Liver and Multi-Organ Exchange

Kidney exchange, where candidates with inoperable organ failure trade incompatible but willing donors, is a life-saving alternative to the deceased donor waitlist, which has inadequate supply to meet demand. Computer scientists and economists study this problem because it represents an opportunity to field a real barter exchange that improves sustainability of life and creates significant societal value. In this paper, we first consider extending large-scale organ exchange to liver lobes. Liver exchange has its own interesting aspects that differ from kidney exchange. We describe and implement a general, and to our knowledge the most realistic, organ exchange compatibility graph generator and show that it addresses important weaknesses in the most commonly used kidney exchange generator. We show liver exchange clearing results on this demographically accurate data, and optimally clear liver exchanges at the estimated nationwide size using an enhancement to the fielded kidney exchange clearing algorithm. We then explore cross-organ donation where a candidate needing a kidney and a candidate needing a liver can swap donors, and show that this increases the total number of lives saved. We conclude with thoughts regarding the fielding of a nationwide liver or joint liver-kidney exchange from a legal and computational point of view.