Background: The new UNOS kidney allocation system (KAS) prioritizes the transplant of highly sensitized patients with a calculated Panel Reactive Antibody (cPRA) ≥80 and extremely sensitized patients with a cPRA ≥98%. However, the actual effects of the new KAS on individual centers are currently unknown.

Methods: This is a single center retrospective review of deceased donor renal transplants in patients with a PRA ≥ 80 performed during the 6 months prior to the implementation of the new KAS (pre-KAS) and 6 months after the implementation of the new KAS (post-KAS).

Results: No significant increase in the number of patients transplanted with a cPRA ≥ 80% was noted, 25% (20/80) in the pre-KAS cohort compared to 23% (17/74) in the post-KAS cohort (p=0.36). However, when examining only patients with a cPRA≥ 98% there was a significant increase from 8.8% (7/80) pre-KAS compared to 23% (17/74) post-KAS, (p<0.001). Thus, we observed an increase in average PRA for highly sensitized patients of 8.2% (from 91.6 to 99.8%, p<0.001). Additionally, there was a significant increase in the number of imported kidneys for highly sensitized patients, from 25% (5/20) in the pre-KAS cohort to 88.2% (15/17) in the post-KAS cohort, p=<0.001. Two additional imported kidneys in the post-KAS cohort were not transplanted due to a positive crossmatch and instead went to non-sensitized, back up patients. The increase in imported kidneys was associated with an increase in the average cold ischemic time (CIT) from 15.5 ± 6.1hrs pre-KAS to 21.7 ± 6.48hrs post-KAS, p=0.01. This was not, however, associated with an increase in delayed graft function (DGF), p=0.28. Furthermore, there was no difference in the kidney donor profile index (KDPI) between the two groups, 30±22% pre-KAS and 27±15% post-KAS, respectively, p=0.74. Importantly, no graft losses or patient deaths were observed in either group.

Conclusions: The new KAS has led to a significant increase in patients transplanted with a cPRA ≥ 98%. However, it has also been accompanied by a significant reduction in patients transplanted with a cPRA between 80% and 98%. Despite a higher percentage of imported kidneys with longer CIT and higher PRA, we report excellent short-term outcomes in the post-KAS. More study is needed to determine the long-term outcomes of extremely sensitized patients transplanted within the new KAS.

CITATION INFORMATION: Grodstein E, Bennett R, Anderson J, Press G, Djamali A, Kaufman D, Redfield R. Transplanting the Extremely Sensitized Patient: The University of Wisconsin Experience with the New Kidney Allocation System. Am J Transplant. 2016;16 (suppl 3).

« Back to 2016 American Transplant Congress