CHICAGO, May 17, 1999 — Nearly two-thirds of all livers donated by children since 1991 were transplanted into adults instead of their peers on the national liver transplant waiting list, despite an increase in the number of pediatric donors, an analysis of nearly 30,000 liver transplants performed in the United States shows.
With fewer of these livers available for children, surgeons have been forced to look at alternative options, such as those involving transplanting a piece of a liver. These types of procedures have increased dramatically, with adults—as either living or cadaveric donors—the primary source of these liver segments. But such efforts have had an impact neither on the waiting list death rate nor on the total number of transplants in children each year, reported University of Pittsburgh researchers today at the American Society of Transplantation (AST) 18th Annual Scientific Meeting.
"How can we assure that children are better served? One might propose a preferential allocation system that matches pediatric organs to the highest-risk children. Another option is the greater exploitation and broader sharing of split liver grafts. Such measures could enhance the survival of these children to levels similar to the entire transplant population," said Rakesh Sindhi, M.D., research assistant professor of surgery at the University of Pittsburgh’s Thomas E. Starzl Transplantation Institute and Children’s Hospital of Pittsburgh.
"Split livers, on the other hand, could essentially double the number of organs available for transplant for both children and adults," he added.
The review of the United Network for Organ Sharing (UNOS) Scientific Registry data of transplants performed between 1991 and 1998 showed that 4,288 of 6,028 pediatric livers were used in adults. While the number of adults who received livers from child donors increased each year (446 in 1991 to 544 in 1998), alternative procedures to combat the "shortage" of organs for children became more and more commonplace. As a result, about one-third of all the pediatric transplants now use segmental grafts, those cadaveric livers that are reduced or split in two or those donated by a living-related adult.
The use of living-related donors, whereby a parent, in most cases, donates a segment of his or her liver to the child, increased three-fold, from 22 in 1991 to 67 in the past few years. Surgeons also began using a technique to divide adult cadaveric livers; children receive the smaller segment while the larger piece is transplanted into adults. Survival for patients who receive split livers is no different than for those who receive whole grafts. Yet while the use of these cadaveric split liver grafts has increased more than 10 times, the potential is not being met, the analysis shows. For instance, in 1997 there were 115 split-liver transplants performed, but there were 427 potential donors of livers that could have been divided to benefit 854 adults and children.
Of the 29,172 liver transplants reviewed from the UNOS registry, 25,534 were in adults and 4,186 were in children. Pediatric livers were transplanted into 4,288 adults and 2,707 children. Pediatric patients with adult livers had a lower one-year graft survival rate than the children who received pediatric organs, 67.9 percent versus 75.5 percent. About 75 children have died each year on the waiting list since 1991.
Under the current organ allocation system, donated organs are preferentially used in the local area where they originate, even if there may be a patient—adult or child—in greater need elsewhere. Only if the organ is not placed locally is it offered on a regional and then national basis. UNOS, which sets organ allocation policy, is being asked by the U. S. Department of Health and Human Services to make improvements to the system to de-emphasize geographic factors. By order of Congress, the Institute of Medicine of the National Academy of Sciences is currently conducting a review of the UNOS system and the government’s proposal. The report is due out this summer.
The Pittsburgh study was co-authored by John J. Fung, M.D., Ph.D., professor of surgery and chief of transplantation at the University of Pittsburgh Medical Center and the Starzl Transplant Institute; and Jorge Reyes, M.D., associate professor of surgery and chief of pediatric transplantation at Children’s Hospital and the Starzl Transplant Institute.