31.01 Graft and Patient Survival after A2-incompatible Donor Kidney Transplantation

S. Bisen¹, S. Getsin¹, T. Chiang¹, S. Yu¹, K. Jackson¹, D. Segev¹, A. Massie^{1 1}Johns Hopkins University School Of Medicine,Department Of Surgery,Baltimore, MD, USA

Introduction:

ABO type B and O recipients have increased difficulty identifying a compatible donor for living donor kidney transplantation. They are also harder to match in incompatible kidney transplantation (IKT) registries due to a shortage of ABO-compatible donors. The Kidney Allocation System (KAS), implemented in 2014, increased offers of ABO type A2 donor kidneys to type O and B recipients, and A2B to B recipients (A2i). To better inform the living donor selection process and ensure the safety of patients, we sought to evaluate the association between A2i deceased donor kidney transplantation (DDKT) or A2i living donor kidney transplantation (LDKT) and graft and patient survival.

 

Methods:

Using SRTR data from 2000-2019, we identified adult, first-time kidney transplant recipients with blood type O or B who underwent ABO-compatible or A2i DDKT, or ABO-compatible or A2i LDKT. Inverse probability weighted Cox regression was used to compare post-transplantation mortality, all-cause graft failure, and death-censored graft failure between A2i and compatible recipients.

 

Results:

We identified 1232 DDKT recipients and 345 LDKT recipients reported as A2i. Patient mortality was comparable between A2i and compatible DDKT recipients (wHR _0.710.93_1.21, p=0.6). There was no evidence of a difference between A2i versus compatible DDKT recipients with regards to all-cause graft failure (wHR _0.881.11_1.40, p=0.4) and death-censored graft failure (wHR _0.931.24_1.66, p=0.14). When comparing A2i versus compatible LDKT recipients, there was no difference in weighted post-transplant survival (wHR _0.801.06_1.39, p=0.7). When death was regarded as graft failure (all-cause), the weighted hazard ratio of graft failure was _1.051.35_1.73 (p=0.02), when comparing A2i to compatible LDKT recipients. When death was regarded as censorship rather than graft failure (death-censored), the weighted hazard ratio was _1.241.71_2.36 (p=0.001), meaning that the hazard of death-censored graft failure was 1.71 times higher in A2i LDKT recipients than compatible LDKT recipients. 

 

Conclusion:

There is no evidence of harm resulting from prioritizing A2i DDKT in the KAS era. There is, however, some evidence of harm resulting from prioritizing A2i LDKT in the KAS era with regards to death-censored graft failure.