P141Kas three years later: life after the bolus effect

Aim The new Kidney Allocation System (KAS) resulted in a significant bolus in the transplantation of 99–100 CPRA candidates due to increased priority. We examined the impact of an individualized approach to maintain a high transplant rate for these candidates three years after KAS implementation. Methods The early post-KAS period (EPKAS) was defined as deceased donor transplants occurring in 2015 and 2 year post-KAS period (2YPKAS) as 2016 and 2017. Donor specific antibody positivity (DSA+) was defined by single antigen bead assays performed pre-transplant (±7 days) and 90 days post-transplant (±14 days). Flow cytometric crossmatches (FCXM) were performed using the pre-transplant serum, donor lymphocytes, and acquisition on a BD Canto instrument. Data from SRTR was used to assess outcome at 1 year for our center and nationally. Results Nationally, transplantation of 99–100 CPRA candidates rose sharply (17.7%) in the EPKAS period and has since tapered (10%) in the 2YPKAS period. At our center, we observed a similar increase in the EPKAS period (16%, n = 30) but this trend increased further during the 2YPKAS period (28%, n = 75). In the EPKAS period, 60% (n = 18) of 99–100 CPRA recipients were DSA+ and 39% (n = 7) of DSA+ recipients were also FCXM positive. 61% (n = 11) of DSA+ recipients during this period had persistent DSA at 90 + days post-transplant. In the 2YPKAS period, a similar percentage (57%, n = 43) of 99–100 CPRA recipients were DSA+ at time of transplant; however, fewer (8%, n = 6) DSA+ recipients were also FCXM+. Correspondingly, fewer (34%, n = 26) DSA+ recipients had persistent DSA at 90 + days post-transplant. A total of five (5%) candidates in the post-KAS era experienced a rise in DSA post-transplant that required intervention. The hazard ratio for 1 year graft survival was 1.05 for our center and 1.00 nationally. Conclusions Our center continues to successfully transplant 99–100 CPRA candidates at a rate higher than the national average. This has been achieved through a personalized approach for defining unacceptable antigens and assessing donor offers, transplanting across DSA barriers, and a stringent post-transplant monitoring protocol. Refinement in our approach in the 2 year post-KAS has resulted in more compatible transplants, less DSA persistence, and the maintenance of good clinical outcomes. A.M. Jackson: 3. Speaker’s Bureau; Company/Organization; Thermo-Fisher.