liver transplantation. Split liver transplantation occurs when a donated adult liver is carefully segmented into two unequally sized portions—the larger segment is given to an adult patient and the smaller portion to a child—saving two people from a single organ.
Because the liver has the ability to regenerate (re-grow), both segments grow larger and are able to take on the work of a whole liver. Currently, a liver is only split if the person atop the organ donor list is too small to receive a whole liver and if his or her surgeon is willing to split the liver instead of waiting for a smaller organ to become available. If allocation policies were changed slightly, to put more smaller recipients higher on the list, it would make more livers available to be split—saving or dramatically improving life for young patients awaiting a new liver.
“If we can increase the number of split livers from 120 to 200, an increase of less than 2 percent of all the livers transplanted each year, it would make grafts available to virtually every small child on the waiting list,” says Kim. “With that increased availability, we could save almost all those children. Given the current national debate on how pediatric grafts are allocated, it’s my hope that implementing this change would benefit both children and adults favorably.”
Because split liver transplantation offers surgeons the rare opportunity to save two people with a single graft, one might assume that the procedure would be universally accepted. However, widespread adoption of the technique has been slow. One of the main barriers to full acceptance of split livers is outdated data that imply partial livers aren’t as safe for transplant as whole ones.
To address these concerns, Kim and a team of researchers led by Ryan Cauley, MD, MPH, have spent years analyzing data that closely examine every split liver case done in the United States for the past 15 years. Their findings, recently published in two different research studies, show that split livers carry almost no additional risk to either the child or adult who receive a partial graft.
“When doctors first began splitting donated livers in the mid-1990s, there was evidence that split grafts were more likely to fail than a whole one. But, as time went on and the surgeons who were splitting the livers got better at it, those additional risks were eliminated,” Kim says. “After an extensive review of all available split liver data, it’s clear that in the modern era both children and adults who receive partial livers are at virtually no increased risk for graft failure compared with those who received a whole organ.”
Based on his research, Kim believes the time is right to change organ donor policy, giving children top priority on the transplant waiting list. By doing so, pediatric transplant surgeons would have increased access to grafts and could split the first liver to become available to allocate to their patient, while the larger segment is allocated to the next adult atop the list—providing perfectly safe grafts for two people at no additional risk to anyone’s health.
“At this point, the data say there is no valid reason for a surgeon to prefer a whole graft over a split one,” he says. “If we can change allocation policies to reflect that, it will allow pediatric transplant surgeons to save the lives of many sick children.”
To learn more about Boston Children’s Hospital’s research on split livers, see these press releases:
- Split Liver Transplants for Young Children Proven to be as Safe as Whole Organ Transplantation in the United States