In Brief

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The face of hepatic transplantation has changed considerably from its experimental beginnings more than 50 years ago to a nowadays nearly standardized procedure representing the therapy of choice for patients with end-stage liver diseases. Thomas Starzl was the first surgeon who performed 3 liver transplantations in humans in 1963. The first patient died during the operation, the second within 7 days, and the third recipient survived for 22 days. The crucial breakthrough can be traced to the 1980s with the introduction of cyclosporine A. Until then, extensive efforts were made to reach the current status of liver transplantation. A better understanding of the hepatic anatomy, rapid improvement in surgical technique, and the multidisciplinary setup extended the application and indications for liver transplantation, leading to growing waiting lists. Contrary to that positive development, stagnation of available deceased donor organs limited further progress, resulting in growing mortality for patients awaiting liver transplantation. The discrepancy between organs and recipients forced the transplant community to develop alternatives to whole organ transplantation to increase the net organ numbers. To split 1 liver into 2 functional grafts has turned out to be an efficient tool to extend the organ pool while the development of living donor liver transplantation could increase the donor pool. Both variants turned out to be feasible and save procedures, providing promising results with survival rates comparable to that of whole organ transplantation.

The actual aims of liver transplantation are to ensure the recipient the best possible outcome with respectable patient and graft survival and a high quality of life. Therefore, careful handling of the different steps of the transplant procedure is recommended. First, the donor must be selected, respecting the intended procedure. Regarding split liver transplantation, there are stricter demands of the deceased donor compared with whole organ transplantation. Due to the complex and time-consuming split procedure that results in 2 smaller grafts, the organ quality must be even higher, requiring “younger and healthier” donors. A further distinction must be made between left lateral split and full split procedures. The full split procedure, providing 2 grafts for 2 adult recipients, places the highest demands for graft quality and also surgical skill because this is the most challenging technique. In accordance, selection of the respective recipient must be performed thoroughly as well. Split liver grafts should be reserved for elective patients, respecting the higher demand of liver mass in urgent and mostly troubled situations. In pediatric recipients the status of the patient does not limit the use of split liver grafts due to relatively higher graft-to-recipient-weight-ratio, which is reached in almost every case, and the absolute rareness of size-matched whole organs.

The current allocation system of the model of end-stage liver disease (MELD) has complicated the optimal application of split liver transplantation due to the concept of “the sickest first,” hindering selection of the elective recipients who would benefit the most from a segmental graft.

After careful donor and recipient selection and an accurate surgical technique of harvesting, eventually splitting of the graft and implantation procedure, the postoperative care is the next important issue for a positive outcome of the liver transplant recipient. The postoperative care involves a multidisciplinary team of anesthesiologists, hepatologists, radiologists, nurses, psychologists, and others. The team must provide the optimal support to prevent complications and to detect complications in case of such events. The recipient is endangered by several surgical complications particularly in the early postoperative course including mainly vascular and biliary complications. Prevention of graft loss due to vascular problems often requires immediate diagnosis and intervention; routine use of Doppler ultrasound has shown to be 1 of the keys in detecting the majority of vascular events. Biliary complications remain the Achilles' heel even in split and living donor liver transplantation, leaving the biliary reconstruction as 1 of the challenges to optimize the surgical procedure.

In the long-term course, most adverse events are related to immunosuppression, which is nowadays individualized but still associated with significant side effects. To develop feasible strategies of tolerance induction is 1 of the main topics in transplant research, and even if we noticed several promising approaches in that field there is still no tolerance-inducing protocol that can be safely and successfully used in a major group of patients.

Development in living donor liver transplantation (LDLT) has reached the point where pediatric LDLT represents a routine procedure with minimal risks for the living donor of a left lateral liver lobe. Adult LDLT has also become a widely accepted technique with very good results, but the discussion about the donor risk remains distinguished. Harvesting a right liver lobe from a healthy altruistic donor is the most invasive procedure one can imagine, and despite all ethical issues, this intervention must be justified by minimizing the donor's risk before any other aspect, and the donor's risk must be put into consideration with the donor's and recipient's benefit. Future work in this field will be to enable the transplantation of smaller grafts such as full left or even left lateral liver lobes from living donors with acceptable results. Even if we can safely transplant LDLT recipients with a graft-to-body-weight ratio of 0.8 compared with 1.0 to 1.2 in split liver transplantation, due to a higher graft quality and short ischemic times in LDLT, we are not yet able to routinely reduce that limit down to 0.5 or less, which would be desirable.

Even if the transplant community were able to reach the current excellent results in pediatric and adult liver transplantation with 5-year survival rates of approximately 80%, there are still limitations and boundaries that necessitate further effort. Split liver transplantation as a reliable extension of the organ pool should be supported for a widespread application with the ability for graft and recipient matching for optimal outcome. The transplantation of small grafts especially in LDLT, maybe in combination with stem cell or hepatocyte application, opens the future for liver transplantation. Together with new immunosuppression or tolerance-inducing strategies, representing a gain in quality of life, the nowadays “adolescent” face of hepatic transplantation may come of age.