Living donor liver transplantation with special reference to ABO-incompatible grafts and small-for-size grafts

Living donor liver transplantation (LDLT) has developed on the basis of increased safety of conventional liver surgery and the need for expanding donor sources, especially in children. Indications for LDLT were soon extended to adult patients in Japan, where cadaveric donation was limited. The right liver is now routinely transplanted to adults to avoid small-for-size graft syndrome, even though the right liver graft has the disadvantages of less remaining donor liver and the question of donor safety. Assessing the suitable size or quality of the graft, as well as of the remnant donor liver, is one of the most important problems in adult LDLT. Although several tactics have been proposed to manage the small-for-size syndrome, their efficacy remains a question. We suggest that small-for-size syndrome is preventable by engaging in careful donor selection or using effective agents for hepatic microcirculatory disturbance control. Sometimes for LDLT only ABO-incompatible grafts are available from relatives, but they must be transplanted despite the expected poor outcome in adults and older children. To overcome the problems in this situation, we developed a novel protocol including intraportal infusion therapy with methylprednisolone, prostaglandin E1, and gabexate mesylate. Two adult patients undergoing ABO-incompatible LDLT have now survived 53 and 35 months after transplantation with good liver function. However, the other two patients suffered thrombotic microangiopathy postoperatively and died owing to cerebral hemorrhage or multiple organ failure, respectively. Further investigation is needed to improve the outcome of liver transplantation across the ABO blood group barrier.