A disturbing trend has developed in the field of organ transplantation during the past several years. The number of recipients is constantly increasing while the number of donors remains relatively unchanged. This trend has led to a persistently widening gap between organ demand and organ supply. According to UNOS (United Network for Organ Sharing), in 1994, 4,059 patients were on the liver transplant list and 3,653 liver transplants were performed in the United States. Just three years later, in 1997, the waiting list increased to 9,637 patients, but only 4,165 liver transplants were performed. In just one year, from 1995 to 1996, the waiting time for Status III (waiting at home) patients doubled to almost 500 days. Although the 1998 UNOS Report has not been released yet, the trend seems consistent since at our center last year, only Status IIA (waiting in ICU) or rarely Status IIB (waiting in the hospital) patients were transplanted. With the absence of artificial liver support, chronically ill patients are now faced with increased morbidity and mortality while waiting for a transplant. There is approximately 10, 15 and 20% difference in 5-year patient and graft survival between patients who were Status III pre-transplant and those who were Status IIB, Status IIA, and Status IIA or I (acute liver failure) on life support, respectively. The use of marginal donor livers has been a relatively new concept and involves utilization of elderly donors or donors with hemodynamic instability. However, there is about a 20% difference in 5-year patient and graft survival between patients receiving organs from optimal donors compared to marginal grafts.

The idea of transplantation from living-related donors goes back to the early 1950s in kidney transplants. Currently, about 30% of all renal transplants performed in the United States are from live donors, and, increasingly, live donors are being considered in lung, pancreas, and small intestine transplantation. The first live-donor liver transplantation was performed in 1988 and was popularized by Christoph Broelsch from Hamburg, Germany. Currently, there are 18 centers performing live donor liver transplants in children in the United States. This approach offers the opportunity to eliminate waiting time, improve immunologic match, and reduce ischemia reperfusion injury by decreasing cold ischemia time. The long-term results have been superior compared with other modalities, as well. In pediatric patients in the United States, 1-year patient and graft survival was 88.4% and 75.6% for the live donor, 82.6% and 70.9% for the whole organ, 82.0% and 60.3% for the split-liver, and 74.4% and 61.1% for the size-reduced liver approaches, respectively. An even more striking difference was shown in recipients in recipients less than 1 year old. Patient and graft survival at 1 year was 89.4% and 83.3% for the live donor, 76.5% and 62.3% for the whole organ, and 75.0% and 62.7% for the size-reduced liver approaches, respectively. The number of split grafts in this recipient population was inadequate for comparison.

Having achieved superior results in pediatric patients, live- donor liver transplants are now increasingly being considered in adults. There were several reports of successful outcomes in adults. In a series reported from Hong Kong, 13 adult patients received an extended right lobe of liver from live donors. Eighty-six percent patient survival was reported with a follow-up period of 5 to 10 months. The left hepatic lobe of the donor was utilized in all cases in a Japanese series of 13 adult patients. Eighty five percent recipient survival was achieved with follow-up ranging from 2 to 35 months. Recently, reports from transplant centers in the United States described the successful use of the right lobe and left lateral hepatic segment from live donors.

Certain guidelines have been developed in the selection of recipients and donors for live-donor liver transplantation. The recipient must have chronic progressive or fulminant hepatic failure and be listed as a liver transplant candidate on the UNOS waiting list for a cadaveric liver transplant. Liver transplantation from live donors should be considered when no donor organ is forthcoming and the patient continues to deteriorate. This option should be presented to the patient and family by the referring physician or by the members of the transplant team. It is ideal if the inquiry regarding live-liver donation is initiated by the patient's family. The procedure details, benefits, and risks are explained to the patient and family by members of the liver transplant team.

Live donors should be healthy adults (18 to 55 years old) and preferably close relatives. Unrelated donors may be considered in special circumstances. Live donation is not considered from people with long-standing type I diabetes and hypertension, obesity, HIV infection, previous malignancy, chronic medical conditions or infectious disease, hematological disorders, chronic liver disease, significant alcohol use, propensity to or evidence of thromboembolism, psychiatric disorders, or mental disabilities. The evaluation of the potential donors is preferably done at the transplant center. The work-up of potential donors includes completion of a specific questionnaire, psychosocial evaluation, physician interview, and physical examination, chest x-ray, EKG, standard laboratory hematology and chemistry tests, viral serology (HBV and HCV) and abdominal CT scan for liver volume determination and the calculation of optimal graft size. Additional tests or consultations may be necessary based on the initial evaluation. Once the work-up is completed, the candidacy of the donor and recipient is discussed at the candidate selection conference.

The live donor approach for adult recipients offers the same advantages as for pediatric patients. The only limitation is the selection of a donor with optimal volume that will permit adequate function in the recipient following engraftment. The volume of the graft should not be below 50% of the required liver volume, which is estimated as 2% of body weight of the recipient. Therefore, the small size recipient and large size donor combination is likely to be successful. Because liver resection is not a risk-free operation, the donor's safety has to be carefully addressed. In most cases of live-liver donation, 25% of the liver is removed if it is for the child, and 50% for the adult. Almost all donor operations have been accomplished without the need for blood transfusion. The resected liver usually regenerates in both the donor and recipient in 6-8 weeks. No long-term adverse effects for the donor were reported from the overall experience of major transplant centers involved in living-related liver transplantation.