Failure to convert computer-identified possible Kidney Paired Donation (KPD) exchanges into transplants has prohibited KPD from reaching its full potential. The purpose of this study is to review and analyze the efficacy of two different methods of generating KPD transplants.

METHODS

The Alliance for Paired Donation (APD) utilizes an optimization algorithm that selects either simultaneous closed loop exchanges (Cycles) or Non-simultaneous Extended Altruistic Donor (NEAD) chains. NEAD chains are initiated by a non-directed donor (NDD) and end with an overhanging bridge donor, who is entered back into the pool. This bridge donor can then initiate another NEAD chain at a later date. Computer-generated potential cycles and NEAD chains are presented to transplant centers for review, at which point they become a formal offer. The progress in moving from offer to completed transplants was tracked and recorded in order to calculate the success rate (SR).

RESULTS

Between January 2007 and December 2013 the APD performed 200 transplants: 169 within the APD as well as 31 in collaboration with other KPD programs. Of the 169 APD transplants, 41 (24.2%) were performed through cycles (Figure 1a). In contrast, 128 out of 169 transplants (75.8%) were performed through chains (Figure 1b), suggesting that chains were three times more successful than cycles. The APD made 393 offers to transplant centers, of which 137 (35%) were cycles and 256 (65%) were chains. The SR of cycles was 12.5%, compared to 27.3% for chains. The overall SR was 22.1%.

CONCLUSIONS

The APD, in conjunction with other registries, has successfully performed 200 KPD transplants, the majority of which were NEAD chains. Though chains were not actively sought over cycles, the results demonstrate that chains were 1) more likely to be found by the optimization algorithm and 2) more likely to progress to completed transplants than cycles. The concept of a bridge-donor introduces significant flexibility in generating transplants. We propose that NEAD chains are the most effective tool to increase the efficiency in KPD programs.