Types of Living Exchanges

• Simple gift – as it sounds • Paired exchange – also as it sounds. Motivated by ABO incompatibility, positive crossmatch • Cascade exchange – see board diagram. Motivated by ABO incompatibility, positive crossmatch, and often desire to increase transplants • Continued next slide

Types of Living Exchanges (cont)

• List paired exchange – (Living) donor 1 donates an organ to UNOS wait list (recipient 2). Afterward, recipient 1 is given highest priority for the next available ABO compatible organ from the list. Why would anyone do this? Hint: has to do with ABO incompatibility… • List cascade exchange – as above, only to start a cascade exchange (see previous slide)

A worry about list paired and cascade exchanges

• “The potential harm to wait-list candidates of blood type O was raised by Ross and Woodle in 2000…and the data from Region 1 has confirmed those fears. In the first 17 list-paired exchange transplants performed, only 1 donor was of blood type O...and only one recipient of the next appropriate deceased donor organ was not of blood type O (Delmonico, et al. 2004)” (Ross, 2006)

Worry (cont)

• “Thus, even though the number of organs is increased by the list-paired exchange program, it is increased at the expense of those who are already worse off. Since candidates of blood type O already have a longer than average wait time, these exchanges further disadvantage those who are already worst off…” (Ross, 2006)