An analysis, based on national data reported to the United Network for Organ Sharing (UNOS), found that transplanting infant hearts across incompatible blood group is as safe as transplantation with compatible blood group types. “There was no difference in outcome between incompatible and compatible transplantation in these infants,” said Luca A. Vricella, M.D., senior author of the study.

“ABO-incompatible heart transplantation can be performed safely in infants with a low incidence of hyperacute rejection,” Patel said. “ABO-incompatible heart transplantation should be considered in infants to maximize donor organ utilisation and reduce mortality among infants,” Vricella said the impact of using incompatible donor hearts could significantly reduce the number of infants who die while on the waiting list to receive donor hearts. “Mortality could be reduced by at least 20 percent by using incompatible donors,” said Vricella, chief of paediatric heart transplantation at Johns Hopkins Medical Institutions in Baltimore, Md. “There would be a huge impact on infants who otherwise have to rely on a very small donor pool.”

The study examined data on infant heart transplant recipients reported to UNOS from 1999 to 2007. Of the 591 infants who underwent transplantation, 35 infants (6 percent) received hearts from ABO-incompatible donors. Two ABO-compatible infants died from hyperacute rejection, while no ABO- incompatible infants died from hyperacute rejection.

One key reason incompatible transplantation works in infants is the role of antibodies known as isohemagglutinins. Until age 12 to 14 months, infants have immature immune systems with little or no production of these antibodies. That means they will not have pre-formed antibodies against the donor heart, lowering the risk of rejection.; Source: American Heart Association