How does living donor liver transplantation (LDLT) compare to living donor kidney transplantation (LDKT) in terms of difficulty, chances of success for the recipient, compatibility issues, level of risk and recovery time for the donor, etc.? How many living donor liver transplants have been performed to date?

Answer: Removing a section of a volunteer donor's liver is a probably a riskier undertaking compared to removing a kidney. However, since the procedure is relatively new in comparison, there are insufficient data to quantify the risk. 

To date there have been more than 60,000 reported live kidney donations, and there have been about 20 reported donor moralities, for an estimated risk of ~0.03%. Comparable data for living donation of the liver are not available, but the risk is believed to be on the order of 0.5-1.0%.

Generally the same ABO compatibility issues are present for liver donors as for kidney donors, but the number of antigen matches with the recipient does not seem to matter as much as it does for kidney recipients.

Regarding the chance of success, the graft survival rate for living donor kidney transplants is far superior to the graft survival rate for living donor liver transplants. Recovery time for the donor should be roughly similar for liver and kidney donors. The liver grows back to normal size after a segment is removed, and in this sense it is unique among solid organs. The remaining kidney of someone that has a kidney removed generally enlarges and functions at about 80% of what someone with two normal kidneys would.

The 1997 UNOS Annual Report lists the number of liver transplants from living donors through 1996 in Table 1. The peak was 60 in 1994. From 1989 to 1996 there were ~250 living donor liver transplants and about 24,000 liver transplants from cadaver donors.
-Jeffrey Punch, MD